A four-piece subminiature periscopic lens

Abstract

The application provides a four-piece type ultra-small periscopic lens, which comprises, in sequence from an object side to an image side along an optical axis, a prism, a first lens, a second lens, a third lens, a fourth lens and an aperture stop; the first lens is a positive lens and a double-convex lens; the second lens is a positive lens, a convex surface towards an image plane and a concave surface towards an object plane; the third lens is a negative lens, a convex surface towards an image plane and a concave surface towards an object plane; and the fourth lens is a positive lens, a concave surface towards an image plane and a convex surface towards an object plane. The lens enables a device to realize a smaller and thinner appearance design while maintaining a high-performance optical system; through optimization of the design of the prism and the optical path structure, the utilization rate of light is improved, and light loss is reduced, so that the volume of the lens is further reduced under the premise of ensuring imaging quality. The lens is also committed to providing a wider focal length range and better optical performance to meet the diversified needs of users for shooting in different application scenarios.

Description

Technical Field

[0001] This invention relates to the field of optical equipment, and more specifically, to a four-element ultra-miniature periscope lens. Background Technology

[0002] With the widespread adoption of electronic products such as smartphones, drones, virtual reality (VR), and augmented reality (AR) devices, the market demands increasingly smaller, lighter, and higher-performance optical lenses. In this context, periscope lenses, as an important technological solution, utilize prisms or mirrors to fold the light path, enabling long-focal-length optical designs within a limited device thickness. This significantly improves optical zoom capabilities and has led to their widespread application in high-end mobile photography and other fields.

[0003] However, traditional periscope lenses still have significant limitations in their structural design. First, their optical modules occupy a large space inside the device, especially when high-magnification zoom or large aperture is required. This typically necessitates multiple lenses and complex optical path folding structures, making it difficult to effectively control the overall length and size of the module. This characteristic limits their application in devices that strive for an extremely compact design, and also restricts the layout space for other functional components such as battery capacity and heat dissipation modules.

[0004] Secondly, in terms of optical path processing, traditional designs often suffer from light efficiency loss due to multiple reflections, affecting image brightness and signal-to-noise ratio, especially in low-light environments. Furthermore, the inherent characteristics of the folded optical path structure often limit the size of the photosensitive element, thus affecting the effective photosensitive area of ​​the image sensor and hindering further improvements in image quality. Although the industry has attempted to improve optical performance and control size through aspherical lenses and glass-plastic hybrid materials, the increased number of lenses also brings problems such as higher assembly precision requirements and increased costs.

[0005] It is worth noting that with the expansion of application scenarios, emerging fields such as small drones, lightweight wearable devices, and VR / AR headsets are placing increasingly stringent demands on the size, weight, and environmental adaptability of lenses. Traditional periscope lenses, due to their complex structure and significant weight, are difficult to integrate effectively in these space-constrained and highly portable environments. Therefore, the industry urgently needs an innovative optical design solution that achieves a better balance in terms of overall optical length, radial dimensions, imaging performance, and structural adaptability to meet the increasingly demanding comprehensive requirements of modern electronic devices for lens modules. Summary of the Invention

[0006] This invention addresses the technical problems existing in the prior art by proposing a four-element ultra-miniature periscope lens, aiming to solve the problem that traditional periscope lenses are difficult to apply in miniaturized and lightweight electronic devices due to size and weight limitations, while overcoming the problems of complex optical path design and difficulty in balancing imaging quality and compact structure.

[0007] The technical solution provided by this invention is as follows: A four-element ultra-miniature periscope lens includes a prism, a first lens, a second lens, a third lens, a fourth lens, and an aperture stop arranged sequentially from the object side along the optical axis to the image side. The first lens is a positive lens, specifically a biconvex lens; The second lens is a positive lens, with a convex surface facing the image plane and a concave surface facing the object plane; The third lens is a negative lens, with a convex surface facing the image plane and a concave surface facing the object plane; The fourth lens is a positive lens, with a concave surface facing the image plane and a convex surface facing the object plane.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Optionally, the focal length of the first lens is f1, and the focal length of the lens is f, satisfying the following condition: 0.8 ≤ |f1 / f| ≤ 1.1.

