TW201802522A - Miniature wide-angle lens system - Google Patents

Abstract

A miniature wide-angle lens system includes, from an object side to an image side, a first lens, a second lens, a stop, a third lens, a fourth lens and a fifth lens. The first lens has negative power, a convex surface toward the object side and a concave surface toward the image side. The second lens has positive power and two convex surfaces on both sides. The third lens has positive power and two convex surfaces on both sides. The fourth lens has negative power, a concave surface toward the object side and a convex surface toward the image side. The fifth lens has positive power, a convex surface toward the object side and a concave surface toward the image side. Thereby, the objectives of miniaturization and wide-angle can be fulfilled.

Description

Miniaturized wide-angle lens

The present invention relates to an optical system, and more particularly to a five-piece wide-angle lens having miniaturization characteristics.

A wide-angle lens is a lens with a short focal length and a large viewing angle. It is characterized by a long depth of field, a wide range of scenery, and an increase in the spatial depth of the picture.

However, a general wide-angle lens tends to cause a problem of a long system length. In order to improve the aforementioned problems, the applicant has attempted to improve the wide-angle lens to have both miniaturization characteristics.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a five-piece lens having miniaturization and wide-angle characteristics.

In order to achieve the above and other objects, the present invention provides a miniaturized wide-angle lens including a first lens, a second lens, an aperture, a third lens, a fourth lens, and a fifth from the object side to the image side. In the lens, the first lens has a negative refractive power, the object side is convex and the image side is concave, the second lens has positive refractive power, the object side and the image side are convex, and the third lens has positive refractive power, and the object side and the image side The fourth lens has a negative refractive power, the object side surface is a concave surface and the image side surface is a convex surface, the fifth lens has a positive refractive power, the object side surface is a convex surface, and the image side surface is a concave surface.

In order to achieve the above and other objects, the present invention also provides a miniaturized wide-angle lens, which includes a first lens, a second lens, an aperture, a third lens, a fourth lens, and a second from the object side to the image side. The fifth lens has a negative refractive power, and the product of the curvature radius of the object side surface and the radius of curvature of the image side surface is positive, and the second lens has a positive refractive power, and the product of the curvature radius of the object side surface and the radius of curvature of the image side surface is a negative value. The three lenses have a positive refractive power, and the product of the radius of curvature of the object side surface and the radius of curvature of the image side surface is negative, and the fourth lens has a negative refractive power, and the product of the radius of curvature of the object side surface and the radius of curvature of the image side surface is positive, and the fifth lens has a positive value. The refractive power, the product of the radius of curvature of the side of the object and the radius of curvature of the side of the image is a positive value.

In order to achieve the above and other objects, the present invention also provides a miniaturized wide-angle lens, which includes a first lens, a second lens, an aperture, a third lens, a fourth lens, and a second from the object side to the image side. The fifth lens has a negative refractive power, the radius of curvature of the object side is positive and larger than the radius of curvature of the image side surface, and the second lens has a positive refractive power, and the radius of curvature of the object side surface is positive and larger than the radius of curvature of the image side surface thereof. The third lens has positive refractive power, the radius of curvature of the object side is positive and larger than the radius of curvature of the image side surface, and the fourth lens has negative refractive power, the radius of curvature of the object side surface is negative and larger than the radius of curvature of the image side surface, and the fifth lens has positive For the refractive power, the radius of curvature of the side of the object and the radius of curvature of the image side are positive values.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: vd3-vd4>25; wherein vd3 is the dispersion coefficient of the third lens, and vd4 is the dispersion coefficient of the fourth lens, thereby improving the lateral chromatic aberration.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: 100<FOV<160; wherein the FOV is the angle of view of the miniaturized wide-angle lens, thereby capturing a wider range of images.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: TTL/F<2.4; wherein TTL is the total length of the system of the miniaturized wide-angle lens, F is the system focal length value of the miniaturized wide-angle lens, and more preferably the following relationship is satisfied: 1.6 <TTL/F<2.4, which helps to shorten the system length and improve portability for profitable applications.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: FNO<2.8; wherein FNO is the aperture value of the miniaturized wide-angle lens, and more preferably, the following relationship is satisfied: 1.8<FNO<2.8, thereby contributing to the increase of the system Concentrating ability to improve image quality in low light conditions.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: ∣R2/R3∣<0.4; wherein R2 is the radius of curvature of the side of the first lens image, and R3 is the radius of curvature of the side of the second lens object, thereby helping to improve the overall brightness. .

