Optical system, camera module and terminal equipment

Abstract

The invention provides an optical system, a camera module and terminal equipment, and belongs to the technical field of optical imaging. The optical system comprises a prism and a lens assembly. The prism comprises an image side surface; the lens assembly is located on the side where the image side is located, and a first optical axis of the lens assembly coincides with a second optical axis of the image side; the size of the lens assembly in at least one direction perpendicular to the first optical axis is L1, the size of the prism in the same direction is L2, and L1 is smaller than or equal to L2. The optical system comprises the prism and the lens assembly, and the size L1 of the lens assembly in at least one direction perpendicular to the first optical axis is smaller than or equal to the size L2 of the prism in the same direction, so that the size of the whole optical system in the direction is smaller than or equal to L2, and the size of the optical system in the direction is small. And the development requirements of miniaturization and micromation of the camera module can be met.

Description

Technical Field

[0001] The present disclosure relates to the field of optical imaging technology, and in particular to an optical system, a camera module and a terminal device. Background Art

[0002] Nowadays, portable terminal devices have gradually become smaller. At the same time, all brands have chosen to upgrade the shooting performance of terminal devices to enhance the competitiveness of their products.

[0003] At present, the size of photosensitive elements in camera modules used in terminal devices continues to increase, and at the same time, the requirements for imaging quality are getting higher and higher. However, the size of prisms and optical lenses in the lens part cannot be compressed indefinitely, which is not conducive to the miniaturization and ultra-thin development of camera modules. Summary of the invention

[0004] The present disclosure provides an optical system, a camera module and a terminal device, which can solve the problems existing in the related technologies.

[0005] The technical solution is as follows:

[0006] In one aspect, an optical system is provided, the optical system comprising: a prism and a lens assembly;

[0007] The prism includes an image side surface;

[0008] The lens assembly is located on the side where the image side is located, and the first optical axis of the lens assembly is arranged to coincide with the second optical axis of the image side;

[0009] The dimension of the lens assembly along at least one direction perpendicular to the first optical axis is L1, and the dimension of the prism along the same direction is L2, wherein L1≤L2.

[0010] In some embodiments, the lens assembly includes at least two lenses, and the at least two lenses are arranged sequentially along the first optical axis;

[0011] The focal length of the lens farthest from the image side among the at least two lenses is fi, and the equivalent side length of the orthographic projection of the image side along the second optical axis is Y', where -2.5 <fi / Y'<-0.4。

[0012] In some embodiments, the central curvature radius of the surface of the lens closest to the image side surface among the at least two lenses and facing the image side surface is R1, wherein 0 <R1 / Y'<12。

[0013] In some embodiments, the prism further includes an object side surface, and a third optical axis of the object side surface is perpendicular to the first optical axis;

[0014] The dimension of the lens assembly along the direction where the third optical axis is located is L1, and the dimension of the prism along the direction where the third optical axis is located is L2.

[0015] In some embodiments, the lens assembly includes at least two lenses, and the at least two lenses are arranged in sequence along the first optical axis, wherein the outer circumference size of at least one of the lenses is L3, wherein L3>L2;

[0016] The lens having an outer circle size of L3 is provided with a trimming portion on at least one side along the direction of the third optical axis, so that the size of the lens along the direction of the third optical axis is shortened to L1.

[0017] In some embodiments, the field of view of the lens assembly is greater than or equal to 55°.

[0018] In some embodiments, the combined focal length of the lens assembly is f, and the diagonal size of the imaging sensor arranged on the light-exiting side of the lens assembly is IH, wherein 0.5≤f / IH≤0.9.

[0019] In some embodiments, the optical system further comprises an aperture element, wherein the aperture element is located between the image side surface and the lens assembly, the aperture element has an annular structure, the clear aperture of the aperture element is D, and the combined focal length of the lens assembly is f, wherein 1.0<f / D<1.95.

[0020] In some embodiments, the distance between the aperture element and the image side surface is T1, where 0.02≤T1≤2.0;

[0021] and / or,

[0022] The distance between the aperture element and the lens assembly is T2, where 0 <T2≤1。

[0023] On the other hand, a camera module is provided, the camera module comprising the optical system described in the present disclosure, and a photosensitive element;

[0024] The photosensitive element is located at the light-emitting side of the lens assembly, and the light sequentially passes through the object side of the prism, the image side of the prism, and the lens assembly to irradiate the photosensitive element.

[0025] On the other hand, a terminal device is provided, the terminal device comprising: the camera module described in the present disclosure, and a housing module;

[0026] The shell module is provided with a light-transmitting area, and the light-transmitting area corresponds to the object side of the prism. The light passes through the light-transmitting area, the object side of the prism, the image side of the prism, and the lens assembly in sequence to irradiate the photosensitive element.

[0027] The beneficial effects of the technical solution provided by the present disclosure include at least:

[0028] The optical system disclosed in the present invention includes a prism and a lens assembly. The dimension L1 of the lens assembly along at least one direction perpendicular to the first optical axis is less than or equal to the dimension L2 of the prism along the same direction, so that the dimension of the entire optical system along this direction is less than or equal to L2. The dimension of the optical system along this direction is small, which can meet the miniaturization and micro-miniaturization development needs of the camera module. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 is a schematic structural diagram of an optical system provided by an embodiment of the present disclosure;

[0031] Figure 2 is a schematic diagram of the structure of a lens provided by an embodiment of the present disclosure;

[0032] Figure 3 is a schematic diagram of the field of view angle of the optical system provided by an embodiment of the present disclosure;

[0033] Figure 4 is a schematic structural diagram of an optical system provided by another embodiment of the present disclosure;

[0034] Figure 5 is a schematic diagram of an aperture element provided by an embodiment of the present disclosure in a first position;

[0035] Figure 6 is a schematic diagram of an aperture element provided by an embodiment of the present disclosure in a second position;

[0036] Figure 7 is a structural schematic diagram of an optical system provided by yet another embodiment of the present disclosure;

[0037] Figure 8 yes Figure 7 A graph showing aberration characteristics of the optical system shown;

[0038] Fig. 9 is a structural schematic diagram of an optical system provided by yet another embodiment of the present disclosure;

[0039] Fig.10 yes Fig. 9 A graph showing aberration characteristics of the optical system shown;

[0040] Fig.11 is a structural schematic diagram of an optical system provided by yet another embodiment of the present disclosure;

[0041] Fig.12 yes Fig.11 A graph showing aberration characteristics of the optical system shown;

[0042] Fig.13 It is a structural schematic diagram of a camera module and a terminal device provided in an embodiment of the present disclosure.

