TWI687732B - Three-piece infrared single wavelength projection lens system - Google Patents

Abstract

A three-piece infrared single wavelength projection lens system, in order from an image side to an image source side: a stop; a first lens element with a positive refractive power having an image-side surface being convex near an optical axis and an image source-side surface being concave near the optical axis; a second lens element with a negative refractive power having an image source-side surface being concave near the optical axis; and a third lens element with a positive refractive power having an image-side surface being concave near the optical axis and an image source-side surface being convex near the optical axis. Such arrangements can provide a three-piece infrared single wavelength projection lens system with better image sensing function.

Description

Three-piece infrared single-wavelength projection lens set

The invention relates to a projection lens group, in particular to a miniaturized three-piece infrared single-wavelength projection lens group applied to electronic products.

Today's digital imaging technology is constantly innovating and changing, especially digital carriers such as digital cameras and mobile phones are moving towards miniaturization, so that photosensitive elements such as CCD or CMOS are also required to be more compact. 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 reception and sensing of game consoles. In order to make the range of the game consoles to sense users wider, most of the lens sets that receive infrared wavelengths at present have a larger angle of view. The wide-angle lens group is the mainstream.

Among them, the applicant has also proposed a number of lens sets related to infrared wavelength reception. However, the current game consoles are mainly based on 3D games that are more three-dimensional, real and realistic, so the current or the applicant's previous lens sets are all based on The detection of 2D plane games is a demand, so that it cannot meet the depth sensing effect of 3D games.

In addition, the infrared lens receiving and sensing lens sets dedicated to game consoles use plastic lenses in pursuit of low cost. First, the poor transparency of the material is one of the key factors affecting the depth detection accuracy of the game console. Second, plastic lenses are easy to The ambient temperature is too hot or too cold, so that the focal length of the lens group changes and accurate focus detection cannot be achieved. As mentioned above, the current infrared wavelength receiving lens group cannot meet the two major technical issues of accurate 3D game depth distance sensing.

In view of this, how to provide accurate depth distance detection and reception, and prevent the change of the focal length of the lens group from affecting the depth detection effect, is now the technical bottleneck of the infrared wavelength receiving lens group that is eager to overcome.

The purpose of the present invention is to provide a three-piece infrared single-wavelength projection lens group, in particular to a three-piece infrared single-wavelength projection lens group with better image sensing function.

In order to achieve the aforementioned objective, a three-piece infrared single-wavelength projection lens set provided by the present invention includes, in order from the imaging side to the image source side, an aperture; a first lens with positive refractive power, and its imaging side surface A convex surface at the near optical axis, a concave surface at the image source side surface, at least one surface of the imaging side surface and the image source side surface is aspherical; a second lens with negative refractive power, the image source side surface A concave surface near the optical axis, at least one surface of the imaging side surface and the image source side surface is aspheric; and a third lens with positive refractive power, the imaging side surface is concave near the optical axis, and its image source side surface Near the optical axis is a convex surface, and at least one of the imaging side surface and the image source side surface is aspherical.

Preferably, wherein the overall focal length of the three-piece infrared single-wavelength projection lens group is f, the combined focal length of the first lens and the second lens is f12, and the following conditions are satisfied: 0.4 <f/f12 <1.2. In this way, through the proper configuration of the refractive power of the first lens and the second lens, the characteristics of both large viewing angle and miniaturization are effectively achieved.

Preferably, the overall focal length of the three-piece infrared single-wavelength projection lens group is f, the combined focal length of the second lens and the third lens is f23, and the following conditions are satisfied: 0.6 <f/f23 <1.8. In this way, the three-piece infrared single-wavelength projection lens set can achieve a balance between shortening the total optical length and correcting aberrations.

Preferably, the focal length of the first lens is f1, and the focal length of the second lens is f2, and the following conditions are satisfied: -3.0 <f1/f2 <-1.2. In this way, the configuration of the refractive power of the first lens and the second lens is more suitable, which can help to reduce the excessive increase of the system aberration.

