TW201814350A - Four-piece infrared single wavelength lens system - Google Patents

Abstract

A four-piece infrared single wavelength lens system includes, in order from the object side to the image side: an aperture stop; a first lens element with a positive refractive power has a convex object-side surface and a concave image-side surface; a second lens element with a positive refractive power has a concave object-side surface and a convex image-side surface; a third lens element with a refractive power has a concave object-side surface and a convex image-side surface; a fourth lens element with a refractive power has a convex object-side surface and a concave image-side surface.

Description

Four-piece infrared single-wavelength lens set

The present invention relates to a lens group, and more particularly to a miniaturized four-piece infrared single-wavelength lens set for use in electronic products.

Nowadays, digital imaging technology is constantly innovating and changing. Especially in digital cameras such as digital cameras and mobile phones, miniaturization is being developed. Photosensitive components such as CCD or CMOS are also required to be more miniaturized. In addition to the application of infrared focusing lenses, In the field of photography, in recent years, it has also been widely used in the field of infrared receiving and sensing of game machines, and in order to make the range of the user of the game machine wider, the lens group that receives the infrared wavelength is mostly in the angle of drawing. The wide-angle lens group is the mainstream.

Among them, the applicant has previously proposed a number of lens sets for infrared wavelength reception. However, the current game machine is mainly a 3D game with more stereo, real and realistic feeling. Therefore, the current lens group of the applicant or the applicant is The 2D plane game detection is so demanding that it cannot satisfy the depth sensing effect of the 3D game.

Furthermore, the infrared receiving and sensing lens sets for game machines are made of plastic lenses for the pursuit of low cost. The poor light transmittance of the materials is one of the key factors affecting the depth detection accuracy of the game machine. Secondly, the plastic lenses are easy to be used. The ambient temperature is too hot or too cold, so that the focal length of the lens group changes and the focus cannot be detected accurately. As mentioned above, the lens group that receives the infrared wavelength is unable to meet the two technical problems of accurate sensing of the depth of the 3D game.

In view of this, how to provide an accurate depth-distance detection, reception, and prevention of the focal length change of the lens group affects the depth detection effect, and the lens group that is the infrared wavelength receiving is currently eager to overcome the technical bottleneck.

The object of the present invention is to provide a four-piece infrared single-wavelength lens set, in particular to a four-piece infrared single-wavelength lens set with improved drawing angle, high resolution capability, short lens length and small distortion.

In order to achieve the foregoing objective, a four-piece infrared single-wavelength lens set according to the present invention includes, in order from the object side to the image side, an aperture; a first lens having a positive refractive power and an object side thereof. The surface near-optical axis is convex, and the image side surface is concave at the near-optical axis, and at least one surface of the object-side surface and the image-side surface is aspherical; a second lens has a positive refractive power, and the object side surface is low-beam The axis is a concave surface, and the image side surface is convex at the near optical axis, and at least one surface of the object side surface and the image side surface is aspherical; a third lens has a refractive power, and the object side surface is concave at the near optical axis The image side surface of the image has a convex surface, and at least one surface of the object side surface and the image side surface is aspherical; a fourth lens has a refractive power, and the object side surface is convex at the near optical axis, and the image side thereof The surface near-optical axis is a concave surface, and at least one surface of the object-side surface and the image-side surface is aspherical, and at least one surface of the object-side surface and the image-side surface has at least one inflection point.

Preferably, wherein the focal length of the first lens is f1, the focal length of the second lens is f2, and the following condition is satisfied: 0.8 < f1/f2 < 2.3. Thereby, the refractive power arrangement of the first lens and the second lens is suitable, which is advantageous for obtaining a wide angle of view (angle of view) and reducing excessive increase of system aberration.

Preferably, wherein the second lens has a focal length of f2, the third lens has a focal length of f3, and satisfies the following condition: -0.6 < f2/f3 < 0.5. Thereby, the peripheral resolution and illumination of the system can be improved.

Preferably, wherein the third lens has a focal length of f3, the fourth lens has a focal length of f4, and satisfies the following condition: -28 < f3/f4 < 3. This effectively balances the system's flexural force configuration and helps reduce sensitivity to improve manufacturing yield.