[0043] The reference numerals in the figures represent respectively:

[0044] 1. Prism;

[0045] 11. Image side surface; 110. Second optical axis; 12. Object side surface; 120. Third optical axis; 13. Reflection surface;

[0046] 2. Lens assembly;

[0047] 20, first optical axis; 21, lens; 210, trimming portion; 22, aperture element; 23, filter element;

[0048] 211, first lens; 212, second lens; 213, third lens; 214, fourth lens; 215, fifth lens; 216, sixth lens; 217, seventh lens; 218, eighth lens;

[0049] 3. Photosensitive element;

[0050] 4. Shell module;

[0051] 41. Light-transmitting area. DETAILED DESCRIPTION

[0052] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0053] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positional relationships based on the attached Figure 1The orientation or positional relationship shown is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present disclosure.

[0054] As the size of the camera system's photosensitive elements continues to increase, and the requirements for image quality are getting higher and higher, the limitations of height space on imaging have become particularly prominent. Therefore, a series of folded optical path optical systems have been developed, such as periscope lenses.

[0055] The periscope lens is a lens that uses a prism (or mirror) to reflect light at a certain angle, thus solving the biggest challenge of mobile phone camera optics - lens length. In order to arrange more glass (or plastic) elements in a limited height space, the lens is flipped and placed flat inside the camera instead of extending it, thus alleviating the space requirement of the lens in the thickness direction of the smartphone.

[0056] However, the periscope lens in the related art is still large in size and cannot achieve the optimal configuration of height space and various optical parameters.

[0057] Therefore, the present disclosure provides an optical system, so that the size of the entire optical system along a certain direction is small, and the direction may be the height direction of the optical system, thereby meeting the miniaturization and micro-miniaturization development needs of the camera module.

[0058] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0059] On the one hand, combined with Figure 1 As shown, this embodiment provides an optical system, which includes: a prism 1 and a lens assembly 2.

[0060] The prism 1 includes an image side surface 11; the lens assembly 2 is located on the side where the image side surface 11 is located, and the first optical axis 20 of the lens assembly 2 is arranged to coincide with the second optical axis 110 of the image side surface 11; the dimension of the lens assembly 2 along at least one direction perpendicular to the first optical axis 20 is L1, and the dimension of the prism 1 along the same direction is L2, wherein L1≤L2.

[0061] The optical system of this embodiment includes a prism 1 and a lens assembly 2. The dimension L1 of the lens assembly 2 along at least one direction perpendicular to the first optical axis 20 is less than or equal to the dimension L2 of the prism 1 along the same direction, so that the dimension of the entire optical system along this direction is less than or equal to L2. The dimension of the optical system along this direction is small, which can meet the miniaturization and micro-miniaturization development needs of the camera module.

[0062] Exemplarily, the prism 1 further includes an object side surface 12, and light can be transmitted into the prism 1 from the object side surface 12, emitted from the image side surface 11, enter the lens assembly 2, and finally illuminate the photosensitive element 3 on the other side of the lens assembly 2. In this process, the prism 1 is used to change the propagation direction of the light entering through the object side surface 12.

[0063] In some possible implementations, the direction of the dimension L1 is the height direction of the lens assembly 2 , so that the dimension of the optical system along the height direction is small, which is conducive to the miniaturization and micro-miniaturization of the camera module.

[0064] In some possible implementations, the refractive index n1 of the prism 1 satisfies n1 ≥ 1.7.

[0065] The refractive index n1 of prism 1 is negatively correlated with the size of prism 1 in the thickness direction of the terminal. When the refractive index n1 of prism 1 is larger, the refractive ability of prism 1 is stronger, and the height of prism 1 in the lens is smaller and can meet the light refraction needs. When the refractive index n1 of prism 1 is smaller, the refractive ability of prism 1 is weaker, and the height of prism 1 in the lens needs to meet the larger size to meet the light refraction needs.

[0066] Optionally, the prism 1 may be made of a combination of multiple materials.

[0067] Exemplarily, the prism 1 may include a body and a folding patch. The body may be made of a material with a relatively small refractive index, and the folding patch may be made of a material with a relatively large refractive index.

[0068] In some optional implementations, the fold-enhancing patch is attached to the side wall of the main body, and the fold-enhancing patch and the side wall of the main body can be connected by bonding.

[0069] The material constituting the prism 1 may be optical glass, or quartz glass, etc. Alternatively, it may be resin, alkali metal halide, etc. The material of the prism 1 is not limited in the embodiment of the present disclosure.

[0070] In some other possible implementations, refer to Figure 4 As shown, the prism 1 also includes a reflective surface 13, which intersects with the second optical axis 110 of the image side surface 11 and the third optical axis 120 of the object side surface 12 respectively. The light transmitted from the object side surface 12 along the third optical axis 120 can be totally reflected on the reflective surface 13, and then transmitted from the image side surface 11 along the second optical axis 110, thereby realizing a change in the propagation direction of the light.

[0071] For example, Figure 4As shown, the prism 1 can be a triangular prism structure, the top and bottom surfaces of the triangular prism structure can both be isosceles right triangles, and are parallel to each other, and the three side walls are perpendicular to the top surface. The side walls where the two right-angled sides of the top surface are located are the image side surface 11 and the object side surface 12 of the prism 1, respectively, and the side where the hypotenuse of the top surface is located is the reflection surface 13 of the prism 1.

