Ultrathin lens

Abstract

The utility model relates to the field of optical lenses, in particular to an ultra-thin lens, which sequentially comprises a diaphragm, a first lens, a second lens and a third lens from an object side to an image side along an optical axis. The first lens has positive focal power; the object side surface of the second lens in a paraxial region is a convex surface, and the image side surface of the second lens in the paraxial region is a concave surface; the third lens has positive focal power; the fourth lens has positive focal power; the fifth lens has negative focal power; the relational expression of TTL / ImgHlt is met; 1.07); tTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, and ImgH is half of the length of a diagonal line of an effective pixel area on the imaging surface. According to the ultrathin lens, the five lenses are adopted, and through cooperation of the focal power and the surface type of each lens, the center thickness of each lens, the axial distance between the lenses and the like, the optical lens has the advantages of miniaturization and high imaging quality, and is suitable for small portable electronic mobile equipment.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, in particular to an ultra-thin lens. Background Art

[0002] With the continuous development of science and technology, portable electronic devices such as smart phones and tablets are gradually moving towards lighter and thinner, with higher configurations and performance, which puts more and more stringent requirements on the lenses used in conjunction with them. Miniaturized photographic lenses with good imaging quality have become the mainstream in the current market.

[0003] However, it is difficult for current miniaturized photographic lenses to simultaneously meet the requirements of high pixel density and short overall length. Utility Model Content

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the utility model provides an ultra-thin lens, which is mainly composed of five lenses, and all of the five lenses adopt a plastic aspherical design. Through the reasonable design of the optical focal length and surface shape of the first lens to the fifth lens, and the coordination of the optical focal length, surface shape, center thickness of each lens and the axial spacing between each lens, it is ensured that the lens has a small volume and good imaging quality.

[0005] In order to achieve the above-mentioned purpose, the main technical solutions adopted by the utility model include:

[0006] An ultra-thin lens, which is composed of the following components from the object side to the image side along the optical axis:

[0007] Aperture;

[0008] a first lens having positive optical power;

[0009] a second lens having negative optical power, wherein the object side surface of the second lens in the paraxial region is convex and the image side surface is concave;

[0010] a third lens having positive refractive power;

[0011] a fourth lens having positive refractive power;

[0012] a fifth lens having negative optical power;

[0013] The lens satisfies the following relationship:

[0014] TTL / ImgH<1.07

[0015] Wherein, TTL is the distance from the object side of the first lens to the imaging plane on the optical axis, and ImgH is half of the diagonal length of the effective pixel area on the imaging plane.

[0016] By meeting the above conditions, the lens is miniaturized, easy to hide and convenient to carry.

[0017] Furthermore, the lens satisfies the following relationship:

[0018] DFOV>92°

[0019] Wherein, DFOV is the field of view of the lens.

[0020] By satisfying the above relationship, a larger lens field of view angle and a larger shooting field of view range are achieved.

[0021] Furthermore, the lens satisfies the following relationship:

[0022] 0.35 <CT 2 / CT 1 <0.5

[0023] Among them, CT 2 is the center thickness of the second lens on the optical axis, CT 1 is the center thickness of the first lens on the optical axis.

[0024] Satisfying the above relationship is beneficial to lens molding and manufacturing.

[0025] Furthermore, the lens satisfies the following relationship:

[0026] 0.9 <CT 4 / CT 5 <1

[0027] Among them, CT 4 is the center thickness of the fourth lens on the optical axis, CT 5 is the center thickness of the fifth lens on the optical axis.

[0028] Satisfying the above relationship is beneficial to lens molding and manufacturing.

[0029] Furthermore, the lens satisfies the following relationship:

[0030] 1<(R7+R8) / (R7-R8)<1.4

[0031] Wherein, R7 is the curvature radius of the object side of the fourth lens, and R8 is the curvature radius of the image side of the fourth lens.

[0032] By satisfying the above relationship, the shape of the fourth lens is restricted, which is beneficial to the performance improvement and the processing and production of the fourth lens.

[0033] Furthermore, the lens satisfies the following relationship:

[0034] 0.5<|F 5 | / F<0.7

[0035] Among them, F 5is the focal length of the fifth lens, and F is the focal length of the lens.

[0036] Through the effective coordination of lens focal lengths, the lens has the advantages of miniaturization and higher imaging quality.

