TWI390245B - Zoom lens and imaging module - Google Patents

Description

Optical zoom lens and imaging module

The present invention relates to imaging technology, and in particular to an optical zoom lens and an imaging module.

In recent years, with the changes in market demand and characteristics, today's network cameras are widely used in military defense, police patrol, home security, etc., and their importance and universality have gradually improved. However, currently available zoom cameras in day and night network cameras typically have a lower optical zoom ratio.

In addition, with the development of semiconductor technology, image sensors applied to previous network camera imaging systems, such as Charge Coupled Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS) devices, are improving. At the same time, the graphics element is developed in the direction of miniaturization to meet the consumer's requirements for imaging quality and portability of the imaging system. Therefore, the zoom lens in the imaging system needs to increase the resolution and reduce the size to meet the high image quality and small size requirements of the image sensor.

In view of this, it is necessary to provide an optical zoom lens and an imaging module that are miniaturized and have high image quality.

An optical zoom lens that is disposed positively with an image. The optical zoom lens includes, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, a third lens group having negative power, and positive refractive power. Fourth lens group with positive power A fifth lens group and a sixth lens group having positive power. The optical zoom lens satisfies the conditional expression: 25 < TT / fw < 27; 8.5 mm < BFL < 12.5 mm; (v2 + v5) - (v1 + v6) > 60. Wherein, TT is the distance from the object side end of the first lens group to the imaging surface, fw is the shortest focal length of the optical zoom lens, and BFL is the distance from the image side end of the sixth lens group to the imaging surface, v1, v2, v5, V6 is the Abbe number of the first, second, fifth, and sixth lens groups, respectively.

An imaging module includes an optical zoom lens and an image sensor disposed opposite the optical zoom lens. The optical zoom lens includes, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, a third lens group having negative power, and positive refractive power. a fourth lens group, a fifth lens group having positive power, and a sixth lens group having positive power. The imaging module satisfies the conditional formula: 25<TT/fw<27; 8.5mm<BFL<12.5mm; (v2+v5)-(v1+v6)>60; wherein TT is the object side end of the first lens group The distance to the imaging surface of the image sensor, fw is the shortest focal length of the optical zoom lens, and the BFL is the distance from the image side end of the sixth lens group to the imaging surface of the image sensor, v1, v2, v5, V6 is the Abbe number of the first, second, fifth, and sixth lens groups, respectively.

The optical zoom lens satisfies the conditional formula: 25<TT/fw<27, which can effectively limit the power to shorten the lens length; meet the conditional formula: 8.5mm<BFL<12.5mm, and can be mounted on the image sensor using a standard interface. Up; meet the conditional formula: (v2+v5)-(v1+v6)>60, which can correct the color difference and make it available both day and night.

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 to FIG. 3 , the imaging module of the first embodiment of the present invention includes an optical zoom lens 100 and an image sensor 200 disposed opposite the optical zoom lens 100 . In this embodiment, the imaging module is applied to a network camera.

The optical zoom lens 100 includes, in order from the object side to the image side, a first lens group 10 having positive power, a second lens group 20 having negative power, and a third lens group 30 having negative power, having The fourth lens group 40 of positive power, the fifth lens group 50 having positive power, and the sixth lens group 60 having positive power. At the time of imaging, the light is incident on the optical zoom lens 100 from the object side, and sequentially passes through the first lens group 10, the second lens group 20, the third lens group 30, the fourth lens group 40, the fifth lens group 50, and the sixth lens group 60. The image is then focused (imaged) onto an imaging surface 99 of the image sensor 200. The optical zoom lens 100 may further include a protective glass 97 disposed on the object side of the imaging surface 99 for protecting the sensing surface of the image sensor 200 from damage.

When the optical zoom lens 100 is zoomed, the first, fourth, and sixth lens groups 10, 40, 60 are fixed, and the second, third, and fifth lens groups 20, 30, 50 are moved along the optical axis. In this way, the effective focal length of the optical zoom lens 100 can be changed by changing the position between the respective lens groups to realize the zoom function. Since the first lens group 10 is fixed at the time of zooming, the optical zoom lens 100 can be designed to be zoomed in the body, making it easier to achieve miniaturization, and is convenient for the optical zoom lens 100 to be dustproof and waterproof and to reduce damage.

