CN219978607U

CN219978607U - Optical lens, projection module and electronic equipment

Info

Publication number: CN219978607U
Application number: CN202321021499.5U
Authority: CN
Inventors: 和建航
Original assignee: Jiangxi Jinghao Optical Co Ltd
Current assignee: Jiangxi Jinghao Optical Co Ltd
Priority date: 2023-04-28
Filing date: 2023-04-28
Publication date: 2023-11-07
Anticipated expiration: 2033-04-28

Abstract

The utility model discloses an optical lens, a projection module and electronic equipment, wherein the optical lens is provided with five lenses with refractive power, the five lenses are sequentially arranged from an imaging side to an image source side along an optical axis, the first lens, the fourth lens and the fifth lens are provided with positive refractive power, the second lens and the third lens are provided with negative refractive power, and the imaging side surface of the first lens is a convex surface at a paraxial region; the imaging side surface and the image source side surface of the second lens are respectively convex and concave at the paraxial region; the imaging side surface and the image source side surface of the third lens are concave at a paraxial region; the image source side surface of the fourth lens is convex at a paraxial region; the imaging side surface of the fifth lens is convex at a paraxial region; the optical lens satisfies the following relation: 3.1< TTL/ImgH <3.4. The optical lens, the projection module and the electronic equipment provided by the utility model realize the light, thin and miniaturized design of the optical lens and improve the projection imaging quality of the optical lens.

Description

Optical lens, projection module and electronic equipment

Technical Field

The present utility model relates to the field of optical imaging technologies, and in particular, to an optical lens, a projection module, and an electronic device.

Background

In an augmented Reality (Augmented Reality, abbreviated as AR) device and a Virtual Reality (VR) device, an optical lens is an indispensable part. Along with the development of the augmented reality technology and the virtual reality technology, miniaturization and super-cleaning are also gradually becoming the development trend of the optical lens, however, in the related art, under the condition of meeting the design trend of miniaturization of the optical lens, high-quality projection imaging of the optical lens is still difficult to realize.

Disclosure of Invention

The embodiment of the utility model discloses an optical lens, a projection module and electronic equipment, which can improve the projection imaging quality of the optical lens while realizing the light, thin and miniaturized design of the optical lens.

In order to achieve the above object, in a first aspect, the present utility model discloses an optical lens having five lens elements with refractive power, the five lens elements being a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element in this order from an imaging side to an image source side along an optical axis;

the first lens element with positive refractive power has a convex imaging-side surface at a paraxial region;

the second lens element with negative refractive power has a convex image-side surface at a paraxial region and a concave image-source side surface at a paraxial region;

The third lens element with negative refractive power has a concave image-side surface at a paraxial region and a concave image-source-side surface at a paraxial region;

the fourth lens element with positive refractive power has a convex image-source-side surface at a paraxial region;

the fifth lens element with positive refractive power has a convex imaging-side surface at a paraxial region;

the optical lens satisfies the following relation: 3.1< TTL/ImgH <3.4;

wherein TTL is the total optical length of the optical lens, and ImgH is the imaging height of the optical lens.

In the optical lens provided by the application, the first lens has positive refractive power, and the imaging side surface of the first lens is convex at a paraxial region, so that reasonable convergence of light rays and projection imaging to an imaging surface are facilitated; the second lens element with negative refractive power has a convex image-side surface at a paraxial region thereof, and a concave image-source side surface at a paraxial region thereof, so that light rays expanding toward the image-side surface can enter the second lens element at a smaller incident angle, thereby reducing reflection and aberration generated at the second lens element; the third lens element with negative refractive power has a concave image-side surface and a concave image-source side surface at a paraxial region, and is used for diverging a concentrated light beam, so that aberration of the optical lens element can be corrected, and imaging quality can be improved; the fourth lens element with positive refractive power has a convex image-source side surface at a paraxial region thereof, which is beneficial to assisting the fifth lens element in converging light rays and avoiding unnecessary aberration caused by excessive refractive power of the fifth lens element; the fifth lens element with positive refractive power has a convex image-side surface at a paraxial region, which facilitates focusing more light sources and improves the luminous flux of projection, and is beneficial to balancing the planar configuration of the fifth lens element with the source-side surface and enhancing the light focusing capability of the fifth lens element.

