Turn-back prism assembly and optical lens

Abstract

The utility model provides a turn-back prism assembly and an optical lens. The turn-back prism assembly is sequentially provided with an incident surface, a plurality of reflecting surfaces and an emergent surface along the direction of a light path, at least one stray light total reflection surface is arranged among the reflecting surfaces, and the stray light total reflection surface is used for reflecting stray light generated in the turn-back prism assembly and transmitting imaging light. The turn-back prism assembly solves the problem that the turn-back prism assembly in the prior art is easy to generate an internal reflection prism ghost image.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging equipment technology, and more specifically, to a folding prism assembly and an optical lens. Background Technology

[0002] With the development of electronic products, optical imaging systems play a crucial role. Users have increasingly higher demands for video recording capabilities in electronic devices, requiring them to meet diverse photographic needs. As electronic products trend towards miniaturization, optical lenses also need to evolve towards miniaturization, especially telephoto lenses. To meet the imaging requirements of telephoto lenses, they often employ retroprism assemblies to reduce their size. However, retroprism assemblies are prone to generating internal reflection ghosting, which negatively impacts the image quality of the optical lens.

[0003] In other words, existing reflective prism assemblies are prone to generating ghost images from the internal reflective prism. Utility Model Content

[0004] The main objective of this invention is to provide a folding prism assembly and an optical lens to solve the problem of ghosting images caused by internal reflection prisms in existing folding prism assemblies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a folding prism assembly is provided, which has an incident surface, multiple reflecting surfaces and an exit surface in sequence along the optical path. At least one stray light total reflection surface is provided between the multiple reflecting surfaces. The stray light total reflection surface is used to reflect stray light generated in the folding prism assembly and transmit imaging light.

[0006] Furthermore, the folding prism assembly includes multiple prisms, which are spaced apart from each other, and at least one of the adjacent prisms has a stray light total reflection surface on its critical surface.

[0007] Furthermore, there is an air gap between two adjacent prisms; or there is a connecting adhesive layer between two adjacent prisms, and the refractive index of the connecting adhesive layer is less than the refractive index of the prism.

[0008] Furthermore, the folding prism assembly, along the optical path, sequentially includes: an incident surface, a first reflecting surface, a second reflecting surface, a first stray light total internal reflection surface, a third reflecting surface, a second stray light total internal reflection surface, a fourth reflecting surface, a fifth reflecting surface, and an exit surface. The imaging light travels from the incident surface to the first reflecting surface. The first reflecting surface reflects the imaging light to the second reflecting surface. The second reflecting surface reflects the imaging light to the third reflecting surface. The third reflecting surface reflects the imaging light to the fourth reflecting surface. The fourth reflecting surface reflects the imaging light to the fifth reflecting surface. The fifth reflecting surface reflects the imaging light to the exit surface. A portion of the stray light generated within the folding prism assembly is totally reflected by the first stray light total internal reflection surface and cannot be incident on the third reflecting surface. The imaging light then passes through the first stray light total internal reflection surface and is incident on the third reflecting surface. Another portion of the stray light generated within the folding prism assembly is totally reflected by the second stray light total internal reflection surface and cannot be incident on the fourth reflecting surface. The imaging light then passes through the second stray light total internal reflection surface and is incident on the fourth reflecting surface.

[0009] Furthermore, the incident surface, the second reflecting surface, the fourth reflecting surface, and the exiting surface are located on the same plane; and / or the first reflecting surface, the third reflecting surface, and the fifth reflecting surface are located on different planes.

[0010] Furthermore, the folding prism assembly includes, in sequence along the optical path: an incident surface, a first reflecting surface, a second reflecting surface, a first penetrating surface, a second penetrating surface, a third reflecting surface, a third penetrating surface, a fourth penetrating surface, a fourth reflecting surface, a fifth reflecting surface, and an exiting surface. The first penetrating surface and the second penetrating surface are spaced apart to form a first gap, and the third penetrating surface and the fourth penetrating surface are spaced apart to form a second gap. The first penetrating surface serves as a first stray light total reflection surface, and the third penetrating surface serves as a second stray light total reflection surface.

[0011] Furthermore, the folding prism assembly includes a first prism, a second prism, and a third prism arranged in sequence. There is a first gap between the first prism and the second prism, and a second gap between the second prism and the third prism. A connecting adhesive layer is provided at the first gap and the second gap.

[0012] Furthermore, the first, second, and third prisms have the same thickness.