[0037] The beneficial effects of the utility model are:

[0038] The utility model provides an ultra-thin lens. By rationally designing the optical power and surface shape of the first lens to the fifth lens, and coordinating the optical power, surface shape, center thickness of each lens and the axial distance between each lens, the lens has the advantages of ultra-thinness and high imaging quality, and is suitable for small portable electronic mobile devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0040] Figure 2 is an astigmatism field curvature curve diagram of Example 1 of the utility model;

[0041] Figure 3 is an optical distortion curve diagram of Example 1 of the utility model;

[0042] Figure 4 This is a graph of the MTF transfer function of Example 1 of the utility model;

[0043] Figure 5 This is a schematic diagram of the structure of Embodiment 2 of the present utility model;

[0044] Figure 6 is an astigmatism field curvature curve diagram of Example 2 of the utility model;

[0045] Figure 7 This is an optical distortion curve diagram of Example 2 of the utility model;

[0046] Figure 8 This is a graph of the MTF transfer function of Example 2 of the present utility model;

[0047] Fig. 9 This is a schematic diagram of the structure of Embodiment 3 of the present utility model;

[0048] Fig.10 is an astigmatism field curvature curve diagram of Example 3 of the utility model;

[0049] Fig.11 This is an optical distortion curve diagram of Example 3 of the utility model;

[0050] Fig.12 This is the MTF transfer function curve diagram of Example 3 of the utility model.

[0051] In the figure: 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, aperture; 7, filter. DETAILED DESCRIPTION

[0052] 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.

[0053] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0054] In this article, the surface of each lens closest to the object is called the object-side surface, and the surface of each lens closest to the imaging plane is called the image-side surface.

[0055] An ultra-thin lens provided in an embodiment of the utility model is composed of the following components in sequence from the object side to the image side along the optical axis:

[0056] Aperture 6;

[0057] A first lens 1 having positive refractive power;

[0058] a second lens 2 having negative optical power, wherein the object side surface of the second lens 2 in the paraxial region is convex, and the image side surface is concave;

[0059] a third lens 3 having positive refractive power;

[0060] a fourth lens 4 having positive refractive power;

[0061] a fifth lens 5 having negative optical power;

[0062] The lens satisfies the following relationship:

[0063] TTL / ImgH<1.07

[0064] Wherein, TTL is the distance from the object side of the first lens 1 to the imaging plane on the optical axis, and ImgH is half of the diagonal length of the effective pixel area on the imaging plane.

[0065] By meeting the above conditions, the lens is miniaturized, easy to hide and convenient to carry.

[0066] Specifically, the lens satisfies the following relationship:

[0067] DFOV>92°

[0068] Wherein, DFOV is the field of view of the lens.

[0069] By satisfying the above relationship, a larger lens field of view angle and a larger shooting field of view range are achieved.

[0070] Specifically, the lens satisfies the following relationship:

[0071] 0.35 <CT 2 / CT 1 <0.5

[0072] Among them, CT 2 is the center thickness of the second lens 2 on the optical axis, CT 1 is the center thickness of the first lens 1 on the optical axis.

[0073] Satisfying the above relationship is beneficial to lens molding and manufacturing.

[0074] Specifically, the lens satisfies the following relationship:

[0075] 0.9 <CT 4 / CT 5 <1

[0076] Among them, CT 4 is the center thickness of the fourth lens 4 on the optical axis, CT 5 is the center thickness of the fifth lens 5 on the optical axis.

[0077] Satisfying the above relationship is beneficial to lens molding and manufacturing.

[0078] Specifically, the lens satisfies the following relationship:

[0079] 1<(R7+R8) / (R7-R8)<1.4

[0080] Wherein, R7 is the curvature radius of the object side surface of the fourth lens 4, and R8 is the curvature radius of the image side surface of the fourth lens 4.

[0081] By satisfying the above relationship, the shape of the fourth lens 4 is restricted, which is beneficial to the performance improvement and the processing and production of the fourth lens 4.

[0082] Specifically, the lens satisfies the following relationship:

[0083] 0.5<|F 5 | / F<0.7

[0084] Among them, F 5 is the focal length of the fifth lens 5, and F is the focal length of the lens.

[0085] Through the effective coordination of lens focal lengths, the lens has the advantages of miniaturization and higher imaging quality.

[0086] The above-mentioned lens may further include a filter 7 for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface according to the specific needs of the embodiment. In the absence of specific requirements, the filter 7 or the protective glass may not be used.

[0087] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0088] Example 1

[0089] The present embodiment provides an ultra-thin lens, which is composed of an aperture 6, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5 and a filter 7 in sequence from the object side to the image side along the optical axis. The incident light passes through the above components in sequence and finally forms an image on the imaging surface. The first lens 1 has a positive refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The second lens 2 has a negative refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The third lens 3 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fourth lens 4 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fifth lens 5 has a negative refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a concave surface. The filter 7 is arranged between the fifth lens 5 and the imaging surface.

[0090] Table 1 shows the surface type, radius of curvature, thickness and material properties of each lens in Example 1. The units of the radius of curvature and thickness are both millimeters (mm).

[0091] Table 1 is a table of lens parameters of Example 1

[0092]

[0093] In this embodiment, the surface shape x of each aspheric lens can be defined by, but not limited to, the following aspheric surface formula:

[0094]

[0095] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; A iThe following table 2 shows the coefficients A of the higher order terms of the aspheric mirror surfaces S1-S10 that can be used in Example 1. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 , A 30 .

