TWI742822B - Four-piece infrared projection lens system - Google Patents

Abstract

A four-piece infrared projection lens system, in order from an image side to an image source side: a first lens element with a refractive power and made of glass; a second lens element with a refractive power; a third lens element with a refractive power, and a fourth lens element with a positive refractive power, wherein a focal length of the second lens element is f2, a central thickness of the second lens element along the optical axis is CT2, and they satisfy the relation: -28<f2/CT2<161. Such a system has a larger focal length, high resolution, short length, less distortion.

Description

Four-piece infrared projection lens group

The present invention is related to lens sets, and particularly refers to a miniaturized four-piece infrared projection lens set applied to electronic products.

Nowadays, digital imaging technology continues to innovate and change. In particular, digital carriers such as digital cameras and mobile phones are developing towards miniaturization, and photosensitive elements such as CCD or CMOS are also required to be miniaturized. In infrared focusing lens applications, in addition to using In the field of photography, in recent years, it has also been widely used in the field of infrared receiving and sensing of game consoles. In order to make the game consoles have a wider range of sensing users, the current lens groups that receive infrared wavelengths mostly have larger angles of view. The wide-angle lens group is the mainstream.

Among them, the applicant has previously proposed a number of lens sets related to infrared wavelength reception. However, the current game machine is mainly based on 3D games with more three-dimensional, real and realistic sense. Therefore, the current or the applicant’s previous lens sets are all based on 2D flat game detection is a demand, so that it cannot meet the depth sensing function that 3D games focus on.

In addition, the infrared receiver and sensor lens set for game consoles uses plastic lenses in pursuit of low cost. The poor light transmittance of the material is one of the key factors that affect the lack of depth detection accuracy of game consoles. 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 cannot be accurately focused and detected. As mentioned above, the current lens group receiving infrared wavelengths cannot meet the two major technical issues of accurate sensing of depth and distance in 3D games.

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

The purpose of the present invention is to provide a four-piece infrared projection lens set, especially a four-piece infrared projection lens set with improved focal length, high resolution capability, short lens length, and small distortion.

In order to achieve the foregoing objective, a four-piece infrared projection lens set according to the present invention includes an aperture and an optical group composed of four lenses, which sequentially includes the aperture from the imaging side to the image source side: the aperture; The first lens has refractive power and is made of glass, the imaging side surface of the first lens is convex near the optical axis, and at least one of the imaging side surface and the image source side surface of the first lens is aspherical; a second A lens having refractive power, the imaging side surface of the second lens is convex near the optical axis, the image source side surface of the second lens is concave at the near optical axis, and the imaging side surface and the image source side surface of the second lens At least one surface is aspherical; a third lens having refractive power, the imaging side surface of the third lens is concave near the optical axis, and at least one of the imaging side surface and the image source side surface of the third lens is aspherical A fourth lens with positive refractive power, the image source side surface of the fourth lens is convex near the optical axis, and at least one of the imaging side surface and the image source side surface of the fourth lens is aspherical; wherein the first The focal length of the two lenses is f2, the thickness of the second lens on the optical axis is CT2, and the following conditions are met: -28<f2/CT2<161. In this way, the internal space of the lens can be effectively used to achieve the miniaturization of the lens.

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: -45<f2/f3<10. In this way, the peripheral resolution and illuminance of the system can be improved.

Preferably, the curvature radius of the imaging side surface of the fourth lens is R7, and the separation distance between the third lens and the fourth lens on the optical axis is T34, and the following conditions are met: -63<R7/T34<192. Thereby, the distance between the mirror surfaces can be shortened to achieve the miniaturization of the lens.

Preferably, the maximum angle of view of the four-piece infrared projection lens group is FOV, which satisfies the following condition: FOV<36. In this way, it is helpful for the beam to be projected in a concentrated manner, increasing the illuminance of the projection surface, and thereby improving its quality.

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<f1/f2<1. In this way, the refractive power configuration of the first lens and the second lens is more suitable, which can help reduce the excessive increase in system aberrations.

Preferably, the focal length of the third lens is f3, and the focal length of the fourth lens is f4, and the following conditions are satisfied: -2<f3/f4<0.1. In this way, the refractive power configuration of the system can be effectively balanced, which helps to reduce the sensitivity and improve the manufacturing yield.

