TW202319796A - Optical imaging system, image capturing device, and electronic equipment - Google Patents

Abstract

An optical imaging system, an image capturing device, and an electronic equipment is disclosed. The optical imaging system includes a first lens, an aperture diaphragm, a second lens, a third lens, an infrared filter, and a fourth lens arranged in sequence along an optical axis from an object side to an image side. The first lens and the third lens have positive refractive power. The fourth lens has negative refractive power. The optical imaging system satisfies with -10＜f3/f4＜0、-5＜f/f2＜10, and -5＜f/f4＜0. f represents the total effective focal length of the optical imaging system. f2 represents the effective focal length of the second lens. f3 represents the effective focal length of the third lens. f4 represents the effective focal length of the fourth lens. The infrared filter, arranged between the image-side surface of the third lens and the object-side surface of the fourth lens, suppress the incident angle of light to the infrared filter within 20 degrees, thereby reducing the offset of the center cut-off wavelength of the incident light spectrum.

Description

Optical imaging system, imaging device and electronic equipment

The present invention relates to an optical imaging technology, and in particular to an optical imaging system, an imaging device and electronic equipment.

In recent years, with the rise of domestic mobile phones, major mobile phone manufacturers have set off an upsurge in the popularization of wide-angle cameras for mobile phones. Wide-angle lens shooting has a super large viewfinder range. Shooting can not only enhance the sense of depth and space of the picture, but also have an exaggerated elongated and enlarged effect, giving people the visual impact of "near large, far small". For various holiday gatherings, the wide-angle camera has a wider field of view and can take group photos of multiple people. Although wide-angle lenses have great advantages in market applications, as mobile phones become thinner and thinner, the design of the optical system of wide-angle lenses and the size of the image sensor at the imaging end are limited by technology and industrial standards. scene image. The optical design of wide-angle lenses with short focal lengths has become one of the hotspots in industrial lens design at present. However, with the optical system of wide-angle lenses with short focal lengths, as the back focal length becomes shorter, the chief ray angle (CRA) incident on the image plane will become larger.

Since the image sensor of the mobile phone camera lens is more sensitive to near-infrared light that cannot be seen by the human eye, the digital signal processor cannot correctly calculate the color, resulting in serious color cast. Therefore, the general optical system will add an infrared filter between the lens and the sensor. The function of this filter is to filter out the non-visible infrared light-sensitive band to reduce noise and improve the image quality of the visible light band. The specification is generally 650 nanometers. The transmittance near the wavelength is 50%. The infrared filters of the optical system in the prior art are arranged behind all the optical lenses of the optical system. The production of optical thin films is generally designed according to the normal incident angle of light, so the change of the incident angle will cause the optical properties of the film layer to change accordingly, the incident angle becomes larger, the central wavelength shifts to the short wavelength direction, and the light transmittance changes. Low. That is to say, the infrared filter has a spectral shift characteristic, so when the light passes through the infrared filter, as the incident light angle of the surrounding large field of view increases, the cut-off wavelength will drift physically, and the angle of 0-35° The offset at incidence will increase to around 50nm. When the main light angle is 35 degrees, the difference in cut-off wavelength between the center and the edge causes less red light to enter the edge, resulting in a color shading phenomenon in which the center of the image is red and the edge is blue. In order to solve these problems, the existing technology mainly adopts the method of coating the optical filter, but this method, on the one hand, the coating will be more difficult, the process is complicated, and the production cost is high; on the other hand, the problem of spectral shift cannot be completely solved. Still can cause color difference problem.

Therefore, the present invention aims at addressing the above problems, and proposes an optical imaging system, an imaging device, and electronic equipment to solve the problems caused by the prior art.