Furthermore, the optical lens satisfies the relation: 3.1< TTL/ImgH <3.4. Wherein TTL is the total optical length of the optical lens, and ImgH is the imaging height of the optical lens. When the relation is satisfied, the image source surface size of the optical lens and the optical total length of the optical lens are balanced, so that the structure of the optical lens is more compact, the miniaturized design is realized, the telecentricity of the optical lens is reduced, the telecentricity of the optical lens is improved, the depth of field of the optical lens is improved, the uniformity of the optical lens is improved, and the requirement of high-quality projection imaging is met. When the upper limit of the relation is exceeded, the volume of the optical lens is too large, the weight is too high, the production cost is too high, and when the lower limit of the relation is exceeded, the telecentricity of the optical lens is too low, and the uniformity and the projection quality of the optical lens are easily affected.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 5.3mm < f tan (FOV) <5.5mm. Wherein f is the focal length of the optical lens and FOV is the maximum field angle of the optical lens. When the relation is satisfied, the focal length of the optical lens and the field angle of the optical lens are balanced, the optical total length of the optical lens is controlled, the miniaturized design of the optical lens is realized, the distortion of the edge view field of the optical lens is improved, the size of the optical lens in the direction vertical to the optical axis and the size of the image source surface of the image display element are limited, and the miniaturized design of the projection module and the electronic equipment with the projection function is further realized, for example, the device is applicable to AR/VR glasses, and the diameter of the glasses frame of the AR/VR glasses is reduced, so that the device is convenient for a user to wear. When the upper limit of the relation is exceeded, the focal length of the optical lens is too large, so that the volume of the optical lens is too large, the miniaturization design is not facilitated, or the angle of view of the optical lens is too large, the distortion of the edge view field of the optical lens is too large, and the realization of high-quality projection imaging is not facilitated. When the focal length of the optical lens is smaller than the lower limit of the relation, the difficulty of the production process of the optical lens is easily increased, the production cost is not reduced, or the field angle of the optical lens is smaller, the field range of the optical lens is reduced, the imaging information of the optical lens is incomplete, and the projection quality is influenced.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.31mm ² <T45*f*tan(HFOV)<0.33mm ² . Wherein T45 is an air gap between the fourth lens element and the fifth lens element on the optical axis, f is a focal length of the optical lens element, and HFOV is half of a maximum field angle of the optical lens element. When the relation is satisfied, the air gap between the fourth lens and the fifth lens on the optical axis is limited, the total optical length of the optical lens is shortened, and light is realizedThe miniaturized design of optical lens avoids the interference between fourth lens and fifth lens that the too little distance between fourth lens and the fifth lens leads to simultaneously, reduces the assembly degree of difficulty and the bad risk of optical lens.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: f1/f+f2/f < -5 >. Wherein f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f is the focal length of the optical lens. When the above relation is satisfied, it is beneficial to reasonably distributing the refractive power of the first lens and the second lens, and preventing the first lens and the second lens from being excessively bent due to excessively concentrated refractive power of the first lens and the second lens, or preventing the refractive power of the first lens and the second lens from being excessively weak so as to be unfavorable for correcting the aberration of the optical lens, thereby being beneficial to ensuring the projection imaging quality of the optical lens.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.6< f4/f <0.9. Wherein f4 is the focal length of the fourth lens, and f is the focal length of the optical lens. When the relation is satisfied, the refractive power contribution of the fourth lens element is reasonably distributed, the surface of the fourth lens element is prevented from being excessively bent due to the excessively strong refractive power of the fourth lens element, the tolerance sensitivity of the optical lens element is reduced, the refractive power of the fourth lens element is prevented from being excessively weak, the pressure of correcting aberration of other lens elements is increased, and the projection imaging quality of the optical lens element is ensured.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 2< |R2/R1|. Wherein R2 is a radius of curvature of the image source side surface of the first lens at the optical axis, and R1 is a radius of curvature of the image side surface of the first lens at the optical axis. When the relation is satisfied, the curvature radius of the imaging side surface and the curvature radius of the image source side surface of the first lens are balanced, and the processing difficulty of the first lens is prevented from being increased due to overlarge difference of the curvature radius of the imaging side surface and the curvature radius of the image source side surface of the first lens.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 1.1< R3/R4<1.3. Wherein R3 is a radius of curvature R4 of the imaging side surface of the second lens at the optical axis, and R4 is a radius of curvature of the imaging side surface of the second lens at the optical axis. When the relation is satisfied, the curvature radius of the imaging side surface and the curvature radius of the image source side surface of the second lens are balanced, and the processing difficulty of the second lens is prevented from being increased due to overlarge difference of the curvature radius of the imaging side surface and the curvature radius of the image source side surface of the second lens.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 2.8< |R7/f|. Wherein R7 is a radius of curvature of the imaging side surface of the fourth lens at the optical axis, and f is a focal length of the optical lens. When the above relation is satisfied, the refractive power of the fourth lens element is advantageously limited, and the influence of the excessive refractive power of the fourth lens element on the imaging quality of the optical lens system is avoided.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.6< CT1/(CT2+CT3) <0.8. Wherein, CT1 is the thickness of the first lens on the optical axis CT2 is the thickness of the second lens on the optical axis CT3 is the thickness of the third lens on the optical axis CT 2. When the above relation is satisfied, the thicknesses of the first lens, the second lens and the third lens on the optical axis can be controlled within a proper range, so that the situation that the thickness of the single lens is too large or too small to cause difficult processing is avoided.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 1.3< CT4/CT2<2.5. Wherein, CT2 is the thickness of the second lens on the optical axis, and CT4 is the thickness of the fourth lens on the optical axis. When the relation is satisfied, the center thicknesses of the second lens and the fourth lens are controlled within a reasonable range, the situation that the optical lens is difficult to process due to overlarge difference of the center thicknesses of the second lens and the fourth lens is avoided, the processing cost of the optical lens is controlled, and the processing precision of the optical lens is guaranteed.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 1< CT4/CT5<1.6. Wherein, CT5 is the thickness of the fifth lens element on the optical axis, and CT4 is the thickness of the fourth lens element on the optical axis. When the relation is satisfied, the center thicknesses of the fourth lens and the fifth lens are controlled within a reasonable range, the situation that the optical lens is difficult to process due to overlarge center thickness difference of the fourth lens and the fifth lens is avoided, the processing cost of the optical lens is controlled, and the processing precision of the optical lens is guaranteed.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.4< SAG32/CT3<0.6. The SAG32 is a distance between the maximum caliber of the image source side surface of the third lens and an intersection point of the image source side surface of the third lens and the optical axis in the optical axis direction, and the CT3 is a thickness of the third lens on the optical axis. When the relation is satisfied, the control of the surface shape of the third lens is facilitated, and the processing difficulty and the bad risk of the third lens are avoided from being increased due to the fact that the third lens is excessively bent.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 2< T23/ET23<6.5. Wherein T23 is an air gap between the second lens and the third lens on the optical axis, and ET23 is a distance from a maximum aperture of an image source side surface of the second lens to a maximum aperture of an image forming side surface of the third lens in the optical axis direction. When the relation is satisfied, the air gap between the second lens and the third lens and the curvature radius of the image source side surface of the second lens and the imaging side surface of the third lens are controlled within a reasonable range, the total optical length of the optical lens is shortened, the miniaturized design of the optical lens is realized, interference between the second lens and the third lens caused by too small distance between the second lens and the third lens is avoided, meanwhile, the second lens and the third lens are prevented from being excessively bent, and the process difficulty and the bad risk of the optical lens are reduced.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.5< ET4/CT4<0.71. Wherein ET4 is the distance from the maximum aperture of the imaging side surface of the fourth lens to the maximum effective aperture of the image source side surface of the fourth lens in the optical axis direction, and CT4 is the thickness of the fourth lens on the optical axis. When the relation is satisfied, the ratio of the edge thickness to the center thickness of the fourth lens is limited within a certain range, and the processing and the production of the fourth lens are facilitated.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.6< SD11/SD52<0.8. Wherein SD11 is the effective half-caliber of the imaging side surface of the first lens, and SD52 is the effective half-caliber of the image source side surface of the fifth lens. When the relation is satisfied, the curvature radius of the imaging side surface of the first lens and the curvature radius of the image source side surface of the fifth lens are limited, the overlarge caliber difference at two sides of the optical lens is avoided, the center balance of the optical lens is kept, and meanwhile, the installation of the optical lens is facilitated.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 2.5< TD/SD52<2.7. Where TD is the distance between the imaging side surface of the first lens element and the image source side surface of the fifth lens element on the optical axis, and SD52 is the effective half-caliber of the image source side surface of the fifth lens element. When the above relation is satisfied, the total optical length of the optical lens and the caliber of the image source side surface of the fifth lens are advantageously controlled within a reasonable range, so that the volume of the optical lens and the imaging performance of the optical lens are balanced.

As an alternative implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens satisfies the relation: 0.13< CT1/TD <0.18. Wherein CT1 is the thickness of the first lens element on the optical axis, and TD is the distance between the image-side surface of the first lens element and the image-source side surface of the fifth lens element on the optical axis. When the relation is satisfied, the center thickness of the first lens is favorably controlled, and the problem that the first lens is too large in thickness and is unfavorable for realizing the miniaturization design of the optical lens is avoided.