Preferably, the focal length of the second lens is f2, and the combined focal length of the second lens and the third lens is f23, and the following conditions are satisfied: -38<f2/f23<10. In this way, the refractive power of the lens can be adjusted, which is helpful for correcting aberrations, compressing the total length, and adjusting the viewing angle.

Preferably, the focal length of the second lens is f2, and the combined focal length of the first lens and the second lens is f12, and the following conditions are satisfied: -8.5<f2/f12<32. As a result, the resolution capability of the four-piece infrared projection lens group can be significantly improved.

Preferably, the focal length of the first lens is f1, and the combined focal length of the third lens and the fourth lens is f34, and the following conditions are satisfied: -2.2<f1/f34<1.1. In this way, the refractive power of the lens can be adjusted, which is helpful for correcting aberrations, compressing the total length, and adjusting the viewing angle.

Preferably, the combined focal length of the second lens and the third lens is f23, and the four lenses The overall focal length of the infrared projection lens group is f and meets the following conditions: -1.5<f23/f<0.75. In this way, the refractive power of the lens can be adjusted, which is helpful for correcting aberrations, compressing the total length, and adjusting the viewing angle.

Preferably, the focal length of the second lens is f2, and the distance from the imaging side surface of the first lens to the image source surface on the optical axis is TL, and meets the following conditions: -5<f2/TL<21. Thereby, it is beneficial to maintain the miniaturization of the four-piece infrared projection lens set to be mounted on thin and light electronic products.

Preferably, the radius of curvature of the image source side surface of the first lens is R2, and the thickness of the first lens on the optical axis is CT1, and the following conditions are satisfied: -5<R2/CT1<26. This contributes to the moldability of the lens.

Preferably, the radius of curvature of the imaging side surface of the second lens is R3, and the distance between the first lens and the second lens on the optical axis is T12, and the following conditions are met: 40<R3/T12<136. Thereby, the distance between the mirror surfaces can be shortened to achieve the miniaturization of the lens.

Preferably, the curvature radius of the image source side surface of the third lens is R6, the focal length of the third lens is f3, and the following conditions are satisfied: -5<R6/f3<3. This contributes to the correction of high-order aberrations and astigmatism.

Preferably, the radius of curvature of the imaging side surface of the fourth lens is R7, and the combined focal length of the third lens and the fourth lens is f34, and the following conditions are satisfied: -10<R7/f34<5.5. In this way, the formability of the lens is improved.

Preferably, the separation distance between the second lens and the third lens on the optical axis is T23, and the thickness of the third lens on the optical axis is CT3, and the following conditions are satisfied: 0.4<T23/CT3<2.8. In this way, the thickness of the lens and the distance between the lenses can be adjusted to reduce the influence of manufacturing tolerances on the imaging quality.

Preferably, the separation distance between the third lens and the fourth lens on the optical axis is T34, and the thickness of the fourth lens on the optical axis is CT4, and the following conditions are satisfied: 0.04<T34/CT4<1.1. With this, The lens thickness and lens spacing can be adjusted to reduce the impact of manufacturing tolerances on image quality.

Preferably, the overall focal length of the four-piece infrared projection lens group is f, and the focal length of the second lens is f2, and the following conditions are satisfied: -1.5<f/f2<1.9. In this way, to ensure that the lens group has sufficient refractive power to achieve the purpose of short lens length.

Preferably, the curvature radius of the image source side surface of the first lens is R2, and the curvature radius of the image source side surface of the third lens is R6, and the following conditions are satisfied: -5<R2/R6<2.5. Thereby, the curvature of each lens can be balanced to increase the formability of the lens.

Preferably, the radius of curvature of the imaging side surface of the fourth lens is R7, and the thickness of the fourth lens on the optical axis is CT4, and the following conditions are satisfied: -32<R7/CT4<17. In this way, the formability of the lens is improved.

Regarding the technology, means and other effects adopted by the present invention to achieve the above-mentioned objects, nine preferred and feasible embodiments are described in detail below in conjunction with the drawings.

