Optical components, imaging structures, biometric modules and mobile terminals

Abstract

The present invention relates to an optical component, an imaging structure, a biometric recognition module and a mobile terminal. The optical component sequentially includes, from the object surface to the imaging surface: a first lens having a negative refractive power, wherein the image side surface of the first lens is concave; a second lens having a positive refractive power, wherein the object side surface of the second lens is concave and the image side surface is convex; a third lens having a positive refractive power, wherein the image side surface of the third lens is convex; the optical component satisfies the following relationship: 8.5 < TTL / f < 11.0; wherein, TTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, and f is the effective focal length of the optical component. When the above relationship is satisfied, the optical component can be miniaturized, and the optical component can have a reasonable focal length. At the same time, the wide-angle characteristic of the optical component can also be realized.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging, and in particular to an optical component, an imaging structure, a biometric recognition module and a mobile terminal. Background Art

[0002] In recent years, with the advent of the full-screen craze, fingerprint recognition has become a basic configuration for mobile phones, and fingerprint recognition solutions are constantly innovating and breaking through. At present, there are three types of fingerprint recognition technologies on the mobile phone market: capacitive, ultrasonic, and optical. First of all, although the traditional capacitive fingerprint recognition technology is mature, it can no longer meet the needs of consumers in the full-screen era, and can only stay on low-end and mid-end mobile phones in the future. Secondly, ultrasonic fingerprint recognition has strong anti-counterfeiting recognition capabilities, but the technology is not mature enough, the cost is high, and it does not have the conditions for mass production. Finally, the optical under-screen fingerprint technology is developing rapidly, has good anti-interference and stability, and the cost can be reasonably controlled. Therefore, optical under-screen fingerprint recognition technology is the preferred choice in the era of full-screen high-end products. At present, some optical lenses on the market are large in size and cannot meet the market's demand for miniaturization of optical lenses. With the development of the electronic equipment market, large-volume optical lenses are more suitable for low-end and mid-end products rather than high-end products. Therefore, at this stage, there is an urgent need for a miniaturized optical lens to meet the growing market demand. Summary of the invention

[0003] Based on this, it is necessary to provide an optical component, an imaging structure, a biometric module and a mobile terminal to solve the problem of miniaturization of optical lenses.

[0004] An optical component, the optical component comprises, from the object plane to the imaging plane, the following:

[0005] A first lens having negative refractive power, wherein the image side surface of the first lens is a concave surface;

[0006] a second lens having positive refractive power, wherein the object-side surface of the second lens is concave and the image-side surface is convex;

[0007] a third lens having positive refractive power, wherein the image side surface of the third lens is a convex surface;

[0008] The optical components satisfy the following relationship:

[0009] 8.5 <TTL / f<11.0;

[0010] Wherein, TTL is the distance from the object side of the first lens to the imaging surface on the optical axis, and f is the effective focal length of the optical component. When the above relationship is satisfied, the optical component can be miniaturized and have a reasonable focal length, and at the same time, the wide-angle characteristic of the optical component can be achieved.

[0011] In one embodiment, the optical component further includes an aperture, and the aperture is arranged between the first lens and the second lens. By arranging the aperture between the first lens and the second lens, the optical component can better control the amount of light passing through, which is conducive to improving the imaging effect.

[0012] In one embodiment, the optical component satisfies the following relationship:

[0013] 3.1 <SD12 / SD21<3.9;

[0014] Among them, SD12 is the effective semi-aperture of the image side of the first lens, and SD21 is the effective semi-aperture of the object side of the second lens.

[0015] When the above relationship is satisfied, the molding difficulty of the first lens in the optical component is reduced, and the off-axis field aberration can be corrected to improve the imaging quality. At the same time, the miniaturization of the optical component can also be ensured.

[0016] In one embodiment, the optical component satisfies the following relationship:

[0017] 0.9 <f2 / f3<2.7;

[0018] Wherein, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens. When the above relationship is satisfied, the optical component has a reasonable optical power, can correct the spherical aberration of the optical component, and reduce the sensitivity of the optical component.