[0013] The first prism is a first trapezoidal prism. The lower base of the first trapezoidal prism includes an incident surface and a second reflecting surface. The side of the first trapezoidal prism away from the second prism has a first reflecting surface, and the side of the first prism close to the second prism has a first stray light total reflection surface.

[0014] The second prism is a second trapezoidal prism. The upper base of the second trapezoidal prism is flush with the lower base of the first trapezoidal prism, and the lower base of the second prism has a third reflecting surface. The side of the second trapezoidal prism away from the first prism has a second stray light total reflection surface.

[0015] The third prism is a third trapezoidal prism. The lower base of the third trapezoidal prism is flush with the upper base of the second trapezoidal prism. The lower base of the third trapezoidal prism has a fourth reflecting surface and an exiting surface. The side of the third trapezoidal prism away from the second prism has a fifth reflecting surface.

[0016] Furthermore, the first stray light total reflection surface and the incident surface have a first included angle β1, which is greater than or equal to 30° and less than or equal to 47°.

[0017] Furthermore, the second stray light total reflection surface has a second included angle β2 with the incident surface, the second included angle β2 being greater than or equal to 133° and less than or equal to 150°.

[0018] Furthermore, the first stray light total reflection surface has a first included angle β1 with the incident surface, and the second stray light total reflection surface has a second included angle β2 with the incident surface, with the first included angle β1 and the second included angle β2 being complementary.

[0019] Furthermore, the stray light total reflection surface is not parallel to the side surface of the folding prism assembly.

[0020] Furthermore, the incident surface has a first central axis, and the exit surface has a second central axis. The distance t between the first central axis and the second central axis and the refractive index n of the prism assembly satisfy the following condition: 14.07mm≤t / n≤19.41mm.

[0021] Furthermore, the refractive index n of the folding prism assembly satisfies: 1.5 ≤ n ≤ 1.55.

[0022] According to another aspect of the present invention, an optical lens is provided, including the above-described folding prism assembly.

[0023] The present invention provides a prism assembly with an incident surface, multiple reflecting surfaces and an exit surface in sequence along the optical path. At least one stray light total reflection surface is provided between the multiple reflecting surfaces. The stray light total reflection surface is used to reflect stray light generated in the prism assembly and transmit imaging light.

[0024] Light rays undergo multiple reflections within the refraction prism assembly to increase the optical path length. However, these multiple reflections increase the risk of stray light, potentially leading to ghosting. This application addresses this issue by incorporating at least one stray light total internal reflection surface within the refraction prism assembly. This surface allows imaging light to pass through while reflecting stray light, preventing it from following the imaging light to the next reflection surface. This reduces stray light exiting the exit surface and further minimizes the risk of ghosting. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0026] Figure 1 A schematic diagram of the structure of a folding prism assembly according to an optional embodiment of the present invention is shown;

[0027] Figure 2 It shows Figure 1 Schematic diagram of optical path transmission of the central folding prism assembly;

[0028] Figure 3 A schematic diagram of the structure of a folding prism assembly according to another optional embodiment of the present invention is shown;

[0029] Figure 4 It shows Figure 3 Schematic diagram of optical path transmission of the central folding prism assembly;

[0030] Figure 5 A schematic diagram of the optical path transmission of a folding prism assembly according to another optional embodiment of the present invention is shown;

[0031] Figure 6 A schematic diagram of the optical path transmission of a folding prism assembly according to another optional embodiment of the present invention is shown.

[0032] The above figures include the following reference numerals:

[0033] 10. Incident surface; 20. Exit surface; 30. First reflecting surface; 40. Second reflecting surface; 50. First stray light total reflection surface; 60. Third reflecting surface; 70. Second stray light total reflection surface; 80. Fourth reflecting surface; 90. Fifth reflecting surface; 100. Sixth reflecting surface; 110. Second penetrating surface; 120. Fourth penetrating surface; 130. First prism; 140. Second prism; 150. Third prism; 160. Fourth prism; 170. Third stray light total reflection surface; 180. Seventh reflecting surface; 190. Eighth reflecting surface; 200. Ninth reflecting surface; 210. Sixth penetrating surface. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0037] To address the problem of ghosting images caused by internal reflection prisms in existing technologies, this invention provides a prism assembly and an optical lens.

[0038] In an optional embodiment of this invention, the optical lens includes the following reflecting prism assembly, and the optical lens having the following reflecting prism assembly has the advantages of low ghosting energy and high imaging quality.

[0039] like Figures 1 to 6 As shown, the folding prism assembly has an incident surface 10, multiple reflecting surfaces and an exit surface 20 in sequence along the optical path. There is at least one stray light total reflection surface between the multiple reflecting surfaces. The stray light total reflection surface is used to reflect stray light generated in the folding prism assembly and transmit imaging light.