Preferably, the focal length of the second lens is f2, and the focal length of the third lens is f3, and the following conditions are satisfied: -1.3 <f2/f3 <-0.1. Thereby, the configuration of the refractive power of the second lens and the third lens is more balanced, which is helpful for the correction of aberration and the reduction of sensitivity.

Preferably, the focal length of the first lens is f1, and the focal length of the third lens is f3, and the following conditions are satisfied: 0.7 <f1/f3 <1.8. In this way, the positive refractive power of the first lens is effectively distributed to reduce the sensitivity of the three-piece infrared single-wavelength projection lens group.

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 conditions are satisfied: 0.1 <f1/f23 <1.2. With this, the resolution capability of the three-piece infrared single-wavelength projection lens set is significantly improved.

Preferably, the combined focal length of the first lens and the second lens is f12, and the focal length of the third lens is f3, and the following conditions are satisfied: 2.3 <f12/f3 <4.4. With this, the resolution capability of the three-piece infrared single-wavelength projection lens set is significantly improved.

Preferably, the radius of curvature of the imaging side surface of the first lens is R1, and the radius of curvature of the image source side surface of the first lens is R2, and the following conditions are satisfied: 0.01 <R1/R2 <1.04. This effectively reduces the spherical aberration and astigmatism of the three-piece infrared single-wavelength projection lens group.

Preferably, the radius of curvature of the imaging side surface of the second lens is R3, and the radius of curvature of the image source side surface of the second lens is R4, and the following conditions are satisfied: -1.65 <R3/R4 <13.5. This effectively reduces the spherical aberration and astigmatism of the three-piece infrared single-wavelength projection lens group.

Preferably, the radius of curvature of the imaging side surface of the third lens is R5, and the radius of curvature of the image source side surface of the third lens is R6, and the following conditions are satisfied: 1.6 <R5/R6 <4.4. This effectively reduces the spherical aberration and astigmatism of the three-piece infrared single-wavelength projection lens group.

Preferably, the thickness of the first lens on the optical axis is CT1, and the thickness of the second lens on the optical axis is CT2, and the following conditions are satisfied: 2.5 <CT1/CT2 <4.0. This can contribute to the moldability and homogeneity of the lens.

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 conditions are satisfied: 0.05 <CT2/CT3 <1.05. In this way, an appropriate balance between imaging quality and sensitivity is obtained.

Preferably, the thickness of the first lens on the optical axis is CT1, and the thickness of the third lens on the optical axis is CT3, and the following conditions are satisfied: 0.6 <CT1/CT3 <2.6. This can contribute to the moldability and homogeneity of the lens.

Preferably, wherein the overall focal length of the three-piece infrared single-wavelength projection lens group is f, the distance from the imaging side surface of the first lens to the image source surface on the optical axis is TL, and the following conditions are satisfied: 0.7 <f /TL <1.9. In this way, it is advantageous to maintain the miniaturization of the three-piece infrared single-wavelength projection lens group to be mounted on thin and light electronic products.

Preferably, the refractive index of the first lens is n1, the refractive index of the second lens is n2, and the refractive index of the third lens is n3, and the following conditions are satisfied: 1.5<n1, n2, n3<1.7. By this, a larger refractive index is provided to enhance the refractive power of the lens.

With regard to the techniques, means and other effects adopted by the present invention to achieve the above-mentioned objectives, six preferred and feasible embodiments are described in detail below with reference to the drawings.

<First embodiment>

Please refer to FIGS. 1A and 1B, wherein FIG. 1A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to the first embodiment of the present invention, and FIG. 1B is the three-piece type of the first embodiment in order from left to right. Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from Figure 1A, three pieces The infrared single-wavelength projection lens set includes an aperture 100, a first lens 110, a second lens 120, a third lens 130, and an image source surface 180 along the optical axis 190 in order from the imaging side to the image source side. The refractive lenses in the infrared single-wavelength projection lens group are three (110, 120, 130), and any two adjacent lenses in the three-piece infrared single-wavelength projection lens group have an air on the optical axis 190 interval.