[0096] Table 2 shows the high-order coefficients of various aspherical mirror surfaces that can be used in Example 1.

[0097] Table 2 is a table of high-order coefficients of various aspherical mirror surfaces in Example 1

[0098] Surface serial number k <![CDATA[A 4 ]]> <![CDATA[A 6 ]]> <![CDATA[A 8 ]]> <![CDATA[A 10 ]]> 1 -4.922E-01 3.212E-03 -1.065E-03 -4.427E-04 -7.468E-05 2 -3.129E+00 -3.132E-02 1.431E-03 -4.662E-04 -2.578E-04 3 -1.228E+01 -5.675E-03 4.438E-03 -5.249E-04 -1.911E-04 4 1.612E+01 -5.428E-03 -3.966E-03 -3.790E-03 -1.249E-03 5 8.514E+00 -4.710E-02 1.215E-02 5.659E-03 2.218E-03 6 -9.185E+01 -1.532E-01 1.593E-02 1.620E-02 1.016E-02 7 -2.272E+01 -2.461E-01 -8.036E-02 1.191E-03 1.885E-02 8 -4.741E+00 2.650E-02 -3.026E-02 6.306E-03 1.386E-02 9 -1.724E+00 -6.885E-02 2.868E-01 -2.065E-01 9.432E-02 10 -2.109E+01 -1.184E+00 2.886E-01 2.438E-03 6.067E-02 Surface serial number <![CDATA[A 12 ]]> <![CDATA[A 14 ]]> <![CDATA[A 16 ]]> <![CDATA[A 18 ]]> <![CDATA[A 20 ]]> 1 -4.327E-05 3.820E-06 -3.465E-06 -2.113E-06 -3.143E-06 2 -1.331E-05 -4.458E-06 4.577E-06 -2.419E-07 -4.134E-06 3 -1.292E-06 4.951E-06 -2.543E-06 -4.731E-08 -3.366E-06 4 -1.344E-04 1.820E-04 2.085E-04 1.156E-04 3.707E-05 5 -3.381E-04 -4.616E-04 -2.307E-04 -7.481E-05 -8.316E-06 6 5.028E-03 2.145E-03 9.694E-04 2.235E-04 4.691E-05 7 1.327E-02 3.363E-03 -1.995E-03 -2.419E-03 -1.171E-03 8 -1.777E-03 -4.365E-03 7.855E-04 1.718E-03 -2.619E-04 9 -6.488E-02 1.839E-02 -7.514E-03 -1.001E-02 4.947E-03 10 1.716E-04 1.084E-02 1.306E-02 1.140E-02 -3.211E-04 Surface serial number <![CDATA[A 22 ]]> <![CDATA[A 24 ]]> <![CDATA[A 26 ]]> <![CDATA[A 28 ]]> <![CDATA[A 30 ]]> 1 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 2 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 3 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 4 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 5 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 6 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 7 -1.472E-04 2.098E-04 1.534E-04 5.349E-05 1.737E-05 8 -3.474E-04 0.000E+00 0.000E+00 0.000E+00 0.000E+00 9 -5.983E-04 -4.312E-03 1.403E-03 -2.177E-03 -8.495E-04 10 -5.089E-03 -5.884E-03 -1.788E-03 1.469E-04 4.243E-04

[0099] Table 3 below shows important parameters in Example 1.

[0100] Table 3 is a table of important parameters of Example 1.

[0101]

[0102] The specific lens structure of this embodiment is as follows Figure 1 As shown in Table 1-3 and Figure 1 The lens shape and various parameters of the lens of the current embodiment are shown.

[0103] Figure 2 The astigmatism and field curvature curve of this embodiment is shown, and it can be seen that the lens has a good ability to improve astigmatism and field curvature.

[0104] Figure 3 The optical distortion curve of this embodiment is shown. The maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0105] Figure 4 The MTF transfer function curve of this embodiment is shown. The MTF at the center field of view of 1 / 4 frequency is greater than 0.75, which has a high resolution.

[0106] Example 2

[0107] The present embodiment provides an ultra-thin lens, which is composed of an aperture 6, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5 and a filter 7 in sequence from the object side to the image side along the optical axis. The incident light passes through the above components in sequence and finally forms an image on the imaging surface. The first lens 1 has a positive refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The second lens 2 has a negative refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The third lens 3 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fourth lens 4 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fifth lens 5 has a negative refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a concave surface. The filter 7 is arranged between the fifth lens 5 and the imaging surface.

[0108] Table 4 shows the surface type, radius of curvature, thickness and material properties of each lens in Example 2. The units of the radius of curvature and thickness are both millimeters (mm).