[0019] In one embodiment, the optical component satisfies the following relationship:

[0020] -2.9 <f1 / f<-2;

[0021] f1 is the effective focal length of the first lens, and f is the effective focal length of the optical component. When the above relationship is satisfied, the optical component can reduce spherical aberration and have a sufficiently large field of view.

[0022] In one embodiment, the optical component satisfies the following relationship:

[0023] 1.4 <Nd1<1.7;

[0024] 1.4 <Nd2<1.7;

[0025] Wherein, Nd1 is the refractive index of the first lens, and Nd2 is the refractive index of the second lens. When the above relationship is satisfied, the thickness of the first lens and the second lens can be effectively controlled, the processing difficulty of the first lens and the second lens can be reduced, and the product yield can be improved.

[0026] In one embodiment, the optical component satisfies the following relationship:

[0027] 5<|R6 / R7|<60;

[0028] Wherein, R6 is the curvature radius of the object side of the third lens, and R7 is the curvature radius of the image side of the third lens. When the above relationship is satisfied, the spherical aberration and astigmatism of the optical component can be effectively corrected to improve the imaging quality.

[0029] An imaging structure includes a photosensitive element, a reflector, and the optical assembly described in any of the above embodiments, wherein the photosensitive element is arranged on the imaging surface of the optical assembly, and the reflector is arranged on the object surface of the optical assembly. The incident light enters the optical assembly after being reflected by the reflector, and finally reaches the photosensitive element. By adopting the optical assembly, the imaging structure has the characteristics of small volume and better flexibility during installation. At the same time, the use of the reflector also enables the imaging structure to have functions such as changing the optical axis, rotating the image, guiding, and scanning.

[0030] A biometric identification module comprises a housing and the imaging structure described in the above embodiment, wherein the imaging structure is arranged in the housing. The biometric identification module can identify biometric information such as fingerprints and palm prints. At the same time, due to the use of a small-volume imaging structure, the biometric identification module also has a small volume, so that it can be applied to more small electronic devices and has better installation flexibility. In addition, the housing can prevent external light from causing imaging interference to the imaging structure.

[0031] A mobile terminal includes a middle frame and the biometric identification module in the above embodiment, wherein the biometric identification module is installed in the middle frame. By providing the biometric identification module, the mobile terminal has the function of identifying biometric information such as fingerprints and palm prints. At the same time, the small size of the biometric identification module makes the installation of components in the mobile terminal more flexible and can keep the size of the mobile terminal small. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of an optical component provided in accordance with a first embodiment of the present invention;

[0033] Figure 2 : are the longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical component in the first embodiment;

[0034] Figure 3 A schematic diagram of an optical component provided for a second embodiment of the present invention;

[0035] Figure 4: are the longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical component in the second embodiment;

[0036] Figure 5 A schematic diagram of an optical component provided in accordance with a third embodiment of the present invention;

[0037] Figure 6 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical component in the third embodiment;

[0038] Figure 7 A schematic diagram of an optical component provided in accordance with a fourth embodiment of the present invention;

[0039] Figure 8 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical component in the fourth embodiment;

[0040] Fig. 9 A schematic diagram of an optical component provided in accordance with a fifth embodiment of the present invention;

[0041] Fig.10 : are longitudinal spherical aberration diagram (mm), astigmatism diagram (mm) and distortion diagram (%) of the optical component in the fifth embodiment;

[0042] Fig.11 A schematic diagram of an imaging structure provided by an embodiment of the present invention;

[0043] Fig.12 A schematic diagram of a biometric recognition module provided by an embodiment of the present invention;

[0044] Fig.13 A schematic diagram of a mobile terminal provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0046] It should be noted that when an element is referred to as being "fixed to" another original, it may be directly on another element or may also have a centered element. When an element is considered to be "connected" to another original, it may be directly connected to another element or may simultaneously have a centered element. On the contrary, when an element is referred to as being "directly on" another original, there is no intermediate element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of this article are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0048] like Figure 1 As shown, the optical assembly 10 in one embodiment of the present invention includes a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power, which are arranged in sequence from the object plane to the image plane. The first lens L1 includes an object-side surface S1 and an image-side surface S2, and the image-side surface S2 is a concave surface; the second lens L2 includes an object-side surface S4 and an image-side surface S5, and the object-side surface S4 is a concave surface, and the image-side surface S5 is a convex surface; the third lens L3 includes an object-side surface S6 and an image-side surface S7, and the image-side surface S7 is a convex surface.

