Fingerprint recognition optical lens

Abstract

The present invention relates to the technical field of optical lenses, and discloses a fingerprint recognition optical lens. The fingerprint recognition optical lens is sequentially provided with a glass plate, a first lens, a second lens, a third lens and a filter along the optical axis from the object side to the image side, and a diaphragm is arranged between the second lens and the third lens; the first lens has a negative optical power, and the paraxial regions of the object-side surface and the image-side surface are both concave surfaces; the second lens has a positive optical power, the paraxial region of the object-side surface is a convex surface, and the paraxial region of the image-side surface is a concave surface; the third lens has a positive optical power, and the paraxial regions of the object-side surface and the image-side surface are both convex surfaces; the optical lens satisfies the following condition: 2.4 < OBH / TTL < 4; wherein, TTL is the total length from the bottom of the cover plate to the image plane, and OBH is the object height of the fingerprint recognition optical lens. The fingerprint recognition optical lens provided by the present invention has good optical performance while meeting the design requirements of wide-angle, large aperture and fingerprint recognition.

Description

Technical Field

[0001] The present invention relates to the field of optical lenses, and in particular to a fingerprint recognition optical lens suitable for smart devices such as smartphones. Background Art

[0002] As electronic products develop in a trend of being thinner, lighter, and more functional, miniaturized camera lenses with good imaging quality have become the mainstream in the current market. However, the current fingerprint recognition lens is still relatively large in size, so the fingerprint module also occupies a large space, making it impossible for the installed device to have a thinner body. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a fingerprint recognition optical lens, which can greatly shorten the total length of the lens on the basis of a large object height.

[0004] The fingerprint identification optical lens of the present invention has a small volume and good imaging quality.

[0005] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0006] The present invention provides a fingerprint recognition optical lens, which is sequentially arranged along the optical axis from the object side to the image side: a glass plate, a first lens, a second lens, a third lens and a filter, wherein an aperture is arranged between the second lens and the third lens; the first lens has a negative focal length, and the paraxial regions of the object side surface and the image side surface are both concave; the second lens has a positive focal length, and the paraxial regions of the object side surface are convex, and the paraxial region of the image side surface is concave; the third lens has a positive focal length, and the paraxial regions of the object side surface and the image side surface are both convex; the fingerprint recognition optical lens satisfies the following conditional formula:

[0007] 2.4 <OBH / TTL<4

[0008] Among them, TTL is the total length from the bottom of the cover to the image plane, and OBH is the object height of the fingerprint recognition optical lens. If this condition is met, it means that the lens has the characteristics of large object height and short total length.

[0009] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0010] 1 <F2 / F3<3.2

[0011] Among them, F2 is the focal length of the second lens, and F3 is the focal length of the third lens. Meeting this conditional formula helps the lens reduce aberrations and improve resolution.

[0012] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0013] FNO≤1.5

[0014] Among them, FNO is the aperture value of the fingerprint recognition optical lens. If this condition is met, it means that the lens has a large aperture and a large amount of light entering.

[0015] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0016] 0.7 <CT2 / CT1<1

[0017] Among them, CT2 is the total length from the object side surface of the first lens to the image plane, and CT1 is the total length from the front surface of the glass plate to the object side surface of the first lens. If this condition is met, it means that the lens has a small total length and there is enough space for the fingerprint module.

[0018] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0019] OBH>7.8

[0020] Where OBH is the object height of the optical lens. If this condition is met, it means that the lens has a large object height, which meets the size required for fingerprint recognition.

[0021] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0022] ANG≤62°

[0023] Wherein, ANG is the maximum value of the surface angles of the first lens, the second lens or the third lens. Satisfying this conditional expression indicates that the lens surface shape is good and has high mass production performance.

[0024] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0025] 1.0 <V2 / V3<3.0

[0026] Wherein, V2 is the Abbe number of the second lens, and V3 is the Abbe number of the third lens. Satisfying this conditional expression helps to reduce the aberration of the optical lens.

[0027] Furthermore, the fingerprint recognition optical lens satisfies the following conditional formula:

[0028] HFOV>128°

[0029] Wherein, HFOV is the field of view of the fingerprint recognition optical lens. When this condition is met, the optical lens has a larger zoom ratio, and can image a larger object height onto a smaller image plane.