The first lens 110 has a positive refractive power and is made of plastic. The imaging side surface 111 is convex near the optical axis 190, and the image source side surface 112 is concave near the optical axis 190. The imaging side surface 111 and the image The source side surfaces 112 are all aspherical.

The second lens 120 has a negative refractive power and is made of plastic material. The imaging side surface 121 is convex near the optical axis 190 and the image source side surface 122 is concave near the optical axis 190. The imaging side surface 121 and the image The source side surfaces 122 are all aspherical.

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

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

Where z is the position value along the optical axis 190 at the height h with the surface vertex as a reference; c is the curvature of the lens surface close to 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 the conic constant, and A, B, C, D, E, F, G,... … Is a high-order aspheric coefficient.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the focal length of the three-piece infrared single-wavelength projection lens group is f, and the f-number of the three-piece infrared single-wavelength projection lens group is Fno. The maximum field angle (drawing angle) of the three-piece infrared single-wavelength projection lens group is FOV, and the values are as follows: f=4.48 (mm); Fno=2.88; and FOV=13.4 (degrees).

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the overall focal length of the three-piece infrared single-wavelength projection lens group is f, and the combined focal length of the first lens 110 and the second lens 120 is f12, and meets The following conditions: f/f12 = 0.79.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the overall focal length of the three-piece infrared single-wavelength projection lens group is f, and the combined focal length of the second lens 120 and the third lens 130 is f23, and meets The following conditions: f/f23 = 1.36.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the focal length of the first lens 110 is f1, and the focal length of the second lens 120 is f2, and the following conditions are satisfied: f1/f2 = -2.59.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the focal length of the second lens 120 is f2, and the focal length of the third lens 130 is f3, and the following conditions are satisfied: f2/f3 = -0.53.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the focal length of the first lens 110 is f1, and the focal length of the third lens 130 is f3, and the following conditions are satisfied: f1/f3 = 1.36.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the focal length of the first lens 110 is f1, the combined focal length of the second lens 120 and the third lens 130 is f23, and the following conditions are satisfied: f1/f23 = 0.60.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the combined 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 = 3.87.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the radius of curvature of the imaging side surface 111 of the first lens 110 is R1, and the radius of curvature of the image source side surface 112 of the first lens 110 is R2, and it satisfies the following Condition: R1/R2 = 0.40.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the radius of curvature of the imaging side surface 121 of the second lens 120 is R3, and the radius of curvature of the image source side surface 122 of the second lens 120 is R4, and meets the following Condition: R3/R4 = 12.82.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the imaging side surface 131 of the third lens 130 has a radius of curvature of R5, and the image source side surface 132 of the third lens 130 has a radius of curvature of R6, and satisfies the following Condition: R5/R6 = 2.88.

In the three-piece infrared single-wavelength projection lens set of the first embodiment, the thickness of the first lens 110 on the optical axis 190 is CT1, and the thickness of the second lens 120 on the optical axis 190 is CT2, and the following conditions are satisfied : CT1/CT2 = 3.42.

In the three-piece infrared single-wavelength projection 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 satisfied : CT2/CT3 = 0.40.

In the three-piece infrared single-wavelength projection lens set of the first embodiment, the thickness of the first lens 110 on the optical axis 190 is CT1, and the thickness of the third lens 130 on the optical axis 190 is CT3, and the following conditions are satisfied : CT1/CT3 = 1.37.

In the three-piece infrared single-wavelength projection lens group of the first embodiment, the overall focal length of the three-piece infrared single-wavelength projection lens group is f, and the imaging side surface 111 to the image source surface 180 of the first lens 110 are on the optical axis The distance over 190 is TL and meets the following conditions: f/TL = 1.35.

In the three-piece infrared single-wavelength projection lens set of the first embodiment, the refractive index of the first lens 110 is n1, the refractive index of the second lens 120 is n2, and the refractive index of the third lens 130 is n3, And meet the following conditions: n1, n2, n3 = 1.64.

Refer to Table 1 and Table 2 below.