100, 200, 300, 400, 500, 600, 700, 800, 900: aperture

110, 210, 310, 410, 510, 610, 710, 810, 910: the first lens

111, 211, 311, 411, 511, 611, 711, 811, 911: imaging side surface

112, 212, 312, 412, 512, 612, 712, 812, 912: the side surface of the image source

120, 220, 320, 420, 520, 620, 720, 820, 920: second lens

121, 221, 321, 421, 521, 621, 721, 821, 921: imaging side surface

122, 222, 322, 422, 522, 622, 722, 822, 922: the side surface of the image source

130, 230, 330, 430, 530, 630, 730, 830, 930: third lens

131, 231, 331, 431, 531, 631, 731, 831, 931: imaging side surface

132, 232, 332, 432, 532, 632, 732, 832, 932: the side surface of the image source

140, 240, 340, 440, 540, 640, 740, 840, 940: fourth lens

141, 241, 341, 441, 541, 641, 741, 841, 941: imaging side surface

142, 242, 342, 442, 542, 642, 742, 842, 942: the side surface of the image source

180, 280, 380, 480, 580, 680, 780, 880, 980: image source surface

190, 290, 390, 490, 590, 690, 790, 890, 990: optical axis

f: The focal length of the four-piece infrared projection lens group

Fno: The aperture value of the four-piece infrared projection lens group

FOV: Maximum field of view in the four-piece infrared projection lens group

f1: focal length of the first lens

f2: the focal length of the second lens

f3: focal length of the third lens

f4: focal length of the fourth 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

f34: The combined focal length of the third lens and the fourth lens

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

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

R6: The curvature radius of the image source side surface of the third lens

R7: The radius of curvature of the imaging side surface of the fourth lens

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

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

T23: The distance between the second lens and the third lens on the optical axis

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

CT1: The thickness of the first lens on the optical axis

CT2: The thickness of the second lens on the optical axis

CT3: The thickness of the third lens on the optical axis

CT4: The thickness of the fourth lens on the optical axis

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

Fig. 1B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set of the first embodiment in sequence from left to right.

2A is a schematic diagram of a four-piece infrared projection lens set according to the second embodiment of the present invention.

Fig. 2B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set of the second embodiment in sequence from left to right.

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

Figure 3B shows the curvature and distortion of the four-piece infrared projection lens set in the third embodiment from left to right. Curve chart.

4A is a schematic diagram of a four-piece infrared projection lens group according to the fourth embodiment of the present invention.

FIG. 4B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set in the fourth embodiment in order from left to right.

FIG. 5A is a schematic diagram of a four-piece infrared projection lens group according to the fifth embodiment of the present invention.

FIG. 5B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set in the fifth embodiment in order from left to right.

FIG. 6A is a schematic diagram of a four-piece infrared projection lens group according to the sixth embodiment of the present invention.

FIG. 6B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set in the sixth embodiment in order from left to right.

FIG. 7A is a schematic diagram of a four-piece infrared projection lens group according to a seventh embodiment of the present invention.

Fig. 7B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set in the seventh embodiment, from left to right.

FIG. 8A is a schematic diagram of a four-piece infrared projection lens group in the eighth embodiment of the present invention.

Fig. 8B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens set in the eighth embodiment from left to right.

FIG. 9A is a schematic diagram of a four-piece infrared projection lens group according to the ninth embodiment of the present invention.

Fig. 9B is a graph showing the curvature of field and the distortion of the four-piece infrared projection lens group in the ninth embodiment, from left to right.

<First embodiment>

Please refer to FIG. 1A and FIG. 1B, in which FIG. 1A shows the fourth embodiment according to the first embodiment of the present invention The schematic diagram of the infrared projection lens unit of the sheet type, FIG. 1B shows the curve of field curvature and the distortion of the four-piece infrared projection lens unit of the first embodiment in order from left to right. It can be seen from FIG. 1A that the four-piece infrared projection lens group 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 imaging side to the image source side. The fourth lens 140 and the image source surface 180, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 100 is arranged between the projected object and the image source side surface 112 of the first lens 110. The four-piece infrared projection lens group can project the light from an image source surface 180 on the image source side to the projected object measured by the imaging source.

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

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

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

The fourth lens 140 has positive refractive power and is made of plastic. Its imaging side surface 141 is concave near the optical axis 190, and its image source side surface 142 is convex near the optical axis 190, and the imaging side surface 141 and the image The source side surfaces 142 are all aspherical.

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

Where z is the position value referenced by the surface vertex at the height of h along the optical axis 190; 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 transparent The curvature radius of the mirror surface close to the optical axis 190, h is the vertical distance between the lens surface and the optical axis 190, k is the conic constant, and A, B, C, D, E, F, ... are high-order aspheric surfaces coefficient.