Preferably, wherein the focal length of the first lens is f1, the focal length of the third lens is f3, and the following condition is satisfied: -0.9 < f1/f3 < 0.7. Thereby, the positive refractive power of the first lens is effectively distributed, and the sensitivity of the four-piece infrared single-wavelength lens group is reduced.

Preferably, wherein the focal length of the second lens is f2, the focal length of the fourth lens is f4, and the following condition is satisfied: -1 < f2/f4 < 0.2. Therefore, the system's positive refractive power distribution is more suitable, which is beneficial to correct system aberrations to improve the imaging quality of the system.

Preferably, wherein the first lens and the second lens have a combined focal length of f12, the third lens has a focal length of f3, and satisfies the following condition: -0.6 < f12/f3 < 0.5. Thereby, it is advantageous to obtain a wide angle of view (angle of view) and to effectively correct the curvature of field.

Preferably, wherein the combined focal length of the first lens and the second lens is f12, the combined focal length of the third lens and the fourth lens is f34, and the following condition is satisfied: -1.0 < f12/f34 < -0.05. Thereby, it is advantageous to obtain a wide angle of view (angle of view) and to effectively correct the curvature of field.

Preferably, wherein the focal length of the first lens is f1, the combined focal length of the second lens and the third lens is f23, and the following condition is satisfied: 0.3 < f1/f23 < 2.1. Thereby, when f1/f23 satisfies the above conditions, the four-chip infrared single-wavelength lens group can significantly improve the resolution ability while obtaining a wide angle of view (angle of view).

Preferably, wherein the focal length of the first lens is f1, the combined focal length of the second lens, the third lens and the fourth lens is f234, and the following condition is satisfied: 0.3 < f1/f234 < 1.3. Thereby, it is advantageous to obtain a wide angle of view (angle of view) and to effectively correct the curvature of field.

Preferably, wherein the first lens, the second lens and the third lens have a combined focal length of f123, the fourth lens has a focal length of f1, and satisfies the following condition: 0.3 < f1/f234 < 1.3. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, the distance between the first lens and the second lens on the optical axis is T12, the thickness of the second lens on the optical axis is CT2, and the following condition is satisfied: 0.3<T12/CT2<1.0. Thereby, the height of the off-axis incident light passing through the first lens and the second lens is relatively large, so that the second lens has sufficient ability to correct the curvature of field, distortion and coma of the four-chip infrared single-wavelength lens group. Helps to correct the quality of the image.

Preferably, the thickness of the second lens on the optical axis is CT2, and the thickness of the third lens on the optical axis is CT3, and the following condition is satisfied: 0.3<0.5 < CT2/CT3 < 2.2. Thereby, when the above conditions are satisfied, the moldability and homogeneity of the lens are facilitated.

Preferably, the thickness of the third lens on the optical axis is CT3, and the distance between the third lens and the fourth lens on the optical axis is T34, and the following condition is satisfied: 7 < CT3/T34 < 18. Thereby, by distributing the thickness of the third lens and the spacing between the lenses, the overall length of the overall lens system can be shortened.

Preferably, wherein the first lens has a dispersion coefficient of V1, the second lens has a dispersion coefficient of V2, and satisfies the following condition: 30 < V1 - V2 < 42. Thereby, it is advantageous to correct the chromatic aberration of the system.

Preferably, wherein the maximum viewing angle of the four-chip infrared single-wavelength lens group is FOV, and the following condition is satisfied: 70 < FOV < 100. Thereby, the four-piece infrared single-wavelength lens group can have a suitable larger field of view.

The present invention has been described with reference to the preferred embodiments of the present invention in order to attain

<First Embodiment>

1A and FIG. 1B, FIG. 1A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a first embodiment of the present invention, and FIG. 1B is a four-chip infrared of the first embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As shown in FIG. 1A, the four-chip infrared single-wavelength lens assembly includes an aperture 100 and an optical group. The optical group includes a first lens 110, a second lens 120, and a third lens 130 from the object side to the image side. The fourth lens 140 and the imaging surface 180, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 100 is disposed between the image side surface 112 of the first lens 110 and the subject.

