TW201539030A - Six-piece wide-angle lens module - Google Patents

Abstract

Disclosed is a six-piece wide-angle lens, sequentially comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens from an object side to an image side. The first lens has a negative refractive power. The second to fourth lenses all have a positive refractive power. The fifth lens has a negative refractive power. The six-piece wide-angle lens satisfies the following relation, where f is a system focal length of the six-piece wide-angle lens, f1 is a focal length of the first lens. When the six-piece wide-angle lens satisfies the above relation, a property of big iris and small distortion can be acquired.

Description

Six-piece wide-angle lens

The present invention relates to a camera system, and more particularly to a six-piece wide-angle lens.

The so-called wide-angle lens refers to 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 is prone to the disadvantages of large chromatic aberration and large distortion. In order to improve the problem of large chromatic aberration and large distortion, the applicant tried to improve the wide-angle lens, but found that the wide-angle lens is not easy to combine the characteristics of large aperture, low chromatic aberration and low distortion.

In view of the above, one of the main objects of the present invention is to provide a wide-angle lens having a large aperture and a small distortion characteristic.

In order to achieve the foregoing and other objects, the present invention provides a six-piece wide-angle lens that sequentially includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens from the object side to the image side. And a sixth lens, the first lens has a negative refractive power, the second to fourth lenses each have a positive refractive power, the fifth lens has a negative refractive power, and the six-piece wide-angle lens satisfies the following relationship: Where f is the focal length of the system of the six-piece wide-angle lens, and f ₁ is the focal length of the first lens. When the six-piece wide-angle lens satisfies the pre-existing relationship, a large aperture and a small distortion can be obtained. If the value of f ₁ /f is smaller than the range of the previous disclosure, it is easy to generate large distortion, and if the value of f _i /f is larger than the range of the previous disclosure, it is difficult to obtain a large aperture.

In addition, the six-piece wide-angle lens preferably satisfies the following relationship: Among them, ImH is the maximum image height of the six-chip wide-angle lens, and θ is the half-field angle corresponding to the maximum image height. When the six-piece wide-angle lens satisfies the pre-existing relationship, a wide viewing angle and a small distortion can be obtained. If the ratio is less than 1, the angle of view of the system is small, and if the ratio is greater than 1.5, the distortion is likely to occur.

In addition, the six-piece wide-angle lens preferably satisfies the following relationship: The TTL is the total length of the six-chip wide-angle lens. When the six-piece wide-angle lens satisfies the pre-existing relationship, it is possible to obtain a miniaturized and wide-angle characteristic.

In the foregoing lens, the first lens can provide wide-angle characteristics, the second lens can assist in correcting the distortion caused by the first lens and correct the astigmatism, and the object side of the second lens is preferably convex, which helps to improve The amount of light entering makes the image have high brightness characteristics. Wherein, the first lens or the second lens has at least one aspherical surface, thereby reducing the incident angle of the peripheral light and achieving a more desirable distortion correction effect. The third lens with positive refractive power can shorten the overall length of the system and achieve the purpose of miniaturization of the lens, and the object side of the third lens is preferably convex. This design helps to correct astigmatism. The fourth lens and the fifth lens can be easily generated by reducing the wide-angle system through the dispersion coefficient. The color difference problem is preferably to satisfy the relationship of Vd4-Vd5>25. The sixth lens can improve the field curvature phenomenon and adjust the light angle of the incident sensor to increase the amount of light received by the sensor. Preferably, the sixth lens At least one of the object side and the image side has an inflection point, and this design helps to reduce the influence of the coma caused by the large aperture.

100‧‧‧Six-piece wide-angle lens

110‧‧‧ first lens

120‧‧‧second lens

130‧‧‧ third lens

140‧‧‧Fourth lens

150‧‧‧ fifth lens

160‧‧‧ sixth lens

170‧‧‧ flat lenses

200‧‧‧Six-piece wide-angle lens

210‧‧‧ first lens

220‧‧‧second lens

230‧‧‧ third lens

240‧‧‧Fourth lens

250‧‧‧ fifth lens

260‧‧‧ sixth lens

300‧‧‧Six-piece wide-angle lens

310‧‧‧ first lens

320‧‧‧second lens

330‧‧‧ third lens

340‧‧‧Fourth lens

350‧‧‧ fifth lens

360‧‧‧ sixth lens

ST‧‧‧ aperture

A‧‧‧ object side

B‧‧‧ image side

Fig. 1 is a view showing the composition of a lens of the first embodiment of the present invention.