[0049] In some embodiments, an infrared bandpass filter L4 is further disposed between the third lens L3 and the imaging surface S10, and the infrared bandpass filter L4 includes an object-side surface S8 and an image-side surface S9. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared bandpass filter L4 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0050] The light emitted or reflected by the object enters the optical assembly 10 from the object side, passes through the first lens L1, the second lens L2, the third lens L3 and the infrared bandpass filter L4 in sequence, and finally reaches the imaging surface S10.

[0051] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0052] 8.5 <TTL / f<11.0;

[0053] Wherein, TTL is the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis, and f is the effective focal length of the optical component 10. In some embodiments, the relationship of TTL / f can be 8.82, 8.85, 8.90, 9, 9.3, 9.8, 10, 10.03, 10.05, 10.50 or 10.91. When the above relationship is satisfied, the optical component 10 can be miniaturized and have a reasonable focal length, and at the same time, the wide-angle characteristic of the optical component 10 can be achieved.

[0054] In some embodiments, an aperture ST0 is further provided between the first lens L1 and the second lens L2. The aperture ST0 is provided to better control the amount of light passing through, reduce the amount of light passing through when the light is strong, and increase the amount of light passing through when the light is weak, thereby improving the imaging effect.

[0055] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0056] 3.1 <SD12 / SD21<3.9;

[0057] Wherein, SD12 is the effective semi-aperture of the image side surface S2 of the first lens L1, and SD21 is the effective semi-aperture of the object side surface S4 of the second lens L2. In some embodiments, the relationship between SD12 / SD21 can be 3.22, 3.34, 3.46, 3.53, 3.57, 3.66, or 3.67. When the above relationship is satisfied, the molding difficulty of the first lens L1 in the optical component 10 can be reduced, and the off-axis field aberration can be corrected to improve the imaging quality. At the same time, the miniaturization of the volume of the optical component 10 can also be ensured.

[0058] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0059] 0.9 <f2 / f3<2.7;

[0060] Wherein, f2 is the effective focal length of the second lens L2, and f3 is the effective focal length of the third lens L3. In some embodiments, the relationship of f2 / f3 can be 0.91, 0.93, 1.02, 1.34, 1.63, 1.95, 2.04, 2.32, 2.46 or 2.69. When the above relationship is satisfied, the optical component 10 has a reasonable optical power, can correct the spherical aberration of the optical component 10, and reduce the sensitivity of the optical component 10.

[0061] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0062] -2.9 <f1 / f<-2;

[0063] f1 is the effective focal length of the first lens L1, and f is the effective focal length of the optical assembly 10. In some embodiments, the relationship of f1 / f can be -2.78, -2.77, -2.63, -2.55, -2.43, -2.37, -2.21 or -2.22. When the above relationship is satisfied, the optical assembly 10 can reduce spherical aberration and have a sufficiently large field of view.

[0064] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0065] 1.4 <Nd1<1.7;

[0066] 1.4 <Nd2<1.7;

[0067] Wherein, Nd1 is the refractive index of the first lens L1, and Nd2 is the refractive index of the second lens L2. In some embodiments, Nd1 can be 1.55, 1.56, 1.58, 1.62, 1.63 or 1.64, and Nd2 can also be 1.55, 1.56, 1.58, 1.62, 1.63 or 1.64. When the above relationship is satisfied, the thickness of the first lens L1 and the second lens L2 can be effectively controlled, the difficulty of lens processing can be reduced, and the product yield can be improved.

[0068] In some embodiments, the optical assembly 10 satisfies the following relationship:

[0069] 5<|R6 / R7|<60;

[0070] Wherein, R6 is the radius of curvature of the object-side surface S6 of the third lens L3, and R7 is the radius of curvature of the image-side surface S7 of the third lens L3. In some embodiments, the relationship of |R6 / R7| can be 5.75, 5.83, 10.73, 15.64, 20.27, 26.36, 35.38, 39.85, 45.56 or 59.55. When the above relationship is satisfied, the spherical aberration and astigmatism of the optical component 10 can be effectively corrected to improve the imaging quality.