The first lens 110 has a positive refractive power and is made of a plastic material. The object side surface 111 is convex at the near optical axis 190, and the image side surface 112 is concave at the near optical axis 190, and the object side surface 111 and the image side are Surface 112 is aspherical.

The second lens 120 has a positive refractive power and is made of a plastic material. The object side surface 121 is a concave surface at the near optical axis 190, and the image side surface 122 is convex at the near optical axis 190, and the object side surface 121 and the image side are Surface 122 is aspherical.

The third lens 130 has a negative refractive power and is made of a plastic material. The object side surface 131 is concave at the near optical axis 190, and the image side surface 132 is convex at the near optical axis 190, and the object side surface 131 and the image side are The surfaces 132 are all aspherical.

The fourth lens 140 has a positive refractive power and is made of a plastic material. The object side surface 141 is convex at the near optical axis 190, and the image side surface 142 is concave at the near optical axis 190, and the object side surface 141 and the image side are The surface 142 is aspherical, and at least one surface of the object side surface 141 and the image side surface 142 has at least one inflection point.

The aspherical curve equations of the above lenses are expressed as follows:

Where z is the position value with reference to the surface apex at a position of height h in the direction of the optical axis 190; c is the curvature of the lens surface near the optical axis 190, and is the reciprocal of the radius of curvature (R) (c = 1/R) R is the radius of curvature of the lens surface near the optical axis 190, h is the vertical distance of the lens surface from the optical axis 190, k is a conic constant, and A, B, C, D, E, G, ... are High order aspheric coefficient.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the four-piece infrared single-wavelength lens group is f, and the aperture value (f-number) of the four-piece infrared single-wavelength lens group is Fno, four-piece type. The maximum field of view (arrow angle) in the infrared single-wavelength lens set is FOV, and its values are as follows: f = 1.699 (mm); Fno = 2; and FOV = 84 (degrees).

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the first lens 110 is f1, the focal length of the second lens 120 is f2, and the following condition is satisfied: f1/f2 = 1.10.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the second lens 120 is f2, the focal length of the third lens 130 is f3, and the following condition is satisfied: f2/f3 = -0.41.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the third lens 130 is f3, the focal length of the fourth lens 140 is f4, and the following condition is satisfied: f3/f4 = -0.15.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the first lens 110 is f1, the focal length of the third lens 130 is f3, and the following condition is satisfied: f1/f3 = -0.45.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the second lens 120 is f2, and the focal length of the fourth lens 140 is f4, and the following condition is satisfied: f2/f4 = 0.06.

In the four-piece infrared single-wavelength lens set of the first embodiment, the composite focal length of the first lens 110 and the second lens 120 is f12, and the focal length of the third lens 130 is f3, and the following conditions are satisfied: f12/f3 = -0.27.

In the four-piece infrared single-wavelength lens group of the first embodiment, the composite focal length of the first lens 110 and the second lens 120 is f12, and the combined focal length of the third lens 130 and the fourth lens 140 is f34, and the following is satisfied. Condition: f12/f34 = -0.24.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the first lens 110 is f1, and the combined focal length of the second lens 120 and the third lens 130 is f23, and the following conditions are satisfied: f1/f23 = 0.52.

In the four-piece infrared single-wavelength lens group of the first embodiment, the focal length of the first lens 110 is f1, and the combined focal length of the second lens 120, the third lens 130, and the fourth lens 140 is f234, and the following conditions are met. : f1/f234 = 0.62.

In the four-piece infrared single-wavelength lens group of the first embodiment, the composite focal length of the first lens 110, the second lens 120, and the third lens 130 is f123, and the focal length of the fourth lens 140 is f4, and the following conditions are met. : f123/f4 = 0.06.

In the four-piece infrared single-wavelength lens group of the first embodiment, the distance between the first lens 110 and the second lens 120 on the optical axis 190 is T12, and the thickness of the second lens 120 on the optical axis 190 is CT2. And meet the following conditions: T12/CT2 = 0.76.

In the four-piece infrared single-wavelength lens set of the first embodiment, the thickness of the second lens 120 on the optical axis 190 is CT2, and the thickness of the third lens 130 on the optical axis 190 is CT3, and the following conditions are met: CT2/CT3 = 0.77.