As an optional implementation manner, in an embodiment of the first aspect of the present utility model, the optical lens further includes a diaphragm, where the diaphragm is located on the imaging side of the first lens, and the optical lens satisfies the relationship: 0.93< TD/SD <0.95. Wherein SD is the distance between the aperture stop and the image-source side surface of the fifth lens element on the optical axis, and TD is the distance between the image-forming side surface of the first lens element and the image-source side surface of the fifth lens element on the optical axis. When the relation is satisfied, the distance between the diaphragm and the first lens is controlled within a proper range, and the problem that the assembly difficulty is increased due to too close distance between the diaphragm and the first lens or the volume of the optical lens is increased due to too far distance between the diaphragm and the first lens is avoided.

In a second aspect, the present utility model discloses a projection module, where the projection module includes an image display element and the optical lens according to the first aspect, and the image display element is disposed on an image source side of the optical lens. The projection module with the optical lens can effectively control the total optical length of the optical lens, realize the light, thin and miniaturized design of the optical lens, and also be beneficial to improving the telecentric property of the optical lens so as to improve the depth of field of the optical lens, be beneficial to improving the uniformity of the optical lens and improve the projection imaging quality of the optical lens.

In a third aspect, the utility model also discloses an electronic device, which comprises a housing and the projection module set in the second aspect, wherein the projection module set is arranged on the housing. The electronic equipment with the projection module can effectively control the total optical length of the optical lens, realize the light, thin and miniaturized design of the optical lens, and also be beneficial to improving the telecentric property of the optical lens so as to improve the depth of field of the optical lens, be beneficial to improving the uniformity of the optical lens and improve the projection imaging quality of the optical lens.

Compared with the prior art, the utility model has the beneficial effects that:

The embodiment of the utility model provides an optical lens, a projection module and electronic equipment, wherein the optical lens adopts five lenses, and the refractive power and the surface shape of the five lenses are designed, so that the optical lens meets the relation: 3.1< TTL/ImgH <3.4, so as to balance the size of the image source surface of the optical lens and the optical total length of the optical lens, so that the optical lens has a more compact structure, realizes miniaturized design, is beneficial to reducing the telecentricity of the optical lens, improves the depth of field of the optical lens, is beneficial to improving the uniformity of the optical lens, and meets the requirements of high-quality projection imaging.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a projection module with an optical lens according to a first embodiment of the present utility model; the method comprises the steps of carrying out a first treatment on the surface of the

Fig. 2 is a longitudinal spherical aberration diagram (mm), astigmatic curve diagram (mm) and distortion curve diagram (%) of an optical lens according to the first embodiment of the present application;

FIG. 3 is a schematic diagram of a projection module with an optical lens according to a second embodiment of the present application; the method comprises the steps of carrying out a first treatment on the surface of the

Fig. 4 is a longitudinal spherical aberration diagram (mm), astigmatic curve diagram (mm) and distortion curve diagram (%) of an optical lens according to a second embodiment of the present application;

FIG. 5 is a schematic diagram of a projection module with an optical lens according to a third embodiment of the present application; the method comprises the steps of carrying out a first treatment on the surface of the

Fig. 6 is a longitudinal spherical aberration diagram (mm), astigmatic curve diagram (mm) and distortion curve diagram (%) of an optical lens according to a third embodiment of the present application;

fig. 7 is a schematic structural diagram of a projection module with an optical lens according to a fourth embodiment of the present application; the method comprises the steps of carrying out a first treatment on the surface of the

Fig. 8 is a longitudinal spherical aberration diagram (mm), astigmatic curve diagram (mm) and distortion curve diagram (%) of an optical lens according to a fourth embodiment of the present application;

fig. 9 is a schematic structural diagram of a projection module with an optical lens according to a fifth embodiment of the present application; the method comprises the steps of carrying out a first treatment on the surface of the

Fig. 10 is a longitudinal spherical aberration diagram (mm), astigmatic curve diagram (mm) and distortion curve diagram (%) of an optical lens according to a fifth embodiment of the present application;

fig. 11 is a schematic structural diagram of an electronic device provided by the present application.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, according to a first aspect of the present utility model, an optical lens 100 is disclosed, wherein the optical lens 100 has five lens elements with refractive power, and the five lens elements are a first lens element L1, a second lens element L2, a third lens element L3, a fourth lens element L4 and a fifth lens element L5 in order from an image-forming side to an image-source side along an optical axis. During projection, the image light beam sequentially enters the fifth lens L5, the fourth lens L4, the third lens L3, the second lens L2 and the first lens L1 from the image source of the fifth lens L5 and is emitted to an imaging component at the imaging side to realize projection imaging.

The first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, and the fifth lens element L5 with positive refractive power. The image-forming side surface S1 of the first lens element L1 can be convex at the paraxial region O, the image-source side surface S2 of the first lens element L1 can be convex or concave at the paraxial region O, the image-forming side surface S3 of the second lens element L2 can be convex at the paraxial region O, the image-source side surface S4 of the second lens element L2 can be concave at the paraxial region O, the image-source side surface S5 of the third lens element L3 can be concave at the paraxial region O, the image-source side surface S6 of the third lens element L3 can be concave at the paraxial region O, the image-source side surface S7 of the fourth lens element L4 can be convex or concave at the paraxial region O, the image-source side surface S9 of the fifth lens element L5 can be convex at the paraxial region O, and the image-source side surface S10 of the fifth lens element L5 can be convex or concave at the paraxial region O.

In the optical lens 100 of the present application, the first lens element L1 has positive refractive power, and the image-source side surface S2 of the first lens element L1 is convex at the paraxial region O, which is beneficial for reasonably converging light and projecting and imaging onto an imaging surface; the second lens element L2 with negative refractive power has a convex image-side surface S3 at a paraxial region O, and a concave image-source side surface S4 at the paraxial region O, so that light rays expanding toward the image side can enter the second lens element L2 at a smaller incident angle and reflection and aberration generated at the second lens element L2 can be reduced; the third lens element L3 with negative refractive power has a concave image-side surface S5 and a concave image-source side surface S6 at a paraxial region O, which are configured to diverge a concentrated light beam, thereby being beneficial to correcting aberration of the optical lens element 100 and improving imaging quality; the fourth lens element L4 with positive refractive power has a convex image-source side surface S8 at a paraxial region O, which is beneficial to assisting the fifth lens element L5 in converging light rays and avoiding unnecessary aberration caused by excessive refractive power of the fifth lens element L5; the fifth lens element L5 with positive refractive power has a convex image-side surface S9 at a paraxial region O, which is beneficial to focusing more light sources and improving the projected luminous flux, and the design of the fifth lens element L5 with convex image-side surface S9 at a paraxial region O is beneficial to balancing the planar configuration of the image-source side surface S10 of the fifth lens element L5 and enhancing the light focusing capability of the fifth lens element L5.

In some embodiments, the materials of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4 and the fifth lens L5 may be plastic, so that the optical lens 100 has good optical effect and good portability. In addition, the plastic material is easier to process the lens, so that the processing cost of the optical lens 100 can be reduced.

In some embodiments, the lens material of the optical lens 100 may be glass, and the lens with glass material can withstand higher or lower temperature and has excellent optical effect and better stability.