The present invention provides an optical imaging system, imaging device and electronic equipment, which suppresses the incident angle of light to the infrared filter to be substantially within 20 degrees, thereby reducing the offset of the central cut-off wavelength of the spectrum of the incident light, thereby improving In the optical system of the wide-angle lens, the central wavelength of the cut-off spectrum of the infrared filter shifts to the short wavelength direction, which causes image quality distortion problems such as color shading, and also greatly reduces the size of the infrared filter, eliminating the need for Manufactured by complex techniques to reduce production costs.

In one embodiment of the present invention, an optical imaging system includes a first lens, a diaphragm, a second lens, a third lens, an infrared filter, and a fourth lens arranged in sequence along the optical axis from the object side to the image side , wherein the first lens and the third lens have positive refractive power, the fourth lens has negative refractive power, and the optical imaging system satisfies: -10<f3/f4<0; -5<f/f2<10; and -5 <f/f4<0, where f is the total effective focal length of the optical imaging system, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens.

In one embodiment of the present invention, the second lens has positive or negative optical power.

In an embodiment of the present invention, the object side and the image side of the first lens, the second lens, the third lens and the fourth lens are all aspherical surfaces.

In one embodiment of the present invention, the object side and the image side of the infrared filter are spherical surfaces.

In one embodiment of the present invention, the position of the near optical axis and the circumference of the object side of the first lens are convex, and the position of the near optical axis and the circumference of the image side of the first lens are concave.

In one embodiment of the present invention, the position of the near optical axis on the object side of the second lens is convex, and the positions of the near optical axis and the circumference of the image side of the second lens are concave.

In one embodiment of the present invention, the near optical axis and the circumference of the object side of the third lens are concave, and the near optical axis and the circumference of the image side of the third lens are convex.

In one embodiment of the present invention, the position of the near optical axis on the object side of the fourth lens is convex, and the position of the near optical axis on the image side of the fourth lens is concave.

In an embodiment of the present invention, an image capturing device includes an optical imaging system and a photosensitive element, wherein the photosensitive element is located on the image side of the optical imaging system.

In an embodiment of the present invention, an electronic device includes an image capturing device and a device main body, wherein the image capturing device is installed on the device main body.

Based on the above, the optical imaging system, imaging device and electronic equipment place the infrared filter between the image side of the third lens and the object side of the fourth lens, so as to suppress the incident angle of light to the infrared filter within 20 degrees , and then reduce the offset of the central cut-off wavelength of the spectrum of the incident light, thereby improving the image quality distortion problems such as color shadows caused by the shift of the central wavelength of the cut-off spectrum of the infrared filter to the short wavelength direction of the optical system of the wide-angle lens , and also greatly reduce the size of the infrared filter, without the need for complex manufacturing processes to reduce manufacturing costs.

In order to make your review committee members have a further understanding and understanding of the structural features and the achieved effects of the present invention, I would like to provide a better embodiment diagram and a detailed description, as follows:

Embodiments of the present invention will be further explained in conjunction with related figures below. Wherever possible, the same reference numerals have been used throughout the drawings and description to refer to the same or similar components. In the drawings, the shape and thickness may be exaggerated for the sake of simplification and convenient labeling. It should be understood that elements not particularly shown in the drawings or described in the specification are forms known to those skilled in the art. Those skilled in the art can make various changes and modifications according to the content of the present invention.

When an element is referred to as being "on", it can generally mean that the element is directly on other elements, or there may be other elements present in between. Conversely, when an element is referred to as being "directly on" another element, it cannot have the other element in between. As used herein, the word "and/or" includes any combination of one or more of the associated listed items.

The following descriptions of "one embodiment" or "an embodiment" refer to at least one specific element, structure or feature associated with one embodiment. Therefore, multiple descriptions of "one embodiment" or "an embodiment" appearing in various places below do not refer to the same embodiment. Furthermore, specific components, structures and features in one or more embodiments may be combined in an appropriate manner.