In the four-piece infrared projection lens group of the first embodiment, the focal length of the four-piece infrared projection lens group is f, the f-number of the four-piece infrared projection lens group is Fno, and the four-piece infrared projection lens group is Fno. The maximum field of view (angle of view) in the group is FOV, and its values are as follows: f=3.92 (mm); Fno=2.3; and FOV=27.4 (degrees).

In the four-piece infrared projection lens set of the first embodiment, the focal length of the second lens 120 is f2, and the thickness of the second lens 120 on the optical axis 190 is CT2, and the following conditions are met: f2/CT2=160.7.

In the four-piece infrared projection lens set 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=-43.76.

In the four-piece infrared projection lens set of the first embodiment, the radius of curvature of the imaging side surface 141 of the fourth lens 140 is R7, 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: R7/T34=-61.36.

In the four-piece infrared projection lens set 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 met: f1/f2=0.04.

In the four-piece infrared projection lens set of the first embodiment, the focal length of the third lens 130 is f3, and the focal length of the fourth lens 140 is f4, and the following conditions are satisfied: f3/f4=-0.95.

In the four-piece infrared projection lens set of the first embodiment, the focal length of the second lens 120 is f2, and the combined focal length of the second lens 120 and the third lens 130 is f23, and the following conditions are met: f2/f23=- 37.43.

In the four-piece infrared projection lens set of the first embodiment, the focal length of the second lens 120 is f2, and the combined focal length of the first lens 110 and the second lens 120 is f12, and the following conditions are met: f2/f12=31.63 .

In the four-piece infrared projection lens set of the first embodiment, the focal length of the first lens 110 is f1, the combined focal length of the third lens 130 and the fourth lens 140 is f34, and the following conditions are met: f1/f34=0.91 .

In the four-piece infrared projection lens group of the first embodiment, the combined focal length of the second lens 120 and the third lens 130 is f23, and the overall focal length of the four-piece infrared projection lens group is f, and the following conditions are met: f23 /f=-0.56.

In the four-piece infrared projection lens set of the first embodiment, the focal length of the second lens 120 is f2, the distance from the imaging side surface 111 of the first lens 110 to the image source surface 180 on the optical axis 190 is TL, and Meet the following conditions: f2/TL=20.63.

In the four-piece infrared projection lens set of the first embodiment, the curvature radius of the image source side surface 112 of the first lens 110 is R2, and the thickness of the first lens 110 on the optical axis 190 is CT1, and the following conditions are met: R2/CT1=6.51.

In the four-piece infrared projection lens set of the first embodiment, the curvature radius of the imaging side surface 121 of the second lens 120 is R3, and the distance between the first lens 110 and the second lens 120 on the optical axis 190 is T12, And meet the following conditions: R3/T12=48.18.

In the four-piece infrared projection lens set of the first embodiment, the image source side surface 132 of the third lens 130 has a curvature radius of R6, and the focal length of the third lens 130 is f3, and the following conditions are met: R6/f3=- 1.10.

In the four-piece infrared projection lens set of the first embodiment, the radius of curvature of the imaging side surface 141 of the fourth lens 140 is R7, and the combined focal length of the third lens 130 and the fourth lens 140 is f34, and the following conditions are met: R7/f34=-9.31.

In the four-piece infrared projection lens set of the first embodiment, the distance between the second lens 120 and the third lens 130 on the optical axis 190 is T23, and the thickness of the third lens 130 on the optical axis 190 is CT3. And meet the following conditions: T23/CT3=2.10.

In the four-piece infrared projection lens set of the first embodiment, the distance between the third lens 130 and the fourth lens 140 on the optical axis 190 is T34, and the thickness of the fourth lens 140 on the optical axis 190 is CT4. And meet the following conditions: T34/CT4=0.50.

In the four-piece infrared projection lens group of the first embodiment, the overall focal length of the four-piece infrared projection lens group is f, and the focal length of the second lens 120 is f2, and the following conditions are met: f/f2=0.05.

In the four-piece infrared projection lens set of the first embodiment, the image source side surface 112 of the first lens 110 has a radius of curvature of R2, and the image source side surface 132 of the third lens 130 has a radius of curvature of R6, and meets the following conditions : R2/R6=1.61.

In the four-piece infrared projection lens set of the first embodiment, the curvature radius of the imaging side surface 141 of the fourth lens 140 is R7, and the thickness of the fourth lens 140 on the optical axis 190 is CT4, and the following conditions are met: R7 /CT4=-30.75.

Refer to Table 1 and Table 2 below for cooperation.