[0072] Combination Figure 1 As shown, in some embodiments, the lens assembly 2 includes at least two lenses 21, and the at least two lenses 21 are arranged in sequence along the first optical axis 20; the focal length of the lens 21 farthest from the image side surface 11 among the at least two lenses 21 is fi, and the equivalent side length of the orthographic projection of the image side surface 11 along the second optical axis 110 is Y', where -2.5 <fi / Y'<-0.4。

[0073] When the ratio of the focal length fi of the lens 21 farthest from the image side surface 11 to the equivalent side length Y' of the image side surface 11 satisfies the above value range, the lens assembly 2 of this embodiment can have the advantages of both height size and optical effect.

[0074] Exemplarily, the value of fi / Y' is, for example, -2.4, -2.2, -2.0, -1.5, -1.2, -1.0, -0.8, -0.6, -0.5, and the like.

[0075] As another example, the number of lenses 21 of the lens assembly 2 is, for example, two, three, four, and so on.

[0076] Focal length is one of the characteristics of a lens. It refers to the distance between the point where the lens converges parallel light and the center of the lens. The size of the focal length determines the imaging ability of the lens. The smaller the focal length, the stronger the imaging ability, and the ability to focus light onto a smaller point. The size of the focal length also determines the magnification of the lens. The smaller the focal length, the greater the magnification.

[0077] The focal length of a lens is determined by the shape and refractive index of the lens.

[0078] Optionally, the lens 21 farthest from the image side surface 11 is at least one of a convex lens, a biconvex lens, a concave lens and a biconcave lens.

[0079] Among them, for a convex lens, the focal length depends on the radius of curvature of the lens. The smaller the radius of curvature, the smaller the focal length. For a double convex lens, the focal length depends on the geometric mean of the two radii of curvature. For a concave lens, the focal length depends on the radius of curvature of the lens. The larger the radius of curvature, the smaller the focal length. For a double concave lens, the focal length depends on the geometric mean of the two radii of curvature. In addition, the refractive index of the lens will also affect the size of the focal length. The refractive index is a measure of the medium's ability to refract light. Lenses of different materials have different refractive indices. The larger the refractive index, the smaller the focal length.

[0080] For each lens 21 in the lens assembly 2, the mirror surface close to the prism 1 is the object side of the lens 21, and the mirror surface away from the prism 1 is the image side of the lens 21. For any lens 21, both the object side and the image side of the lens 21 can be aspherical surfaces, and the surface shape of the aspherical surface can be defined by the following formula:

[0081]

[0082] Where z represents the depth of the aspheric surface, r represents the distance between a specific point on the aspheric surface and the optical axis of the prism, k represents the cone coefficient, and u = r / r n , r n is the normalized curvature, a m represents the mth order aspheric coefficient, Q m represents an m-th order polynomial.

[0083] In this way, using a polynomial to represent the aspheric surface shape can make the object side surface shape and the image side surface shape of the lens more stable, less likely to have mutation points, and less likely to cause abnormal refraction or reflection when light is projected through the lens.

[0084] In some possible implementations, the equivalent side length of the orthographic projection of the image side surface 11 of the prism 1 along the second optical axis 110 and the equivalent side length of the orthographic projection of the object side surface 12 of the prism 1 along the third optical axis 120 are equal and are both Y', which can satisfy 0.74Y≤Y'≤0.88Y.

[0085] When the prism 1 is a triangular prism with an isosceles right triangle top surface, and the object side surface 12 of the prism 1 is parallel to the first optical axis 20 of the lens assembly 2, the two equivalent sides of the prism 1 are both the lengths of the right-angled sides of the triangular prism top surface.

[0086] When the object side surface 12 and the image side surface 11 of the prism 1 can both be curved surfaces,

[0087]

[0088] In this embodiment, taking the prism 1 as a triangular prism whose top surface is an isosceles right triangle as an example (hereinafter taking the prism 1 as a triangular prism whose top surface is an isosceles right triangle as an example), the length of the right-angled side of the top surface of the prism 1 is related to the optical factor Q of the lens, the refractive index n1 of the prism 1, the distance T between the lens assembly 2 and the image side surface 11, the body diagonal H of the photosensitive element 3 and the aperture coefficient F of the lens, and the preset value Y of the length of the right-angled side of the top surface of the prism 1 can be determined by the above formula.

[0089] According to the experimental data results, when the right-angle side length of the top surface of the prism 1 (i.e., the equivalent side length Y') and the preset value Y satisfy the relationship 0.74Y≤Y'≤0.88Y, the imaging quality of the optical system meets the requirements and at the same time can greatly reduce the size of the optical system in the height direction to adapt to the miniaturization trend of portable terminals.

[0090] Combination Figure 1 As shown, in some embodiments, the central curvature radius of the surface of the lens 21 closest to the image side surface 11 of the at least two lenses 21 facing the image side surface 11 is R1, where 0 <R1 / Y'<12。

[0091] When the ratio of the central curvature radius R1 of the surface of the lens 21 closest to the image side surface 11 facing the image side surface 11 to the equivalent side length Y' of the image side surface 11 satisfies the above value range, the lens assembly 2 of this embodiment can have the advantages of both height size and optical effect.

[0092] Exemplarily, the value of R1 / Y' is, for example, 0.1, 0.5, 1, 3, 4, 6, 8, 10, 12, etc.

[0093] Optionally, the lens 21 closest to the image side surface 11 is at least one of a convex lens, a biconvex lens, a concave lens and a biconcave lens.

[0094] Combination Figure 1 , 2 As shown, in some embodiments, the prism 1 also includes an object side surface 12, and the third optical axis 120 of the object side surface 12 is perpendicular to the first optical axis 20; the dimension of the lens assembly 2 along the direction of the third optical axis 120 is L1, and the dimension of the prism 1 along the direction of the third optical axis 120 is L2.