The disclosure is particularly described with the following examples, which are for illustration only, since various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the disclosure, and therefore this The scope of protection of the disclosed content shall be subject to the definition of the appended patent application scope. Throughout the specification and claims, the meanings of "a" and "the" include that such description includes "one or at least one" of the element or component, unless the content clearly specifies otherwise. Furthermore, as used in the present disclosure, singular articles also include descriptions of plural elements or components, unless it is obvious from the specific context that the plural is excluded. Also, as applied in this description and all claims below, the meaning of "in" may include "in" and "on" unless the content clearly dictates otherwise. The terms (terms) used throughout the specification and patent claims, unless otherwise specified, generally have the ordinary meaning of each term used in this field, in the disclosed content and in the special content. Certain terms used to describe the disclosure are discussed below or elsewhere in this specification to provide practitioners with additional guidance in describing the disclosure. The use of examples anywhere throughout the specification, including examples of any terms discussed herein, is for illustration only and certainly does not limit the scope and meaning of the disclosure or any exemplified terms. Likewise, the present disclosure is not limited to the various embodiments presented in this specification.

It will be understood that the terms "comprising", "including", "having", "containing", "involving", etc. as used herein are open-ended The (open-ended) means including but not limited to. In addition, any embodiment or scope of claims of the present invention does not necessarily achieve all the objectives or advantages or features disclosed in the present invention. In addition, the abstract and title are only used to assist in the search of patent documents, and are not used to limit the scope of patent applications for inventions.

The terms "substantially", "around", "about" or "approximately" as used herein shall generally mean within 20% of a given value or range, Preferably within 10%. Furthermore, quantities provided herein may be approximate, thus meaning that the words "about", "about" or "approximately" may be used unless otherwise stated. When a quantity, concentration, or other value or parameter has a specified range, preferred range, or tabulated upper and lower ideal values, it shall be deemed to specifically disclose all ranges formed by any pair of upper and lower limits or ideal values, regardless of Whether the areas are disclosed separately. For example, if a certain length of the disclosed range is X centimeters to Y centimeters, it should be deemed that the disclosed length is H centimeters and H can be any real number between X and Y.

A kind of optical imaging system of the present invention will be proposed below, and its infrared filter is positioned between the image side of the third lens and the object side of the fourth lens, to suppress the incident angle of light to the infrared filter within 20 degrees, Further reducing the offset of the central cut-off wavelength of the spectrum of the incident light, thereby improving the color shading and other images caused by the shift of the central wavelength of the cut-off spectrum of the infrared filter to the short wavelength direction of the optical system of the wide-angle lens The problem of quality distortion is also greatly reduced, and the size of the infrared filter is greatly reduced, so that it does not need to be produced by complicated processes to reduce the production cost.

Fig. 1 is a schematic structural view of an optical imaging system according to an embodiment of the present invention. Please refer to FIG. 1 below to introduce the optical imaging system 100 . The optical imaging system 100 includes a first lens L1 , a diaphragm S1 , a second lens L2 , a third lens L3 , an infrared filter L5 and a fourth lens L4 arranged in sequence along the optical axis from the object side to the image side. The optical axis is indicated by a dashed line. The diaphragm S1 is mainly used as an aperture to limit the width, position and imaging range of imaging rays. In order to suppress the incident angle of light to the infrared filter L5 within 20 degrees and achieve the purpose of wide-angle imaging, the first lens L1 and the third lens L3 have positive refractive power, and the fourth lens L4 has negative refractive power, because Positive optical power has the effect of light convergence, and negative optical power has the effect of light divergence. The optical imaging system 100 satisfies: -10<f3/f4<0; -5<f/f2<10; and -5<f/f4<0, where f is the total effective focal length of the optical imaging system 100, the first lens L1 The effective focal length is represented by f1, f2 is the effective focal length of the second lens L2, f3 is the effective focal length of the third lens L3, and f4 is the effective focal length of the fourth lens L4. In addition, the second lens L2 has positive or negative refractive power, which can be designed according to requirements. The optical imaging system 100 can be applied to wide-angle and ultra-wide-angle camera modules with a short focal length and wide field of view (FOV) of thin and light mobile phones, ultra-wide-angle surveillance cameras with a short focal length, or optical modules.