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: 0.1<D34; wherein D34 is the spacing of the third and fourth lenses on an optical axis, thereby reducing the probability of spot generation.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: 0.6<F3/F<0.9; wherein F3 is the focal length value of the third lens, and F is the focal length value of the miniaturized wide-angle lens, thereby shortening the total length of the system.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: |F1/F| > 1; wherein F1 is the focal length value of the first lens, and F is the focal length value of the miniaturized wide-angle lens, thereby making the system easier to have wide-angle characteristics.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: D12/IMGH>0.1; wherein D12 is the distance between the first and second lenses on an optical axis, and IMGH is the maximum image height of the miniaturized wide-angle lens, thereby contributing to Improve the phenomenon of field curvature.

In the above miniaturized wide-angle lens, the first, second, fourth, and fifth lenses may be plastic lenses and both sides may be aspherical, and the third lens may be plastic or glass; if the third lens is plastic The double-sided lens can be aspherical, and the miniaturized wide-angle lens is lighter in weight and lower in cost; if the third lens is made of glass, the defocusing phenomenon caused by temperature change can be effectively improved, and the double-sided phenomenon thereof It can also be aspherical.

The aforementioned miniaturized wide-angle lens can satisfy the following relationship: 0.4<R1/F<0.7, 0.2<R2/F<0.35, 0.9<R3/F<3.7, -1.4<R4/F<-1, 0.6<R5/F <1.6, -0.8<R6/F<-0.6, -0.2<R7/F<-0.3, -0.6<R8/F<-0.4, 0.5<R9/F<0.8, 0.5<R10/F<1.1, - 0.9<F/F1<-0.7, 0.6<F/F2<1.1, 1.2<F/F3<1.5, -1.2<F/F4<-0.8, 0.1<F/F5<0.4, 3.5<ALT/Gaa<4.9 Wherein R1 is the radius of curvature of the side of the first lens, R2 is the radius of curvature of the side of the first lens image, R3 is the radius of curvature of the side of the second lens, and R4 is the radius of curvature of the side of the second lens image. R5 is the radius of curvature of the side surface of the third lens object, R6 is the radius of curvature of the side surface of the third lens image, R7 is the radius of curvature of the side surface of the fourth lens object, and R8 is the radius of curvature of the side surface of the fourth lens image, R9 is a radius of curvature of a side surface of the fifth lens, R10 is a radius of curvature of a side surface of the fifth lens image, F1 is a focal length value of the first lens, F2 is a focal length value of the second lens, and F3 is a focal length of the third lens Value, F4 is the focus of the fourth lens The distance value, F5 is the focal length value of the fifth lens, ALT is the sum of the thicknesses of the first to fifth lenses on an optical axis, and Gaa is the sum of the gap lengths of the first to fifth lenses on the optical axis. Thereby, the miniaturized wide-angle lens has the characteristics of miniaturization and wide angle.

Please refer to FIG. 1 , which is a first embodiment of the present invention. The miniaturized wide-angle lens (hereinafter referred to as a miniaturized lens) sequentially includes a first lens on the optical axis L from the object side A to the image side B. 10, a second lens 20, an aperture ST, a third lens 30, a fourth lens 40 and a fifth lens 50, on the image side B is provided with CCD, CMOS or other photosensitive elements (not shown), A flat lens 60 such as a filter and/or a cover glass may be disposed between the photosensitive element and the fifth lens 50. The number of the flat lenses 60 may be increased or decreased or not set as needed.

In this embodiment, the first lens 10 has a negative refractive power, the object side surface is convex and the image side surface is concave, and the curvature radius of the object side surface is larger than the curvature radius of the image side surface, and the product of the object side surface curvature radius and the image side surface curvature radius is In the positive value, the object side surface and the image side surface of the first lens 10 made of plastic may be aspherical surfaces, thereby making the miniaturized lens have wide-angle characteristics and improving the distortion phenomenon. In this paper, when the surface center of a curved surface is closer to the image side than the surface itself, the curvature radius of the surface is positive; otherwise, when the surface center of a curved surface is closer to the object side than the surface itself, the surface is The radius of curvature is negative.