[0109] Table 4 is a table of lens parameters of Example 2

[0110]

[0111] In this embodiment, each aspheric surface shape can be defined by the formula (1) in the above embodiment 1. Table 5 below shows the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30 of each aspheric mirror surface S1-S10 that can be used in embodiment 2.

[0112] Table 5 is a table of high-order coefficients of various aspherical mirror surfaces in Example 2

[0113]

[0114]

[0115] Table 6 below shows important parameters in Example 2.

[0116] Table 6 is a table of important parameters of Example 2.

[0117]

[0118] The specific lens structure of this embodiment is as follows Figure 5 Table 4-6 and Figure 5 The lens shape and various parameters of the lens of the current embodiment are shown.

[0119] Figure 6 The astigmatism and field curvature curve of this embodiment is shown, and it can be seen that the lens has a good ability to improve astigmatism and field curvature.

[0120] Figure 7 The optical distortion curve of this embodiment is shown. The maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0121] Figure 8 The MTF transfer function curve of this embodiment is shown. The MTF at the center field of view of 1 / 4 frequency is greater than 0.75, which has a high resolution.

[0122] Example 3

[0123] The present embodiment provides an ultra-thin lens, which is composed of an aperture 6, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5 and a filter 7 in sequence from the object side to the image side along the optical axis. The incident light passes through the above components in sequence and finally forms an image on the imaging surface. The first lens 1 has a positive refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The second lens 2 has a negative refractive power, and the object side surface of its paraxial region is a convex surface, and the image side surface is a concave surface. The third lens 3 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fourth lens 4 has a positive refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a convex surface. The fifth lens 5 has a negative refractive power, and the object side surface of its paraxial region is a concave surface, and the image side surface is a concave surface. The filter 7 is arranged between the fifth lens 5 and the imaging surface.

[0124] Table 7 shows the surface type, radius of curvature, thickness and material properties of each lens in Example 3. The units of the radius of curvature and thickness are both millimeters (mm).

[0125] Table 7 is a table of lens parameters of Example 3

[0126]

[0127] In this embodiment, the surface type of each aspherical surface can be defined by the formula (1) in the above embodiment 1. Table 8 below shows the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of each aspherical mirror surface S1-S10 that can be used in embodiment 3.

[0128] Table 8 is a table of high-order coefficients of various aspherical mirror surfaces in Example 3

[0129]

[0130]

[0131] Table 9 below shows important parameters in Example 3.

[0132] Table 9 is a table of important parameters of Example 3.

[0133]

[0134] The specific lens structure of this embodiment is as follows Fig. 9 Table 7-9 and Fig. 9 The lens shape and various parameters of the lens of the current embodiment are shown.

[0135] Fig.10 The astigmatism and field curvature curve of this embodiment is shown, and it can be seen that the lens has a good ability to improve astigmatism and field curvature.

[0136] Fig.11 The optical distortion curve of this embodiment is shown. The maximum distortion of the lens is less than 2%, indicating that the lens has a good ability to improve distortion.

[0137] Fig.12 The MTF transfer function curve of this embodiment is shown. The MTF at the center field of view of 1 / 4 frequency is greater than 0.75, which has a high resolution.

[0138] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An ultra-thin lens, characterized in that: Along the optical axis from the object side to the image side, it is composed of: Aperture; a first lens having positive optical power; a second lens having negative optical power, wherein the object side surface of the second lens in the paraxial region is convex and the image side surface is concave; a third lens having positive refractive power; a fourth lens having positive refractive power; a fifth lens having negative optical power; The lens satisfies the following relationship: TTL / ImgH<1.07 Wherein, TTL is the distance from the object side of the first lens to the imaging plane on the optical axis, and ImgH is half of the diagonal length of the effective pixel area on the imaging plane.

2. An ultra-thin lens as claimed in claim 1, characterized in that: The lens satisfies the following relationship: DFOV>92° Wherein, DFOV is the field of view of the lens.

3. An ultra-thin lens as claimed in claim 1, characterized in that: The lens satisfies the following relationship: 0.35 <CT2 / CT1<0.5 Wherein, CT2 is the center thickness of the second lens on the optical axis, and CT1 is the center thickness of the first lens on the optical axis.

4. The ultra-thin lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.9 <CT4 / CT5<1 Wherein, CT4 is the center thickness of the fourth lens on the optical axis, and CT5 is the center thickness of the fifth lens on the optical axis.

5. The ultra-thin lens according to claim 1, characterized in that: The lens satisfies the following relationship: 1<(R7+R8) / (R7-R8)<1.4 Wherein, R7 is the curvature radius of the object side of the fourth lens, and R8 is the curvature radius of the image side of the fourth lens.

6. The ultra-thin lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.5<|F5| / F<0.7 Among them, F5 is the focal length of the fifth lens, and F is the focal length of the lens.

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