TW201903455A - 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: a stop, a first lens element with a positive refractive power, a second lens element with a positive refractive power, a third lens element with a negative refractive power, and a fourth lens element with a positive refractive power. Such arrangements can provide a four-piece infrared single wavelength lens system which has a wide field of view, high resolution, short length and less distortion.

Description

Four-piece infrared single-wavelength lens set

The present invention relates to a four-piece infrared single-wavelength lens set, 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 groups for infrared wavelength reception, such as: "Single FOCUS WIDE-ANGLE LENS MODULE" of the Republic of China application No. 098100552, No. 098125378, only the current game system The 3D game is more stereoscopic, real and realistic. Therefore, the current or the applicant's previous lens group is based on the 2D plane game detection, so that the depth sensing effect of the 3D game focus cannot be satisfied.

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 shaft is concave, 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 negative refractive power, and the object side surface is at the near optical axis. a concave surface having a convex surface at a near-optical axis of the image side surface, at least one surface of the object side surface and the image side surface being aspherical; and a fourth lens having a positive refractive power, the object side surface being convex at a near optical axis, The image side surface has a concave surface at the near optical axis, and at least one surface of the object side surface and the image side surface is aspherical.

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: 0.005 < f1/f2 < 0.09. Thereby, the refractive power arrangement of the first lens and the second lens is suitable, which can be beneficial to reduce excessive increase of system aberration.

Preferably, wherein the focal length of the second lens is f2, the focal length of the third lens is f3, and the following condition is satisfied: -42 < f2/f3 < -3.2. Thereby, the arrangement of the refractive power of the second lens and the third lens is balanced, which contributes to the correction of the aberration and the reduction of the sensitivity.

Preferably, 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: -2.1 < f3/f4 < -1.3. Thereby, the total optical length of the system is effectively reduced.

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: -0.55 < f1/f3 < -0.15. Thereby, the refractive power of the first lens is effectively distributed, and the sensitivity of the four-piece infrared single-wavelength lens group is lowered.

Preferably, wherein the focal length of the first lens is f1, the focal length of the third lens is f4, and the following condition is satisfied: 0.35 < f1/f4 < 0.77. Thereby, the refractive power of the first lens is effectively distributed, and the sensitivity of the four-piece infrared single-wavelength lens group is lowered.

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: 6.0 < f2 / f4 < 68.5. Therefore, the system's negative refractive power distribution is more suitable, which is beneficial to correct system aberrations to improve the imaging quality of the system.

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: -0.55 < f1/f23 < -0.1. Thereby, when f1/f23 satisfies the above conditions, the resolution capability of the four-chip infrared single-wavelength lens group can be significantly improved.

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: 0.1 < f12/f34 < 0.45. Thereby, the curvature of field can be effectively corrected.

Preferably, wherein the focal length of the second lens is f2, the combined focal length of the third lens and the fourth lens is f34, and the following condition is satisfied: 2.7 < f2 / f34 < 30. Thereby, the curvature of field can be effectively corrected.

Preferably, wherein the second lens and the third lens have a combined focal length of f23, the fourth lens has a focal length of f4, and satisfies the following condition: -2.5 < f23/f4 < 1.2. Thereby, when f23/f4 satisfies the above conditions, the resolution capability of the four-chip infrared single-wavelength lens group can be significantly improved.

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: 0.13 < f1/f234 < 0.5. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

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 f4, and satisfies the following condition: 0.55 < f123/f4 < 1.25. By proper configuration of the refractive power, it helps to reduce the occurrence of spherical aberration and astigmatism.

Preferably, wherein the fourth lens has a refractive index of N4, and the fourth lens has a dispersion coefficient of V4 and satisfies the following condition: 1.61 < N4; V4 < 25. Thereby, the chromatic aberration of the four-piece infrared single-wavelength lens group is effectively reduced, and the aberration balance ability is preferably provided.

Preferably, wherein the overall focal length of the four-piece infrared single-wavelength lens group is f, the distance from the object side surface of the first lens to the imaging plane on the optical axis is TL, and the following condition is satisfied: 0.5 < f/TL < 0.9. Thereby, it is advantageous to maintain the miniaturization of the four-piece infrared single-wavelength lens group for mounting on a thin electronic product.

The present invention has been described in connection with the preferred embodiments of the present invention in accordance with the accompanying drawings.

<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, the infrared filter element 170, 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 object side surface 111 and the image side surface 112 of the first lens 110.

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 infrared filter element 170 is made of glass and disposed between the fourth lens 140 and the imaging surface 180 without affecting the focal length of the four-piece infrared single-wavelength lens group.

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 (angle 2ω) in the infrared single-wavelength lens set is FOV, and its values are as follows: f = 2.962 (mm); Fno = 2.0; and FOV = 78.7 (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 = 0.09.

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 = -41.366.

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 = -1.603.

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 = -0.390.

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 fourth lens 140 is f4, and the following condition is satisfied: f1/f4 = 0.625.

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 fourth lens 140 is f4, and the following condition is satisfied: f2/f4 = 66.328.

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 = -0.405.

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 = 0.279.

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 combined focal length of the third lens 130 and the fourth lens 140 is f34, and the following conditions are satisfied: f2/f34 = 28.143.