The second lens 20 has a positive refractive power, and the object side surface and the image side surface are both convex surfaces. At this time, the product of the curvature radius of the object side surface and the curvature radius of the image side surface is a negative value, and the curvature radius of the object side surface is positive and larger than the curvature radius of the image side surface. The object side surface and the image side surface of the second lens 20 made of plastic may be aspherical. Thereby, the second lens 20 can be used to improve the chromatic aberration generated by the first lens 10.

The third lens 30 has a positive refractive power, and the object side surface and the image side surface are convex surfaces, that is, the curvature radius of the object side surface is positive and larger than the curvature radius of the image side surface, and the product of the curvature radius of the object side surface and the curvature radius of the image side surface is Negative value, the object side surface and the image side surface of the third lens 30 made of glass may be aspherical surfaces, thereby effectively improving the defocusing phenomenon caused by temperature changes.

The fourth lens 40 has a negative refractive power, and the object side surface is concave and the image side surface is convex, that is, the curvature radius of the object side surface is negative and larger than the curvature radius of the image side surface, and the object side surface curvature radius and the image side surface curvature radius The product has a positive value, and the object side and the image side of the fourth lens 40 made of plastic may be aspherical. The design of the fourth lens 40, which is convex on the side, helps to shorten the overall length of the system, and its image side can have an inflection point to improve lateral chromatic aberration.

The fifth lens 50 has a positive refractive power, and the object side surface is convex and the image side surface is concave, that is, the curvature radius of the object side surface is positive and smaller than the curvature radius of the image side surface, and the product of the object side surface curvature radius and the image side surface curvature radius For positive values, the object side and the image side of the fifth lens 50 made of plastic may be aspherical, and the fifth lens 50 has at least one inflection point in the object side and the image side surface, thereby improving the chief ray angle (chief) Ray angle) and helps to shorten the length of the system.

The design parameters of the miniaturized lens of this embodiment are as shown in Table 1 below:

Table I

In this embodiment, the object side surface and the image side surface of the first to fifth lenses 10, 20, 30, 40, 50 are aspherical surfaces, and the surface shape thereof satisfies the following aspherical formula.

Where c = 1 / r, r is the radius of curvature of the surface, h is the height of the light on the surface, k is the cone coefficient, A is the second order coefficient, B is the fourth order coefficient, C is the sixth order coefficient, D For the eighth-order coefficient, E is the tenth-order coefficient, F is the twelfth-order coefficient, G is the fourteenth-order coefficient, and H is the sixteenth-order coefficient. The parameters of each aspheric surface of the first embodiment are as shown in Table 2 below:

Table II

Based on the foregoing design, the focal length value F of the system of the present embodiment is 2.8 mm, the length of the system is 6 mm, the focal length of the first lens is -3.439 mm, the focal length of the second lens is 2.924 mm, and the focal length of the third lens is 1.976 mm. The focal length of the fourth lens is -2.195 mm, the focal length of the fifth lens is 8.522 mm, the angle of view at the maximum image height is 131 degrees, and the aperture value is 2.4.

At this time, the values of the relationship of the miniaturized lens are as shown in Table 3 below:

Table 3

In this way, the lens has the characteristics of miniaturization and wide-angle, and the lateral chromatic aberration diagram is as shown in FIG. 1A, the maximum lateral chromatic aberration is less than 2.5 μm, and the F-theta distortion diagram is shown in FIG. 1B, and the maximum F-theta is shown. The distortion is not more than ± 5.2%.

Please refer to FIG. 2, which is a second embodiment of the present invention, and the lens configuration is similar to that of the first embodiment, except that the third lens is made of a plastic material, thereby reducing manufacturing cost and reducing weight. The design parameters of the miniaturized lens of this embodiment are as shown in Table 4 below:

Table 4

In this embodiment, the object side surface and the image side surface of the first to fifth lenses 10, 20, 30, 40, 50 are all aspherical surfaces, and the surface shape thereof satisfies the above-described aspherical formula, and the aspheric surfaces of the second embodiment are The parameters are as shown in Table 5 below:

Table 5

Based on the foregoing design, the focal length value F of the system of the present embodiment is 2.7 mm, the length of the system is 6 mm, the focal length of the first lens is -3.141 mm, the focal length of the second lens is 2.694 mm, and the focal length of the third lens is 2.201 mm. The focal length of the fourth lens is -2.738 mm, the focal length of the fifth lens is 11.807 mm, the angle of view at the maximum image height is 140 degrees, and the aperture value is 2.4.