[0095] Through the above arrangement, the light along the third optical axis 120 can be transmitted into the prism 1 from the object side surface 12, emitted from the image side surface 11, enter the lens assembly 2 along the first optical axis 20, and finally illuminate the photosensitive element 3 on the other side of the lens assembly 2. In this process, the prism 1 is used to change the propagation direction of the light from the third optical axis 120 to the first optical axis 20.

[0096] The dimension of the lens assembly 2 along the direction of the third optical axis 120 is L1, which is conducive to reducing the dimension of the lens assembly 2 along this direction, reducing the height of the lens assembly 2 along the direction of the third optical axis 120, and thus optimizing the height of the camera module.

[0097] Combination Figure 1 , 2As shown, in some embodiments, the lens assembly 2 includes at least two lenses 21, and the at least two lenses 21 are arranged in sequence along the first optical axis 20, wherein the outer circumferential dimension of at least one lens 21 is L3, wherein L3>L2; the lens 21 with an outer circumferential dimension of L3 is provided with a cutting portion 210 along at least one side edge in the direction of the third optical axis 120, so that the dimension of the lens 21 along the direction of the third optical axis 120 is shortened to L1.

[0098] Normally, the outer circumferential dimensions of the lenses 21 in the lens assembly 2 are not exactly the same, with some lenses 21 having larger outer circumferential dimensions and some lenses 21 having smaller outer circumferential dimensions. Therefore, if the size of the larger lenses 21 can be limited, the height of the optical system can be effectively reduced.

[0099] In this embodiment, for a lens 21 having an outer circumferential size L3 which is larger than a size L2 of the prism 1 , a trimming portion 210 is arranged on at least one side of the lens 21 along the direction of the third optical axis 120 , so that the size of the lens 21 in the direction of the third optical axis 120 is reduced.

[0100] Combination Figure 3 As shown, in some embodiments, the field of view of the lens assembly 2 is greater than or equal to 55°.

[0101] In this embodiment, the field of view of the lens assembly 2 is greater than or equal to 55°, and the corresponding field of view of the light that can be received by the photosensitive element 3 is greater than or equal to 55°. Therefore, the optical system using this embodiment can have a larger field of view, improving the user's experience of using the electronic device.

[0102] Combination Figure 3 As shown, in some embodiments, the combined focal length of the lens assembly 2 is f, and the diagonal size of the imaging sensor (or photosensitive element) arranged on the light-emitting side of the lens assembly 2 is IH, where 0.5≤f / IH≤0.9.

[0103] When the ratio of the combined focal length f of the lens assembly 2 and the diagonal size IH of the photosensitive element 3 satisfies the above-mentioned range of values, the field of view angle range of the optical system is approximately 58°-90°. Compared with the conventional wide-angle lens with a field of view angle range of approximately 70°-90°, this optical system has a larger field of view angle range.

[0104] The photosensitive element 3 is a component that converts light into an image.

[0105] The photosensitive element 3 has a rectangular plate-shaped structure, and the diagonal length of the rectangular plate-shaped structure is IH.

[0106] For the camera module of the optical system composed of the integrated prism 1, the lens assembly 2 and the photosensitive element 3, the optical factor Q satisfies 0.5≤Q≤0.9. The optical factor Q is the ratio of the focal length f of the lens assembly 2 to the diagonal length IH of the photosensitive element 3.

[0107] like Figure 3 As shown, the combined focal length of the lens assembly 2 is f, and the diagonal size of the photosensitive element 3 is IH. According to the trigonometric function relationship, if the field angle is α, then 0.5H / f=tan(α / 2), and according to the inverse tangent formula, α=2arctan(1 / (2Q)).

[0108] In this embodiment, the optical factor Q can measure the field of view of the optical system. When the optical factor Q of the camera module satisfies 0.5≤Q≤0.9, the field of view of the optical system ranges from about 58° to 90°, having a larger field of view range.

[0109] In some possible examples, technicians can adjust the optical factor Q of the camera module according to product requirements, and the field of view of the optical system changes accordingly. After adjustment, the field of view of the lens can be greater than or equal to 55°.

[0110] Combination Figure 4 As shown, in some embodiments, the optical system further includes an aperture element 22, which is located between the image side surface 11 and the lens assembly 2, and has an annular structure. The aperture of the aperture element 22 is D, and the combined focal length of the lens assembly 2 is f, wherein 1.0<f / D<1.95.

[0111] The ratio of the combined focal length f of the lens assembly 2 to the clear aperture D of the aperture element 22 may also be referred to as the aperture coefficient F, that is, the aperture coefficient F satisfies 1.0<F<1.95.

[0112] In this embodiment, when the relative positions of the lens assembly 2 and the aperture element 22 remain unchanged, the larger the aperture D of the aperture element 22, the larger the size of the corresponding prism 1 in the thickness direction of the terminal device, the larger the amount of light entering the photosensitive element 3 through the aperture element 22, and the better the imaging quality. Correspondingly, when the relative positions of the lens assembly 2 and the aperture element 22 remain unchanged, the smaller the aperture D of the aperture element 22, the smaller the size of the corresponding prism 1 in the thickness direction of the terminal, the smaller the amount of light entering the photosensitive element 3 through the aperture element 22, and the poorer the imaging quality. Based on this, technicians can set the aperture coefficient of the optical system according to actual needs to balance the imaging quality of the optical system and the size of the optical system in the thickness direction of the terminal.

[0113] According to the experimental data results, when the aperture coefficient F satisfies 1.0<F<1.95, the imaging quality of the camera module using this optical system meets the requirements, and at the same time can greatly reduce the size of the optical system in the terminal thickness direction to adapt to the miniaturization trend of portable terminals.

[0114] Exemplarily, the actual value of the aperture factor F may be 1.61.