Fig. 2 is a field curvature and distortion diagram of the first embodiment of the present invention.

Figure 3 is a diagram showing the composition of a lens of a second embodiment of the present invention.

Figure 4 is a field curvature and distortion diagram of a second embodiment of the present invention.

Fig. 5 is a view showing the composition of a lens of a third embodiment of the present invention.

Figure 6 is a field curvature and distortion diagram of a third embodiment of the present invention.

Please refer to Figure 1. In the first embodiment of the present invention, a six-piece wide-angle lens 100 includes a first lens 110, a second lens 120, an aperture ST, a third lens 130, and a second from the object side A to the image side B. The fourth lens 140, the fifth lens 150 and the sixth lens 160 are provided with CCD, CMOS or other photosensitive elements (not shown) on the image side B, and may be additionally connected between the photosensitive element and the sixth lens 160. A flat lens 170 such as a filter and/or a cover glass is provided, and the number of the flat lenses 170 can be increased or decreased or not set as needed.

In the aforementioned six-piece wide-angle lens 100, the first lens 110 has a negative refractive power, the object side is convex and the image side is concave, and the first lens 110 can provide system wide-angle characteristics.

The second lens 120 has a positive refractive power, the object side is convex and the image side is concave Therefore, the second lens 120 can correct the distortion and astigmatism generated by the first lens, and the design of the convex object side A can increase the amount of light incident, so that the image has high brightness characteristics.

The third lens 130 has a positive refractive power, and both the object side and the image side surface are convex. The third lens 130 can shorten the overall length of the system, and the design of the convex object side A can correct the aberration.

The fourth lens 140 has a positive refractive power, and both the object side and the image side surface are convex.

The fifth lens 150 has a negative refractive power, and both the object side surface and the image side surface are concave, and the object side surface of the fifth lens 150 substantially matches the image side surface of the fourth lens 140, and the dispersion coefficients of the fourth and fifth lenses 140 and 150 are substantially matched. It can be matched with each other to reduce the chromatic aberration, and preferably satisfies the relationship of Vd4-Vd5>25, wherein Vd4 is the dispersion coefficient of the fourth lens, and Vd5 is the dispersion coefficient of the fifth lens.

The sixth lens 160 has a positive refractive power, which can improve the curvature of field and adjust the angle of the light incident on the sensor, thereby increasing the amount of light received by the sensor, and the image side of the sixth lens 160 has an inflection point. Can reduce the impact of large aperture caused by coma.

In the first embodiment, the design parameters of the six-piece wide-angle lens 100 are as shown in Table 1 below:

Wherein, the object side surface and the image side surface of the first to sixth lenses 110, 120, 130, 140, 150, 160 are all aspherical surfaces, and the surface shape thereof satisfies the following 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 fourth-order coefficient, B is the sixth-order coefficient, C is the eighth-order coefficient, D For the tenth order coefficient, E is the twelfth order coefficient, F is the fourteenth order coefficient, and G is the fifteenth order coefficient.

In the first lens 110 to the sixth lens 160 of this embodiment, the parameters of each aspheric surface are as shown in Table 2 below:

Based on the foregoing design, the focal length f of the system of the present embodiment is 2.08 mm, the system length TTL is 13.50 mm, the half angle of view at the maximum image height of 2.856 mm is 54.5 degrees, and the aperture value (f-number) is 2.2.

At this time, the ratio (f ₁ /f) of the focal length f _{1 of the} first lens 110 to the focal length f of the system is -1.707, The value is 1.02, and the ratio of the system focal length f to the total system length TTL (f/TTL) is 0.154. As a result, the six-chip wide-angle lens 100 has large aperture, small distortion, wide angle and miniaturization, and its curvature of field and distortion. The simulation results are shown in Figure 2.

Please refer to Figure 3. The second embodiment of the present invention shows a six-piece wide-angle lens 200, and its structural configuration is substantially similar to that of the first embodiment. The design parameters are as shown in Table 3 below:

In the second embodiment, the object side and the image side of the first lens 210, the second lens 220, the third lens 230, and the sixth lens 260 are aspherical surfaces and satisfy the aspherical surface formula, wherein each aspheric surface The parameters are as shown in Table 4 below:

On the other hand, the object side surface and the image side surface of the fourth lens 240 and the fifth lens 250 are both spherical surfaces, and a glue is applied therebetween to form a glue mirror group.