[0071] In some other embodiments, the first lens L1, the second lens L2 and the third lens L3 may be made of glass or plastic.

[0072] In addition, the aspheric surface formulas of the first lens L1, the second lens L2 and the third lens L3 are:

[0073]

[0074] Among them, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the distance from any point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula.

[0075] First embodiment

[0076] like Figure 1 In the first embodiment shown, the optical assembly 10 includes, from the object plane to the image plane, a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power. Figure 2 Graphs 1 and 2 are longitudinal spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical component 10 in the first embodiment.

[0077] Among them, the object side surface S1 of the first lens L1 is concave at the optical axis, and the image side surface S2 of the first lens L1 is concave at the optical axis; the object side surface S1 of the first lens L1 is convex at the circumference, and the image side surface S2 of the first lens L1 is concave at the circumference. The object side surface S4 of the second lens L2 is concave at the optical axis, and the image side surface S5 of the second lens L2 is convex at the optical axis; the object side surface S4 of the second lens L2 is concave at the circumference, and the image side surface S5 of the second lens L2 is convex at the circumference. The object side surface S6 of the third lens L3 is concave at the optical axis, and the image side surface S7 of the third lens L3 is convex at the optical axis; the object side surface S6 of the third lens L3 is concave at the circumference, and the image side surface S7 of the third lens L3 is convex at the circumference.

[0078] In addition, the first lens L1 , the second lens L2 , and the third lens L3 are all made of plastic, and both the object-side surface and the image-side surface are aspherical. Since the lenses are all made of plastic, the weight and cost of the optical component 10 are reduced.

[0079] An infrared bandpass filter L4 is also provided between the third lens L3 and the imaging surface S10. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared bandpass filter L4 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0080] Specifically, the optical component 10 also satisfies the following relationship:

[0081] TTL / f=8.95;

[0082] When the above relationship is satisfied, the optical component 10 has the characteristics of miniaturization and a reasonable focal length. At the same time, the wide-angle characteristic of the optical component 10 can also be achieved. The optical component 10 having the above relationship has a better off-axis field of view, thereby improving the imaging quality. At the same time, since the above relationship also ensures the miniaturization of the volume of the optical component 10, it has good application prospects in fields such as mobile phone lenses and under-screen fingerprints that require high device miniaturization.

[0083] The optical assembly 10 is further provided with a stop ST0, which is provided between the first lens L1 and the second lens L2. The stop ST0 can reduce the amount of light passing when the light is strong and increase the amount of light passing when the light is weak, thereby improving the imaging effect of the optical assembly 10.

[0084] In addition, the optical assembly 10 also includes the following relationships:

[0085] SD12 / SD21=3.3;

[0086] In this case, the difficulty of molding the first lens L1 in the optical component 10 can be reduced, and the off-axis field aberration can be corrected to improve the imaging quality. Meanwhile, the miniaturization of the volume of the optical component 10 can also be ensured.

[0087] f2 / f3=1.70;

[0088] When the above relationship is satisfied, the optical component 10 has a reasonable optical power, which can correct the spherical aberration of the optical component 10 and reduce the sensitivity of the optical component 10;

[0089] f1 / f=-2.44;

[0090] When the above relationship is satisfied, the optical assembly 10 can reduce spherical aberration and have a sufficiently large field of view;

[0091] Nd1=1.55;

[0092] Nd2=1.55;

[0093] When the above relationship is satisfied, the thickness of the first lens L1 and the second lens L2 can be effectively controlled, the processing difficulty of the first lens L1 and the second lens L2 can be reduced, and the product yield can be improved;

[0094] |R6 / R7|=15.09;

[0095] When the above relationship is satisfied, the spherical aberration and astigmatism of the optical component 10 can be effectively corrected, thereby improving the imaging quality.

[0096] In the first embodiment, the effective focal length of the optical assembly 10 is f=0.60 mm, the aperture number is FNO=2.28, the field of view FOV=137 degrees, and the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis is TTL=5.37 mm.