[0010] Optionally, the combined focal length of the second lens, the third lens, and the fourth lens is f234, and the lens focal length is f, satisfying the following conditions: 1.6 ≤ |f234 / f| ≤ 2.8.

[0011] Optionally, the focal length of the fourth lens is f4, and the focal length of the lens is f, satisfying the following condition: 0.6 ≤ |f4 / f| ≤ 0.7.

[0012] Optionally, the focal length of the first lens is f1, and the combined focal length of the second, third, and fourth lenses is f234, satisfying the following condition: 0.3 ≤ |f1 / f234| ≤ 0.7.

[0013] Optionally, the Abbe number vd of both the first lens and the fourth lens satisfies the following condition: 50 ≤ vd ≤ 60.

[0014] Optionally, the total optical length (TTL) of the lens optical system of the four-element ultra-compact periscope lens satisfies the following condition: 4.0mm ≤ TTL ≤4.4mm.

[0015] The present invention provides a four-element ultra-compact periscope lens, which combines a prism, an aperture stop, and four lenses according to a specific surface shape and a reasonable distribution of optical power, and has the following beneficial effects: This four-element ultra-compact periscope lens aims to achieve a smaller size and lighter weight, enabling its widespread application in various electronic devices with strict space and weight constraints, not just mobile phones. This lens design significantly shortens the physical length of the lens, allowing for a smaller, thinner form factor while maintaining a high-performance optical system. By optimizing the prism design and optical path structure, light utilization is improved and light loss is reduced, further minimizing the lens size while ensuring image quality. The lens also strives to provide a wider focal length range and better optical performance to meet the diverse shooting needs of users in different application scenarios, such as long-distance high-definition shooting in small drones or convenient everyday shooting in wearable devices. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the MFT performance of a four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the FFT modulation transfer function data of the defocusing change of the four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention at a specified frequency. Figure 4 This is a schematic diagram of light distortion and field curvature at any pupil of the four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention. Figure 5 Ray fan diagram of the four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the relative illumination of the four-element ultra-miniature periscope lens provided in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the structure of the four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention; Figure 8 This is a schematic diagram of the MFT performance of a four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention. Figure 9 This is a schematic diagram of the FFT modulation transfer function data of the defocusing change of the four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention at a specified frequency. Figure 10This is a schematic diagram of light distortion and field curvature at any pupil of the four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention. Figure 11 Ray fan diagram of the four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention; Figure 12 This is a schematic diagram of the relative illumination of the four-element ultra-miniature periscope lens provided in Embodiment 2 of the present invention; Figure 13 This is a schematic diagram of the structure of the four-piece ultra-miniature periscope lens provided in Embodiment 3 of the present invention; Figure 14 This is a schematic diagram of the MFT performance of the four-element ultra-miniature periscope lens provided in Embodiment 3 of the present invention. Figure 15 This is a schematic diagram of the FFT modulation transfer function data of the defocusing change of the four-element ultra-small periscope lens provided in Embodiment 3 of the present invention at a specified frequency. Figure 16 This is a schematic diagram of light distortion and field curvature at any pupil of the four-element ultra-miniature periscope lens provided in Embodiment 3 of the present invention. Figure 17 Ray fan diagram of the four-piece ultra-miniature periscope lens provided in Embodiment 3 of the present invention; Figure 18 This is a schematic diagram of the relative illumination of the four-element ultra-miniature periscope lens provided in Embodiment 3 of the present invention; Figure 19 This is a schematic diagram of the structure of the four-piece ultra-miniature periscope lens provided in Embodiment 4 of the present invention; Figure 20 This is a schematic diagram of the MFT performance of the four-element ultra-miniature periscope lens provided in Embodiment 4 of the present invention. Figure 21 This is a schematic diagram of the FFT modulation transfer function data of the defocusing change of the four-element ultra-miniature periscope lens provided in Embodiment 4 of the present invention at a specified frequency. Figure 22 This is a schematic diagram of light distortion and field curvature at any pupil of the four-element ultra-miniature periscope lens provided in Embodiment 4 of the present invention. Figure 23 Ray fan diagram of the four-piece ultra-miniature periscope lens provided in Embodiment 4 of the present invention; Figure 24 This is a schematic diagram of the relative illumination of the four-element ultra-miniature periscope lens provided in Embodiment 4 of the present invention; The attached diagram lists the components represented by each number as follows: STO, aperture stop; L1, first lens; L2, second lens; L3, third lens; L4, fourth lens. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Description of relevant feature parameters in this invention: TTL is the total optical length of the lens optical system (the distance from the center point of the first lens surface to the center point of the image surface on the central optical axis). f1 is the focal length of the first lens; f2 is the focal length of the second lens; f3 is the focal length of the third lens; f234 is the focal length of the combined lens consisting of the second, third, and fourth lenses; f is the lens focal length (focal length is a measure of the convergence or divergence of light in an optical system; it refers to the distance from the optical center of the lens to the focal point where parallel light converges when incident).