Table 1 is the detailed structural data of the first embodiment of FIG. 1A, in which the units of radius of curvature, thickness and focal length are mm, and surfaces 0-9 sequentially represent the surfaces from the imaging side to the image source side. Table 2 is aspheric data in the first embodiment, where k represents the conical coefficient in the aspheric curve equation, and A, B, C, D, E, F, G... are high-order aspheric coefficients. In addition, the tables in the following embodiments correspond to the schematic diagrams and aberration curves of the embodiments. The definitions of the data in the tables are the same as those in Table 1 and Table 2 of the first embodiment, and are not repeated here.

<Second embodiment>

Please refer to FIGS. 2A and 2B, wherein FIG. 2A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a second embodiment of the present invention, and FIG. 2B is a three-piece type of the second embodiment in order from left to right Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from FIG. 2A, the three-piece infrared single-wavelength projection lens set includes an aperture 200, a first lens 210, a second lens 220, a third lens 230, and an image source surface along the optical axis 290 in order from the imaging side to the image source side 280, wherein the refractive lens in the three-piece infrared single-wavelength projection lens group is three (210, 220, 230), and any two adjacent lenses in the three-piece infrared single-wavelength projection lens group are between the light Each shaft 290 has an air gap.

The first lens 210 has a positive refractive power and is made of plastic material. The imaging side surface 211 is convex near the optical axis 290 and the image source side surface 212 is concave near the optical axis 290. The imaging side surface 211 and the image The source side surfaces 212 are all aspherical.

The second lens 220 has a negative refractive power and is made of plastic. The imaging side surface 221 is convex near the optical axis 290, and the image source side surface 222 is concave near the optical axis 290. The imaging side surface 221 and the image The source side surfaces 222 are all aspherical.

The third lens 230 has a positive refractive power and is made of plastic. The imaging side surface 231 is concave near the optical axis 290, and the image source side surface 232 is convex near the optical axis 290. The imaging side surface 231 and the image The source side surfaces 232 are all aspherical.

Refer to Table 3 and Table 4 below.

In the second embodiment, the curve equation of the aspherical surface is expressed 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 will not be repeated here.

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

<Third Embodiment>

Please refer to FIGS. 3A and 3B, wherein FIG. 3A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a third embodiment of the present invention, and FIG. 3B is a three-piece type of the third embodiment in order from left to right. Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from FIG. 3A, the three-piece infrared single-wavelength projection lens group includes an aperture 300, a first lens 310, a second lens 320, a third lens 330, and an image source surface along the optical axis 390 in order from the imaging side to the image source side 380, wherein the refractive lens in the three-piece infrared single-wavelength projection lens group is three (310, 320, 330), and any two adjacent lenses in the three-piece infrared single-wavelength projection lens group are between the light Each shaft 390 has an air gap.

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

The second lens 320 has a negative refractive power and is made of plastic. The imaging side surface 321 is convex near the optical axis 390, and the image source side surface 322 is concave near the optical axis 390. The imaging side surface 321 and the image The source side surfaces 322 are all aspherical.

The third lens 330 has a positive refractive power and is made of plastic. The imaging side surface 331 is concave near the optical axis 390, and the image source side surface 332 is convex near the optical axis 390. The imaging side surface 331 and the image The source side surfaces 332 are all aspherical.

Refer to Table 5 and Table 6 below.

In the third embodiment, the curve equation of the aspherical surface is expressed 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 will not be repeated here.

Together with Tables 5 and 6, the following data can be derived:

<Fourth embodiment>

Please refer to FIGS. 4A and 4B, wherein FIG. 4A shows a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a fourth embodiment of the present invention, and FIG. 4B is a three-piece type of the fourth embodiment in order from left to right. Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from FIG. 4A, the three-piece infrared single-wavelength projection lens group includes an aperture 400, a first lens 410, a second lens 420, a third lens 430, and an image source surface along the optical axis 490 in order from the imaging side to the image source side 480, wherein the refractive lens in the three-piece infrared single-wavelength projection lens group is three (410, 420, 430), and any two adjacent lenses in the three-piece infrared single-wavelength projection lens group are between the light Each shaft 490 has an air gap.