[0097] In this embodiment, the optical component 10 also satisfies the conditions in Table 1 and Table 2. The elements from the object plane to the imaging plane are arranged in the order of the elements from top to bottom in Table 1. The Y radius in Table 1 is the radius of curvature. Surface numbers 1 and 2 are respectively the object side surface S1 and the image side surface S2 of the first lens L1, that is, the surface with a smaller lens surface number is the object side surface, and the surface with a larger surface number is the image side surface. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens. K in Table 2 is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula.

[0098] Table 1

[0099]

[0100] Table 2

[0101]

[0102]

[0103] Second embodiment

[0104] like Figure 3 In the second embodiment shown, the optical assembly 10 includes, from the object plane to the image plane, a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power. Figure 4 Graphs 1 and 2 are longitudinal spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical component 10 in the second embodiment.

[0105] Among them, the object side surface S1 of the first lens L1 is concave at the optical axis, and the image side surface S2 of the first lens L1 is concave at the optical axis; the object side surface S1 of the first lens L1 is convex at the circumference, and the image side surface S2 of the first lens L1 is concave at the circumference. The object side surface S4 of the second lens L2 is concave at the optical axis, and the image side surface S5 of the second lens L2 is convex at the optical axis; the object side surface S4 of the second lens L2 is concave at the circumference, and the image side surface S5 of the second lens L2 is convex at the circumference. The object side surface S6 of the third lens L3 is concave at the optical axis, and the image side surface S7 of the third lens L3 is convex at the optical axis; the object side surface S6 of the third lens L3 is concave at the circumference, and the image side surface S7 of the third lens L3 is convex at the circumference.

[0106] In addition, the first lens L1 , the second lens L2 , and the third lens L3 are all made of plastic, and both the object-side surface and the image-side surface are aspherical. Since the lenses are all made of plastic, the weight and cost of the optical component 10 are reduced.

[0107] An infrared bandpass filter L4 is also provided between the third lens L3 and the imaging surface S10. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared filter L5 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0108] In the second embodiment, the effective focal length of the optical assembly 10 is f=0.47 mm, the aperture number is FNO=2.43, the field of view FOV=131 degrees, and the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis is TTL=5.10 mm.

[0109] In this embodiment, the optical component 10 also satisfies the conditions in Table 3 and Table 4. The elements from the object plane to the imaging plane are arranged in the order of the elements from top to bottom in Table 3. The Y radius in Table 3 is the radius of curvature. Surface numbers 1 and 2 are respectively the object side surface S1 and the image side surface S2 of the first lens L1, that is, the surface with a smaller lens surface number is the object side surface, and the surface with a larger surface number is the image side surface. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens. K in Table 4 is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula.

[0110] Table 3

[0111]

[0112] Table 4

[0113]

[0114] According to the parameter information provided in Example 2, the following data can be obtained:

[0115]

[0116]

[0117] Third embodiment

[0118] like Figure 5 In the third embodiment shown, the optical assembly 10 includes, from the object side to the image side, a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power. Figure 6 Graphs 1 and 2 are longitudinal spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical component 10 in the third embodiment.

[0119] Among them, the object side surface S1 of the first lens L1 is concave at the optical axis, and the image side surface S2 of the first lens L1 is concave at the optical axis; the object side surface S1 of the first lens L1 is convex at the circumference, and the image side surface S2 of the first lens L1 is concave at the circumference. The object side surface S4 of the second lens L2 is concave at the optical axis, and the image side surface S5 of the second lens L2 is convex at the optical axis; the object side surface S4 of the second lens L2 is concave at the circumference, and the image side surface S5 of the second lens L2 is convex at the circumference. The object side surface S6 of the third lens L3 is concave at the optical axis, and the image side surface S7 of the third lens L3 is convex at the optical axis; the object side surface S6 of the third lens L3 is concave at the circumference, and the image side surface S7 of the third lens L3 is convex at the circumference.

[0120] In addition, the first lens L1 , the second lens L2 , and the third lens L3 are all made of plastic, and both the object-side surface and the image-side surface are aspherical. Since the lenses are all made of plastic, the weight and cost of the optical component 10 are reduced.