[0030] The beneficial effects of the present invention are as follows: the fingerprint identification optical lens provided by the present invention adopts three lenses, and through the coordination of the focal length, surface shape, center thickness of each lens and the axis spacing between each lens, the optical lens has the advantages of miniaturization and high quality, and is suitable for small portable electronic mobile devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of the fingerprint recognition optical lens of the present invention is shown;

[0032] Figure 2 A schematic structural diagram of a fingerprint recognition optical lens according to Embodiment 1 of the present invention is shown;

[0033] Figure 3 The astigmatism field curvature diagram of the fingerprint recognition optical lens of Example 1 of the present invention is shown;

[0034] Figure 4 The distortion curve diagram of the fingerprint recognition optical lens of Example 1 of the present invention is shown;

[0035] Figure 5 An optical modulation transfer function curve diagram of the fingerprint recognition optical lens according to Embodiment 1 of the present invention is shown;

[0036] Figure 6 A schematic diagram of the structure of a fingerprint recognition optical lens according to Embodiment 2 of the present invention is shown;

[0037] Figure 7 The astigmatism field curvature diagram of the fingerprint recognition optical lens of Example 2 of the present invention is shown;

[0038] Figure 8 The distortion curve diagram of the fingerprint recognition optical lens of Example 2 of the present invention is shown;

[0039] Fig. 9 An optical modulation transfer function curve diagram of the fingerprint recognition optical lens of Example 2 of the present invention is shown;

[0040] Fig.10 A schematic diagram of the structure of a fingerprint recognition optical lens according to Embodiment 2 of the present invention is shown;

[0041] Fig.11 The astigmatism field curvature diagram of the fingerprint recognition optical lens of Example 3 of the present invention is shown;

[0042] Fig.12 The distortion curve diagram of the fingerprint recognition optical lens of Example 3 of the present invention is shown;

[0043] Fig.13 The optical modulation transfer function curve of the fingerprint recognition optical lens according to embodiment 3 of the present invention is shown.

[0044] In the figure: 1. Glass plate; 2. First lens; 3. Second lens; 4. Third lens; 5. Filter; 6. Aperture; 7. Image plane. DETAILED DESCRIPTION

[0045] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0046] like Figure 1 As shown, the present invention provides a fingerprint recognition optical lens. The fingerprint recognition optical lens is provided with: a glass plate 1, a first lens 2, a second lens 3, a third lens 4, a filter 5 and an image plane 7 in sequence along the optical axis from the object side to the image side. An aperture 6 is provided between the second lens 3 and the third lens 4 for adjusting the light transmittance of the optical lens. The first lens 2 has a negative optical focal length, and the paraxial areas of the object side surface and the image side surface are both concave. The second lens 3 has a positive optical focal length, and the paraxial area of ​​the object side surface is convex, and the paraxial area of ​​the image side surface is concave. The third lens 4 has a positive optical focal length, and the paraxial areas of the object side surface and the image side surface are both convex.

[0047] Example 1

[0048] For specific design parameters of the fingerprint recognition optical lens of this embodiment 1, please refer to the following table.

[0049] Table 1 (a) shows the surface type, curvature radius, thickness and material of each lens of the optical lens of Example 1. The units of the curvature radius and thickness are both millimeters (mm).

[0050] Table 1(a)

[0051]

[0052] Table 1(b) shows the surface aspheric coefficients of each lens of the optical lens of Example 1.

[0053] Table 1(b)

[0054] Face number 3 4 5 6 8 9 K -1.11E+00 2.77E-01 -9.90E+01 1.07E+01 -9.45E+01 -3.30E+00 A4 1.04E+01 -5.97E+00 7.59E+01 1.43E+01 -1.09E+01 4.35E+01 A6 -7.39E+01 7.42E+02 -5.20E+03 -1.81E+03 7.48E+03 -8.54E+03 A8 3.62E+02 -1.71E+04 2.42E+05 1.37E+05 -1.62E+06 8.13E+05 A10 -1.19E+03 2.03E+05 -7.48E+06 -1.05E+07 1.89E+08 -4.63E+07 A12 2.61E+03 -1.30E+06 1.48E+08 6.65E+08 -1.26E+10 1.68E+09 A14 -3.77E+03 4.16E+06 -1.80E+09 -2.50E+10 4.88E+11 -3.88E+10 A16 3.43E+03 -5.20E+06 1.21E+10 4.75E+11 -1.07E+13 5.57E+11

[0055] In this embodiment, the specific parameters of the optical lens are shown in the following table:

[0056] Table 1(c)

[0057]

[0058] According to Table 1 (a) and Table 1 (b), the shape of the lens and various properties of the lens of Example 1 are clearly displayed.