The first lens 410 has a positive refractive power and is made of plastic. The imaging side surface 411 is convex near the optical axis 490, and the image source side surface 412 is concave near the optical axis 490. The imaging side surface 421 and the image The source side surfaces 422 are all aspherical.

The second lens 420 has a negative refractive power and is made of plastic. The imaging side surface 421 is convex near the optical axis 490, and the image source side surface 422 is concave near the optical axis 490. The imaging side surface 421 and the image The source side surfaces 422 are all aspherical.

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

Refer to Table 7 and Table 8 below.

In the fourth embodiment, the curve equation of the aspherical surface is expressed 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 will not be repeated here.

Together with Table 7 and Table 8, the following data can be calculated:

<Fifth Embodiment>

Please refer to FIGS. 5A and 5B, wherein FIG. 5A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a fifth embodiment of the present invention, and FIG. 5B is a three-piece type of the fifth embodiment in order from left to right. Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from FIG. 5A, the three-piece infrared single-wavelength projection lens group includes an aperture 500, a first lens 510, a second lens 520, a third lens 530, and an image source surface along the optical axis 590 in order from the imaging side to the image source side 580, wherein the refractive lens in the three-piece infrared single-wavelength projection lens group is three (510, 520, 530), and any two adjacent lenses in the three-piece infrared single-wavelength projection lens group are between the light Each shaft 590 has an air gap.

The first lens 510 has positive refractive power and is made of plastic material. The imaging side surface 511 is convex near the optical axis 590 and the image source side surface 512 is concave near the optical axis 590. The imaging side surface 511 and the image The source side surfaces 512 are all aspherical.

The second lens 520 has a negative refractive power and is made of plastic material. The imaging side surface 521 is concave near the optical axis 590 and the image source side surface 522 is concave near the optical axis 590. The imaging side surface 511 and the image The source side surfaces 512 are all aspherical.

The third lens 530 has a positive refractive power and is made of plastic. The imaging side surface 531 is concave near the optical axis 590, the image source side surface 532 is convex near the optical axis 590, and the imaging side surface 531 and the image The source side surfaces 532 are all aspherical.

Refer to Table 9 and Table 10 below.

In the fifth embodiment, the curve equation of the aspherical surface is expressed 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 will not be repeated here.

Together with Tables 9 and 10, the following data can be calculated:

<Sixth Embodiment>

Please refer to FIGS. 6A and 6B, wherein FIG. 6A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a sixth embodiment of the present invention, and FIG. 6B is a three-piece type of the sixth embodiment in order from left to right. Infrared single-wavelength projection lens group non-point and distortion curve. As can be seen from FIG. 6A, the three-piece infrared single-wavelength projection lens group includes an aperture 600, a first lens 610, a second lens 620, a third lens 630, and an image source surface along the optical axis 690 in order from the imaging side to the image source side 680, wherein the refractive lens in the three-piece infrared single wavelength projection lens group is three (610, 620, 630), and any two adjacent lenses in the three-piece infrared single wavelength projection lens group are between the light Each shaft 690 has an air gap.

The first lens 610 has a positive refractive power and is made of plastic. The imaging side surface 611 is convex near the optical axis 690, and the image source side surface 612 is concave near the optical axis 690. The imaging side surface 611 and the image The source side surfaces 612 are all aspherical.

The second lens 620 has a negative refractive power and is made of plastic material. The imaging side surface 621 is convex near the optical axis 690 and the image source side surface 622 is concave near the optical axis 690. The imaging side surface 611 and the image The source side surfaces 612 are all aspherical.

The third lens 630 has a positive refractive power and is made of plastic material. The imaging side surface 631 is concave near the optical axis 690, the image source side surface 632 is convex near the optical axis 690, and the imaging side surface 631 and the image The source side surfaces 632 are all aspherical.

Refer to Table 11 and Table 12 below.