In the four-piece infrared single-wavelength lens group of the first embodiment, the thickness of the third lens 130 on the optical axis 190 is CT3, and the distance between the third lens 130 and the fourth lens 140 on the optical axis 190 is T34. And meet the following conditions: CT3/ T34 = 14.15.

In the four-piece infrared single-wavelength lens group of the first embodiment, the first lens 110 has a dispersion coefficient of V1, and the second lens 120 has a dispersion coefficient of V2 and satisfies the following conditions: V1-V2 = 32.03.

Refer to Table 1 and Table 2 below for reference.

Table 1 is the detailed structural data of the first embodiment of Fig. 1A, in which the unit of curvature radius, thickness and focal length is mm, and the surfaces 0-11 sequentially represent the surface from the object side to the image side. Table 2 is the aspherical surface data in the first embodiment, wherein the cone surface coefficients in the a-spherical curve equation of k, A, B, C, D, E, F, G, H, ... are high-order aspherical coefficients. In addition, the table of the following embodiments corresponds to the schematic diagram and the aberration diagram of each embodiment, and the definition of the data in the table is the same as the definitions of Table 1 and Table 2 of the first embodiment, and details are not described herein.

<Second embodiment>

2A and 2B, wherein FIG. 2A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a second embodiment of the present invention, and FIG. 2B is a four-chip infrared of the second embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As shown in FIG. 2A, the four-chip infrared single-wavelength lens assembly includes an aperture 200 and an optical group. The optical group includes a first lens 210, a second lens 220, and a third lens 230 from the object side to the image side. The fourth lens 240 and the imaging surface 280, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 200 is disposed between the image side surface 212 of the first lens 210 and the object.

The first lens 210 has a positive refractive power and is made of a plastic material. The object side surface 211 is convex at the near optical axis 290, and the image side surface 212 is concave at the near optical axis 290, and the object side surface 211 and the image side are Surface 212 is aspherical.

The second lens 220 has a positive refractive power and is made of a plastic material. The object side surface 221 is concave at the near optical axis 290, and the image side surface 222 is convex at the near optical axis 290, and the object side surface 221 and the image side are Surfaces 222 are all aspherical.

The third lens 230 has a negative refractive power and is made of a plastic material. The object side surface 231 is concave at the near optical axis 290, and the image side surface 232 is convex at the near optical axis 290, and the object side surface 231 and the image side are Surfaces 232 are all aspherical.

The fourth lens 240 has a negative refractive power and is made of a plastic material. The object side surface 241 is convex at the near optical axis 290, and the image side surface 242 is concave at the near optical axis 290, and the object side surface 241 and the image side are The surface 242 is aspherical, and at least one surface of the object side surface 241 and the image side surface 242 has at least one inflection point.

Refer to Table 3 and Table 4 below.

In the second embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

With Table 3 and Table 4, the following data can be derived:

<Third embodiment>

Please refer to FIG. 3A and FIG. 3B , wherein FIG. 3A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a third embodiment of the present invention, and FIG. 3B is a four-chip infrared of the third embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As can be seen from FIG. 3A, the four-chip infrared single-wavelength lens assembly includes an aperture 300 and an optical group. The optical group sequentially includes a first lens 310, a second lens 320, and a third lens 330 from the object side to the image side. The fourth lens 340 and the imaging surface 380, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 300 is disposed between the image side surface 312 of the first lens 310 and the subject.

The first lens 310 has a positive refractive power and is made of a plastic material. The object side surface 311 is convex at the near optical axis 390, and the image side surface 312 is concave at the near optical axis 390, and the object side surface 311 and the image side are Surfaces 312 are all aspherical.

The second lens 320 has a positive refractive power and is made of a plastic material. The object side surface 321 is concave at the near optical axis 390, and the image side surface 322 is convex at the near optical axis 390, and the object side surface 321 and the image side are Surfaces 322 are all aspherical.

The third lens 330 has a negative refractive power and is made of a plastic material. The object side surface 331 is concave at the near optical axis 390, and the image side surface 332 is convex at the near optical axis 390, and the object side surface 331 and the image side are Surface 332 is aspherical.