[0019] This invention provides a four-element ultra-compact periscope lens, such as... Figure 1 As shown, the perspective lens includes four lenses, arranged from the object side along the optical axis to the image side, in the following order: prism, first lens, second lens, third lens, fourth lens, and aperture stop. The first lens is a positive lens, specifically a biconvex lens; The second lens is a positive lens, with a convex surface facing the image plane and a concave surface facing the object plane; The third lens is a negative lens, with a convex surface facing the image plane and a concave surface facing the object plane; The fourth lens is a positive lens, with a concave surface facing the image plane and a convex surface facing the object plane.

[0020] Based on the above technical solution, the present invention can also be improved as follows.

[0021] Optionally, the focal length of the first lens is f1, and the focal length of the lens is f, satisfying the following condition: 0.8 ≤ |f1 / f| ≤ 1.1.

[0022] Optionally, the combined focal length of the second lens, the third lens, and the fourth lens is f234, and the lens focal length is f, satisfying the following conditions: 1.6 ≤ |f234 / f| ≤ 2.8.

[0023] Optionally, the focal length of the fourth lens is f4, and the focal length of the lens is f, satisfying the following condition: 0.6 ≤ |f4 / f| ≤ 0.7.

[0024] Optionally, the focal length of the first lens is f1, and the combined focal length of the second, third, and fourth lenses is f234, satisfying the following condition: 0.3 ≤ |f1 / f234| ≤ 0.7.

[0025] Optionally, the Abbe number vd of both the first lens and the fourth lens satisfies the following condition: 50 ≤ vd ≤ 60.

[0026] Optionally, the total optical length (TTL) of the lens optical system of the four-element ultra-compact periscope lens satisfies the following condition: 4.0mm ≤ TTL ≤4.4mm.

[0027] Example 1 This embodiment provides a structure for a four-element ultra-compact periscope lens, as shown below. Figure 1 As shown in the table below, the lens data of the four-element ultra-compact periscope lens in this embodiment are as follows:

[0028] In this embodiment, the characteristic parameter values ​​of the four-element ultra-miniature periscope lens are:

[0029] All of the above feature parameters fall within the following parameter range: 0.8 ≤ |f1 / f| ≤ 1.1; 1.6 ≤ |f234 / f| ≤ 2.8; 0.6 ≤ |f4 / f| ≤ 0.7; 0.3 ≤ |f1 / f234| ≤ 0.7.

[0030] It should be noted that the full name of the modulation transfer function (MTF) is Modulation Transfer Function. MTF comprehensively reflects the contrast and resolution characteristics of a lens. It is measured by instruments, which can completely eliminate the influence of objective factors such as film and subjective factors of human interpretation.

[0031] MTF (Mean Transmission Factor) is one of the best tools for quantifying the overall imaging performance of a system in terms of resolution and contrast. A higher MTF value indicates a higher system resolution and the ability to convey finer details. MTF is a method of combining resolution and contrast into a single specification or rule. An MTF curve displays both resolution and contrast information simultaneously, allowing it to evaluate lenses according to the needs of a specific application and to compare the performance of multiple lenses.

[0032] Figure 2 The image shows the MTF performance of the four-element ultra-compact periscope lens in Example 1. The X and Y axes represent the following: the horizontal axis represents different density levels (0-90 lp / mm); the vertical axis represents the lens performance percentage from 0 to 100. A higher MTF curve indicates a higher lens MTF score and better performance. A higher density (90 lp / mm) MTF curve score indicates a stronger ability to observe small objects.