[0121] An infrared bandpass filter L4 is also provided between the third lens L3 and the imaging surface S10. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared bandpass filter L4 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0122] In the third embodiment, the effective focal length of the optical assembly 10 is f=0.65 mm, the aperture number is FNO=2.3, the field of view FOV=134 degrees, and the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis is TTL=5.74 mm.

[0123] In this embodiment, the optical component 10 also satisfies the conditions in Table 5 and Table 6. The elements from the object plane to the image plane are arranged in the order of the elements from top to bottom in Table 5. The Y radius in Table 5 is the radius of curvature. Surface numbers 1 and 2 are respectively the object side surface S1 and the image side surface S2 of the first lens L1, that is, the surface with a smaller lens surface number is the object side surface, and the surface with a larger surface number is the image side surface. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens. K in Table 6 is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula.

[0124] Table 5

[0125]

[0126] Table 6

[0127]

[0128] According to the parameter information provided in Example 3, the following data can be obtained:

[0129]

[0130]

[0131] Fourth embodiment

[0132] like Figure 7 In the fourth embodiment shown, the optical assembly 10 includes, from the object plane to the image plane, a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power. Figure 8Graphs 1 and 2 are longitudinal spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical component 10 in the fourth embodiment.

[0133] Among them, the object side surface S1 of the first lens L1 is concave at the optical axis, and the image side surface S2 of the first lens L1 is concave at the optical axis; the object side surface S1 of the first lens L1 is convex at the circumference, and the image side surface S2 of the first lens L1 is concave at the circumference. The object side surface S4 of the second lens L2 is concave at the optical axis, and the image side surface S5 of the second lens L2 is convex at the optical axis; the object side surface S4 of the second lens L2 is concave at the circumference, and the image side surface S5 of the second lens L2 is convex at the circumference. The object side surface S6 of the third lens L3 is convex at the optical axis, and the image side surface S7 of the third lens L3 is convex at the optical axis; the object side surface S6 of the third lens L3 is convex at the circumference, and the image side surface S7 of the third lens L3 is convex at the circumference.

[0134] In addition, the first lens L1 , the second lens L2 , and the third lens L3 are all made of plastic, and both the object-side surface and the image-side surface are aspherical. Since the lenses are all made of plastic, the weight and cost of the optical component 10 are reduced.

[0135] An infrared bandpass filter L4 is also provided between the third lens L3 and the imaging surface S10. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared bandpass filter L4 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0136] In the fourth embodiment, the effective focal length of the optical assembly 10 is f=0.55 mm, the aperture number is FNO=2.35, the field of view FOV=141 degrees, and the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis is TTL=5.75 mm.

[0137] In this embodiment, the optical component 10 also satisfies the conditions in Table 7 and Table 8. The elements from the object plane to the imaging plane are arranged in the order of the elements from top to bottom in Table 7. The Y radius in Table 7 is the radius of curvature. Surface numbers 1 and 2 are respectively the object side surface S1 and the image side surface S2 of the first lens L1, that is, the surface with a smaller lens surface number is the object side surface, and the surface with a larger surface number is the image side surface. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens. K in Table 8 is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula.

[0138] Table 7

[0139]

[0140] Table 8

[0141]

[0142] According to the parameter information provided in the fourth embodiment, the following data can be obtained:

[0143]

[0144]

[0145] Fifth embodiment

[0146] like Fig. 9 In the third embodiment shown, the optical assembly 10 includes, from the object plane to the image plane, a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with positive refractive power. Fig.10 Graphs 1 and 2 are longitudinal spherical aberration (mm), astigmatism (mm), and distortion (%) of the optical component 10 in the fifth embodiment.

[0147] Among them, the object side surface S1 of the first lens L1 on the optical axis is concave, and the image side surface S2 is concave; the object side surface S1 on the circumference is convex, and the image side surface S2 is concave. The object side surface S4 of the second lens L2 on the optical axis is concave, and the image side surface S5 is convex; the object side surface S4 on the circumference is concave, and the image side surface S5 is convex. The object side surface S6 of the third lens L3 on the optical axis is convex, and the image side surface S7 is convex; the object side surface S6 on the circumference is convex, and the image side surface S7 is convex.