The fourth lens 340 has a negative refractive power and is made of a plastic material. The object side surface 341 is convex at the near optical axis 390, and the image side surface 342 is concave at the near optical axis 390, and the object side surface 341 and the image side are The surface 342 is aspherical, and at least one surface of the object side surface 341 and the image side surface 342 has at least one inflection point.

Refer to Table 5 and Table 6 below for reference.

In the third embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

With Table 5 and Table 6, the following data can be derived:

<Fourth embodiment>

Please refer to FIG. 4A and FIG. 4B , wherein FIG. 4A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a fourth embodiment of the present invention, and FIG. 4B is a four-chip infrared of the fourth embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As shown in FIG. 4A, the four-chip infrared single-wavelength lens assembly includes an aperture 400 and an optical group. The optical group includes a first lens 410, a second lens 420, and a third lens 430 from the object side to the image side. The fourth lens 440 and the imaging surface 480, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 400 is disposed between the image side surface 412 of the first lens 410 and the object.

The first lens 410 has a positive refractive power and is made of a plastic material. The object side surface 411 is convex at the near optical axis 490, and the image side surface 412 is concave at the near optical axis 490, and the object side surface 411 and the image side are Surface 412 is aspherical.

The second lens 420 has a positive refractive power and is made of a plastic material. The object side surface 421 is concave at the near optical axis 490, and the image side surface 422 is convex at the near optical axis 490, and the object side surface 421 and the image side are Surface 422 is aspherical.

The third lens 430 has a positive refractive power and is made of a plastic material. The object side surface 431 is concave at the near optical axis 490, and the image side surface 432 is convex at the near optical axis 490, and the object side surface 431 and the image side are Surface 432 is aspherical.

The fourth lens 440 has a negative refractive power and is made of a plastic material. The object side surface 441 is convex at the near optical axis 490, and the image side surface 442 is concave at the near optical axis 490, and the object side surface 441 and the image side are The surface 442 is aspherical, and at least one surface of the object side surface 441 and the image side surface 442 has at least one inflection point.

Refer to Table 7 and Table 8 below for reference.

In the fourth embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

The following data can be derived from Table 7 and Table 8:

<Fifth Embodiment>

5A and 5B, wherein FIG. 5A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a fifth embodiment of the present invention, and FIG. 5B is a four-chip infrared of the fifth embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As shown in FIG. 5A, the four-chip infrared single-wavelength lens assembly includes an aperture 500 and an optical group. The optical group includes a first lens 510, a second lens 520, and a third lens 530 from the object side to the image side. The fourth lens 540 and the imaging surface 580, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 500 is disposed between the image side surface 512 of the first lens 510 and the subject.

The first lens 510 has a positive refractive power and is made of a plastic material. The object side surface 511 is convex at the near optical axis 590, and the image side surface 512 is concave at the near optical axis 590, and the object side surface 511 and the image side are Surface 512 is aspherical.

The second lens 520 has a positive refractive power and is made of a plastic material. The object side surface 521 is concave at the near optical axis 590, and the image side surface 522 is convex at the near optical axis 590, and the object side surface 521 and the image side are Surface 522 is aspherical.

The third lens 530 has a positive refractive power and is made of a plastic material. The object side surface 531 is concave at the near optical axis 590, and the image side surface 532 is convex at the near optical axis 590, and the object side surface 531 and the image side are Surface 532 is aspherical.

The fourth lens 540 has a negative refractive power and is made of a plastic material. The object side surface 541 is convex at the near optical axis 590, and the image side surface 542 is concave at the near optical axis 590, and the object side surface 541 and the image side are The surface 542 is aspherical, and at least one surface of the object side surface 541 and the image side surface 542 has at least one inflection point.

Refer to Table 9 and Table 10 below.

In the fifth embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

The following data can be derived from Table 9 and Table 10:

<Sixth embodiment>

6A and 6B, wherein FIG. 6A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a sixth embodiment of the present invention, and FIG. 6B is a four-chip infrared of the sixth embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As shown in FIG. 6A, the four-chip infrared single-wavelength lens assembly includes an aperture 600 and an optical group. The optical group includes a first lens 610, a second lens 620, and a third lens 630 from the object side to the image side. The fourth lens 640 and the imaging surface 680, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 600 is disposed between the image side surface 612 of the first lens 610 and the object.