Table 1 shows the detailed structure data of the first embodiment in FIG. 1A, in which the unit of the radius of curvature, the thickness and the focal length are mm, and the surface 0-11 indicates the surface from the imaging side to the image source side in sequence. Table 2 is the aspheric surface data in the first embodiment, where k represents the conical surface coefficient in the aspheric curve equation, and A, B, C, D, E, F... are high-order aspheric surface coefficients. In addition, the following embodiment tables correspond to the schematic diagrams and aberration curve diagrams of the respective embodiments, and the definitions of the data in the tables are the same as those in Table 1 and Table 2 of the first embodiment, and will not be repeated here.

<Second Embodiment>

Please refer to Figures 2A and 2B, where Figure 2A shows a schematic diagram of a four-piece infrared projection lens set according to a second embodiment of the present invention, and Figure 2B shows the four-piece infrared projection of the second embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 2A that the four-piece infrared projection lens group 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 imaging side to the image source side. The fourth lens 240 and the image source surface 280, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 200 is set between the projected object and the Between the image source side surface 212 of the first lens 210. The four-piece infrared projection lens group can project light from an image source surface 280 on the image source side to the projected object measured by the imaging source.

The first lens 210 has positive refractive power and is made of glass. Its imaging side surface 211 is convex near the optical axis 290, and its image source side surface 212 is concave near the optical axis 290, and 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. Its imaging side surface 221 is convex near the optical axis 290, and its image source side surface 222 is concave near the optical axis 290, and the imaging side surface 221 and the image The source side surfaces 222 are all aspherical.

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

The fourth lens 240 has a positive refractive power and is made of plastic. Its imaging side surface 241 is convex near the optical axis 290, and its image source side surface 242 is convex near the optical axis 290, and the imaging side surface 241 and the image The source side surfaces 242 are all aspherical.

Refer to Table 3 and Table 4 below for cooperation.

In the second embodiment, the curve equation of the aspheric 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.

In conjunction with Table 3 and Table 4, the following data can be calculated:

<Third Embodiment>

Please refer to FIGS. 3A and 3B, where FIG. 3A shows a schematic diagram of a four-piece infrared projection lens set according to a third embodiment of the present invention, and FIG. 3B shows the four-piece infrared projection lens of the third embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 3A that the four-piece infrared projection lens group includes an aperture 300 and an optical group. The optical group includes a first lens 310, a second lens 320, a third lens 330, and an optical group from the imaging side to the image source side. The fourth lens 340 and the image source surface 380, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 300 is arranged between the projected object and the image source side surface 312 of the first lens 310. The four-piece infrared projection lens group can project the light from an image source surface 380 on the image source side to the projected object measured by the imaging source.

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

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

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

The fourth lens 340 has positive refractive power and is made of plastic. Its imaging side surface 341 is convex near the optical axis 390, and its image source side surface 342 is convex near the optical axis 390, and the imaging side surface 341 and the image The source side surfaces 342 are all aspherical.

Refer to Table 5 and Table 6 below for cooperation.

In the third embodiment, the curve equation of the aspheric 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.

In conjunction with Table 5 and Table 6, the following data can be calculated:

<Fourth Embodiment>

Please refer to FIGS. 4A and 4B, where FIG. 4A shows a schematic diagram of a four-piece infrared projection lens set according to a fourth embodiment of the present invention, and FIG. 4B shows the four-piece infrared projection lens of the fourth embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 4A that the four-piece infrared projection lens group 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 imaging side to the image source side. The fourth lens 440 and the image source surface 480, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 400 is arranged between the projected object and the image source side surface 412 of the first lens 410. The four-piece infrared projection lens set can project the light from an image source surface 480 on the image source side to the projected object measured by the imaging source.

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

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

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

The fourth lens 440 has positive refractive power and is made of plastic. Its imaging side surface 441 is convex near the optical axis 490, and its image source side surface 442 is convex near the optical axis 490, and the imaging side surface 441 and the image The source side surfaces 442 are all aspherical.

Refer to Table 7 and Table 8 below for cooperation.

In the fourth embodiment, the curve equation of the aspheric 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.

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

<Fifth Embodiment>

Please refer to FIGS. 5A and 5B, where FIG. 5A shows a schematic diagram of a four-piece infrared projection lens set according to a fifth embodiment of the present invention, and FIG. 5B shows the four-piece infrared projection lens of the fifth embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 5A that the four-piece infrared projection lens group 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 imaging side to the image source side. The fourth lens 540 and the image source surface 580, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 500 is set between the projected object and the Between the image source side surface 512 of the first lens 510. The four-piece infrared projection lens group can project the light from an image source surface 580 on the image source side to the projected object measured by the imaging source.