[0115] When the distance between the photosensitive element 3 and the prism 1 and the aperture D of the aperture element 22 remain unchanged, Figure 5 and Figure 6 ,in Figure 5 The aperture element 22 is shown to be arranged between the image side surface 11 of the prism 1 and the lens assembly 2, Figure 6 It is shown that the aperture element 22 is arranged between the lens assembly 2 and the light-sensing element 3 .

[0116] It can be seen from the figure that compared with Figure 5 As shown, Figure 6 In the solution shown in which the aperture element 22 is arranged between the lens assembly 2 and the photosensitive element 3, the light needs to pass through the lens assembly 2 in a larger area, which requires the lens assembly 2 to have a larger size, that is, the height of the lens assembly 2 is larger, and the size of the optical system is larger. Figure 5 In the solution shown, the aperture element 22 is arranged between the image side surface 11 of the prism 1 and the lens assembly 2. The range of the light after being converged by the aperture element 22 is smaller, and it will pass through the lens assembly 2 in a smaller area. At the same time, the required image side surface 11 of the prism 1 is also smaller. Therefore, the arrangement of the aperture element 22 between the prism 1 and the lens assembly 2 is more conducive to reducing the size of the optical system. In addition, it can be seen that when the distance from the photosensitive element 3 to the prism 1 and the aperture D of the aperture element 22 are equal, the closer the aperture element 22 is to the image side surface 11 of the prism 1, the more conducive it is to reducing the size of the prism 1 and the lens assembly 2.

[0117] Combination Figure 4 As shown, in some embodiments, the distance between the aperture element 22 and the image side surface 11 is T1, wherein 0.02mm≤T1≤2.0mm; when the distance T1 between the aperture element 22 and the image side surface 11 of the prism 1 satisfies the above-mentioned value range, the imaging quality of the camera module using the optical system meets the requirements, and at the same time, the size of the optical system in the terminal thickness direction can be greatly reduced to adapt to the miniaturization trend of portable terminals.

[0118] Exemplarily, the value of the distance T1 between the diaphragm element 22 and the image side 11 of the prism 1, for example, is 0.02 mm, 0.04 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, and so on.

[0119] As shown in combination with Figure 4 In some embodiments, the distance between the diaphragm element 22 and the lens assembly 2 is T2, where 0 < T2 ≤ 1 mm, with reference to the surface of the lens 21 closest to the diaphragm element 22 in the lens assembly 2 facing the image side 11 of the prism 1. When the distance T2 between the diaphragm element 22 and the lens assembly 2 satisfies the above value range, the imaging quality of the camera module applying this optical system meets the requirements, and at the same time, the size of the optical system in the thickness direction of the terminal can be significantly reduced to adapt to the miniaturization trend of portable terminals.

[0120] Exemplarily, the value of the distance T2 between the diaphragm element 22 and the lens assembly 2, for example, is 0.01 mm, 0.02 mm, 0.04 mm, 0.06 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, and so on.

[0121] As shown in reference to Fig.13 The mirror surface of the lens 21 closest to the prism 1 in the lens assembly 2 facing the prism 1 is a convex mirror surface, and the diaphragm element 22 is sleeved on the outer ring of the convex mirror surface of the lens 21, so that the value of the distance T2 between the diaphragm element 22 and the lens assembly 2 can be [-1 mm, 0]. In this way, the size of the optical system in the direction along the first optical axis 20 can be further reduced.

[0122] As shown in combination with Figure 7 、 9 In some embodiments, the optical system further includes a filter element 23, and the filter element 23 is located between the photosensitive element 3 and the lens assembly 2.

[0123] The filter element 23 has a thin plate-like structure. The filter element 23 is used to filter infrared light in the light passing through the lens assembly 2 and prevent the infrared light from entering the photosensitive element 3 to improve the imaging quality of the optical system.

[0124] The material of the filter element 23 can be glass, such as colored glass, or can be plastic. The embodiments of the present disclosure do not limit the material of the filter element 23.

[0125] As shown in combination with Figure 7 、 9As shown, in some embodiments, the lens assembly 2 includes a first lens 211, a second lens 212, a third lens 213, a fourth lens 214, a fifth lens 215, a sixth lens 216, a seventh lens 217 and an eighth lens 218 arranged in sequence along the first optical axis 20, wherein the first lens 211 is closest to the image side surface 11 of the prism 1, the eighth lens 218 is farthest from the image side surface 11 of the prism 1, and the photosensitive element 3 is arranged on the light emitting side of the eighth lens 218.

[0126] The refractive index of the first lens 211 may be n2, and the refractive index n1 of the prism 1 and the refractive index n2 of the first lens 211 satisfy 0.83<(n1 / n2)<1.7. In this way, the height of the prism 1 and the thickness of the first lens 211 can be reduced, thereby reducing the size of the optical system.

[0127] In example (1), the semi-diagonal size of the photosensitive element 3 is 8.166 mm; the right-angle side length of the prism 1 is 12 mm; the EFL (Effective Focal Length) of the optical system is 10.75 mm, the FOV (Field of View) is 73°, the aperture coefficient is 1.69, and the CRA (Confocal Laser Scanning Microscope) is 35; the distance TTL between the aperture element 22 and the photosensitive element 3 is 13.567 mm, and the distance T2 between the aperture element 22 and the first lens 211 is -1.19525 mm.

[0128] The optical characteristics of each element of the optical system are shown in Table 1 below, and the optical characteristics include the radius of curvature R, the thickness of the element or the distance d from the next element, the refractive index nd, and the Abbe number (dispersion coefficient) vd.

[0129] Table 1

[0130]

[0131] Tables 2 and 3 below show the aspheric surface coefficients of the 16 surfaces included in the first lens 211 to the eighth lens 218. The first lens 211 to the eighth lens 218 have a total of 8 lens object sides (surfaces facing the prism) and 8 lens image sides (surfaces facing the photosensitive element), and these 8 lens object sides and 8 lens image sides are all aspheric surfaces.