The first lens 610 has a positive refractive power and is made of a plastic material. The object side surface 611 is convex at the near optical axis 690, and the image side surface 612 is concave at the near optical axis 690, and the object side surface 611 and the image side are Surface 612 is aspherical.

The second lens 620 has a positive refractive power and is made of a plastic material. The object side surface 621 is concave at the near optical axis 690, and the image side surface 622 is convex at the near optical axis 690, and the object side surface 621 and the image side are Surface 622 is aspherical.

The third lens 630 has a positive refractive power and is made of a plastic material. The object side surface 631 is concave at the near optical axis 690, and the image side surface 632 is concave at the near optical axis 690, and the object side surface 631 and the image side are Surface 632 is aspherical.

The fourth lens 640 has a negative refractive power and is made of a plastic material. The object side surface 641 is convex at the near optical axis 690, and the image side surface 642 is concave at the near optical axis 690, and the object side surface 641 and the image side are The surface 642 is aspherical, and at least one surface of the object side surface 641 and the image side surface 642 has at least one inflection point.

Referring again to Table 11 and Table 12 below.

In the sixth embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

The following data can be derived from Table 11 and Table 12:

<Seventh embodiment>

Please refer to FIG. 7A and FIG. 7B , wherein FIG. 7A is a schematic diagram of a four-chip infrared single-wavelength lens group according to a seventh embodiment of the present invention, and FIG. 7B is a four-chip infrared of the seventh embodiment from left to right. Image curvature and distortion curve of single-wavelength lens set. As can be seen from FIG. 7A, the four-chip infrared single-wavelength lens assembly includes an aperture 700 and an optical group. The optical group sequentially includes a first lens 710, a second lens 720, and a third lens 730 from the object side to the image side. The fourth lens 740 and the imaging surface 780, wherein the four-piece infrared single-wavelength lens group has four refractive lenses. The aperture 700 is disposed between the image side surface 712 of the first lens 710 and the subject.

The first lens 710 has a positive refractive power and is made of a plastic material. The object side surface 711 is convex at the near optical axis 790, and the image side surface 712 is concave at the near optical axis 790, and the object side surface 711 and the image side are Surface 712 is aspherical.

The second lens 720 has a positive refractive power and is made of a plastic material. The object side surface 721 is concave at the near optical axis 790, and the image side surface 722 is convex at the near optical axis 790, and the object side surface 721 and the image side are Surface 722 is aspherical.

The third lens 730 has a positive refractive power and is made of a plastic material. The object side surface 731 is concave at the near optical axis 790, and the image side surface 732 is convex at the near optical axis 790, and the object side surface 731 and the image side are Surface 732 is aspherical.

The fourth lens 740 has a negative refractive power and is made of a plastic material. The object side surface 741 is convex at the near optical axis 790, and the image side surface 742 is concave at the near optical axis 790, and the object side surface 741 and the image side are The surface 742 is aspherical, and at least one surface of the object side surface 741 and the image side surface 742 has at least one inflection point.

Refer to Table 13 and Table 14 below.

In the seventh embodiment, the aspherical curve equation represents the form as in the first embodiment. In addition, the definitions of the parameters in the following table are the same as those in the first embodiment, and are not described herein.

The following data can be derived from Table 13 and Table 14:

The four-piece infrared single-wavelength lens set provided by the invention can be made of plastic or glass. When the lens material is plastic, the production cost can be effectively reduced. When the lens is made of glass, a four-piece infrared single can be added. The degree of freedom in the configuration of the refractive power of the wavelength lens set. In addition, the object side surface and the image side surface of the lens in the four-piece infrared single-wavelength lens group may be aspherical, and the aspheric surface can be easily formed into a shape other than the spherical surface, and more control variables are obtained to reduce the aberration, and further The number of lenses used is reduced, so that the overall length of the four-piece infrared single wavelength lens set of the present invention can be effectively reduced.