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

The second lens 520 has positive refractive power and is made of plastic. Its imaging side surface 521 is convex near the optical axis 590, and its image source side surface 522 is concave near the optical axis 590, and the imaging side surface 521 and image The source side surfaces 522 are all aspherical.

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

The fourth lens 540 has positive refractive power and is made of plastic. Its imaging side surface 541 is convex near the optical axis 590, and its image source side surface 542 is convex near the optical axis 590, and the imaging side surface 541 and the image The source side surfaces 542 are all aspherical.

Refer to Table 9 and Table 10 below for cooperation.

In the fifth embodiment, the curve equation of the aspheric 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.

With Table 9 and Table 10, the following data can be calculated:

<Sixth Embodiment>

Please refer to FIGS. 6A and 6B, in which FIG. 6A shows a schematic diagram of a four-piece infrared projection lens set according to the sixth embodiment of the present invention, and FIG. 6B shows the four-piece infrared projection lens of the sixth embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 6A that the four-piece infrared projection lens group 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 imaging side to the image source side. The fourth lens 640 and the image source surface 680, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 600 is arranged between the projected object and the image source side surface 612 of the first lens 610. The four-piece infrared projection lens group can project the light from an image source surface 680 on the image source side to the projected object measured by the imaging source.

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

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

The third lens 630 has negative refractive power and is made of plastic. Its imaging side surface 631 is concave near the optical axis 690, and its 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.

The fourth lens 640 has a positive refractive power and is made of plastic. Its imaging side surface 641 is convex near the optical axis 690, and its image source side surface 642 is convex near the optical axis 690, and the imaging side surface 641 and the image The source side surfaces 642 are all aspherical.

Refer to Table 11 and Table 12 below for cooperation.

In the sixth embodiment, the curve equation of the aspheric 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.

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

<Seventh Embodiment>

Please refer to FIGS. 7A and 7B, in which FIG. 7A shows a schematic diagram of a four-piece infrared projection lens set according to a seventh embodiment of the present invention, and FIG. 7B shows the four-piece infrared projection lens of the seventh embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 7A that the four-piece infrared projection lens group includes an aperture 700 and an optical group. The optical group includes a first lens 710, a second lens 720, a third lens 730, and an optical group from the imaging side to the image source side. The fourth lens 740 and the image source surface 780, wherein the four lenses with refractive power in the four-piece infrared projection lens group are four. The aperture 700 is arranged between the projected object and the image source side surface 712 of the first lens 710. The four-piece infrared projection lens group can project the light from an image source surface 780 on the image source side to the projected object measured by the imaging source.

The first lens 710 has positive refractive power and is made of glass. Its imaging side surface 711 is convex near the optical axis 790, its image source side surface 712 is concave near the optical axis 790, and the imaging side surface 711 and image The source side surfaces 712 are all aspherical.

The second lens 720 has positive refractive power and is made of plastic. Its imaging side surface 721 is convex near the optical axis 790, and its image source side surface 722 is concave near the optical axis 790, and the imaging side surface 721 and image The source side surfaces 722 are all aspherical.

The third lens 730 has negative refractive power and is made of plastic. Its imaging side surface 731 is concave near the optical axis 790, and its image source side surface 732 is concave near the optical axis 790, and the imaging side surface 731 and the image The source side surfaces 732 are all aspherical.

The fourth lens 740 has positive refractive power and is made of plastic. Its imaging side surface 741 is concave near the optical axis 790, and its image source side surface 742 is convex near the optical axis 790, and the imaging side surface 741 and the image The source side surfaces 742 are all aspherical.

Refer to Table 13 and Table 14 below for cooperation.

In the seventh embodiment, the aspherical curve equation 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.

In conjunction with Table 13 and Table 14, the following data can be calculated:

<Eighth Embodiment>

Please refer to FIGS. 8A and 8B, where FIG. 8A shows a schematic diagram of a four-piece infrared projection lens set according to the eighth embodiment of the present invention, and FIG. 8B shows the four-piece infrared projection lens of the eighth embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from Figure 8A that the four-piece infrared projection lens The group system includes an aperture 800 and an optical group. The optical group includes a first lens 810, a second lens 820, a third lens 830, a fourth lens 840, and an image source surface 880 in sequence from the imaging side to the image source side. Among them, there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 800 is arranged between the projected object and the image source side surface 812 of the first lens 810. The four-piece infrared projection lens group can project the light from an image source surface 880 on the image source side to the projected object measured by the imaging source.