[0033] The meanings of solid and dashed lines: Solid lines represent the MTF curve generated parallel to the diameter direction, called the sagittal curve; dashed lines represent the MTF curve generated perpendicular to the diameter direction, called the meridional curve. The closer the solid and dashed lines are, the closer the MTF performance of the lens is in the meridional and sagittal directions, and the better the lens performance.

[0034] Different solid / dashed line groups represent different field of view heights. A field of view height of 0 indicates the center of the lens. The larger the field of view height, the farther away from the center. The MTF performance of each line is closer, indicating good consistency between the center and the edge of the lens.

[0035] Figure 3 This is a schematic diagram of the FFT modulation transfer function data of the four-element ultra-small periscope lens of Example 1 at a specified frequency to show the defocus change; it can be seen that the more concentrated the curve is and the higher the peak value is, the better the corresponding lens imaging effect.

[0036] Figure 4 This is a schematic diagram of the distortion and field curvature of light rays at any pupil of the four-element ultra-compact periscope lens of Example 1. Wave represents the distortion and field curvature of light rays at any pupil within an arbitrary field of view. The field curvature diagram on the left shows the curve of the distance from the image plane to the paraxial image plane as a function of the field of view coordinates; the distortion diagram on the right shows the difference between the true image height and the ideal image height for each field of view, with better imaging results closer to the center.

[0037] Figure 5 The image shown is a Ray fan diagram of the four-element ultra-compact periscope lens of Example 1. The smaller the value, the better the imaging effect.

[0038] Figure 6This is a relative illumination diagram of the four-element ultra-small periscope lens in Example 1. The higher the value, the better the relative illumination.

[0039] Example 2 This embodiment provides a structure for a four-element ultra-compact periscope lens, as shown below. Figure 7 As shown in the table below, the lens data of the four-element ultra-compact periscope lens in this embodiment are as follows:

[0040] In this embodiment, the characteristic parameter values ​​of the four-element ultra-miniature periscope lens are:

[0041] All of the above feature parameters fall within the following parameter range: 0.8 ≤ |f1 / f| ≤ 1.1; 1.6 ≤ |f234 / f| ≤ 2.8; 0.6 ≤ |f4 / f| ≤ 0.7; 0.3 ≤ |f1 / f234| ≤ 0.7.

[0042] Figure 8 The image shows the MTF performance of the four-element ultra-compact periscope lens in Example 2. The X and Y axes represent the following: the horizontal axis represents different density levels (0-90 lp / mm); the vertical axis represents the lens performance percentage from 0 to 100. A higher MTF curve indicates a higher lens MTF score and better performance. A higher density (90 lp / mm) MTF curve score indicates a stronger ability to observe small objects.

[0043] The meanings of solid and dashed lines: Solid lines represent the MTF curve generated parallel to the diameter direction, called the sagittal curve; dashed lines represent the MTF curve generated perpendicular to the diameter direction, called the meridional curve. The closer the solid and dashed lines are, the closer the MTF performance of the lens is in the meridional and sagittal directions, and the better the lens performance.

[0044] Different solid / dashed line groups represent different field of view heights. A field of view height of 0 indicates the center of the lens. The larger the field of view height, the farther away from the center. The MTF performance of each line is closer, indicating good consistency between the center and the edge of the lens.

[0045] Figure 9 This is a schematic diagram of the FFT modulation transfer function data of the four-element ultra-small periscope lens in Example 2, showing the defocus change at a specified frequency; it can be seen that the more concentrated the curve is and the higher the peak value is, the better the corresponding lens imaging effect.

[0046] Figure 10This is a schematic diagram of the distortion and field curvature of light rays at any pupil of the four-element ultra-compact periscope lens in Example 2. Wave represents the distortion and field curvature of light rays at any pupil within an arbitrary field of view. The field curvature diagram on the left shows the curve of the distance from the image plane to the paraxial image plane as a function of the field of view coordinates; the distortion diagram on the right shows the difference between the true image height and the ideal image height for each field of view, with better imaging results closer to the center.

[0047] Figure 11 The image shown is a Ray fan diagram of the four-element ultra-compact periscope lens in Example 2. The smaller the value, the better the imaging effect.

[0048] Figure 12 This is a relative illumination diagram of the four-element ultra-small periscope lens in Example 2. The higher the value, the better the relative illumination.