In some embodiments, at least two lenses of different materials may be disposed in the optical lens 100, for example, a combination of glass lens and plastic lens may be used, but the specific configuration relationship may be determined according to practical requirements, which is not meant to be exhaustive.

In some embodiments, the optical lens 100 satisfies the relationship: 3.1< TTL/ImgH <3.4. Wherein, TTL is the total optical length of the optical lens 100, and ImgH is the imaging height of the optical lens 100. Illustratively, TTL/ImgH can be 3.107, 3.150, 3.191, 3.254, 3.330, 3.331, 3.397, or the like. When the above relation is satisfied, it is beneficial to balance the size of the image source surface 201 of the optical lens 100 and the optical total length of the optical lens 100, so that the structure of the optical lens 100 is more compact, a miniaturized design is realized, the telecentricity of the optical lens 100 is also beneficial to be reduced, the telecentricity of the optical lens 100 is improved, the depth of field of the optical lens 100 is improved, the uniformity of the optical lens 100 is improved, and the requirement of high-quality projection imaging is satisfied. When the upper limit of the above relation is exceeded, the volume of the optical lens 100 is too large, resulting in too high production cost of the optical lens 100, and when the lower limit of the above relation is exceeded, the telecentricity of the optical lens 100 is too low, which easily affects the uniformity and projection quality of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: 5.3mm < f tan (FOV) <5.5mm. Where f is the focal length of the optical lens 100, and FOV is the maximum field angle of the optical lens 100. Illustratively, the f tan (FOV) may be 5.305mm, 5.328mm, 5.396mm, 5.412mm, 5.475mm, 5.502mm, 5.545mm, or the like. When the above relation is satisfied, it is beneficial to balance the focal length of the optical lens 100 and the angle of view of the optical lens 100, to control the total optical length of the optical lens 100, to implement miniaturized design of the optical lens 100, to improve distortion of the peripheral view field of the optical lens 100, and to limit the size of the optical lens 100 in the direction perpendicular to the optical axis O, and the size of the image source surface 201 of the image display element, so as to further implement miniaturized design of the projection module and the electronic device with the projection function, for example, it is suitable for use on AR/VR glasses, to reduce the diameter of the frame of the AR/VR glasses, so as to be worn by the user. When the upper limit of the above relation is exceeded, the focal length of the optical lens 100 is too large, which results in an excessively large volume of the optical lens 100, which is not beneficial to miniaturization design, or an excessively large angle of view of the optical lens 100, which results in excessively large distortion of the field of view at the edge of the optical lens 100, which is not beneficial to realizing high-quality projection imaging. When the focal length of the optical lens 100 is smaller than the lower limit of the above relation, the difficulty of the production process of the optical lens 100 is easily increased, which is not beneficial to reducing the production cost, or the viewing angle of the optical lens 100 is smaller, which reduces the viewing range of the optical lens 100, resulting in incomplete imaging information of the optical lens 100 and affecting the projection quality.

In some embodiments, the optical lens 100 satisfies the relationship: 0.31mm ² <T45*f*tan(FOV)<0.33mm ² . Wherein T45 is an air gap between the fourth lens element L4 and the fifth lens element L5 on the optical axis O, f is a focal length of the optical lens 100, and FOV is half of a maximum field angle of the optical lens 100. Illustratively, t45×f×tan (FOV) may be 0.312 mm2, 0.316mm2, 0.318mm2, 0.320mm2, 0.326mm2, or 0.399 mm2, etc. When the above relation is satisfied, it is beneficial to limit the air gap between the fourth lens L4 and the fifth lens L5 on the optical axis O, shorten the total optical length of the optical lens 100, implement the miniaturized design of the optical lens 100, and avoid interference between the fourth lens L4 and the fifth lens L5 caused by too small distance between the fourth lens L4 and the fifth lens L5, thereby reducing the assembly difficulty and the poor risk of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: f1/f+f2/f < -5 >. Where f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, and f is the focal length of the optical lens 100. Illustratively, f1/f+f2/f can be-716.9307, -705.3948, -704.4750, -696.8077, -413.9916, -366.1251, -122.4999, -5.5222, or-5.1763, etc. When the above relation is satisfied, it is advantageous to reasonably distribute the refractive powers of the first lens element L1 and the second lens element L2, so as to prevent the first lens element L1 and the second lens element L2 from being excessively concentrated in refractive power of the combination of the first lens element L1 and the second lens element L2, or prevent the refractive powers of the first lens element L1 and the second lens element L2 from being excessively weak so as to be unfavorable for correcting the aberration of the optical lens element 100, thereby being advantageous to ensure the projection imaging quality of the optical lens element 100.

In some embodiments, the optical lens 100 satisfies the relationship: 0.6< f4/f <0.9. Where f4 is the focal length of the fourth lens L4, and f is the focal length of the optical lens 100. Illustratively, f4/f can be 0.63, 0.68, 0.71, 0.74, 0.79, 0.86, or 0.872, etc. When the above relation is satisfied, it is beneficial to reasonably distributing the refractive power contribution of the fourth lens element L4, preventing the surface of the fourth lens element L4 from being excessively curved due to the excessively strong refractive power of the fourth lens element L4, reducing the tolerance sensitivity of the optical lens 100, and increasing the aberration correction pressure of the remaining lens elements due to the excessively weak refractive power of the fourth lens element L4, so as to ensure the projection imaging quality of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: 2< |R2/R1|. Wherein R2 is a radius of curvature of the image-source side surface S2 of the first lens L1 at the optical axis O, and R1 is a radius of curvature of the image-forming side surface S1 of the first lens L1 at the optical axis O. Illustratively, |r2/r1| can be 2.021, 3.5, 15.8, 25.66, 58.82, 155.73, 222.626, 329.7193, 335.522, or the like. When the above relation is satisfied, it is beneficial to equalize the radii of curvature of the imaging side surface S1 and the image source side surface S2 of the first lens L1, so as to avoid an increase in the processing difficulty of the first lens L1 caused by an excessive difference in the radii of curvature of the imaging side surface S1 and the image source side surface S2 of the first lens L1.

In some embodiments, the optical lens 100 satisfies the relationship: 1.1< R3/R4<1.3. Wherein R3 is a radius of curvature of the imaging side surface S3 of the second lens L2 at the optical axis O, and R4 is a radius of curvature of the imaging side surface S3 of the second lens L2 at the optical axis O. Illustratively, R3/R4 can be 1.111, 1.157, 1.172, 1.216, 1.224, 1.285, or the like. When the above relation is satisfied, it is beneficial to equalize the radii of curvature of the imaging side surface S3 and the image source side surface S4 of the second lens L2, so as to avoid an increase in the processing difficulty of the second lens L2 caused by an excessive difference in the radii of curvature of the imaging side surface S3 and the image source side surface S4 of the second lens L2.