[0040] Light rays undergo multiple reflections within the refraction prism assembly to increase the optical path. However, these multiple reflections increase the risk of stray light, potentially leading to ghosting. This application addresses this by incorporating at least one stray light total internal reflection surface within the refraction prism assembly. This surface allows imaging light to pass through while reflecting stray light, preventing it from following the imaging light to the next reflection surface. This reduces stray light emanating from the exit surface 20, further minimizing the risk of ghosting.

[0041] It should be noted that the number of stray light total internal reflection surfaces can be designed according to actual needs; it can be one, two, three, or even more, without specific limitations. Generally, the number of stray light total internal reflection surfaces is related to the optical path length of light traveling within the refraction prism assembly. The longer the optical path length, the more times the light is refracted within the refraction prism assembly, increasing the risk of stray light generation, and thus requiring a larger number of stray light total internal reflection surfaces. Conversely, the shorter the optical path length, the fewer times the light is refracted within the refraction prism assembly, decreasing the risk of stray light generation, and thus requiring a smaller number of stray light total internal reflection surfaces.

[0042] In some optional embodiments, the folding prism assembly includes multiple prisms spaced apart from each other. At least one of the adjacent prisms has a stray light total internal reflection surface on its critical surface. It should be noted that the critical surface of a prism refers to the surface adjacent to the other prism in a pair of adjacent prisms; or it can be understood as the two closest surfaces of two adjacent prisms being critical surfaces. A critical surface with stray light total internal reflection must satisfy the total internal reflection condition. The number of prisms is related to the number of stray light total internal reflection surfaces; the number of stray light total internal reflection surfaces is positively correlated with the number of prisms.

[0043] Alternatively, the number of prisms may be one more than the number of stray light total reflection surfaces.

[0044] In some alternative embodiments, there is an air gap between two adjacent prisms. The prism through which the light passes first among the two adjacent prisms has a stray light total internal reflection surface, so that total internal reflection can occur when stray light passes through the stray light total internal reflection surface.

[0045] In some alternative embodiments, a connecting adhesive layer is provided between two adjacent prisms, and the refractive index of the connecting adhesive layer is less than the refractive index of the prism. The prism through which the light passes first among the two adjacent prisms has a stray light total internal reflection surface, so that total internal reflection can occur when stray light passes through the stray light total internal reflection surface.

[0046] In some alternative embodiments, the reflective prism assembly has an overall trapezoidal structure. The trapezoidal structure can be an isosceles trapezoid or a non-isosceles trapezoid. There is no specific limitation here, and it can be designed according to the light transmission path.

[0047] In some alternative embodiments, the stray light total internal reflection surface is not parallel to the side surface of the folding prism assembly. This arrangement reduces the reflection of imaging light by the stray light total internal reflection surface, thus reducing the loss of light energy. For example, the stray light total internal reflection surface is not parallel to the first reflection surface.

[0048] In some optional embodiments, the incident surface 10 has a first central axis, and the exit surface 20 has a second central axis. The distance t between the first and second central axes and the refractive index n of the reflecting prism assembly satisfy the following condition: 14.07 mm ≤ t / n ≤ 19.41 mm. Constraining t / n within a reasonable range facilitates multiple reflections, ensuring that the size of the reflecting prism assembly paired with a long-focal-length optical lens is relatively small, thereby reducing the size of the optical module and enabling the optical lens to meet miniaturization requirements. This is beneficial for achieving miniaturization while meeting telephoto performance requirements. For example, t / n = 15 mm. Another example: t / n = 16 mm. Another example: t / n = 17 mm. Another example: t / n = 18 mm. Another example: t / n = 19 mm.

[0049] In some alternative embodiments, the refractive index n of the reflecting prism assembly satisfies: 1.5 ≤ n ≤ 1.55. This setting facilitates multiple reflections while reducing wasted imaging light and ensuring light intensity. For example, n = 1.51. Another example, n = 1.52. Yet another example, n = 1.53. And yet another example, n = 1.54.

[0050] Example 1

[0051] In this embodiment, the folding prism assembly consists of three prisms, including two stray light total reflection surfaces.