[0049] Example 3 This embodiment provides a structure for a four-element ultra-compact periscope lens, as shown below. Figure 13 As shown in the table below, the lens data of the four-element ultra-compact periscope lens in this embodiment are as follows:

[0050] In this embodiment, the characteristic parameter values ​​of the four-element ultra-miniature periscope lens are:

[0051] All of the above feature parameters fall within the following parameter range: 0.8 ≤ |f1 / f| ≤ 1.1; 1.6 ≤ |f234 / f| ≤ 2.8; 0.6 ≤ |f4 / f| ≤ 0.7; 0.3 ≤ |f1 / f234| ≤ 0.7.

[0052] Figure 14 This is the MTF performance graph for the four-element ultra-compact periscope lens of Example 3. The X and Y axes represent the following: the horizontal axis represents different density levels (0-90 lp / mm); the vertical axis represents the lens performance percentage from 0 to 100. A higher MTF curve indicates a higher lens MTF score and better performance. A higher density (90 lp / mm) MTF curve score indicates a stronger ability to observe small objects.

[0053] The meanings of solid and dashed lines: Solid lines represent the MTF curve generated parallel to the diameter direction, called the sagittal curve; dashed lines represent the MTF curve generated perpendicular to the diameter direction, called the meridional curve. The closer the solid and dashed lines are, the closer the MTF performance of the lens is in the meridional and sagittal directions, and the better the lens performance.

[0054] Different solid / dashed line groups represent different field of view heights. A field of view height of 0 indicates the center of the lens. The larger the field of view height, the farther away from the center. The MTF performance of each line is closer, indicating good consistency between the center and the edge of the lens.

[0055] Figure 15 This is a schematic diagram of the FFT modulation transfer function data of the four-element ultra-small periscope lens of Example 3 at a specified frequency to show the defocus change; it can be seen that the more concentrated the curve is and the higher the peak value is, the better the corresponding lens imaging effect.

[0056] Figure 16 This is a schematic diagram of the distortion and field curvature of light rays at any pupil of the four-element ultra-compact periscope lens in Example 3. Wave represents the distortion and field curvature of light rays at any pupil within an arbitrary field of view. The field curvature diagram on the left shows the curve of the distance from the image plane to the paraxial image plane as a function of the field of view coordinates; the distortion diagram on the right shows the difference between the true image height and the ideal image height for each field of view, with better imaging results closer to the center.

[0057] Figure 17 The image shown is a Ray fan diagram of the four-element ultra-compact periscope lens in Example 3. The smaller the value, the better the imaging effect.

[0058] Figure 18 This is a relative illumination diagram of the four-element ultra-small periscope lens in Example 3. The higher the value, the better the relative illumination.

[0059] Example 4 This embodiment provides a structure for a four-element ultra-compact periscope lens, as shown below. Figure 19 As shown in the table below, the lens data of the four-element ultra-compact periscope lens in this embodiment are as follows:

[0060] In this embodiment, the characteristic parameter values ​​of the four-element ultra-miniature periscope lens are:

[0061] All of the above feature parameters fall within the following parameter range: 0.8 ≤ |f1 / f| ≤ 1.1; 1.6 ≤ |f234 / f| ≤ 2.8; 0.6 ≤ |f4 / f| ≤ 0.7; 0.3 ≤ |f1 / f234| ≤ 0.7.

[0062] Figure 20This is the MTF performance graph for the four-element ultra-compact periscope lens of Example 4. The X and Y axes represent the following: the horizontal axis represents different density levels (0-90 lp / mm); the vertical axis represents the lens performance percentage from 0 to 100. A higher MTF curve indicates a higher lens MTF score and better performance. A higher density (90 lp / mm) MTF curve score indicates a stronger ability to observe small objects.

[0063] The meanings of solid and dashed lines: Solid lines represent the MTF curve generated parallel to the diameter direction, called the sagittal curve; dashed lines represent the MTF curve generated perpendicular to the diameter direction, called the meridional curve. The closer the solid and dashed lines are, the closer the MTF performance of the lens is in the meridional and sagittal directions, and the better the lens performance.

[0064] Different solid / dashed line groups represent different field of view heights. A field of view height of 0 indicates the center of the lens. The larger the field of view height, the farther away from the center. The MTF performance of each line is closer, indicating good consistency between the center and the edge of the lens.