The first lens group 10 includes, in order from the object side to the image side, a first lens 11 having a negative refractive power, a second lens 12 having a positive refractive power, and a third lens 13 having a positive refractive power. Specifically, the second lens 12 is glued to the first lens 11, and the first lens 11, the second lens 12, and the third lens 13 sequentially include S1, S2, S3, S4, and S5 surfaces from the object side to the image side, wherein The image side surface of the first lens 11 and the object side surface of the second lens 12 coincide with the S2 surface.

The second lens group 20 includes, in order from the object side to the image side, a fourth lens 21 having a negative refractive power, a fifth lens 22 having a negative refractive power, and a sixth lens 23 having a positive refractive power. Specifically, the sixth lens 23 is glued to the fifth lens 22, and the fourth lens 21, the fifth lens 22, and the sixth lens 23 sequentially include S6, S7, S8, S9, and S10 surfaces from the object side to the image side, wherein The image side surface of the fifth lens 22 and the object side surface of the sixth lens 23 are overlapped to the S9 surface.

The third lens group 30 includes, in order from the object side to the image side, a seventh lens 31 having a negative refractive power and an eighth lens 32 having a positive refractive power. Specifically, the eighth lens 32 is glued to the seventh lens 31. The seventh lens 31 and the eighth lens 32 sequentially include S11, S12, and S13 surfaces from the object side to the image side, wherein the image side surface of the seventh lens 31 and the object side surface of the eighth lens 32 coincide with the S12 surface.

The fourth lens group 40 includes a ninth lens 41 of positive power. The ninth lens 41 has an image side surface S14 and an object side surface S15. The object side end of the fourth lens group 40 is fixedly provided with an aperture 95. Since the movement of the aperture 95 easily affects the resolution quality, fixing the aperture 95 to the fourth lens group 41 can reduce the number of manufacturing variables and effectively improve the yield. .

The fifth lens group 50 sequentially includes a tenth lens 51 having positive refractive power, an eleventh lens 52 having negative refractive power, a twelfth lens 53 having negative refractive power, and the like from the object side to the image side. A thirteenth lens 54 having positive power. Specifically, the eleventh lens 52 is glued to the tenth lens 51. The tenth lens 51, the eleventh lens 52, the twelfth lens 53, and the thirteenth lens 54 sequentially include surfaces S16, S17, S18, S19, S20, S21, and S22 from the object side to the image side, wherein The image side surface of the ten lens 51 coincides with the object side surface of the eleventh lens 52 as the S20 surface.

The sixth lens group 60 sequentially includes a fourteenth lens 61 having a negative refractive power, a fifteenth lens 62 having a positive refractive power, and a sixteenth lens 63 having a positive refractive power from the object side to the image side. The fourteenth lens 61, the fifteenth lens 62, and the sixteenth lens 63 sequentially include surfaces S23, S24, S25, S26, S27, and S28 from the object side to the image side.

In order to obtain a high zoom magnification, miniaturized optical zoom lens 100, the optical zoom lens 100 satisfies the conditional expression: 25 < TT / fw < 27; (1)

8.5mm<BFL<12.5mm;(2)

(v2+v5)-(v1+v6)>60;(3)

Wherein, TT is the distance from the object side end of the first lens group 10 to the imaging surface. In the present embodiment, since the first lens 11 is disposed closest to the object side end of the first lens group 10, TT is the first lens. The distance from the side of the object to the imaging surface 99, fw is the shortest focal length of the optical zoom lens 100, and the BFL is the distance from the image side end of the sixth lens group 60 to the imaging surface. In this embodiment, the sixteenth lens 63 is closest to the image side end of the sixth lens group 60 Therefore, the BFL is the distance from the image side of the sixteenth lens 63 to the imaging surface 99, and v1, v2, v5, and v6 are the Abbe of the first, second, fifth, and sixth lens groups 10, 20, 50, and 60, respectively. number.

The conditional expression (1) gives the relationship between the total length TT of the optical zoom lens 100 and the shortest effective focal length fw, and is applied to a telephoto with a power of positive-negative-negative-positive-positive-positive arrangement (telephoto). In the imaging structure, the power can be effectively limited to shorten the length of the lens, thereby achieving miniaturization. Specifically, 1/fw is the power of the optical zoom lens 100, such as TT/fw>27, the optical zoom lens 100 has a large power, so that the optical zoom lens 100 needs to use more lens components, and cannot be obtained in a small size. Chemical. If TT/fw<25, the optical zoom lens 100 has too small a power to effectively balance the aberration and affect the resolution quality.