[0148] Among them, the object side surface S1 of the first lens L1 is concave at the optical axis, and the image side surface S2 of the first lens L1 is concave at the optical axis; the object side surface S1 of the first lens L1 is convex at the circumference, and the image side surface S2 of the first lens L1 is concave at the circumference. The object side surface S4 of the second lens L2 is concave at the optical axis, and the image side surface S5 of the second lens L2 is convex at the optical axis; the object side surface S4 of the second lens L2 is concave at the circumference, and the image side surface S5 of the second lens L2 is convex at the circumference. The object side surface S6 of the third lens L3 is convex at the optical axis, and the image side surface S7 of the third lens L3 is convex at the optical axis; the object side surface S6 of the third lens L3 is convex at the circumference, and the image side surface S7 of the third lens L3 is convex at the circumference.

[0149] In addition, the first lens L1 , the second lens L2 , and the third lens L3 are all made of plastic, and both the object-side surface and the image-side surface are aspherical. Since the lenses are all made of plastic, the weight and cost of the optical component 10 are reduced.

[0150] An infrared bandpass filter L4 is also provided between the third lens L3 and the imaging surface S10. The infrared bandpass filter L4 is made of glass and does not affect the focal length of the optical component 10. The infrared bandpass filter L4 is used to adjust the wavelength range of the imaging light, and is specifically used to isolate light interference from other bands in the non-bandpass area to improve the resolution of the optical component 10.

[0151] In the fifth embodiment, the effective focal length of the optical assembly 10 is f=0.58 mm, the aperture number is FNO=2.15, the field of view FOV=135 degrees, and the distance from the object side surface S1 of the first lens L1 to the imaging surface S10 on the optical axis is TTL=5.83 mm.

[0152] In this embodiment, the optical component 10 also satisfies the conditions in Tables 9 and 10. The elements from the object plane to the imaging plane are arranged in the order of the elements from top to bottom in Table 9. The Y radius in Table 9 is the radius of curvature. Surface numbers 1 and 2 are respectively the object side surface S1 and the image side surface S2 of the first lens L1, that is, the surface with a smaller lens surface number is the object side surface, and the surface with a larger surface number is the image side surface. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the object side surface of the next lens. K in Table 10 is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspheric surface shape formula.

[0153] Table 9

[0154]

[0155] Table 10

[0156]

[0157]

[0158] According to the parameter information provided in Example 5, the following data can be obtained:

[0159]

[0160] like Fig.11As shown, in some embodiments, the imaging structure 20 of an embodiment of the present invention includes a reflector 210, a photosensitive element 220 and the optical component 10 in any of the above embodiments. Among them, the reflector 210 is arranged on the object plane of the optical component 10, and the photosensitive element 220 is arranged on the imaging surface S10 of the optical component 10. In some embodiments, the photosensitive element 220 is a charge coupled device or a complementary metal oxide semiconductor. By adopting the optical component 10, the imaging structure 20 has the characteristics of small volume, and by setting the reflector 210, the imaging structure 20 can realize the functions of changing the optical axis, rotating the image, inverting the image and scanning, so that it has greater flexibility in application and is convenient for installation. By applying the optical component 10, the imaging structure 20 has the characteristics of both miniaturization and high resolution, and through the reasonable distribution of optical focal length, the system sensitivity is low. In addition, the imaging structure 20 has good processing technology and has excellent characteristics of wide angle and high pixel.

[0161] refer to Fig.12 In the embodiment shown, the imaging structure 20 can also be applied to a biometric identification module 30 provided with a shell 320. In this case, the biometric identification module 30 includes a light source 310, and the light source 310 and the imaging structure 20 are arranged in the shell 320. The shell 320 can prevent external light from interfering with the imaging structure 20, and prevent the external light from directly colliding with the lens. In some embodiments, the light source 310 is separated from the reflector 210. In other embodiments, the light source 310 is arranged on the surface of the reflector 210. Fig.12 In the illustrated embodiment, the reflector 210 is a reflective prism. In other embodiments, the reflector 210 is a plane beam splitter. When fingerprint recognition is required, the finger is pressed on the reflective surface of the reflector 210. At this time, the light emitted by the light source 310 enters the reflector 210, and the fingerprint pattern information on the reflective surface of the reflector 210 is converted into light information. Subsequently, the light carrying the fingerprint pattern information is reflected into the optical component 10, and is finally received by the photosensitive element 220 and transmitted to the terminal for analysis. In addition, the light emission wavelength of the light source 310 is within the wavelength range allowed to pass by the infrared bandpass filter L4.