At this time, the values of the relationship of the miniaturized lens are as shown in Table 6 below:

Table 6

In this way, the lens has the characteristics of miniaturization and wide-angle. The lateral chromatic aberration diagram is as shown in FIG. 2A, the maximum lateral chromatic aberration is less than 2.5 μm, and the F-theta distortion diagram is shown in FIG. 2B, and the maximum F-theta is shown. The distortion is not more than ± 8.5%.

Please refer to FIG. 3 , which is a third embodiment of the present invention. The lens configuration is similar to that of the first embodiment, but the third lens is made of a plastic material, and the design parameters of the miniaturized lens of this embodiment are As shown in Table 7 below:

Table 7

In this embodiment, the object side surface and the image side surface of the first to fifth lenses 10, 20, 30, 40, 50 are all aspherical surfaces, and the surface shape thereof satisfies the above aspherical formula, and the aspheric surfaces of the third embodiment The parameters are as shown in Table 8 below:

Table eight

Based on the foregoing design, the system focal length value F of the embodiment is 2.9 mm, the system length is 6 mm, the first lens focal length value is -3.502 mm, the second lens focal length value is 4.555 mm, and the third lens focal length value is 1.959 mm. The focal length of the fourth lens is -3.245 mm, the focal length of the fifth lens is 15.403 mm, the angle of view at the maximum image height is 130 degrees, and the aperture value is 2.2.

At this time, the values of the relationship of the miniaturized lens are as shown in Table 9 below:

Table 9

In this way, the lens has the characteristics of miniaturization and wide-angle, and its lateral chromatic aberration diagram is as shown in FIG. 3A, the maximum lateral chromatic aberration is not more than 3.5 μm, and the F-theta distortion diagram is shown in FIG. 3B, and the maximum F-theta is shown. The distortion is not more than ± 7.5%.

Please refer to FIG. 4, which is a fourth embodiment of the present invention. The lens configuration is similar to that of the first embodiment. The design parameters of the miniaturized lens of this embodiment are as shown in Table 10 below:

Table ten

In this embodiment, the object side surface and the image side surface of the first to fifth lenses 10, 20, 30, 40, 50 are all aspherical surfaces, and the surface shape thereof satisfies the above aspherical formula, and the aspheric surfaces of the fourth embodiment The parameters are as shown in Table 11 below:

Table XI

Based on the foregoing design, the focal length value F of the system of the present embodiment is 2.8 mm, the system length is 5.45 mm, the focal length of the first lens is -3.7737 mm, the focal length of the second lens is 2.955 mm, and the focal length of the third lens is 1.965 mm. The focal length of the fourth lens is -2.686 mm, the focal length of the fifth lens is 11.838 mm, the angle of view at the maximum image height is 131 degrees, and the aperture value is 2.4.

At this time, the values of the relationship of the miniaturized lens are as shown in Table 12:

Table 12

In this way, the lens has the characteristics of miniaturization and wide-angle, and its lateral chromatic aberration diagram is as shown in FIG. 4A, the maximum lateral chromatic aberration is less than 2 μm, and the F-theta distortion diagram is shown in FIG. 4B, and the maximum F-theta is shown. The distortion is not more than ±4.9%.

10‧‧‧ first lens
20‧‧‧second lens
30‧‧‧ third lens
40‧‧‧Fourth lens
50‧‧‧ fifth lens
60‧‧‧ flat lenses
A‧‧‧ object side
B‧‧‧ image side
ST‧‧‧ aperture
L‧‧‧ optical axis

Figure 1 is a schematic view of a first embodiment of the present invention.

Fig. 1A is a lateral chromatic aberration diagram of the first embodiment of the present invention.

Fig. 1B is a diagram showing the F-theta distortion of the first embodiment of the present invention.

Figure 2 is a schematic view of a second embodiment of the present invention.

Fig. 2A is a lateral chromatic aberration diagram of the second embodiment of the present invention.

Fig. 2B is a diagram showing the F-theta distortion of the second embodiment of the present invention.

Figure 3 is a schematic view of a third embodiment of the present invention.

Fig. 3A is a lateral chromatic aberration diagram of the third embodiment of the present invention.

Fig. 3B is a diagram showing the F-theta distortion of the third embodiment of the present invention.