The conditional expression (2) limits the back focal length BFL of the optical zoom lens 100 to be between 8.5 mm and 12.5 mm, so that the optical zoom lens 100 conforms to the mounting specifications of the general image sensor 200, thereby facilitating user installation.

The conditional expression (3) gives the relationship between the sum of the Abbe numbers of the second and fifth lens groups 20, 50 and the sum of the Abbe numbers of the first and sixth lens groups 10, 60 to correct the chromatic aberration and make the imaging module Light is received and imaged normally during the day and night. Specifically, if the condition is lower than the lower limit value 60, the chromatic aberration is increased, and the image quality is lowered.

In addition, the optical zoom lens 100 includes at least two aspherical lenses to effectively reduce the volume and enhance the analysis. In the present embodiment, the fourth lens 21 and the ninth lens 41 are aspherical lenses.

Taking the center of the surface of the lens group as the origin and the optical axis as the x-axis, the aspherical surface of the surface of the aspherical mirror is: wherein c is the curvature of the center of the mirror surface, and k is the quadric coefficient. For the height from the optical axis to the surface of the lens group, Σ A _i h ⁱ represents the accumulation of Aihi, i is a natural number, and Ai is the aspherical surface coefficient of the i-th order.

The convention F is the effective focal length of the optical zoom lens 100, FNo is the aperture number of the optical zoom lens 100, and 2ω is the angle of view of the optical zoom lens 100. R is the radius of curvature of the corresponding surface, D is the on-axis distance from the corresponding surface to the latter surface (the length of the optical axis of the two surfaces), and Nd is the corresponding lens group for the d-light (wavelength is 656.3 nm, the same below) The refractive index (the same below), Vd is the Abbe number of the corresponding lens group (aber number).

The optical zoom lens 100 will be further described below with reference to FIGS. 4 to 15.

First embodiment

The optical zoom lens 100 of the present embodiment satisfies the conditions listed in Table 1, Table 2, and Table 3.

The field curvature characteristic curve and the distortion characteristic curve of the optical zoom lens 100 of the present embodiment at a wide angle position (2ω=68.9°), a medium angle position (2ω=8.59°), and a telephoto position (2ω=4.28°) are respectively shown in FIG. 4 . As shown in FIG. 9 (FIG. 4 and FIG. 5 correspond to the optical zoom lens 100 at the wide-angle position, FIGS. 6 and 7 correspond to the optical zoom lens 100 at the intermediate position, and FIGS. 8 and 9 correspond to the optical zoom lens 100 at the telephoto position). . In Fig. 4, Fig. 6, and Fig. 8, the curves t and s are the tangential field curvature characteristic curve and the sagittal field curvature characteristic curve (the same applies hereinafter). It can be seen that the meridional curvature value and the sagittal field curvature value are controlled between -0.05 mm and 0.05 mm. In Fig. 5, Fig. 7, and Fig. 9, the curve dis is a distortion characteristic curve (the same applies hereinafter). It can be seen that the distortion variable is controlled between -6% and 6%. In the first place, the field curvature and distortion aberration generated by the optical zoom lens 100 of the first embodiment at the time of zooming are controlled (corrected) in a small range.

Second embodiment

In the present embodiment, the optical zoom lens 100a has substantially the same structure as the optical zoom lens 100 of the first embodiment, and the difference is that the optical zoom lens 100a of the second embodiment satisfies the conditions listed in Table 4, Table 5, and Table 6. condition.

table 5

The optical zoom lens 100a of the present embodiment has a field curvature characteristic curve and a distortion characteristic curve at a wide angle position (2ω=61.7°), a medium angle position (2ω=7.62°), and a telephoto position (2ω=3.83°), respectively. 10-15 (FIG. 10, FIG. 11 corresponds to the optical zoom lens 100a at the wide-angle position, FIGS. 12 and 13 correspond to the optical zoom lens 100a at the intermediate position, and FIGS. 14 and 15 correspond to the optical zoom lens 100a at the telephoto position) . It can be seen that the meridional field curvature value and the sagittal field curvature value generated by the optical zoom lens 100a of the second embodiment are controlled between -0.05 mm and 0.05 mm; the distortion variable is controlled between -2% and 2%. In the first place, the field curvature and distortion aberration generated by the optical zoom lens 100a of the second embodiment in the zoom range are controlled (corrected) to a small range.