[0162] In addition to fingerprint recognition, the biometric module 30 can also recognize palm prints. At this time, the light emitted by the light source 310 is projected onto the palm through a plane beam splitter. After obtaining the palm print information, the light reflected by the palm re-enters the biometric module 30, and passes through the plane reflector again to reach the optical component 10, and is finally imaged on the photosensitive element 220 and recognized by the terminal.

[0163] At the same time, due to the use of a small imaging structure 20, the biometric identification module 30 also has a small size, so it can be applied to more small electronic devices. In particular, the biometric identification module 30 can be applied to security monitoring and protection products with fingerprint recognition and palm print recognition functions, such as full-screen smart phones, mobile phones and PDAs (Personal Digital Assistants), game consoles, PCs, etc.

[0164] like Fig.13 In one embodiment shown, the mobile terminal 40 includes a middle frame 410 and a biometric identification module 30, and the biometric identification module 30 is installed on the middle frame 410. By providing the biometric identification module 30, the mobile terminal 40 can identify biometric information such as fingerprints and palm prints, and can maintain a small size while maintaining clear identification.

[0165] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0166] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical component, characterized in that: There are three lenses with refractive power. The optical components include: A first lens having negative refractive power, wherein the object-side surface of the first lens on the optical axis is a concave surface, and the image-side surface of the first lens is a concave surface; a second lens having positive refractive power, wherein the object-side surface of the second lens is concave and the image-side surface is convex; a third lens having positive refractive power, wherein the image side surface of the third lens is a convex surface; The optical components satisfy the following relationship: 8.5 <TTL / f<10.5; 3.1 <SD12 / SD21<3.9; Wherein, TTL is the distance from the object side of the first lens to the imaging surface on the optical axis, f is the effective focal length of the optical component, SD12 is the effective semi-aperture of the image side of the first lens, and SD21 is the effective semi-aperture of the object side of the second lens.

2. The optical component according to claim 1, characterized in that The optical assembly further includes an aperture stop disposed between the first lens and the second lens.

3. The optical component according to claim 1, characterized in that The optical components satisfy the following relationship: 3.22 <SD12 / SD21<3.9。 4. The optical component according to claim 1, characterized in that The optical components satisfy the following relationship: 0.9 <f2 / f3<2.7; Wherein, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

5. The optical component according to claim 1, characterized in that The optical components satisfy the following relationship: -2.9 <f1 / f<-2; f1 is the effective focal length of the first lens, and f is the effective focal length of the optical component.

6. The optical component according to claim 1, characterized in that The optical components satisfy the following relationship: 1.4 <Nd1<1.7; 1.4 <Nd2<1.7; Wherein, Nd1 is the refractive index of the first lens, and Nd2 is the refractive index of the second lens.

7. The optical component according to claim 1, characterized in that The optical components satisfy the following relationship: 5<|R6 / R7|<60; Among them, R6 is the curvature radius of the object side of the third lens, and R7 is the curvature radius of the image side of the third lens.

8. An imaging structure, characterized in that: It comprises a photosensitive element, a reflector and the optical component according to any one of claims 1 to 7, wherein the photosensitive element is arranged on the imaging surface of the optical component, the reflector is arranged on the object surface of the optical component, and the incident light enters the optical component after being reflected by the reflector and finally reaches the photosensitive element.

9. A biometric recognition module, characterized in that: It comprises a shell and the imaging structure according to claim 8, wherein the imaging structure is arranged in the shell.

10. A mobile terminal, characterized in that: It comprises a middle frame and the biometric identification module according to claim 9, wherein the biometric identification module is installed in the middle frame.

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