[0059] See also Figure 2, is a schematic diagram of the optical arrangement of the fingerprint recognition optical lens of Example 1. It can be seen that the close arrangement of the lenses of the lens can achieve the structural characteristics of a smaller lens.

[0060] according to Figure 3 The astigmatism and field curvature curves in the figure clearly show that the maximum difference between the astigmatism S-line and T-line of the lens is less than 0.2mm, and the maximum field curvature is less than 0.2mm, indicating that the lens has a good ability to improve astigmatism and field curvature.

[0061] according to Figure 4 The distortion curve in the figure clearly shows that the maximum distortion of the optical lens is about 2%, indicating that the lens has a good ability to improve distortion.

[0062] according to Figure 5 The optical modulation transfer function curve in the figure clearly shows that the lens has good resolving power.

[0063] Example 2

[0064] Figure 6 FIG. 2 shows a schematic diagram of the optical arrangement of the fingerprint recognition optical lens according to Embodiment 2 of the present invention. Figure 6 As shown, the fingerprint recognition optical lens according to an exemplary embodiment of the present invention includes, in order from the object side to the image side along the optical axis: a glass plate, a first lens, a second lens, an aperture, a third lens, a filter, and an image plane.

[0065] For specific design parameters of the fingerprint recognition optical lens of this embodiment, please refer to the table below.

[0066] Table 2 (a) shows the surface type, radius of curvature, thickness and material of each lens of the optical lens of Example 2. The units of the radius of curvature and thickness are both millimeters (mm).

[0067] Table 2(a)

[0068]

[0069] Table 2(b) shows the surface aspheric coefficients of each lens of the optical lens of Example 2.

[0070] Table 2(b)

[0071] Face number 3 4 5 6 8 9 K -1.88E+00 2.48E+00 -9.69E+01 1.08E+01 -9.49E+01 -3.01E+00 A4 1.16E+01 2.80E+00 5.93E+01 1.07E+01 -2.73E+01 2.63E+01 A6 -9.33E+01 8.22E+02 -3.24E+03 -2.42E+03 4.60E+03 -4.61E+03 A8 4.88E+02 -2.69E+04 1.16E+05 3.09E+05 -2.70E+05 3.52E+05 A10 -1.69E+03 4.11E+05 -2.52E+06 -2.40E+07 -1.58E+07 -1.63E+07 A12 3.89E+03 -3.16E+06 3.17E+07 1.11E+09 3.39E+09 4.89E+08 A14 -5.87E+03 1.17E+07 -2.07E+08 -2.93E+10 -2.19E+11 -9.39E+09 A16 5.56E+03 -1.63E+07 4.76E+08 4.06E+11 7.06E+12 1.11E+11

[0072] In this embodiment, the specific parameters of the optical lens are shown in the following table:

[0073] Table 2(c)

[0074]

[0075] According to Table 2 (a) and Table 2 (b), the lens shape and various properties of the lens of the current embodiment are clearly displayed.

[0076] See also Figure 6 , is a schematic diagram of the optical arrangement of the fingerprint recognition optical lens of Example 2. It can be seen that the close arrangement of the lenses of the lens can achieve the smaller structural characteristics of the lens.

[0077] according to Figure 7 The astigmatism and field curvature curves in the figure clearly show that the maximum difference between the astigmatism S-line and T-line of the lens is below 0.2mm, and the maximum field curvature is below 0.2mm, indicating that the lens has a good ability to improve astigmatism and field curvature.

[0078] according to Figure 8 The distortion curve in the figure clearly shows that the maximum distortion of the optical lens is about 3%, indicating that the lens has a good ability to improve distortion.

[0079] according to Fig. 9 The optical modulation transfer function curve in the figure clearly shows that the lens has good resolving power.

[0080] Example 3

[0081] Fig.10 FIG. 2 shows a schematic diagram of the optical arrangement of the fingerprint recognition optical lens of Embodiment 3 of the present invention. Fig.10 As shown, the fingerprint recognition optical lens according to an exemplary embodiment of the present invention includes, in order from the object side to the image side along the optical axis: a glass plate, a first lens, a second lens, an aperture, a third lens, a filter, and an image plane.