In the sixth embodiment, the curve equation of the aspherical surface is expressed 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 will not be repeated here.

Together with Table 11 and Table 12, the following data can be calculated:

The three-piece infrared single-wavelength projection lens set provided by the present invention can be made of plastic or glass. When the lens material is plastic, the production cost can be effectively reduced. When the lens material is glass, three-piece infrared can be added. The degree of freedom of the configuration of the refractive power of the single wavelength projection lens group. In addition, the imaging side surface and the image source side surface of the lens in the three-piece infrared single-wavelength projection lens group can be aspherical, and the aspherical surface can be easily made into a shape other than a spherical surface to obtain more control variables to reduce aberrations In order to reduce the number of lenses used, the total length of the three-piece infrared single-wavelength projection lens group of the present invention can be effectively reduced.

In the three-piece infrared single-wavelength projection lens set provided by the present invention, for a lens with refractive power, if the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is at the near optical axis Convex surface; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at the near optical axis.

100, 200, 300, 400, 500, 600: aperture

110, 210, 310, 410, 510, 610: the first lens

111, 211, 311, 411, 511, 611: imaging side surface

112, 212, 312, 412, 512, 612: image source side surface

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

121, 221, 321, 421, 521, 621: imaging side surface

122, 222, 322, 422, 522, 622: image source side surface

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

131, 231, 331, 431, 531, 631: imaging side surface

132, 232, 332, 432, 532, 632: image source side surface

180, 280, 380, 480, 580, 680: image source

190, 290, 390, 490, 590, 690: optical axis

f: focal length of three-piece infrared single-wavelength projection lens group

Fno: Aperture value of three-piece infrared single-wavelength projection lens group

FOV: The maximum angle of view in the three-piece infrared single-wavelength projection lens group

f1: focal length of the first lens

f2: focal length of the second lens

f3: focal length of the third lens

f12: The combined focal length of the first lens and the second lens

f23: The combined focal length of the second lens and the third lens

R1: radius of curvature of the imaging side surface of the first lens

R2: radius of curvature of the image source side surface of the first lens

R3: radius of curvature of the imaging side surface of the second lens

R4: Radius of curvature of the image source side surface of the second lens

R5: Radius of curvature of the imaging side surface of the third lens

R6: Radius of curvature of the image source side surface of the third lens

CT1: Thickness of the first lens on the optical axis

CT2: thickness of the second lens on the optical axis

CT3: Thickness of the third lens on the optical axis

TL: distance from the imaging side surface of the first lens to the image source surface on the optical axis

n1: refractive index of the first lens

n2: refractive index of the second lens

n3: refractive index of the third lens

FIG. 1A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to the first embodiment of the present invention.

FIG. 1B is a graph of the non-spot aberration and distortion aberration curves of the three-piece infrared single-wavelength projection lens group of the first embodiment in order from left to right.

2A is a schematic diagram of a three-piece infrared single-wavelength projection lens assembly according to a second embodiment of the present invention.

FIG. 2B is a graph of the non-point and distortion convergence curves of the three-piece infrared single-wavelength projection lens group of the second embodiment in order from left to right.

3A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a third embodiment of the present invention.

FIG. 3B is a graph of the non-point convergence and distortion convergence curves of the three-piece infrared single-wavelength projection lens group of the third embodiment in order from left to right.

4A is a schematic diagram of a three-piece infrared single-wavelength projection lens assembly according to a fourth embodiment of the present invention.

FIG. 4B is a graph of the non-point convergence and distortion convergence curves of the three-piece infrared single-wavelength projection lens group of the fourth embodiment in order from left to right.

5A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a fifth embodiment of the present invention.

FIG. 5B is a graph of the non-spot aberration and distortion aberration curves of the three-piece infrared single-wavelength projection lens group of the fifth embodiment in order from left to right.

6A is a schematic diagram of a three-piece infrared single-wavelength projection lens set according to a sixth embodiment of the present invention.

FIG. 6B is a graph of the non-spot aberration and distortion aberration curves of the three-piece infrared single-wavelength projection lens group of the sixth embodiment from left to right.