[0132] Table 2

[0133]

[0134]

[0135] Table 3

[0136] Face number A7 A8 A9 A10 A11 R1 -0.00244 -0.00097 -0.00039 -0.00016 -4.8E-05 R2 -0.00089 0.000561 2.45E-05 0.000185 1.416E-05 R3 0.001876 0.000429 0.000387 0.000147 5.128E-05 R4 0.000674 0.000348 0.000148 6.83E-05 5.104E-05 R5 0.000147 0.000121 3.06E-05 2.74E-05 -9.56E-07 R6 2.6E-05 2.82E-05 -7.5E-06 1.27E-05 -3.53E-07 R7 0.000177 3.74E-05 1.54E-05 6.02E-06 7.956E-06 R8 -4.1E-05 -4.3E-05 -4E-06 -2.9E-06 9.236E-07 R9 8.2E-06 6.43E-05 1.5E-05 1.69E-05 3.8E-06 R10 0.001101 0.000493 -4.6E-05 6.14E-05 -1.14E-05 R11 -0.00268 0.00166 -0.00136 -5.6E-05 4.963E-06 R12 -0.00056 0.000935 0.000107 0.000366 -7.42E-05 R13 0.025394 0.002362 0.006738 0.000392 0.0011301 R14 0.031778 0.015247 0.005208 0.000583 -1.5E-05 R15 -0.01372 0.02122 -0.00318 -0.00142 -0.000154 R16 -0.06373 0.020714 -0.01229 0.005576 -0.001519

[0137] Figure 8 Shows Figure 7 From the graph of the aberration characteristics of the optical system shown, it can be seen that the optical characteristics of the optical system provided by this embodiment are better.

[0138] In example (2), refer to Fig. 9 , the semi-diagonal size of the photosensitive element 3 is 8.166mm; the right-angle side length of the prism is 12mm; the EFL of the optical system is 8.955mm, the FOV is 83°, the aperture coefficient is 1.92, and the CRA is 37; the distance TTL between the aperture element 22 and the photosensitive element 3 is 10.35mm, and the distance T2 between the aperture element and the first lens 211 is -1.0496mm.

[0139] The optical characteristics of each element of the lens are shown in Table 4 below, and the optical characteristics include the radius of curvature, the thickness of the element or the distance to the next element, the refractive index, the Abbe number (chromatic aberration coefficient), and the focal length.

[0140] Table 4

[0141]

[0142] Tables 5 and 6 below show the aspheric surface coefficients of the 16 surfaces included in the first lens 211 to the eighth lens 218. The first lens 211 to the eighth lens 218 have a total of 8 lens object sides (surfaces facing the prism) and 8 lens image sides (surfaces facing the photosensitive element), and these 8 lens object sides and 8 lens image sides are all aspheric surfaces.

[0143] Table 5

[0144]

[0145]

[0146] Table 6

[0147] Face number A7 A8 A9 A10 A11 R1 -0.00148 -0.0008 -0.00037 -0.00014 -3.42E-05 R2 -0.00084 0.000176 0.00024 8.31E-05 3.055E-05 R3 0.000795 0.000348 0.000208 6.84E-06 3.113E-06 R4 -1.7E-05 9.35E-05 2.92E-05 -3.6E-06 4.05E-06 R5 -0.00057 -0.00015 -3.5E-06 1.11E-05 8.113E-06 R6 0.000477 6.95E-05 -3.8E-07 -1.1E-05 -1.2E-06 R7 0.001059 0.000196 4.91E-06 -5E-06 -6.32E-06 R8 0.000442 8.12E-05 1.02E-05 9.49E-06 8.204E-06 R9 0.000446 0.000182 8.61E-05 2.8E-05 1.403E-05 R10 0.002961 0.001301 0.000484 0.000126 2.367E-05 R11 0.005777 0.002269 0.00069 0.000142 4.732E-06 R12 -0.00321 0.000316 0.000159 0.000117 -5.22E-05 R13 0.004262 -0.0058 -0.00016 0.000557 -7.91E-05 R14 0.021735 -0.00987 0.001 0.000831 -0.000205 R15 0.00332 -0.00908 0.0152 -0.00604 0.0029571 R16 -0.04067 0.017652 -0.01094 3.69E-05 0.0005394

[0148] Fig.10 Shows Fig. 9 From the curve diagram of the aberration characteristics of the lens shown, it can be seen that the optical characteristics of the optical system provided by this embodiment are good.

[0149] In example (3), refer to Fig.11The semi-diagonal size of the photosensitive element is 8.166mm; the right-angle side length of the prism is 12mm; the EFL of the optical system is 10.805mm, the FOV is 73°, the aperture coefficient is 1.4, and the CRA is 35; the distance TTL between the aperture element and the photosensitive element is 14.262mm, and the distance T2 between the aperture element and the first lens is 0.53469mm.

[0150] The optical characteristics of each element of the lens are shown in Table 7 below, and the optical characteristics include the radius of curvature, the thickness of the element or the distance from the next element, the refractive index, the Abbe number (chromatic aberration coefficient), and the focal length.

[0151] Table 7

[0152]

[0153]

[0154] Tables 8 and 9 below show the aspheric surface coefficients of the 16 surfaces included in the first lens 211 to the eighth lens 218. The first lens 211 to the eighth lens 218 have a total of 8 lens object sides (surfaces facing the prism) and 8 lens image sides (surfaces facing the photosensitive element), and these 8 lens object sides and 8 lens image sides are all aspheric surfaces.