The main functions of the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are to utilize their large-area and curved features to allow enough light rays to converge and focus on the image side of the optical imaging system 100, and By using enough light signals to be concentrated, images can be produced more quickly. The first lens L1 , the second lens L2 , the third lens L3 and the fourth lens L4 all have a circumference. The first lens L1 can be made of plastic, and the object side S2 and the image side S3 of the first lens L1 can both be aspherical. Preferably, the position of the near optical axis and the circumference of the object side S2 of the first lens L1 can be both convex, which can strengthen the positive refractive power of the first lens L1 that undertakes the main imaging function of the optical imaging system 100, and is conducive to the miniaturization of the module . The position of the near optical axis and the circumference of the image side S3 of the first lens L1 can be a concave surface. The first lens L1 adopts an aspherical lens, which is beneficial to light convergence and imaging, and can be easily made into a shape other than a spherical surface, so as to obtain more control variables and good imaging effects, and to correct aberrations. The second lens L2 can be made of plastic, and both the object side S4 and the image side S5 of the second lens L2 can be aspherical. Preferably, the near optical axis of the object side S4 of the second lens L2 can be convex, and the near optical axis and the circumference of the image side S5 of the second lens L2 can be concave. The second lens L2 adopts an aspheric lens, which is beneficial to light convergence and imaging, and can be easily made into a shape other than a spherical surface to obtain more control variables and good imaging effects, and to correct aberrations. The third lens L3 can be made of plastic, and both the object side S6 and the image side S7 of the third lens L3 can be aspherical. Preferably, the position of the near optical axis and the circumference of the object side S6 of the third lens L3 may be concave, and the position of the near optical axis and the circumference of the image side S7 of the third lens L3 may be convex. The third lens L3 can effectively reduce field curvature and distortion of the system and improve imaging quality. The third lens L3 adopts an aspheric lens, which is beneficial to light convergence and imaging, and can be easily made into a shape other than a spherical surface to obtain more control variables and good imaging effects, and to correct aberrations. The fourth lens L4 can be made of plastic, and both the object side S10 and the image side S11 of the fourth lens L4 can be aspherical. Preferably, the position of the near optical axis of the object side S10 of the fourth lens L4 can be convex, and the position of the near optical axis of the image side S11 of the fourth lens L4 can be concave, so as to facilitate the adjustment of the back focus. The image side S11 of the fourth lens L4 faces the imaging surface S12. The image side S11 of the fourth lens L4 is designed so that the radius of curvature changes from concave to convex in order to better correct the aberration of the off-axis field of view, so as to suppress the incident angle of light to the imaging surface S12, and to more accurately match the photosensitive element. The infrared filter L5 can be made of glass, and the object side S8 and the image side S9 of the infrared filter L5 can both be spherical. The infrared filter L5 is used to filter out light in other bands other than visible light, so as to reduce noise and improve image quality in visible light band.

Figure 2 is a curve diagram of the cut-off wavelength of the spectral center of the infrared filter with an incident angle of 20 degrees according to the present invention. As shown in Figure 1 and Figure 2, because the infrared filter L5 is located between the image side S7 of the third lens L3 and the object side S10 of the fourth lens L4, plus the conditions -10<f3/f4<0, -5<f/f2<10 and -5<f/f4<0 are satisfied, so the incident angle of the light to the infrared filter can be suppressed substantially within 20 degrees, when the wavelength of the incident light is 640 nanometers The transmittance is substantially 50%, so that the offset of the central cutoff wavelength is about 10 nanometers, which is significantly better than the 50 nanometers of the offset of the central cutoff wavelength in the prior art when the incident angle is substantially 35 degrees. Smaller, so it can reduce the offset of the central cut-off wavelength of the spectrum of the incident light, thereby improving the image of color shadows and other images caused by the shift of the central wavelength of the cut-off spectrum of the infrared filter to the short wavelength direction of the optical system of the wide-angle lens Quality distortion problem, and also greatly reduced the size of the infrared filter L5 to improve material utilization. The infrared filter L5 does not need to use complex coating process to reduce production cost.