In summary, the optical zoom lens includes, in order from the object side to the image side, a first lens group 10 having positive power, a second lens group 20 having negative power, and a third having negative power. Lens group 30 with positive power The fourth lens group 40, the fifth lens group 50 having positive power, and the sixth lens group 60 having positive power. It satisfies the conditional formula: 25<TT/fw<27, which can effectively limit the power to shorten the lens length; meet the conditional formula: 8.5mm<BFL<12.5mm, which can be mounted on the image sensor 200 using a standard interface; Conditional formula: (v2+v5)-(v1+v6)>60, which can correct the color difference and make it available both day and night.

In addition, other changes in the spirit of the invention may be made by those skilled in the art, and it is to be understood that these changes are intended to be included within the scope of the invention.

100‧‧‧ optical zoom lens

41‧‧‧Ninth lens

200‧‧‧Image Sensor

50‧‧‧ fifth lens group

10‧‧‧First lens group

51‧‧‧11th lens

11‧‧‧ first lens

52‧‧‧ eleventh lens

12‧‧‧second lens

53‧‧‧ twelfth lens

13‧‧‧ third lens

54‧‧‧13th lens

20‧‧‧second lens group

60‧‧‧ sixth lens group

21‧‧‧Fourth lens

61‧‧‧fourteenth lens

22‧‧‧ fifth lens

62‧‧‧Fifteenth lens

23‧‧‧ sixth lens

63‧‧‧16th lens

30‧‧‧third lens group

95‧‧‧ aperture

31‧‧‧ seventh lens

97‧‧‧protective glass

32‧‧‧ Eighth lens

99‧‧‧ imaging surface

40‧‧‧Fourth lens group

S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28‧‧‧ surface

FIG. 1 is a schematic structural diagram of an imaging module in a wide-angle position according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of an imaging module in a mid-angle position according to an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of an imaging module in a telephoto position according to an embodiment of the present invention.

4 is a field curvature aberration diagram of the imaging module of the first embodiment at a wide angle position.

FIG. 5 is a distortion aberration diagram of the imaging module of the first embodiment at a wide angle position. FIG.

6 is a field curvature aberration diagram of the imaging module of the first embodiment at a mid-angle position.

7 is a distortion aberration diagram of the imaging module of the first embodiment at a mid-angle position.

8 is a field curvature aberration diagram of the imaging module of the first embodiment at a telephoto position.

9 is a distortion aberration diagram of the imaging module of the first embodiment at a telephoto position.

FIG. 10 is a field curvature aberration diagram of the imaging module of the second embodiment at a wide angle position. FIG.

Fig. 11 is a view showing distortion aberration of the imaging module of the second embodiment at a wide angle position.

Fig. 12 is a field curvature aberration diagram of the imaging module of the second embodiment at a mid-angle position.

FIG. 13 is a distortion aberration diagram of the imaging module of the second embodiment at a mid-angle position. FIG.

14 is a field curvature aberration diagram of the imaging module of the second embodiment at a mid-angle position.

15 is a distortion aberration diagram of the imaging module of the second embodiment at a mid-angle position.

100‧‧‧ optical zoom lens

41‧‧‧Ninth lens

200‧‧‧Image Sensor

50‧‧‧ fifth lens group

10‧‧‧First lens group

51‧‧‧11th lens

11‧‧‧ first lens

52‧‧‧ eleventh lens

12‧‧‧second lens

53‧‧‧ twelfth lens

13‧‧‧ third lens

54‧‧‧13th lens

20‧‧‧second lens group

60‧‧‧ sixth lens group

21‧‧‧Fourth lens

61‧‧‧fourteenth lens

22‧‧‧ fifth lens

62‧‧‧Fifteenth lens

23‧‧‧ sixth lens

63‧‧‧16th lens

30‧‧‧third lens group

95‧‧‧ aperture

31‧‧‧ seventh lens

97‧‧‧protective glass

32‧‧‧ Eighth lens

99‧‧‧ imaging surface

40‧‧‧Fourth lens group

S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S15, S16, S17, S18, S19, S20, S21, S22, S23, S24, S25, S26, S27, S28‧‧‧ surface

Claims (18)