In the four-piece infrared single-wavelength lens set provided by the present invention, in the case of a lens having a refractive power, if the lens surface is convex and the convex position is not defined, it indicates that the lens surface is convex at the low beam axis. If the lens surface is concave and the concave position is not defined, it indicates that the lens surface is concave at the low beam axis.

The four-chip infrared single-wavelength lens set provided by the invention is more suitable for the optical system of moving focus, and has the characteristics of excellent aberration correction and good image quality, and can be applied to 3D (3D) image capture in various aspects. In electronic imaging systems such as digital cameras, mobile devices, digital tablets or car photography.

In the above, the above embodiments and drawings are only the preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, that is, the equivalent changes and modifications made by the scope of the present invention are all It should be within the scope of the patent of the present invention.

100, 200, 300, 400, 500, 600, 700‧‧ ‧ aperture

110, 210, 310, 410, 510, 610, 710‧‧‧ first lens

111, 211, 311, 411, 511, 611, 711 ‧ ‧ ‧ side surface

112, 212, 312, 412, 512, 612, 712‧‧‧ side surface

120, 220, 320, 420, 520, 620, 720‧‧‧ second lens

121, 221, 321, 421, 521, 621, 721 ‧ ‧ ‧ side surface

122, 222, 322, 422, 522, 622, 722‧‧‧ side surface

130, 230, 330, 430, 530, 630, 730 ‧ ‧ third lens

131, 231, 331, 431, 531, 631, 731 ‧ ‧ ‧ side surface

132, 232, 332, 432, 532, 632, 732‧‧‧ image side surface

140, 240, 340, 440, 540, 640, 740 ‧ ‧ fourth lens

141, 241, 341, 441, 541, 641, 741‧‧ ‧ side surfaces

142, 242, 342, 442, 542, 642, 742 ‧ ‧ side surface

180, 280, 380, 480, 580, 680, 780‧‧ ‧ imaging surface

190, 290, 390, 490, 590, 690, 790‧‧ ‧ optical axis

f‧‧‧Focus of four-piece infrared single-wavelength lens set

Aperture value of Fno‧‧‧4-piece infrared single-wavelength lens set

Maximum field of view in a FOV‧‧‧ four-chip infrared single-wavelength lens set

F1‧‧‧The focal length of the first lens

F2‧‧‧The focal length of the second lens

f3‧‧‧The focal length of the third lens

F4‧‧‧The focal length of the fourth lens

F12‧‧‧Combined focal length of the first lens and the second lens

F23‧‧‧Combined focal length of the second lens and the third lens

F34‧‧‧Combined focal length of the third lens and the fourth lens

F123‧‧‧Combined focal length of the first lens, the second lens and the third lens

f234‧‧‧Combined focal length of the second lens, the third lens and the fourth lens

V1‧‧‧Dispersion coefficient of the first lens

V2‧‧‧Dispersion coefficient of the second lens

CT2‧‧‧ thickness of the second lens on the optical axis

CT3‧‧‧ thickness of the third lens on the optical axis

T12‧‧‧The distance between the first lens and the second lens on the optical axis

T34‧‧‧The distance between the third lens and the fourth lens on the optical axis

1A is a schematic view of a four-piece infrared single-wavelength lens group according to a first embodiment of the present invention. 1B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the first embodiment from left to right. 2A is a schematic view of a four-piece infrared single-wavelength lens set of a second embodiment of the present invention. 2B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the second embodiment from left to right. Figure 3A is a schematic illustration of a four-piece infrared single wavelength lens set in accordance with a third embodiment of the present invention. 3B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the third embodiment from left to right. 4A is a schematic view of a four-piece infrared single-wavelength lens set according to a fourth embodiment of the present invention. 4B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the fourth embodiment from left to right. Figure 5A is a schematic illustration of a four-piece infrared single wavelength lens set in accordance with a fifth embodiment of the present invention. FIG. 5B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the fifth embodiment from left to right. Figure 6A is a schematic illustration of a four-piece infrared single wavelength lens assembly in accordance with a sixth embodiment of the present invention. Fig. 6B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the sixth embodiment from left to right. Figure 7A is a schematic illustration of a four-piece infrared single wavelength lens set in accordance with a seventh embodiment of the present invention. 7B is a graph showing the curvature of field and the distortion of the distortion of the four-piece infrared single-wavelength lens group of the seventh embodiment from left to right.