[0155] Table 8

[0156] Face number K A3 A4 A5 A6 R1 0.700232 -0.4075 -0.07115 0.01845 0.00599 R2 -1.24346 -0.54145 0.102912 -0.01518 -0.00738 R3 -10.0968 0.059485 0.003819 -0.00135 -0.014 R4 16.1405 -0.18314 0.015762 -0.00511 -0.00034 R5 56.37651 0.034813 0.052746 0.004283 0.000801 R6 12.8196 -0.07895 0.015713 0.007263 0.000948 R7 62.4881 -0.33509 -0.00291 0.009338 0.00052 R8 65.29741 -0.48478 -0.00607 0.010849 -0.00251 R9 -3.47983 -0.59091 -0.0001 0.009893 0.001216 R10 91.32945 -0.71177 0.000262 0.005695 0.003206 R11 96.83952 -0.52365 -0.11164 -0.01757 0.00257 R12 -13.1112 -1.22897 0.156587 -0.02477 0.016902 R13 -15.558 -1.6504 -0.09991 0.077933 0.008548 R14 6.81123 -1.35335 0.2999 0.121543 0.03308 R15 5.290775 -1.34225 0.761562 -0.10962 0.046211 R16 -1.03821 -6.07742 1.070251 -0.26529 0.104402

[0157] Table 9

[0158]

[0159]

[0160] Fig.12 Shows Fig.11 From the curve diagram of the aberration characteristics of the lens shown, it can be seen that the optical characteristics of the optical system provided by this embodiment are good.

[0161] On the other hand, combined Fig.13 As shown, this embodiment provides a camera module, which includes the optical system disclosed in the present invention and a photosensitive element 3; the photosensitive element 3 is located on the light-emitting side of the lens assembly 2, and the light passes through the object side surface 12 of the prism 1, the image side surface 11 of the prism 1, and the lens assembly 2 in sequence to irradiate the photosensitive element 3.

[0162] The camera module of this embodiment adopts the optical system provided by the present disclosure and has all the beneficial technical effects of the present disclosure.

[0163] In this embodiment, the photosensitive element 3 is located in the light-emitting direction of the prism 1 and on the side of the lens assembly 2 far from the image side surface 11. That is, the photosensitive element 3 is located in the light-emitting direction of the lens 21 in the lens assembly 2 that is farthest from the image side surface 11 of the prism 1. When the optical system includes the aperture element 22, the aperture element 22, the lens assembly 2, and the photosensitive element 3 are arranged in sequence in the light-emitting direction of the image side surface 11 of the prism 1.

[0164] In some optional implementations, the light passes through the reflective surface 13 of the prism 1, and the propagation direction changes. Then, the light is emitted from the image side surface 11 of the prism 1 toward the lens group. The photosensitive element 3 is arranged in the light emitting direction of the lens group, so that the structure of the lens can be made more compact.

[0165] The camera module of this embodiment is used to capture images or videos.

[0166] In some possible implementations, the photosensitive element 3 is also called an image sensor, which may be a complementary metal oxide semiconductor (CMOS) or a charge coupled device (CCD). It may also be other types of image sensors other than CMOS or CCD, such as a charge injection device (CID).

[0167] It is understandable that for CMOS, a digital signal processor (DSP) can be integrated into CMOS. CMOS has the advantages of high integration, low power consumption, and low cost, and is more suitable for electronic devices with limited installation space, such as mobile phones.

[0168] In some possible implementations, the camera module may further include a flash. The flash may be a single-color temperature flash or a dual-color temperature flash. The dual-color temperature flash refers to a combination of a warm light flash and a cold light flash, which may be used for light compensation at different color temperatures.

[0169] Exemplarily, the camera module includes a front camera and a rear camera. Usually, the front camera is arranged on the front of the terminal device, and the rear camera is arranged on the back of the terminal device. In some embodiments, there are at least two rear cameras, which are any one of a main camera, a depth of field camera, a wide-angle camera, and a telephoto camera, so as to realize the fusion of the main camera and the depth of field camera to realize the background blur function, the fusion of the main camera and the wide-angle camera to realize the panoramic shooting and the virtual reality (VR) shooting function or other fusion shooting functions.

[0170] On the other hand, combined Fig.13 As shown, this embodiment provides a terminal device, which includes: the camera module disclosed in the present invention, and a shell module 4; the shell module 4 is provided with a light-transmitting area 41, and the light-transmitting area 41 corresponds to the position of the object side surface 12 of the prism 1. The light passes through the light-transmitting area 41, the object side surface 12 of the prism 1, the image side surface 11 of the prism 1, and the lens assembly 2 in sequence to irradiate the photosensitive element 3.

[0171] The terminal device of this embodiment adopts the camera module provided by the present disclosure and has all the beneficial technical effects of the present disclosure.

[0172] Among them, the terminal device can be any of various types of computer system devices that are mobile or portable and perform image acquisition, and can be a tablet computer (portable android device, PAD), a personal digital assistant (personal digital assistant, PDA), a handheld device with image acquisition function, a computing device, a vehicle-mounted device, a wearable device, a virtual reality (virtual reality, VR) terminal device, an augmented reality (augmented reality, AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving, a wireless terminal in remote medical, a wireless terminal in smart grid (smartgrid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smartcity), a wireless terminal in smart home (smart home) and other mobile terminals or fixed terminals. In the embodiments of the present disclosure, the form of the terminal device is not specifically limited.

[0173] In some cases, the terminal device can perform multiple functions (e.g., play music, display video, store pictures, and receive and send phone calls). If necessary, the terminal device can be a device such as a cellular phone, a media player, other handheld devices, a wristwatch device, a pendant device, a handset device, or other compact portable device.

[0174] Below, each component is introduced by taking a smartphone as an example of a terminal device.

[0175] like Fig.13 As shown, the terminal device includes a housing module 4 and a camera module.

[0176] For example, the camera module can be the rear camera of the terminal device, or it can be the front camera of the terminal device. Optionally, in the case where the camera module is the rear camera in the terminal device, the housing module 4 can be the back plate of the terminal device (or back cover, battery cover, back shell, etc., which can be understood as a plate structure arranged on the side opposite to the display screen of the terminal device, which is part of the external structure of the terminal device), and the back plate at least partially has light-transmitting properties, which can meet the light-transmitting requirements of the camera module; in the case where the camera module is the front camera in the terminal device, the housing module 4 can be the display screen in the terminal device, and part of the structure of the display screen has light-transmitting properties, such as the bangs area, the hole area, etc. in the screen cover, which can meet the light-transmitting requirements of the camera module.