[0065] Figure 21 This is a schematic diagram of the FFT modulation transfer function data of the four-element ultra-small periscope lens in Example 4 at a specified frequency to show the defocus change; it can be seen that the more concentrated the curve is and the higher the peak value is, the better the corresponding lens imaging effect.

[0066] Figure 22 This is a schematic diagram of the distortion and field curvature of light rays at any pupil of the four-element ultra-compact periscope lens in Example 4. Wave represents the distortion and field curvature of light rays at any pupil within an arbitrary field of view. The field curvature diagram on the left shows the curve of the distance from the image plane to the paraxial image plane as a function of the field of view coordinates; the distortion diagram on the right shows the difference between the true image height and the ideal image height for each field of view, with better imaging results closer to the center.

[0067] Figure 23 The image shown is a Ray fan diagram of the four-element ultra-compact periscope lens in Example 4. The smaller the value, the better the imaging effect.

[0068] Figure 24 This is a relative illumination diagram of the four-element ultra-small periscope lens in Example 4. The higher the value, the better the relative illumination.

[0069] In summary, the four-element ultra-miniature periscope lens provided in this invention aims to achieve a smaller size and lighter weight, enabling its widespread application in various electronic devices with strict space and weight constraints, and not just limited to mobile phones. This lens design can significantly shorten the physical length of the lens, allowing the device to achieve a smaller and thinner form factor while maintaining a high-performance optical system. For some portable devices with stringent space requirements, such as smartwatches and smart glasses, it can reduce the device size and improve portability without sacrificing image quality.

[0070] Specifically, the front focal length f1 / total focal length f satisfies 0.8 ≤ |f123 / f| ≤ 1.1, which is beneficial for lens distortion correction; the rear focal length f234 / total focal length f satisfies 1.2 ≤ |f456 / f| ≤ 2.6, which is beneficial for improving lens performance; the fourth lens focal length |f4 / f| is between 0.8 and 1.2, which is beneficial for achieving long focal lengths; the Abbe numbers L1 / L4 of the first and fourth lenses satisfy: 50 ≤ vd ≤ 60, which is beneficial for lens chromatic aberration correction; the total optical length of the lens satisfies 4.0~4.4mm (excluding prisms), which is beneficial for achieving a small size.

[0071] Furthermore, by optimizing the prism design and optical path structure, the utilization rate of light is improved and light loss is reduced, thereby further reducing the size of the lens while ensuring image quality. This lens also aims to provide a wider focal length range and better optical performance to meet the diverse shooting needs of users in different application scenarios, such as achieving long-distance high-definition shooting in small drones or convenient everyday shooting in wearable devices.

[0072] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0073] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A four-element ultra-compact periscope lens, characterized in that, It includes a prism, a first lens, a second lens, a third lens, a fourth lens, and an aperture stop arranged sequentially from the object side along the optical axis to the image side; The first lens is a positive lens, specifically a biconvex lens; The second lens is a positive lens, with a convex surface facing the image plane and a concave surface facing the object plane; The third lens is a negative lens, with a convex surface facing the image plane and a concave surface facing the object plane; The fourth lens is a positive lens, with a concave surface facing the image plane and a convex surface facing the object plane.

2. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The focal length of the first lens is f1, and the focal length of the lens is f, satisfying the following condition: 0.8 ≤ |f1 / f| ≤ 1.

1.

3. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The combined focal length of the second lens, the third lens, and the fourth lens is f234, and the lens focal length is f, satisfying the following conditions: 1.6 ≤ |f234 / f| ≤ 2.

8.

4. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The fourth lens has a focal length of f4, and the lens focal length is f, satisfying the following condition: 0.6 ≤ |f4 / f| ≤ 0.

7.

5. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The focal length of the first lens is f1, and the combined focal length of the second, third, and fourth lenses is f234, satisfying the following condition: 0.3 ≤ |f1 / f234| ≤ 0.

7.

6. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The Abbe number vd of both the first lens and the fourth lens satisfies the following condition: 50 ≤ vd ≤ 60.

7. The four-element ultra-compact periscope lens according to claim 1, characterized in that, The total optical length (TTL) of the lens optical system of the four-element ultra-compact periscope lens satisfies the following condition: 4.0mm ≤ TTL ≤4.4mm.

Images