In the four-piece infrared single-wavelength lens group of the first embodiment, the composite focal length of the second lens 120 and the third lens 130 is f23, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f23/f4 = -1.544.

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 = 0.290.

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 = 1.064.

In the four-piece infrared single-wavelength lens group of the first embodiment, the overall focal length of the four-piece infrared single-wavelength lens group is f, and the object-side surface 111 to the imaging surface 180 of the first lens 110 are on the optical axis 190. The distance is TL and the following conditions are met: f/TL = 0.713.

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 surface 0-13 sequentially indicates the surface from the object side to the image side. Table 2 is the aspherical data in the first embodiment, wherein the cone coefficients in the a-spherical curve equation of k, A, B, C, D, E, F, ... are high-order aspheric coefficients. In addition, the tables in the following embodiments correspond to the schematic diagrams of the respective embodiments and the curvature of field and the distortion diagram of the distortion, and the definitions of the data in the table are the same as those of Tables 1 and 2 of the first embodiment, and Add a statement.

<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, the infrared filter element 270, 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 object side surface 211 and the image side surface 212 of the first lens 210.

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 positive 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.

The infrared filter element 270 is made of glass and disposed between the fourth lens 240 and the imaging surface 280 without affecting the focal length of the four-chip infrared single-wavelength lens group.

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, the infrared filter element 370, 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 object side surface 311 and the image side surface 312 of the first lens 310.

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 positive 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.

The infrared filter element 370 is made of glass and disposed between the fourth lens 340 and the imaging surface 380 without affecting the focal length of the four-piece infrared single-wavelength lens group.

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, the infrared filter element 470, 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 object side surface 411 and the image side surface 412 of the first lens 410.

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 negative 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 positive 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.

The infrared filter element 470 is made of glass and disposed between the fourth lens 440 and the imaging surface 480 without affecting the focal length of the four-chip infrared single-wavelength lens group.

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, the infrared filter filter element 570, and the imaging surface 580, wherein the four-piece infrared single-wavelength lens group has four lenses with refractive power. The aperture 500 is disposed between the object side surface 511 and the image side surface 512 of the first lens 510.

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 negative 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 positive 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 the object side surface 541 and the image side surface 542 have at least one surface having at least one inflection point.

The infrared filter element 570 is made of glass and disposed between the fourth lens 540 and the imaging surface 580 without affecting the focal length of the four-chip infrared single-wavelength lens group.

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, the infrared filter element 670, 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 object side surface 611 and the image side surface 612 of the first lens 610.

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 negative 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 convex 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 positive 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 the object side surface 641 and the image side surface 642 have at least one surface having at least one inflection point.

The infrared filter element 670 is made of glass and disposed between the fourth lens 640 and the imaging surface 680 without affecting the focal length of the four-piece infrared single-wavelength lens group.

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:

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‧‧ ‧ aperture

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

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

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

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

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

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

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

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

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

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

141, 241, 341, 441, 541, 641 ‧ ‧ ‧ side surface

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

170, 270, 370, 470, 570, 670‧‧‧ infrared filter elements

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

190, 290, 390, 490, 590, 690‧‧ ‧ 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

V4‧‧‧Dispersion coefficient of the fourth lens

Refractive index of the fourth lens of N4‧‧

TL‧‧‧The distance from the object side surface of the first lens to the imaging surface 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.

Claims (15)

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 negative refractive power, wherein the object side surface is concave at a near optical axis, and the image side surface is convex at a near optical axis, At least one surface of the object side surface and the image side surface is aspherical; and a fourth lens having a positive 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 thereof At least one surface of the surface and the image side surface is aspherical. 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: 0.005 < f1/f2 < 0.09. 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: -42 < f2/f3 < -3.2. 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: -2.1 < f3/f4 < -1.3. 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: -0.55 < f1/f3 < -0.15. 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 fourth lens is f4, and the following condition is satisfied: 0.35 < f1/f4 < 0.77. 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: 6.0 < f2/f4 < 68.5. 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: -0.55 < f1/ F23 < -0.1. 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: 0.1 < f12/f34 < 0.45. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the second lens is f2, the combined focal length of the third lens and the fourth lens is f34, and the following condition is satisfied: 2.7 < f2/f34 < 30. The four-piece infrared single-wavelength lens set according to claim 1, wherein the second lens and the third lens have a combined focal length of f23, the fourth lens has a focal length of f4, and satisfies the following condition: -2.5 < f23/ F4 < 1.2. The four-piece infrared single-wavelength lens set according to claim 1, wherein the focal length of the first lens is f1, and the combined focal length of the second lens, the third lens and the fourth lens is f234, and the following condition is satisfied: 0.13 < f1/f234 < 0.5. 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 f4, and satisfies the following condition: 0.55 < f123/f4 < 1.25. The four-piece infrared single-wavelength lens set according to claim 1, wherein the fourth lens has a refractive index of N4, and the fourth lens has a dispersion coefficient of V4 and satisfies the following condition: 1.61 < N4; V4 < 25. The four-piece infrared single-wavelength lens set according to claim 1, wherein the overall focal length of the four-piece infrared single-wavelength lens group is f, and the distance from the object side surface of the first lens to the imaging surface on the optical axis is TL, and meet the following conditions: 0.5 < f / TL < 0.9.