In some embodiments, the optical lens 100 satisfies the relationship: 2.8< |R7/f|. Where R7 is a radius of curvature of the imaging side surface S7 of the fourth lens L4 at the optical axis O, and f is a focal length of the optical lens 100. Illustratively, |r7/f| can be 2.880, 2.950, 4.763, 5.129, 9.881, 18.24 or 23.84, etc. When the above relation is satisfied, the refractive power of the fourth lens element L4 is advantageously limited, and the influence of the excessive refractive power of the fourth lens element L4 on the imaging quality of the optical lens 100 is avoided, and the increase of the processing difficulty due to the excessive bending of the surface of the fourth lens element L4 is also advantageously avoided.

In some embodiments, the optical lens 100 satisfies the relationship: 0.6< CT1/(CT2+CT3) <0.8. Wherein, CT1 is the thickness of the first lens L1 on the optical axis O, CT2 is the thickness of the second lens L2 on the optical axis O, and CT3 is the thickness of the third lens L3 on the optical axis O. Illustratively, CT 1/(CT 2+ CT 3) may be 0.602, 0.653, 0.733, 0.743, 0.785, etc. When the above relation is satisfied, the thicknesses of the first lens L1, the second lens L2, and the third lens L3 on the optical axis O can be controlled within a proper range, so that the occurrence of the situation that the thickness of the single lens is too large or too small to cause difficult processing can be avoided.

In some embodiments, the optical lens 100 satisfies the relationship: 1.3< CT4/CT2<2.5. Wherein, CT2 is the thickness of the second lens L2 on the optical axis O, and CT4 is the thickness of the fourth lens L4 on the optical axis O. Illustratively, CT4/CT2 may be 1.312, 1.391, 1.430, 1.880, 2.44, 2.87, or the like. When the above relation is satisfied, the center thicknesses of the second lens L2 and the fourth lens L4 are controlled within a reasonable range, so that the situation that the optical lens 100 is difficult to process due to overlarge difference between the center thicknesses of the second lens L2 and the fourth lens L4 is avoided, the processing cost of the optical lens 100 is controlled, and the processing precision of the optical lens 100 is ensured.

In some embodiments, the optical lens 100 satisfies the relationship: 1< CT4/CT5<1.6. Wherein, CT5 is the thickness of the fifth lens L5 on the optical axis O, and CT4 is the thickness of the fourth lens L4 on the optical axis O. Illustratively, CT4/CT5 may be 1.001, 1.03, 1.28, 1.34, 1.53, 1.597, or the like. When the above relation is satisfied, the center thicknesses of the fourth lens L4 and the fifth lens L5 are advantageously controlled within a reasonable range, so that the situation that the optical lens 100 is difficult to process due to the overlarge difference between the center thicknesses of the fourth lens L4 and the fifth lens L5 is avoided, the processing cost of the optical lens 100 is advantageously controlled, and the processing precision of the optical lens 100 is ensured.

In some embodiments, the optical lens 100 satisfies the relationship: 0.4< SAG32/CT3<0.6. The SAG32 is a distance from the maximum caliber of the image source side surface S6 of the third lens L3 to an intersection point of the image source side surface S6 of the third lens L3 and the optical axis O in the direction of the optical axis O, and the CT3 is a thickness of the third lens L3 on the optical axis O. By way of example, SAG32/CT3 may be 0.409, 0.487, 0.510, 0.539, 0.576 or 0.586, etc. When the above relation is satisfied, the control of the surface shape of the third lens L3 is facilitated, and the processing difficulty and the adverse risk of the third lens L3 are prevented from being increased due to the excessive bending of the third lens L3.

In some embodiments, the optical lens 100 satisfies the relationship: 2< T23/ET23<6.5. Wherein T23 is an air gap between the second lens L2 and the third lens L3 on the optical axis O, and ET23 is a distance from a maximum aperture of the image source side surface S4 of the second lens L2 to a maximum aperture of the image forming side surface S5 of the third lens L3 in the direction of the optical axis O. Illustratively, T23/ET23 can be 2.22, 3.89, 4.71, 5.94, 6.07, 6.36, or the like. When the above relation is satisfied, the air gap between the second lens L2 and the third lens L3 and the curvature radius of the image source side surface S4 of the second lens L2 and the image side surface S5 of the third lens L3 are controlled within a reasonable range, so as to shorten the total optical length of the optical lens 100, realize the miniaturized design of the optical lens 100, and avoid interference between the second lens L2 and the third lens L3 caused by too small distance between the second lens L2 and the third lens L3, and avoid excessive bending of the second lens L2 and the third lens L3, thereby reducing the process difficulty and the adverse risk of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: 0.5< ET4/CT4<0.71. Where ET4 is the distance from the maximum aperture of the imaging side surface S7 of the fourth lens L4 to the maximum effective aperture of the image source side surface S8 of the fourth lens L4 in the direction of the optical axis O, and CT4 is the thickness of the fourth lens L4 on the optical axis O. Illustratively, ET4/CT4 may be 0.513, 0.573, 0.640, 0.702, or 0.709, etc. When the above relation is satisfied, it is advantageous to limit the ratio of the edge thickness to the center thickness of the fourth lens L4 within a certain range, and to facilitate the processing and production of the fourth lens L4.

In some embodiments, the optical lens 100 satisfies the relationship: 0.6< SD11/SD52<0.8. Here, SD11 is the effective half-caliber of the imaging side surface S1 of the first lens L1, and SD52 is the effective half-caliber of the image source side surface S10 of the fifth lens L5. Illustratively, SD11/SD52 may be 0.611, 0.699, 0.715, 0.735, 0.789, or the like. When the above relation is satisfied, it is beneficial to limit the radius of curvature of the image side surface S1 of the first lens L1 and the image source side surface S10 of the fifth lens L5, avoid the excessive caliber difference between the two sides of the optical lens 100, and keep the center balance of the optical lens 100, and also facilitate the installation of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: 2.5< TD/SD52<2.7. Where TD is the distance between the image-side surface S1 of the first lens L1 and the image-source side surface S10 of the fifth lens L5 on the optical axis O, and SD52 is the effective half-caliber of the image-source side surface S10 of the fifth lens L5. Illustratively, the TD/SD52 may be 2.524, 2.590, 2.619, 2.672 or 2.698, or the like. When the above relation is satisfied, it is advantageous to control the total optical length of the optical lens 100 and the caliber of the image source side surface S10 of the fifth lens L5 within a reasonable range, so as to balance the volume of the optical lens 100 and the imaging performance of the optical lens 100.

In some embodiments, the optical lens 100 satisfies the relationship: 0.13< CT1/TD <0.18. Wherein CT1 is the thickness of the first lens L1 on the optical axis O, and TD is the distance between the image-side surface S1 of the first lens L1 and the image-source side surface S10 of the fifth lens L5 on the optical axis O. Illustratively, CT1/TD may be 0.133, 0.147, 0.150, 0.165, 0.171, 0.174, or the like. When the above relation is satisfied, it is advantageous to control the center thickness of the first lens L1, and to avoid that the thickness of the first lens L1 is too large to be advantageous to realize the miniaturized design of the optical lens 100.