Claims (16)

A four-piece infrared single-wavelength lens group comprising: an aperture from the object side to the image side; a first lens having a positive refractive power, the object side surface being convex at the near optical axis, and the image side surface being low beam The shaft is concave, and at least one surface of the object side surface and the image side surface is aspherical; a second lens has a positive refractive power, and the object side surface is concave at the near optical axis, and the image side surface is near the optical axis a convex surface, wherein at least one surface of the object side surface and the image side surface is aspherical; a third lens having a refractive power, the object side surface being a concave surface at a near optical axis, and the image side surface being a convex surface at a near optical axis, At least one surface of the side surface and the image side surface is aspherical; a fourth lens having a refractive power, the object side surface being convex at the near optical axis, and the image side surface having a concave surface at the near optical axis, the object side surface and the image At least one surface of the side surface is aspherical, and at least one surface of the object side surface and the image side surface has at least one inflection point. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the first lens is f1, the focal length of the second lens is f2, and the following condition is satisfied: 0.8 < f1/f2 < 2.3. The four-piece infrared single-wavelength lens set according to claim 1, wherein the second lens has a focal length of f2, the third lens has a focal length of f3, and satisfies the following condition: -0.6 < f2/f3 < 0.5. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the third lens is f3, the focal length of the fourth lens is f4, and the following condition is satisfied: -28 < f3/f4 < 3. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the first lens is f1, the focal length of the third lens is f3, and the following condition is satisfied: -0.9 < f1/f3 < 0.7. The four-piece infrared single-wavelength lens set according to claim 1, wherein the second lens has a focal length of f2, the fourth lens has a focal length of f4, and satisfies the following condition: -1 < f2/f4 < 0.2. The four-piece infrared single-wavelength lens set according to claim 1, wherein the first lens and the second lens have a combined focal length of f12, the third lens has a focal length of f3, and satisfies the following condition: -0.6 < f12/ F3 < 0.5. The four-piece infrared single-wavelength lens set according to claim 1, wherein a composite focal length of the first lens and the second lens is f12, and a combined focal length of the third lens and the fourth lens is f34, and the following conditions are met: -1.0 < f12/f34 < -0.05. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the first lens is f1, the combined focal length of the second lens and the third lens is f23, and the following condition is satisfied: 0.3 < f1/f23 < 2.1. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the first lens is f1, the combined focal length of the second lens, the third lens and the fourth lens is f234, and the following condition is satisfied: 0.3 < f1/f234 < 1.3. The four-piece infrared single-wavelength lens set according to claim 1, wherein the first lens, the second lens and the third lens have a combined focal length of f123, the fourth lens has a focal length of f1, and satisfies the following condition: 0.3 < f1/f234 < 1.3. The four-piece infrared single-wavelength lens set according to claim 1, wherein a distance between the first lens and the second lens on the optical axis is T12, and a thickness of the second lens on the optical axis is CT2, and satisfies The following conditions are: 0.3 < T12 / CT2 < 1.0. The four-piece infrared single-wavelength lens set according to claim 1, wherein the thickness of the second lens on the optical axis is CT2, the thickness of the third lens on the optical axis is CT3, and the following condition is satisfied: 0.3< 0.5 < CT2/CT3 < 2.2. The four-piece infrared single-wavelength lens set according to claim 1, wherein the thickness of the third lens on the optical axis is CT3, and the distance between the third lens and the fourth lens on the optical axis is T34, and satisfies The following conditions are: 7 < CT3/T34 < 18. The four-chip infrared single-wavelength lens set according to claim 1, wherein the first lens has a dispersion coefficient of V1, the second lens has a dispersion coefficient of V2, and satisfies the following condition: 30 < V1 - V2 < 42. The four-piece infrared single-wavelength lens set according to claim 1, wherein the maximum angle of view of the four-piece infrared single-wavelength lens group is FOV, and the following condition is satisfied: 70 < FOV<100.