Figure 3(a) is the field curvature diagram of different colored light in the meridian (Tangential) direction of the first embodiment of the present invention, and Figure 3(b) is the field curvature diagram of different colored light in the sagittal (Sagittal) direction of the first embodiment of the present invention ) direction of the field curvature diagram, Figure 4 is the first embodiment of the present invention, the distortion diagram of different colors of light. As shown in FIG. 1 , Table 1 and Table 2, the following introduces the first embodiment of the optical imaging system 100 , which satisfies the conditions of Table 1 and Table 2. Lens Specifications Effective focal length = 2.69 mm F-number (Fno) = 1.9 Total lens length = 4.05 mm surface number surface name surface type radius of curvature thickness Material Refractive index Abbe number Object surface sphere unlimited unlimited S1 light bar sphere unlimited -0.003 S2 first lens Aspherical 1.688 0.405 plastic 1.523 54.828 S3 Aspherical 3.031 0.325 S4 second lens Aspherical 9.888 0.257 plastic 1.642 22.408 S5 Aspherical 9.371 0.335 S6 third lens Aspherical -2.282 0.581 plastic 1.553 68.797 S7 Aspherical -1.159 0.050 S8 infrared filter sphere unlimited 0.2 Glass 1.508 64.20 S9 sphere unlimited 0.050 S10 fourth lens Aspherical 1.121 0.474 plastic 1.534 56.228 S11 Aspherical 0.866 1.374 imaging surface sphere unlimited Table I Aspheric coefficient Face number S2 S3 S4 S5 S6 S7 S10 S11 K -13.734 -89.657 8.349 75.718 2.369 -2.037 -0.876 -1.133 A4 0.2564 0.2190 -0.0743 0.0635 0.3045 0.0275 -0.2773 -0.3299 A6 -0.2961 -0.5085 -0.1003 -0.2391 -0.5905 -0.5722 0.0870 0.2041 A8 0.2963 0.7581 -0.1837 0.2010 0.6631 1.1355 -0.0121 -0.1055 A10 -0.2114 -0.7175 0.3962 -0.0869 -0.0698 -1.2402 -2.4461E-03 0.0388 A12 0.0950 0.3400 -0.4210 -0.1603 -0.5301 0.7861 6.2039E-05 -9.3424E-03 A14 -0.0226 -0.0633 0.1591 0.1689 0.3443 -0.3139 4.6977E-04 1.2487E-03 A16 0.0000 0.0000 0.0000 -0.0439 -0.0420 0.0663 -7.8806E-05 -6.6908E-05 Table II

In Table 2, K is the aspheric conic coefficient, and A4-A16 are the 4th-16th order aspheric coefficients of each surface. As shown in Fig. 3(a), Fig. 3(b) and Fig. 4, they respectively represent the field curvature diagram in the meridian direction, the field curvature diagram in the sagittal direction and the distortion curve diagram in the first embodiment of the present invention, wherein the solid line A wavelength of 656 nm is represented, a dashed line of average length represents a wavelength of 587 nm, and a long and short line represents a wavelength of 486 nm. It can be seen from FIG. 3(a), FIG. 3(b) and FIG. 4 that the aberration of the first embodiment of the optical imaging system is controlled within a reasonable range to ensure the imaging quality.