In some embodiments, the optical lens 100 further includes a stop STO, which may be an aperture stop or a field stop, which may be disposed between the imaging side of the optical lens 100 and the imaging side surface S1 of the first lens L1. It is to be understood that, in other embodiments, the stop STO may be disposed between the image source side surface S4 of the second lens L2 and the image side surface S5 of the third lens L3, or the stop STO may be disposed between the image source side surface S2 of the first lens L1 and the image side surface S3 of the second lens L2, and may be specifically adjusted according to practical situations, which is not particularly limited in this embodiment.

In some embodiments, the optical lens 100 further includes a stop STO, where the stop STO is located on the imaging side of the first lens L1, and the optical lens 100 satisfies the relationship: 0.93< TD/SD <0.95. Here, SD is the distance between the stop STO and the image-source side surface S10 of the fifth lens L5 on the optical axis O, and TD is the distance between the image-forming side surface S1 of the first lens L1 and the image-source side surface S10 of the fifth lens L5 on the optical axis O. Illustratively, the TD/SD may be 0.933, 0.935, 0.943, 0.948, or the like. When the above relation is satisfied, it is beneficial to control the distance between the stop STO and the first lens L1 within a proper range, so as to avoid increasing the assembly difficulty due to too close distance between the stop STO and the first lens L1 or increasing the volume of the optical lens 100 due to too far distance between the stop STO and the first lens L1.

The application also provides a projection module 10, which comprises the optical lens 100 and the image display element 200. The image display element 200 is disposed on an image source of an optical lens, and is used for generating an image beam, and the optical lens is used for projecting the image beam generated by the image display element 200 to an imaging component to form an image frame. For example, the image display element 200 may be an element capable of displaying an image, such as a liquid crystal screen (liquid crystal display, LCD), a liquid crystal on silicon (liquid crystal on silicon, LCOS) panel, a digital micro-mirror device (DMD), or an organic light-emitting diode (OLED). It can be appreciated that the projection module 10 with the optical lens 100 can effectively control the optical total length of the optical lens 100, realize a light, thin and miniaturized design of the optical lens 100, and also facilitate improvement of the telecentricity of the optical lens 100, so as to improve the depth of field of the optical lens 100, facilitate improvement of the uniformity of the optical lens 100, and improve the projection imaging quality of the optical lens 100.

In some embodiments, the projection module further includes a prism L6 and a light source (not shown), the prism L6 is located between the image display element 200 and the optical lens 100, and the prism L6 is used for guiding the illumination beam of the light source to the image display element 200, so that the image display element 200 can generate the image beam and exit to the image source side surface S10 of the fifth lens L5 of the optical lens 100 through the prism L6. Illustratively, the prism L6 may be a rectangular prism.

In some embodiments, the projection module further includes a protective glass L7, and the protective glass L7 may be located between the prism L6 and the image display element 200. Since the protective glass L7 has high light transmittance and high strength, the provision of the protective glass L7 between the prism L6 and the image display element 200 can protect the image display element 200 from the external environment without affecting the normal use of the image display element 200.

The optical lens 100 and the projection module 10 of the present embodiment will be described in detail with specific parameters.

First embodiment

Referring to fig. 1, fig. 1 is a schematic diagram illustrating a projection module 10 according to a first embodiment of the application. The projection module 10 includes an optical lens 100, a prism L6, a cover glass L7, and an image display element 200, which are disposed in order from an imaging side to an image source side along an optical axis O. The optical lens 100 includes a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are disposed in order from the imaging side to the image source side along the optical axis O.

Further, the first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with negative refractive power, the fourth lens element L4 with positive refractive power, and the fifth lens element L5 with positive refractive power.

Further, the image-side surface S1 and the image-source side surface S2 of the first lens L1 are convex at the paraxial region O; the image-side surface S3 and the image-source side surface S4 of the second lens L2 are convex and concave at the paraxial region O, respectively; the imaging side surface S5 and the image source side surface S6 of the third lens L3 are concave at the paraxial region O; the imaging side surface S7 and the image source side surface S8 of the fourth lens L4 are concave and convex at the paraxial region O, respectively; the image-side surface S9 and the image-source side surface S10 of the fifth lens L5 are convex at the paraxial region O.

For example, taking the focal length f= 8.6987mm of the optical lens 100, the field angle fov=32° of the optical lens 100, the total optical length ttl= 16.7822mm of the optical lens 100, and the f-number fno= 8.6987mm as examples, other parameters of the projection module 10 are given in table 1 below. Wherein the elements from the imaging side to the image source side are sequentially arranged in the order of the elements from top to bottom of table 1 along the optical axis O of the optical lens 100. In the same lens, the surface with the smaller surface number is the imaging side surface of the lens, and the surface with the larger surface number is the image source side surface of the lens, for example, the surfaces with the surface numbers 2 and 3 correspond to the imaging side surface S1 and the image source side surface S2 of the first lens L1, respectively. The radius Y in table 1 is the radius of curvature of the imaging side surface or the image source side surface of the corresponding surface number at the paraxial region O. The first value in the "thickness" parameter row of the lens is the thickness of the lens on the optical axis O, and the second value is the distance from the image source side surface of the lens to the latter surface on the optical axis O. The value of the stop STO in the "thickness" parameter array is the distance between the stop STO and the vertex of the latter surface (the vertex refers to the intersection point of the surface and the optical axis O) on the optical axis O, and the direction from the imaging side surface of the first lens L1 to the image source side surface of the last lens is the positive direction of the optical axis O by default. It is understood that the units of Y radius, thickness, and focal length in Table 1 are all mm. And the refractive index and Abbe number of each lens in Table 1 were 587.6nm, and the reference wavelength of the focal length was 530nm.

TABLE 1

In the first embodiment, the object side surface and the image side surface of any one of the first lens L1 and the second lens L2 are aspherical, and the surface shape x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

wherein x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c=1/R (i.e., paraxial curvature c is the inverse of the radius R of Y in table 1 above); k is a conic coefficient; ai is a correction coefficient corresponding to the i-th higher term of the aspherical surface. The higher order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for the respective aspherical lenses S1-S4 in the first embodiment are given in Table 2.

TABLE 2

Referring to fig. 2 (a), fig. 2 (a) shows a longitudinal spherical aberration diagram of the optical lens 100 in the first embodiment at wavelengths of 617nm, 530nm, and 460 nm. In fig. 2 (a), the abscissa in the X-axis direction represents the focus shift, and the ordinate in the Y-axis direction represents the normalized field of view. As can be seen from the graph (a) in fig. 2, the spherical aberration of the optical lens 100 in the first embodiment is effectively controlled, which means that the optical lens 100 in the present embodiment has better imaging quality.