[0177] like Figure 5 As shown, the housing module 4 has a light-transmitting area 41 .

[0178] For example, the light-transmitting area 41 may include a light-through hole that passes through the housing module 4 ; for example, the light-through hole may be a circular through hole, or the light-through hole may be a square through hole.

[0179] For example, the housing module 4 may be a back panel of a terminal device, and the light-transmitting area 41 may be formed directly on the back panel; the back panel may be made of metal, glass or part of it may be a glass substrate. Alternatively, for example, the housing module 4 may be a back panel of a terminal device, and a cover having light-transmitting properties is disposed on the back panel, and the cover forms the light-transmitting area 41; for example, the cover may be a glass substrate.

[0180] Optionally, the housing module 4 may have a rectangular plate structure, the light hole is a circular through hole, and the axis of the light hole is perpendicular to the housing. In this way, the processing difficulty of the light hole can be reduced, and the assembly difficulty between the housing and the first lens can be reduced.

[0181] In some possible implementations, combined with Fig.13 As shown, the first optical axis 20 of the lens assembly 2 is parallel to the extension direction of the shell module 4. When the size of the lens assembly 2 in the direction of the first optical axis 20 increases, the component of the increment of the size of the lens assembly 2 in the direction of the optical axis in the thickness direction of the shell module 4 is zero. The size of the optical system in the thickness direction of the terminal device only depends on the size of the lens assembly 2 in the direction of the third optical axis 120. When the number of lenses 21 in the lens assembly 2 is large, the size of the terminal device in the thickness direction can be significantly reduced, which is beneficial to the miniaturized design of the terminal device.

[0182] It should be noted that the "several" and "at least one" mentioned in this article refer to one or more, and "multiple" and "at least two" refer to two or more. "And / or" describes the association relationship of the associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0183] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0184] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present disclosure.

[0185] The above descriptions are merely embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. An optical system, characterized in that: The optical system comprises: a prism (1) and a lens assembly (2); The prism (1) comprises an image side surface (11); The lens assembly (2) is located on the side where the image side (11) is located, and the first optical axis (20) of the lens assembly (2) is arranged to coincide with the second optical axis (110) of the image side (11); The dimension of the lens assembly (2) along at least one direction perpendicular to the first optical axis (20) is L1, and the dimension of the prism (1) along the same direction is L2, wherein L1≤L2.

2. The optical system according to claim 1, characterized in that The lens assembly (2) comprises at least two lenses (21), and the at least two lenses (21) are arranged in sequence along the first optical axis (20); The focal length of the lens (21) farthest from the image side surface (11) among the at least two lenses (21) is fi, and the equivalent side length of the orthographic projection of the image side surface (11) along the second optical axis (110) is Y', wherein -2.5 <fi / Y'<-0.4。 3. The optical system according to claim 2, characterized in that The central curvature radius of the surface of the lens (21) closest to the image side surface (11) among the at least two lenses (21) and facing the image side surface (11) is R1, wherein 0 <R1 / Y'<12。 4. The optical system according to any one of claims 1 to 3, characterized in that The prism (1) further comprises an object side surface (12), wherein a third optical axis (120) of the object side surface (12) is perpendicular to the first optical axis (20); The size of the lens assembly (2) along the direction of the third optical axis (120) is L1, and the size of the prism (1) along the direction of the third optical axis (120) is L2.

5. The optical system according to claim 4, characterized in that The lens assembly (2) comprises at least two lenses (21), wherein the at least two lenses (21) are arranged in sequence along the first optical axis (20), wherein the outer circumference size of at least one of the lenses (21) is L3, wherein L3>L2; The lens (21) having an outer circle size of L3 is provided with a trimming portion on at least one side along the direction of the third optical axis (120), so that the size of the lens (21) along the direction of the third optical axis (120) is shortened to L1.

6. The optical system according to any one of claims 1 to 5, characterized in that The viewing angle of the lens assembly (2) is greater than or equal to 55°.

7. The optical system according to claim 6, characterized in that The combined focal length of the lens assembly (2) is f, and the diagonal size of the imaging sensor arranged on the light-emitting side of the lens assembly (2) is IH, wherein 0.5≤f / IH≤0.

9.

8. The optical system according to any one of claims 1 to 7, characterized in that The optical system further comprises an aperture element (22), wherein the aperture element (22) is located between the image side surface (11) and the lens assembly (2), the aperture element (22) has an annular structure, the aperture of the aperture element (22) is D, and the combined focal length of the lens assembly (2) is f, wherein 1.0<f / D<1.

95.

9. The optical system according to claim 8, characterized in that The distance between the aperture element (22) and the image side surface (11) is T1, wherein 0.02≤T1≤2.0; and / or, The distance between the aperture element (22) and the lens assembly (2) is T2, wherein 0 <T2≤1。 10. A camera module, characterized in that: The camera module comprises the optical system according to any one of claims 1 to 9, and a photosensitive element (3); The photosensitive element (3) is located on the light-emitting side of the lens assembly (2), and the light rays sequentially pass through the object side surface (12) of the prism (1), the image side surface (11) of the prism (1), and the lens assembly (2) to irradiate the photosensitive element (3).

11. A terminal device, characterized in that: The terminal device comprises: the camera module according to claim 10, and a housing module (4); The housing module (4) is provided with a light-transmitting area (41), the light-transmitting area (41) corresponds to the position of the object side surface (12) of the prism (1), and light sequentially passes through the light-transmitting area (41), the object side surface (12) of the prism (1), the image side surface (11) of the prism (1), and the lens assembly (2) to irradiate the photosensitive element (3).

Images