100: aperture

110: the first lens

111: imaging side surface

112: Image source side surface

120: second lens

121: Imaging side surface

122: Image source side surface

130: third lens

131: Imaging side surface

132: Image source side surface

180: Image source

190: Optical axis

Claims (15)

A three-piece infrared single-wavelength projection lens set, which includes, in order from the imaging side to the image source side: an aperture; a first lens with positive refractive power, a convex surface on the imaging side surface near the optical axis, and an image source side The surface is concave near the optical axis, and at least one of its imaging side surface and the image source side surface is aspheric; a second lens has negative refractive power, and its imaging side surface is convex near the optical axis, and its image source side surface The near-optical axis is concave, and at least one of its imaging-side surface and the image-source-side surface is aspheric; and a third lens has positive refractive power, and its imaging-side surface is concave near the optical axis, and its image-source-side surface Near the optical axis is a convex surface, at least one surface of the imaging side surface and the image source side surface is aspherical; wherein the overall focal length of the three-piece infrared single-wavelength projection lens group is f, the combination of the first lens and the second lens The focal length is f12, and the following conditions are met: 0.4<f/f12<1.2. The three-piece infrared single-wavelength projection lens group according to claim 1, wherein the overall focal length of the three-piece infrared single-wavelength projection lens group is f, and the combined focal length of the second lens and the third lens is f23, and meets The following conditions: 0.6<f/f23<1.8. The three-piece infrared single-wavelength projection lens group according to claim 1, wherein the focal length of the first lens is f1 and the focal length of the second lens is f2, and the following conditions are satisfied: -3.0<f1/f2<-1.2 . The three-piece infrared single-wavelength projection lens set as described in claim 1, wherein the focal length of the second lens is f2 and the focal length of the third lens is f3, and the following conditions are satisfied: -1.3<f2/f3<-0.1 . The three-piece infrared single-wavelength projection lens group according to claim 1, wherein the focal length of the first lens is f1 and the focal length of the third lens is f3, and the following conditions are satisfied: 0.7<f1/f3<1.8. The three-piece infrared single-wavelength projection 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 conditions are satisfied: 0.1<f1/ f23<1.2. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the combined focal length of the first lens and the second lens is f12, and the focal length of the third lens is f3, and the following conditions are satisfied: 2.3<f12/ f3<4.4. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the radius of curvature of the imaging side surface of the first lens is R1, and the radius of curvature of the image source side surface of the first lens is R2, and the following conditions are satisfied: 0.01<R1/R2<1.04. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the radius of curvature of the imaging side surface of the second lens is R3, and the radius of curvature of the image source side surface of the second lens is R4, and the following conditions are satisfied: -1.65<R3/R4<13.5. The three-piece infrared single-wavelength projection lens group according to claim 1, wherein the radius of curvature of the imaging side surface of the third lens is R5, and the radius of curvature of the image source side surface of the third lens is R6, and the following conditions are satisfied: 1.6<R5/R6<4.4. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the thickness of the first lens on the optical axis is CT1, and the thickness of the second lens on the optical axis is CT2, and the following conditions are satisfied: 2.5 <CT1/CT2<4.0. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein 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 conditions are satisfied: 0.05 <CT2/CT3<1.05. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the thickness of the first lens on the optical axis is CT1, and the thickness of the third lens on the optical axis is CT3, and the following conditions are satisfied: 0.6 <CT1/CT3<2.6. The three-piece infrared single-wavelength projection lens group according to claim 1, wherein the overall focal length of the three-piece infrared single-wavelength projection lens group is f, and the imaging side surface of the first lens to the image source surface is on the optical axis The distance is TL and meets the following conditions: 0.7<f/TL<1.9. The three-piece infrared single-wavelength projection lens set according to claim 1, wherein the refractive index of the first lens is n1, the refractive index of the second lens is n2, and the refractive index of the third lens is n3, and satisfies The following conditions: 1.5<n1, n2, n3<1.7.

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