The first lens 810 has negative refractive power and is made of glass. Its imaging side surface 811 is convex near the optical axis 890, and its image source side surface 812 is concave near the optical axis 890, and the imaging side surface 811 and the image The source side surfaces 812 are all aspherical.

The second lens 820 has positive refractive power and is made of plastic. Its imaging side surface 821 is convex near the optical axis 890, and its image source side surface 822 is concave near the optical axis 890, and the imaging side surface 821 and image The source side surfaces 822 are all aspherical.

The third lens 830 has positive refractive power and is made of plastic. Its imaging side surface 831 is concave near the optical axis 890, and its image source side surface 832 is convex near the optical axis 890, and the imaging side surface 831 and the image The source side surfaces 832 are all aspherical.

The fourth lens 840 has positive refractive power and is made of plastic. Its imaging side surface 841 is concave near the optical axis 890, and its image source side surface 842 is convex near the optical axis 890, and the imaging side surface 841 and the image The source side surfaces 842 are all aspherical.

Refer to Table 15 and Table 16 below for cooperation.

In the eighth embodiment, the aspherical curve equation 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.

In conjunction with Table 15 and Table 16, the following data can be calculated:

<Ninth Embodiment>

Please refer to FIGS. 9A and 9B, where FIG. 9A shows a schematic diagram of a four-piece infrared projection lens set according to a ninth embodiment of the present invention, and FIG. 9B shows the four-piece infrared projection lens of the ninth embodiment in order from left to right The curve of field curvature and distortion of the lens group. It can be seen from FIG. 9A that the four-piece infrared projection lens group includes an aperture 900 and an optical group. The optical group includes a first lens 910, a second lens 920, and a third lens 930 from the imaging side to the image source side. The fourth lens 940 and the image source surface 980, wherein there are four lenses with refractive power in the four-piece infrared projection lens group. The aperture 900 is arranged between the projected object and the image source side surface 912 of the first lens 910. The four-piece infrared projection lens group can project the light from an image source surface 980 on the image source side to the projected object measured by the imaging source.

The first lens 910 has negative refractive power and is made of glass. Its imaging side surface 911 is convex near the optical axis 990, and its image source side surface 912 is concave near the optical axis 990, and the imaging side surface 911 and the image The source side surfaces 912 are all aspherical.

The second lens 920 has positive refractive power and is made of plastic. Its imaging side surface 921 is convex near the optical axis 990, and its image source side surface 922 is concave near the optical axis 990, and the imaging side surface 921 and the image The source side surfaces 922 are all aspherical.

The third lens 930 has positive refractive power and is made of plastic. Its imaging side surface 931 is concave near the optical axis 990, and its image source side surface 932 is convex near the optical axis 990, and the imaging side surface 931 and the image The source side surfaces 932 are all aspherical.

The fourth lens 940 has positive refractive power and is made of plastic. Its imaging side surface 941 is concave near the optical axis 990, and its image source side surface 942 is convex near the optical axis 990, and the imaging side surface 941 and the image The source side surfaces 942 are all aspherical.

Refer to Table 17 and Table 18 below for cooperation.

In the ninth embodiment, the curve equation of the aspheric surface is expressed as in the form of 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.

With Table 17 and Table 18, the following data can be calculated:

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

In the four-piece infrared 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 in the low beam. The axis is convex; 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.

The four-piece infrared projection lens set provided by the present invention can be applied to a mobile focusing optical system according to requirements, and has the characteristics of excellent aberration correction and good imaging quality, and can be applied to 3D (three-dimensional) image capture, In electronic imaging systems such as digital cameras, mobile devices, digital tablets or car photography.