Based on the foregoing design, the focal length f of the system of the embodiment is 1.69 mm, and the system is long. The TTL is 12.90mm, the half-angle of the maximum image height of 2.856mm is 64.8 degrees, and the aperture value is 1.8.

At this time, the ratio (f ₁ /f) of the focal length f _{1 of the} first lens 210 to the focal length f of the system is -1.994, The value is 1.259, and the ratio of the system focal length f to the total system length TTL (f/TTL) is 0.131. As a result, the six-chip wide-angle lens 200 has large aperture, small distortion, wide angle and miniaturization, and its curvature of field and distortion. The simulation results are shown in Figure 4.

Please refer to Figure 5. A third embodiment of the present invention shows a six-piece wide-angle lens 300, and its structural configuration is substantially similar to that of the first embodiment. The design parameters are as shown in Table 5 below:

In the third embodiment, the object side surface and the image side surface of the first lens 310, the second lens 320, the third lens 330, and the sixth lens 360 are aspherical surfaces and satisfy the aspherical surface type formula, wherein each aspheric surface The parameters are as shown in Table 6 below:

On the other hand, the object side surface and the image side surface of the fourth lens 340 and the fifth lens 350 are both spherical surfaces, and a glue is applied therebetween to form a glue mirror group.

Based on the foregoing design, the focal length f of the system of the present embodiment is 1.53 mm, the system length TTL is 12.40 mm, the half angle of view at the maximum image height of 2.856 mm is 68.2 degrees, and the aperture value is 2.0.

At this time, the ratio (f ₁ /f) of the focal length f _{1 of the} first lens 310 to the focal length f of the system is -1.987. The value is 1.340, and the ratio of the focal length f of the system to the total system length TTL (f/TTL) is 0.123. As a result, the six-chip wide-angle lens 300 has large aperture, small distortion, wide angle and miniaturization, and its curvature of field and distortion. The simulation results are shown in Figure 6.

By the foregoing design, the six-piece wide-angle lens of the present invention can have a high amount of light incident, and at the same time, can have the functions of correcting chromatic aberration and distortion, that is, the invention can improve the general wide-angle lens defects while maintaining a wide-angle lens. The advantages of the aperture.

It should be noted that, in the foregoing embodiment, the aperture ST is located between the second and third lenses, but the aperture may be disposed at other positions behind the first lens and in front of the fourth lens, for example, at the first position. Between the second lenses or between the third and fourth lenses.

Finally, it must be stated again that the present invention is disclosed in the foregoing embodiments. The constituent elements are for illustrative purposes only and are not intended to limit the scope of the present invention. Alternatives or variations of other equivalent elements are also covered by the scope of the patent application.

100‧‧‧Six-piece wide-angle lens

110‧‧‧ first lens

120‧‧‧second lens

130‧‧‧ third lens

140‧‧‧Fourth lens

150‧‧‧ fifth lens

160‧‧‧ sixth lens

170‧‧‧ flat lenses

ST‧‧‧ aperture

A‧‧‧ object side

B‧‧‧ image side

Claims (9)

A six-piece wide-angle lens comprising, from the object side to the image side, a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a positive refractive power, and a fourth lens having a positive refractive power; a fifth lens having a negative refractive power; and a sixth lens; wherein the six-piece wide-angle lens satisfies the following relationship: Where f is the focal length of the system of the six-piece wide-angle lens, and f ₁ is the focal length of the first lens. The six-piece wide-angle lens as described in claim 1 satisfies the following relationship: Among them, ImH is the maximum image height of the six-chip wide-angle lens, and θ is the half-field angle corresponding to the maximum image height. The six-piece wide-angle lens of claim 1, wherein the object side of the second lens is convex. The six-piece wide-angle lens of claim 1, wherein the object side of the third lens is convex. The six-piece wide-angle lens of claim 1, wherein at least one of an object side and an image side of the sixth lens has an inflection point. The six-piece wide-angle lens as described in claim 1 satisfies the following relationship: The TTL is the total length of the six-chip wide-angle lens. A six-piece wide-angle lens as claimed in claim 1, wherein the sixth lens has a positive refractive power. The six-piece wide-angle lens of claim 1, further comprising an aperture disposed behind the first lens and in front of the fourth lens. The six-piece wide-angle lens of claim 1, wherein the fourth and fifth lenses are a glued lens group.