Referring to fig. 2 (B), fig. 3 (B) shows astigmatic curves of the optical lens 100 of the first embodiment at wavelengths 617nm, 530nm, and 460 nm. Wherein the abscissa along the X-axis direction represents the focus offset, and the ordinate along the Y-axis direction represents the field angle in degrees. T in the astigmatism graph indicates the curvature of the imaging plane in the meridian direction, and S indicates the curvature of the imaging plane in the sagittal direction, and it can be seen from the graph (B) in fig. 3 that at this wavelength, the astigmatism of the optical lens 100 is well compensated.

Referring to fig. 2 (C), fig. 2 (C) is a graph showing distortion curves of the optical lens 100 of the first embodiment at wavelengths of 617nm, 530nm and 460 nm. Wherein the abscissa along the X-axis direction represents distortion and the ordinate along the Y-axis direction represents field angle in degrees. As can be seen from the graph (C) in fig. 2, the distortion of the optical lens 100 becomes well corrected.

Second embodiment

Referring to fig. 3, fig. 3 is a schematic structural diagram of a projection module 10 according to a second embodiment of the application. The projection module 10 includes an optical lens 100, a prism L6, a cover glass L7, and an image display element 200, which are disposed in order from an imaging side to an image source side along an optical axis O. The optical lens 100 includes a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are disposed in order from the imaging side to the image source side along the optical axis O.

Further, in the second embodiment, the refractive powers of the respective lenses coincide with those of the first embodiment. In the second embodiment, however, the surface type of each lens differs from that of the first embodiment in that: the imaging side surface S7 of the fourth lens L4 is convex at the paraxial region O.

In the second embodiment, the effective focal length f= 8.5004mm of the optical lens 100, the field angle fov=32° of the optical lens 100, the total optical length ttl=15.648 mm of the optical lens 100, and the f-number fno= 2.4853 are taken as examples. The other parameters in the second embodiment are given in the following table 3, and the definition of the parameters can be obtained from the description of the foregoing embodiment, which is not repeated here. It is understood that the units of Y radius, thickness, and focal length in Table 3 are all mm. And the refractive index and Abbe number of each lens in Table 3 were 587.6nm, and the reference wavelength of the focal length was 530nm.

TABLE 3 Table 3

In the second embodiment, table 4 gives the higher order coefficients that can be used for each aspherical lens in the second embodiment, where each aspherical surface profile can be defined by the formula given in the first embodiment.

TABLE 4 Table 4

Referring to fig. 4, as can be seen from the longitudinal spherical aberration diagram of fig. 4 (a), the astigmatic curve diagram of fig. B, and the distortion curve diagram of fig. C, the longitudinal spherical aberration and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of the embodiment has good imaging quality. In addition, regarding the wavelengths corresponding to the curves in fig. 4 (a), fig. B, and fig. C), reference may be made to what is described in the first embodiment with respect to fig. 2 (a), fig. B, and fig. C, and the description thereof will not be repeated here.

Third embodiment

Referring to fig. 5, fig. 5 is a schematic diagram illustrating a structure of a projection module 10 according to a third embodiment of the application. The projection module 10 includes an optical lens 100, a prism L6, a cover glass L7, and an image display element 200, which are disposed in order from an imaging side to an image source side along an optical axis O. The optical lens 100 includes a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are disposed in order from the imaging side to the image source side along the optical axis O.

Further, in the third embodiment, the refractive powers of the respective lenses coincide with those of the first embodiment. In the third embodiment, however, the surface type of each lens differs from that of the first embodiment in that: the image-source side surface S2 of the first lens L1 is concave at the paraxial region O, and the image-forming side surface S7 of the fourth lens L4 is convex at the paraxial region O.

In the third embodiment, the effective focal length f= 8.499mm of the optical lens 100, the field angle fov=32° of the optical lens 100, the total optical length ttl= 15.6519mm of the optical lens 100, and the f-number fno= 2.4853 are taken as examples. The other parameters in the third embodiment are given in the following table 5, and the definition of the parameters can be obtained from the foregoing description, which is not repeated here. It is understood that the units of Y radius, thickness, and focal length in Table 5 are all mm. And the refractive index and Abbe number of each lens in Table 5 were 587.6nm, and the reference wavelength of the focal length was 530nm.

TABLE 5

In the third embodiment, table 6 gives the higher order coefficients that can be used for each aspherical lens in the third embodiment, where each aspherical surface profile can be defined by the formula given in the first embodiment.

TABLE 6

Referring to fig. 6, as can be seen from the longitudinal spherical aberration diagram of fig. 6 (a), the astigmatic curve diagram of fig. B, and the distortion curve diagram of fig. C, the longitudinal spherical aberration and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of the embodiment has good imaging quality. In addition, regarding the wavelengths corresponding to the curves in fig. 6 (a), fig. B, and fig. C), reference may be made to what is described in the first embodiment with respect to fig. 2 (a), fig. B, and fig. C, and the description thereof will not be repeated here.

Fourth embodiment

Fig. 7 is a schematic structural diagram of a projection module 10 according to a fourth embodiment of the present application. The projection module 10 includes an optical lens 100, a prism L6, a cover glass L7, and an image display element 200, which are disposed in order from an imaging side to an image source side along an optical axis O. The optical lens 100 includes a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are disposed in order from the imaging side to the image source side along the optical axis O.

Further, in the fourth embodiment, the refractive powers of the respective lenses coincide with those of the first embodiment. In the fourth embodiment, however, the surface type of each lens differs from that of the first embodiment in that: the image-side surface S7 of the fourth lens element L4 is convex at a paraxial region O, and the image-source side surface S10 of the fifth lens element L5 is concave at the paraxial region O.

In the fourth embodiment, the focal length f=8.595 mm of the optical lens 100, the field angle fov=32° of the optical lens 100, the total optical length ttl= 15.6999mm of the optical lens 100, and the f-number fno= 2.4853 are taken as examples. The other parameters in the fourth embodiment are given in the following table 7, and the definition of the parameters can be obtained from the foregoing description, which is not repeated here. It is understood that the units of Y radius, thickness, and focal length in Table 7 are all mm. And the refractive index and Abbe number of each lens in Table 7 were 587.6nm, and the reference wavelength of the focal length was 530nm.

TABLE 7

In the fourth embodiment, table 8 gives the higher order coefficients that can be used for each aspherical lens in the fourth embodiment, where each aspherical surface profile can be defined by the formula given in the first embodiment.

TABLE 8

Referring to fig. 8, as can be seen from the longitudinal spherical aberration diagram of fig. 8 (a), the astigmatic curve diagram of fig. B, and the distortion curve diagram of fig. C, the longitudinal spherical aberration and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of the embodiment has good imaging quality. In addition, regarding the wavelengths corresponding to the curves in fig. 8 (a), fig. B, and fig. C), reference may be made to what is described in the first embodiment with respect to fig. 2 (a), fig. B, and fig. C, and the description thereof will not be repeated here.

Fifth embodiment

Fig. 9 is a schematic diagram of a projection module 10 according to a fifth embodiment of the application. The projection module 10 includes an optical lens 100, a prism L6, a cover glass L7, and an image display element 200, which are disposed in order from an imaging side to an image source side along an optical axis O. The optical lens 100 includes a stop STO, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5, which are disposed in order from the imaging side to the image source side along the optical axis O.