Fig. 5(a) is the field curvature diagram of different color lights in the meridional direction according to the second embodiment of the present invention, and Fig. 5(b) is a field curvature diagram of different color lights in the sagittal direction according to the second embodiment of the present invention , Fig. 6 is a distortion diagram of different color lights according to the second embodiment of the present invention. As shown in FIG. 1 , Table 3 and Table 4, the second embodiment of the optical imaging system 100 is introduced below, which satisfies the conditions in Table 3 and Table 4. Lens Specifications Effective focal length = 2.40 mm Aperture number (Fno) = 1.7 Total lens length = 4.11 mm surface number surface name surface type radius of curvature thickness Material Refractive index Abbe number Object surface sphere unlimited unlimited S1 light bar sphere unlimited -0.368 S2 first lens Aspherical 1.941 0.223 plastic 1.553 68.798 S3 Aspherical 3.966 0.524 S4 second lens Aspherical 4.792 0.841 plastic 1.509 56.317 S5 Aspherical 10.027 0.372 S6 third lens Aspherical -2.683 0.424 plastic 1.523 59.766 S7 Aspherical -1.144 0.050 S8 infrared filter sphere unlimited 0.200 Glass 1.508 64.20 S9 sphere unlimited 0.080 S10 fourth lens Aspherical 1.469 0.768 plastic 1.509 56.317 S11 Aspherical 0.912 0.631 imaging surface sphere unlimited Table three Aspheric coefficient Face number S2 S3 S4 S5 S6 S7 S10 S11 K -13.734 -89.657 8.3485 75.718 -1.5061 -2.2318 -0.876 -1.1328 A4 0.2564 0.2190 -0.0743 0.0635 0.3452 0.0633 -0.2773 -0.3299 A6 -0.2961 -0.5085 -0.1003 -0.2391 -0.6171 -0.4513 0.0870 0.2041 A8 0.2963 0.7581 -0.1837 0.2010 0.6333 0.9466 -0.0121 -0.1055 A10 -0.2114 -0.7175 0.3962 -0.0869 -0.0984 -1.1473 -2.4461E-03 0.0388 A12 0.0950 0.3400 -0.4210 -0.1603 -0.4863 0.8219 6.2039E-05 -9.3424E-03 A14 -0.0226 -0.0633 0.1591 0.1689 0.4191 -0.3088 4.6977E-04 1.2487E-03 A16 0.0000 0.0000 0.0000 -0.0439 -0.1043 0.0471 -7.8806E-05 -6.6908E-05 Table four

In Table 4, K is the aspheric conic coefficient, and A4-A16 are the 4th-16th order aspheric coefficients of each surface. As shown in Fig. 5(a), Fig. 5(b) and Fig. 6, they respectively represent the field curvature diagram in the meridian direction, the field curvature diagram in the sagittal direction and the distortion curve diagram of the second embodiment of the present invention, wherein the solid line A wavelength of 656 nm is represented, a dashed line of average length represents a wavelength of 587 nm, and a long and short line represents a wavelength of 486 nm. It can be seen from FIG. 5(a), FIG. 5(b) and FIG. 6 that the aberration of the second embodiment of the optical imaging system is controlled within a reasonable range to ensure the imaging quality.

Fig. 7 is a schematic structural view of an image capturing device according to an embodiment of the present invention. Please refer to FIG. 7 , the following introduces the imaging device 200 . The image capturing device 200 includes an optical imaging system 100 and a photosensitive element 20 , wherein the photosensitive element 20 is located on the image side of the optical imaging system 100 . The photosensitive element 20 can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) sensor. The optical imaging system 100 has been described above, and will not be repeated here.

Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention. Please refer to FIG. 8, the electronic device 300 is introduced below. The electronic device 300 includes an image capturing device 200 and a device main body 30 , wherein the image capturing device 200 is installed on the device main body 30 . The electronic device 300 includes but is not limited to a desktop computer, a notebook computer, a tablet computer, a smart phone, a digital camera, a smart bracelet, a smart watch or smart glasses.

