Optical lens and electronic device having optical lens

An optical lens includes seven lenses sequentially arranged along an optical axis from an object side to an image side. A fourth lens includes a seventh surface facing the object side and an eighth surface facing the image side. Each of the seventh surface and the eighth surface includes an inflection point. The optical lens satisfies the following conditional formulas: −0.48<tan(EFL4*log(Slope_L42))<−0.38;  conditional formula 1:1 mm<Infp_L41_y<1.05 mm;  conditional formula 2:0.58 mm<Infp_L42_y<0.69 mm;  condition 3:1<(123{circumflex over ( )}T4)/(456{circumflex over ( )}Slope_L41)<1.67.  conditional formula 4:

FIELD

The subject matter herein generally relates to optical lenses, and more particularly to an optical lens of an electronic device.

BACKGROUND

The total optical length of mobile phone lenses has been gradually reduced, but the size of the image sensor has not been reduced. Therefore, it may be desirable that the lens can focus images in a shorter space.

DETAILED DESCRIPTION

FIG.1shows an embodiment of an optical lens100. The optical lens100includes a first lens10, a second lens20, a third lens30, a fourth lens40, an aperture110, a fifth lens50, a sixth lens60, a seventh lens70, a filter80, and an imaging plane90.

The first lens10is an aspheric lens and includes a first surface11and a second surface12. The first surface11is opposite to the second surface12and protrudes toward the object side. The second surface12protrudes toward the image side.

The second lens20is an aspheric lens. The second lens20includes a third surface21and a fourth surface22. The third surface21faces the second surface12and is opposite to the fourth surface22. The third surface21protrudes toward the object side. The fourth surface22is recessed toward the object side.

The third lens30is an aspheric lens. The third lens30includes a fifth surface31and a sixth surface32. The fifth surface31faces the fourth surface22and is opposite to the sixth surface32. The fifth surface31is recessed toward the image side. The sixth surface32is recessed toward the object side.

The fourth lens40is an aspheric lens. The fourth lens40includes a seventh surface41and an eight surface42. The seventh surface41faces the sixth surface32and is opposite to the eighth surface42. The seventh surface41protrudes toward the object side, and the eighth surface42is recessed toward the object side. Both the seventh surface41and the eighth surface42are wave-shaped. Both the seventh surface41and the eighth surface42have at least one inflection point.

The aperture110is located between the fourth lens40and the fifth lens50on the optical axis120. Specifically, the aperture110is located adjacent to the eighth surface42of the fourth lens40.

The fifth lens50is an aspheric lens. The fifth lens50includes a ninth surface51and a tenth surface52. The ninth surface51faces the eighth surface42. The tenth surface52is opposite to the ninth surface51. The ninth surface51is recessed toward the image side, and the tenth surface52is recessed toward the object side.

The sixth lens60is an aspheric lens. The sixth lens60includes an eleventh surface61and a twelfth surface62. The eleventh surface61faces the tenth surface52. The twelfth surface62is opposite to the eleventh surface61. The eleventh surface61is recessed toward the image side, and the twelfth surface62protrudes toward the image side.

The seventh lens70is an aspheric lens. The seventh lens70includes a thirteenth surface71and a fourteenth surface72. The thirteenth surface71faces the twelfth surface62. The fourteenth surface72is opposite to the thirteenth surface71. The thirteenth surface71is recessed toward the image side, and the fourteenth surface72protrudes toward the image side.

The filter80is used to filter out infrared light of light passing through the seventh lens70.

The imaging plane90is used for imaging.

T4=the thickness of the fourth lens40; Slope_L41=the surface slope of the seventh surface41of the fourth lens40at height y=0.654321 mm; EFL4=the equivalent focal length of the fourth lens40; Slope_L42=the surface slope of the eighth surface42of the fourth lens40at height y=0.194875 mm; Infp_L41_y=the height of an inflection point on the seventh surface41of the fourth lens40; Infp_L42_y=the height of an inflection point on the eighth surface42of the fourth lens40.

Conditional formula 1 requires that the fourth lens40be able to condense incident light from a low angle. Conditional formulas 2 and 3 require that the seventh surface41and the eighth surface42of the fourth lens40both be wave-shaped. Conditional formula 4 restricts the thickness and surface slope of the fourth lens40.

The optical lens100will be further elaborated as follows through different embodiments.

The following Tables 1-3 show some parameters of the optical lens100according to a first embodiment. In Table 1, R represents the radius of curvature of the corresponding surface, and T represents the thickness of the corresponding lens. Values in Tables 1-3 all satisfy the above conditional formulas 1-4.

FIG.2shows a characteristic curve diagram of imaging field curvatures of visible light for the first embodiment of the optical lens100. The curves T and S are characteristic curves of a tangential field curvature and a sagittal field curvature, respectively. It can be seen fromFIG.2that the tangential field curvature and the sagittal field curvature of the optical lens100in the first embodiment are controlled within a range of +0.1 mm to −0.3 mm.

FIG.3shows a distortion characteristic curvature of visible light for the first embodiment of the optical lens100. It can be seen that the amount of distortion of the optical lens100is controlled within a range of 0% to 2%.

The following tables 4-6 show some parameters of the optical lens100according to a second embodiment. In Table 4, R represents the radius of curvature of the corresponding surface, and T represents the thickness of the corresponding lens. Values of tables 4-6 all satisfy the above formulas 1-4.

FIG.4shows a characteristic curve diagram of imaging field curvatures of visible light for the second embodiment of the optical lens100. The curves T and S are characteristic curves of a tangential field curvature and a sagittal field curvature, respectively. It can be seen fromFIG.4that the tangential field curvature and the sagittal field curvature of the optical lens100in the first embodiment are controlled within a range of +0.04 mm to −0.2 mm.

FIG.5shows a distortion characteristic curvature of visible light for the second embodiment of the optical lens100. It can be seen that the amount of distortion of the optical lens100is controlled within a range of 0% to 1.6%.

Referring toFIG.6, an electronic device200includes a main body210. The electronic device200further includes at least one optical lens100as described above and arranged in the body210.

The optical lens100and electronic device200provided by the present disclosure satisfy the above conditional formulas 1-4. The fourth lens22is a wave-shaped aspheric lens, so that the light incident into the optical lens100at a low angle can be quickly condensed and focused on the imaging plane90by subsequent lenses. Thus, image focusing can be realized in a shorter space, and an imaging quality of the optical lens100is improved.