Figure 4 is a schematic view of a fourth embodiment of the present invention.

Fig. 4A is a lateral chromatic aberration diagram of the fourth embodiment of the present invention.

Fig. 4B is a diagram showing the F-theta distortion of the fourth embodiment of the present invention.

10‧‧‧ first lens

20‧‧‧second lens

30‧‧‧ third lens

40‧‧‧Fourth lens

50‧‧‧ fifth lens

60‧‧‧ flat lenses

A‧‧‧ object side

B‧‧‧ image side

ST‧‧‧ aperture

L‧‧‧ optical axis

Claims (15)

A miniaturized wide-angle lens includes, in order from the object side to the image side, a first lens having a negative refractive power, a convex side of the object surface and a concave side like the side surface, and a second lens having a positive refractive power, a side surface thereof and an image side surface a convex surface; an aperture; a third lens having a positive refractive power, the object side and the image side are convex; a fourth lens having a negative refractive power, the object side is concave and the side is convex; and a fifth The lens has a positive refractive power, the side of the object is convex and the side of the image is concave. A miniaturized wide-angle lens comprising, in order from the object side to the image side, a first lens having a negative refractive power, a product of a radius of curvature of the object side surface and a radius of curvature of the image side surface being positive; and a second lens having a positive refractive power, The product of the radius of curvature of the side of the object and the radius of curvature of the side of the object is a negative value; an aperture; a third lens having a positive refractive power, the product of the radius of curvature of the object side and the radius of curvature of the side of the image being a negative value; a fourth lens having a negative The refractive power has a positive value of the product of the radius of curvature of the side of the object and the radius of curvature of the side of the image; and a fifth lens having a positive refractive power, and the product of the radius of curvature of the object side and the radius of curvature of the side of the image is a positive value. A miniaturized wide-angle lens includes, in order from the object side to the image side, a first lens having a negative refractive power, a radius of curvature of the object side surface being positive and larger than a radius of curvature of the image side surface thereof; and a second lens having a positive refractive power, The radius of curvature of the side of the object is positive and greater than the radius of curvature of the side of the image; an aperture; a third lens having a positive refractive power, the radius of curvature of the object side is positive and greater than the radius of curvature of the image side; a fourth lens having a negative The refractive power has a radius of curvature on the side of the object which is negative and larger than the radius of curvature of the image side surface; and a fifth lens having a positive refractive power, and the radius of curvature of the object side surface and the radius of curvature of the image side are both positive values. The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: vd3-vd4>25; wherein vd3 is a dispersion coefficient of the third lens, and vd4 is a dispersion coefficient of the fourth lens. The miniaturized wide-angle lens according to any one of claims 1 to 3 further satisfies the following relationship: 100 < FOV < 160; wherein the FOV is the angle of view of the miniaturized wide-angle lens. The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: TTL/F<2.4; wherein TTL is the total length of the system of the miniaturized wide-angle lens, and F is the system focal length value of the miniaturized wide-angle lens . The miniaturized wide-angle lens as described in claim 6 further satisfies the following relationship: 1.6 < TTL / F < 2.4. The miniaturized wide-angle lens according to any one of claims 1 to 3, which satisfies the following relationship: FNO<2.8; wherein FNO is the aperture value of the miniaturized wide-angle lens. The miniaturized wide-angle lens as described in claim 8 satisfies the following relationship: 1.8 < FNO < 2.8. The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: ∣R2/R3∣<0.4; wherein R2 is the radius of curvature of the side of the first lens image, and R3 is the side of the second lens object The radius of curvature. The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: 0.1 < D34; wherein D34 is the pitch of the third and fourth lenses on an optical axis. The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: 0.6 < F3 / F < 0.9; wherein F3 is a focal length value of the third lens, and F is a focal length value of the miniaturized wide-angle lens . The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: |F1/F| > 1; wherein F1 is a focal length value of the first lens, and F is a focal length value of the miniaturized wide-angle lens . The miniaturized wide-angle lens according to any one of claims 1 to 3, further satisfying the following relationship: D12/IMGH>0.1; wherein D12 is the distance between the first and second lenses on an optical axis, IMGH is the small The maximum image height of a wide-angle lens. The miniaturized wide-angle lens according to any one of claims 1 to 3, wherein the image side and the object side of the fifth lens each have an inflection point.