According to the above-mentioned embodiment, the optical imaging system, the imaging device and the electronic equipment place the infrared filter between the image side of the third lens and the object side of the fourth lens, so as to suppress the incident angle of light to the infrared filter at 20° In order to reduce the offset of the central cut-off wavelength of the spectrum of the incident light, thereby improving the image quality of the optical system of the wide-angle lens due to the shift of the central wavelength of the cut-off spectrum of the infrared filter to the short wavelength direction, such as color shadows Distortion problem, and also greatly reduce the size of the infrared filter, no need to use complicated process to reduce production cost.

The above is only a preferred embodiment of the present invention, and is not used to limit the scope of the present invention. Therefore, all equal changes and modifications are made according to the shape, structure, characteristics and spirit described in the patent scope of the present invention. , should be included in the patent application scope of the present invention.

100: Optical imaging system 200: imaging device 20: photosensitive element 300: Electronic equipment 30: Equipment body L1: first lens L2: second lens L3: third lens L4: fourth lens L5: Infrared filter S1: light bar S2, S4, S6, S8, S10: Object side S3, S5, S7, S9, S11: Like side view

Fig. 1 is a schematic structural view of an optical imaging system according to an embodiment of the present invention. Figure 2 is a curve diagram of the cut-off wavelength of the spectral center of the infrared filter with an incident angle of 20 degrees according to the present invention. Fig. 3(a) is the field curvature diagram of different color lights in the meridian (Tangential) direction according to the first embodiment of the present invention. Fig. 3(b) is a field curvature diagram of different color lights in the sagittal direction according to the first embodiment of the present invention. Fig. 4 is a distortion diagram of different color lights in the first embodiment of the present invention. Fig. 5(a) is a field curvature diagram of different color lights in the meridian direction according to the second embodiment of the present invention. Fig. 5(b) is a field curvature diagram in the sagittal direction of different colored lights according to the second embodiment of the present invention. Fig. 6 is a distortion diagram of different color lights according to the second embodiment of the present invention. Fig. 7 is a schematic structural view of an image capturing device according to an embodiment of the present invention. Fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

100: Optical imaging system

L1: first lens

L2: second lens

L3: third lens

L4: fourth lens

L5: Infrared filter

S1: light bar

S2, S4, S6, S8, S10: Object side

S3, S5, S7, S9, S11: Like side view

Claims (10)

An optical imaging system, comprising a first lens, a diaphragm, a second lens, a third lens, an infrared filter and a fourth lens arranged in sequence along the optical axis from the object side to the image side, wherein the first lens and the The third lens has positive refractive power, the fourth lens has negative refractive power, and the optical imaging system satisfies: -10<f3/f4<0; -5<f/f2<10; and -5<f/f4 <0, where f is the total effective focal length of the optical imaging system, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens. The optical imaging system as claimed in claim 1, wherein the second lens has positive or negative refractive power. The optical imaging system according to claim 1, wherein the object side and the image side of the first lens, the second lens, the third lens and the fourth lens are all aspherical. The optical imaging system according to claim 1, wherein the object side and the image side of the infrared filter are spherical surfaces. The optical imaging system according to claim 1, wherein the object side of the first lens is convex near the optical axis and the circumference, and the image side of the first lens is concave near the optical axis and circumference. The optical imaging system according to claim 1, wherein the object side of the second lens is convex near the optical axis, and the image side of the second lens is concave near the optical axis and the circumference. The optical imaging system according to claim 1, wherein the object side of the third lens is concave near the optical axis and the circumference, and the image side of the third lens is convex near the optical axis and the circumference. The optical imaging system according to claim 1, wherein the object side of the fourth lens is convex near the optical axis, and the image side of the fourth lens is concave near the optical axis. An imaging device comprising: An optical imaging system according to any one of Claims 1 to 8; and A photosensitive element is located on the image side of the optical imaging system. An electronic device comprising: a device body; and An imaging device as described in claim 9, installed on the main body of the device.

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