100: Aperture

110: 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

140: fourth lens

141: imaging side surface

142: Image source side surface

180: Image source surface

190: optical axis

Claims (20)

A four-piece infrared projection lens group, including an aperture and an optical group composed of four lenses, from the imaging side to the image source side, including: the aperture; a first lens with refractive power and made of glass , The imaging side surface of the first lens is convex near the optical axis, at least one of the imaging side surface and the image source side surface of the first lens is aspherical; a second lens having refractive power, the second lens The imaging side surface is convex near the optical axis, the image source side surface of the second lens is concave near the optical axis, and at least one of the imaging side surface and the image source side surface of the second lens is aspherical; a third lens , Has refractive power, the imaging side surface of the third lens is concave near the optical axis, and at least one of the imaging side surface and the image source side surface of the third lens is aspherical; a fourth lens has positive refractive power, The image source side surface of the fourth lens is convex near the optical axis, and at least one of the imaging side surface and the image source side surface of the fourth lens is aspherical; wherein the focal length of the second lens is f2, and the second lens The thickness on the optical axis is CT2 and meets the following conditions: -28<f2/CT2≦13.27. The four-piece infrared projection lens set according to 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 met: -45<f2/f3<10. The four-piece infrared projection lens set according to claim 1, wherein the radius of curvature of the imaging side surface of the fourth lens is R7, and the distance between the third lens and the fourth lens on the optical axis is T34, and meets the following requirements Condition: -63<R7/T34<192. The four-piece infrared projection lens set according to claim 1, wherein the maximum field of view of the four-piece infrared projection lens set is FOV, which meets the following conditions: FOV<36. The four-piece infrared projection lens set 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 met: -3<f1/f2<1. The four-piece infrared projection lens set according to claim 1, wherein the focal length of the third lens is f3, and the focal length of the fourth lens is f4, and the following conditions are met: -2<f3/f4<0.1. The four-piece infrared projection lens set according to claim 1, wherein the focal length of the second lens is f2, and the combined focal length of the second lens and the third lens is f23, and the following conditions are met: -38<f2/f23 <10. The four-piece infrared projection lens set according to claim 1, wherein the focal length of the second lens is f2, the combined focal length of the first lens and the second lens is f12, and the following conditions are met: -8.5<f2/f12 <32. The four-piece infrared projection lens set according to claim 1, wherein the focal length of the first lens is f1, the combined focal length of the third lens and the fourth lens is f34, and the following conditions are met: -2.2<f1/f34 <1.1. The four-piece infrared projection lens group according to claim 1, wherein the combined focal length of the second lens and the third lens is f23, the overall focal length of the four-piece infrared projection lens group is f, and the following conditions are met:- 1.5<f23/f<0.75. The four-piece infrared projection lens set according to claim 1, wherein the focal length of the second lens is f2, 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 met : -5<f2/TL<21. The four-piece infrared projection lens set according to claim 1, wherein the radius of curvature of the image source side surface of the first lens is R2, and the thickness of the first lens on the optical axis is CT1, and the following conditions are met: -5 <R2/CT1<26. The four-piece infrared 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 distance between the first lens and the second lens on the optical axis is T12, and meets the following requirements Condition: 40<R3/T12<136. The four-piece infrared projection lens set according to claim 1, wherein the radius of curvature of the image source side surface of the third lens is R6, and the focal length of the third lens is f3, and the following conditions are met: -5<R6/f3 <3. The four-piece infrared projection lens set according to claim 1, wherein the radius of curvature of the imaging side surface of the fourth lens is R7, the combined focal length of the third lens and the fourth lens is f34, and the following conditions are met: -10 <R7/f34<5.5. The four-piece infrared projection lens set according to claim 1, wherein the separation distance between the second lens and the third lens on the optical axis is T23, and the thickness of the third lens on the optical axis is CT3, and meets the following requirements Condition: 0.4<T23/CT3<2.8. The four-piece infrared projection lens set according to claim 1, wherein the distance between the third lens and the fourth lens on the optical axis is T34, and the thickness of the fourth lens on the optical axis is CT4, and meets the following requirements Conditions: 0.04<T34/CT4<1.1. The four-piece infrared projection lens set according to claim 1, wherein the overall focal length of the four-piece infrared projection lens set is f, and the focal length of the second lens is f2, and the following conditions are met: -1.5<f/f2 <1.9. The four-piece infrared projection lens set according to claim 1, wherein the curvature radius of the image source side surface of the first lens is R2, and the curvature radius of the image source side surface of the third lens is R6, and the following conditions are met:- 5<R2/R6<2.5. The four-piece infrared projection lens set according to claim 1, wherein the radius of curvature of the imaging side surface of the fourth lens is R7, the thickness of the fourth lens on the optical axis is CT4, and the following conditions are met: -32< R7/CT4<17.

Images