[0082] For specific design parameters of the fingerprint recognition optical lens of this embodiment, please refer to the table below.

[0083] Table 3 (a) shows the surface type, radius of curvature, thickness and material of each lens of the optical lens of Example 3. The units of the radius of curvature and thickness are both millimeters (mm).

[0084] Table 3(a)

[0085]

[0086]

[0087] Table 3 (b) shows the surface aspheric coefficients of each lens of the optical lens of Example 3.

[0088] Table 3(b)

[0089] Face number 3 4 5 6 8 9 K -1.313E+00 -2.622E-01 -9.888E+01 1.134E+01 -9.900E+01 -2.191E+00 A4 7.457E+00 1.826E+00 1.049E+01 2.673E+01 -1.399E+01 3.449E-01 A6 -4.836E+01 3.259E+02 -4.593E+02 -3.669E+03 2.805E+03 -1.848E+02 A8 2.198E+02 -9.189E+03 1.279E+04 2.548E+05 -2.071E+05 8.583E+03 A10 -6.563E+02 1.271E+05 -2.589E+05 -1.040E+07 8.667E+06 -1.979E+05 A12 1.267E+03 -8.982E+05 3.351E+06 2.574E+08 -2.226E+08 2.748E+06 A14 -1.543E+03 3.089E+06 -2.613E+07 -3.799E+09 3.573E+09 -2.349E+07 A16 1.119E+03 -4.132E+06 1.118E+08 3.075E+10 -3.492E+10 1.183E+08

[0090] In this embodiment, the specific parameters of the optical lens are shown in the following table:

[0091] Table 3(c)

[0092]

[0093] According to Table 3 (a) and Table 3 (b), the shape of the lens and various properties of the lens of the current embodiment are clearly displayed.

[0094] See also Fig.10 , is a schematic diagram of the optical arrangement of the fingerprint recognition optical lens of Example 3. It can be seen that the close arrangement of the lenses of the lens can achieve the smaller structural characteristics of the lens.

[0095] according to Fig.11 The astigmatism and field curvature curves in the figure clearly show that the maximum difference between the astigmatism S-line and T-line of the lens is below 0.2mm, and the maximum field curvature is below 0.2mm, indicating that the lens has a good ability to improve astigmatism and field curvature.

[0096] according to Fig.12 The distortion curve in the figure clearly shows that the maximum distortion of the optical lens is about 2.5%, indicating that the lens has a good ability to improve distortion.

[0097] according to Fig.13 The optical modulation transfer function curve in the figure clearly shows that the lens has good resolving power.

[0098] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A fingerprint recognition optical lens, characterized in that: A glass plate, a first lens, a second lens, a third lens and a filter are sequentially arranged along the optical axis from the object side to the image side, and an aperture is arranged between the second lens and the third lens; The first lens has negative optical power, and the paraxial areas of the object side surface and the image side surface are both concave; The second lens has positive power, the paraxial area of ​​the object side surface is convex, and the paraxial area of ​​the image side surface is concave; The third lens has positive power, and the paraxial areas of the object side surface and the image side surface are both convex; The optical lens meets the following conditions: 3.438≤OBH / TTL<4 HFOV ≥ 135.9° Among them, TTL is the total length from the bottom of the cover to the image plane, OBH is the object height of the fingerprint recognition optical lens, and HFOV is the field of view of the fingerprint recognition optical lens.

2. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: 1 <F2 / F3<3.2 Among them, F2 is the focal length of the second lens, and F3 is the focal length of the third lens.

3. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: FNO≤1.5 Among them, FNO is the aperture value of the fingerprint recognition optical lens.

4. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: 0.7 <CT2 / CT1<1 Wherein, CT2 is the total length from the object side surface of the first lens to the image plane, and CT1 is the total length from the front surface of the glass plate to the object side surface of the first lens.

5. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: OBH>7.8 Among them, OBH is the object height of the optical lens.

6. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: ANG≤62° Here, ANG is the maximum value among the surface angles of the first lens, the second lens or the third lens.

7. The fingerprint recognition optical lens according to claim 1, characterized in that: The optical lens meets the following conditions: 1.0 <V2 / V3<3.0 Wherein, V2 is the Abbe number of the second lens, and V3 is the Abbe number of the third lens.

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