An optical zoom lens that is disposed positively with an imaging lens that includes, in order from the object side to the image side, a first lens group having positive power, a second lens group having negative power, and having a negative a third lens group of power, a fourth lens group having positive power, a fifth lens group having positive power, and a sixth lens group having positive power; an improvement in that the optical zoom lens satisfies a conditional expression : 25 < TT / fw <27; 8.5 mm < BFL < 12.5 mm ; ( v 2 + v 5 )-( v 1 + v 6 )>60; wherein TT is the object side end of the first lens group to the imaging surface The distance, fw is the shortest focal length of the optical zoom lens, BFL is the distance from the image side end of the sixth lens group to the imaging surface, and v1, v2, v5, and v6 are the first, second, fifth, and sixth lens groups, respectively. Number of shells. The optical zoom lens of claim 1, wherein the first lens group sequentially includes a first lens having a negative refractive power, a second lens having a positive refractive power, and having a second optical lens having a positive refractive power from the object side to the image side. A third lens of positive power, the second lens is glued to the first lens. The optical zoom lens of claim 1, wherein the second lens group sequentially includes a fourth lens having a negative refractive power, a fifth lens having a negative refractive power, and a fifth lens having a negative refractive power from the object side to the image side, and A sixth lens having positive power, the sixth lens being glued to the fifth lens. The optical zoom lens of claim 1, wherein the third lens group sequentially includes a seventh lens having a negative refractive power from the object side to the image side, An eighth lens having positive power, the eighth lens being glued to the seventh lens. The optical zoom lens of claim 1, wherein the fourth lens group comprises a ninth lens of positive power. The optical zoom lens according to claim 1, wherein the fifth lens group sequentially includes a tenth lens having positive power from the object side to the image side, and an eleventh lens having negative power, having The twelfth lens of negative power and the thirteenth lens having positive power, the eleventh lens is glued to the tenth lens. The optical zoom lens according to claim 1, wherein the sixth lens group sequentially includes a fourteenth lens having a negative refractive power, a fifteenth lens having a positive refractive power, and a fifteenth lens having a positive refractive power from the object side to the image side. The sixteenth lens with positive power. The optical zoom lens of claim 1, wherein the optical zoom lens comprises at least two aspherical lenses. The optical zoom lens of claim 1, wherein the fourth lens group is fixed with an aperture. An imaging module includes an optical zoom lens and an image sensor disposed opposite to the optical zoom lens, the optical zoom lens including, in order from the object side to the image side, a first lens having positive power a group, a second lens group having a negative power, a third lens group having a negative power, a fourth lens group having a positive power, a fifth lens group having a positive power, and a third having a positive power a six lens group; wherein the optical zoom lens satisfies the conditional expression: 25 < TT / fw <27; 8.5 mm < BFL < 12.5 mm ; ( v 2 + v 5 )-( v 1 + v 6 ) >60; TT is the distance from the object side end of the first lens group to the imaging surface of the image sensor, fw is the shortest focal length of the optical zoom lens, and BFL is the image side of the sixth lens group to the image sensor The distance of the faces, v1, v2, v5, and v6 are the Abbe numbers of the first, second, fifth, and sixth lens groups, respectively. The imaging module of claim 10, wherein the first lens group sequentially includes a first lens having a negative power, a second lens having a positive power, and having a second optical lens from the object side to the image side. A third lens of positive power, the second lens is glued to the first lens. The imaging module of claim 10, wherein the second lens group sequentially includes a fourth lens having a negative refractive power and a fifth lens having a negative refractive power from the object side to the image side, and A sixth lens having positive power, the sixth lens being glued to the fifth lens. The imaging module of claim 10, wherein the third lens group sequentially includes a seventh lens having a negative power from the object side to the image side, and an eighth lens having a positive power, the first lens Eight lenses are glued to the seventh lens. The imaging module of claim 10, wherein the fourth lens group comprises a ninth lens of positive power. The imaging module of claim 10, wherein the fifth lens group sequentially includes a tenth lens having positive power from the object side to the image side, and an eleventh lens having negative power, having The twelfth lens of negative power and the thirteenth lens having positive power, the eleventh lens is glued to the tenth lens. The imaging module of claim 10, wherein the sixth lens group sequentially includes a fourteenth lens having a negative refractive power from the object side to the image side, A fifteenth lens with positive power and a sixteenth lens with positive power. The imaging module of claim 10, wherein the optical zoom lens comprises at least two aspherical lenses. The imaging module of claim 10, wherein the fourth lens group is fixed with an aperture.