Further, in the fifth embodiment, the refractive powers of the respective lenses coincide with those of the first embodiment. In the fifth embodiment, however, the surface type of each lens differs from that of the first embodiment in that: the image-source side surface S2 of the first lens element L1 is concave at a paraxial region O, the image-forming side surface S7 of the fourth lens element L4 is convex at the paraxial region O, and the image-source side surface S10 of the fifth lens element L5 is concave at the paraxial region O.

In the fifth embodiment, the focal length f= 8.5082mm of the optical lens 100, the field angle fov=32° of the optical lens 100, the total optical length ttl= 15.499mm of the optical lens 100, and the f-number fno= 2.4853 are taken as examples. The other parameters in the fifth embodiment are given in the following table 9, and the definition of the parameters can be obtained from the foregoing description, which is not repeated here. It is understood that the units of Y radius, thickness, and focal length in Table 9 are all mm. And the refractive index and Abbe number of each lens in Table 9 were 587.6nm, and the reference wavelength of the focal length was 530nm.

TABLE 9

In the fifth embodiment, table 10 gives the higher order coefficients that can be used for each aspherical lens in the fifth embodiment, where each aspherical surface profile can be defined by the formula given in the first embodiment.

Table 10

Referring to fig. 10, as can be seen from the longitudinal spherical aberration diagram of fig. 10 (a), the astigmatic curve diagram of fig. B, and the distortion curve diagram of fig. C, the longitudinal spherical aberration and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of the embodiment has good imaging quality. In addition, regarding the wavelengths corresponding to the curves in fig. 10 (a), fig. B, and fig. C), reference may be made to what is described in the first embodiment with respect to fig. 2 (a), fig. B, and fig. C, and the description thereof will not be repeated here.

Referring to table 11, table 11 is a summary of the ratios of the relationships in the first embodiment to the fifth embodiment of the present utility model.

TABLE 11

Referring to fig. 11, the utility model further discloses an electronic device 1, where the electronic device 1 includes a housing 20 and the above-mentioned projection module 10, and the projection module 10 is disposed on the housing 20 to form a projection image. The electronic device 1 includes, but is not limited to, smart glasses, smart helmets, and the like. It can be appreciated that the electronic device 1 with the projection module 10 can effectively control the optical overall length of the optical lens 100, and realize a light, thin and miniaturized design of the optical lens 100, thereby realizing a miniaturized design of the projection module and the electronic device, and further being beneficial to improving the telecentricity of the optical lens 100, improving the depth of field of the optical lens 100, improving the uniformity of the optical lens 100, and improving the projection imaging quality of the optical lens 100.

The optical lens, the projection module and the electronic device disclosed in the embodiments of the present utility model are described in detail, and specific examples are applied to the description of the principles and the implementation modes of the present utility model, and the description of the above embodiments is only used to help understand the optical lens, the projection module, the electronic device and the core ideas thereof; meanwhile, as those skilled in the art will vary in the specific embodiments and application scope according to the idea of the present utility model, the present disclosure should not be construed as limiting the present utility model in summary.

Claims

1. An optical lens, characterized in that the optical lens has five lenses with refractive power, and the five lenses are a first lens, a second lens, a third lens, a fourth lens and a fifth lens in sequence from an imaging side to an image source side along an optical axis;

the optical lens satisfies the following relation: 3.1< TTL/ImgH <3.4;

2. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

5.3mm<f*tan(FOV)<5.5mm, and/or 0.31mm ² <T45*f*tan(FOV)<0.33mm ² ；

Wherein f is the focal length of the optical lens, FOV is the maximum angle of view of the optical lens, and T45 is the air gap between the fourth lens and the fifth lens on the optical axis.

3. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

f1/f+f2/f < -5, and/or 0.6< f4/f <0.9;

wherein f is the focal length of the optical lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, and f4 is the focal length of the fourth lens.

4. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

2< |r2/r1|, and/or 1.1< R3/R4<1.3, and/or 2.8< |r7/f|;

wherein, R1 is a radius of curvature of the imaging side surface of the first lens at the optical axis, R2 is a radius of curvature of the image source side surface of the first lens at the optical axis, R3 is a radius of curvature of the imaging side surface of the second lens at the optical axis, R4 is a radius of curvature of the imaging side surface of the second lens at the optical axis, R7 is a radius of curvature of the imaging side surface of the fourth lens at the optical axis, and f is a focal length of the optical lens.

5. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

0.6< ct1/(ct2+ct3) <0.8, and/or 1.3< ct4/CT2<2.5, and/or 1< ct4/CT5<1.6, and/or 0.4< sag32/CT3<0.6, and/or 0.13< ct1/TD <0.18;

wherein, CT1 is the thickness of the first lens element on the optical axis, CT2 is the thickness of the second lens element on the optical axis, CT3 is the thickness of the third lens element on the optical axis, CT4 is the thickness of the fourth lens element on the optical axis, CT5 is the thickness of the fifth lens element on the optical axis, SAG32 is the distance between the maximum aperture of the image source side surface of the third lens element and the intersection point of the image source side surface of the third lens element and the optical axis in the direction of the optical axis, and TD is the distance between the image source side surface of the first lens element and the image source side surface of the fifth lens element on the optical axis.

6. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

2< T23/ET23<6.5, and/or 0.5< ET4/CT4<0.71;

wherein T23 is an air gap between the second lens and the third lens on the optical axis, ET23 is a distance from a maximum caliber of an image source side surface of the second lens to a maximum caliber of an image side surface of the third lens in the optical axis direction, ET4 is a distance from a maximum caliber of an image side surface of the fourth lens to a maximum effective caliber of an image source side surface of the fourth lens in the optical axis direction, and CT4 is a thickness of the fourth lens on the optical axis.

7. The optical lens of claim 1, wherein the optical lens satisfies the following relationship:

0.6< sd11/SD52<0.8, and/or 2.5< td/SD52<2.7;

wherein SD11 is the effective half-caliber of the imaging side surface of the first lens, SD52 is the effective half-caliber of the image source side surface of the fifth lens, TD is the distance between the imaging side surface of the first lens and the image source side surface of the fifth lens on the optical axis, and CT1 is the thickness of the first lens on the optical axis.

8. The optical lens of claim 1, further comprising a stop on the imaging side of the first lens, the optical lens satisfying the following relationship: 0.93< TD/SD <0.95;

wherein SD is the distance between the aperture stop and the image-source side surface of the fifth lens element on the optical axis, and TD is the distance between the image-forming side surface of the first lens element and the image-source side surface of the fifth lens element on the optical axis.

9. A projection module comprising an image display element and the optical lens according to any one of claims 1 to 8, wherein the image display element is provided on an image source side of the optical lens.

10. An electronic device, comprising a housing and the projection module of claim 9, wherein the projection module is disposed on the housing.