[0052] like Figure 1 and Figure 2 As shown, the folding prism assembly, along the optical path, sequentially includes an incident surface 10, a first reflecting surface 30, a second reflecting surface 40, a first stray light total internal reflection surface 50, a third reflecting surface 60, a second stray light total internal reflection surface 70, a fourth reflecting surface 80, a fifth reflecting surface 90, and an exit surface 20. The imaging light rays pass through the incident surface 10 to the first reflecting surface 30. The first reflecting surface 30 reflects the imaging light rays to the second reflecting surface 40, the second reflecting surface 40 reflects the imaging light rays to the third reflecting surface 60, the third reflecting surface 60 reflects the imaging light rays to the fourth reflecting surface 80, and the fourth reflecting surface 80 reflects the imaging light rays... The image light is reflected to the fifth reflecting surface 90, which then reflects it to the exit surface 20. A portion of the stray light generated within the folding prism assembly is totally reflected by the first stray light total internal reflection surface 50, preventing it from reaching the third reflecting surface 60. The image light then passes through the first stray light total internal reflection surface 50 and reaches the third reflecting surface 60. Another portion of the stray light generated within the folding prism assembly is totally reflected by the second stray light total internal reflection surface 70, preventing it from reaching the fourth reflecting surface 80. The image light then passes through the second stray light total internal reflection surface 70 and reaches the fourth reflecting surface 80. In this embodiment, the folding prism assembly has two stray light total internal reflection surfaces, and the image light can pass through these surfaces. A portion of the stray light is totally reflected when passing through these surfaces and does not enter the next reflecting surface, effectively reducing stray light incident on the exit surface 20 and thus reducing the risk of ghosting.

[0053] like Figure 1 and Figure 2As shown, the incident surface 10, the second reflecting surface 40, the fourth reflecting surface 80, and the exit surface 20 are located on the same plane. Placing these components on the same plane allows for a more compact structure of the folding prism assembly, reducing its size and weight to accommodate miniaturized optical lenses. Furthermore, this arrangement simplifies alignment and assembly processes, reduces optical performance loss due to assembly errors, and facilitates control of the imaging light rays along the intended path, minimizing reflection and refraction on unintended paths. This helps reduce stray light generation and improves the imaging quality of the optical system.

[0054] like Figure 1 and Figure 2 As shown, the first reflecting surface 30, the third reflecting surface 60, and the fifth reflecting surface 90 are located on different planes. Setting the first reflecting surface 30, the third reflecting surface 60, and the fifth reflecting surface 90 on different planes facilitates the planning of the transmission path of the imaging light. The included angle between the first reflecting surface 30, the third reflecting surface 60, and the fifth reflecting surface 90 can be designed according to the specific light path so that the imaging light can undergo total internal reflection between multiple reflecting surfaces.

[0055] like Figure 1 and Figure 2 As shown, the reflecting prism assembly, along the optical path, sequentially includes an incident surface 10, a first reflecting surface 30, a second reflecting surface 40, a first penetrating surface, a second penetrating surface 110, a third reflecting surface 60, a third penetrating surface, a fourth penetrating surface 120, a fourth reflecting surface 80, a fifth reflecting surface 90, and an exit surface 20. The first penetrating surface and the second penetrating surface 110 are spaced apart to form a first gap, and the third penetrating surface and the fourth penetrating surface 120 are spaced apart to form a second gap. The first penetrating surface serves as a first stray light total internal reflection surface 50, and the third penetrating surface serves as a second stray light total internal reflection surface 70. Imaging light can pass through the first penetrating surface and enter the second penetrating surface 110. The first gap between the first and second penetrating surfaces 110 causes a change in refractive index when light enters the second penetrating surface 110 from the first penetrating surface, altering the light's transmission path. Simultaneously, the refractive index relationship on both sides of the first penetrating surface satisfies the total internal reflection condition, allowing some stray light incident on the first penetrating surface to undergo total internal reflection. Similarly, imaging light can pass through the third and fourth penetration surfaces. There is a second gap between the third and fourth penetration surfaces 120 so that when light enters the fourth penetration surface 120 from the third penetration surface, the refractive index changes, which can change the transmission path of the light. At the same time, the refractive index relationship on both sides of the third penetration surface satisfies the condition for total internal reflection, so that stray light can undergo total internal reflection when it is incident on the first penetration surface.

[0056] In some alternative embodiments, there is an air gap between the first penetrating surface and the second penetrating surface 110, and an air gap between the third penetrating surface and the fourth penetrating surface 120.

[0057] In some optional embodiments, the reflecting prism assembly includes a first prism 130, a second prism 140, and a third prism 150 arranged sequentially. A first gap exists between the first prism 130 and the second prism 140, and a second gap exists between the second prism 140 and the third prism 150. A connecting adhesive layer is disposed at the first gap and the second gap. The refractive index of the connecting adhesive layer between the first prism 130 and the second prism 140 is less than the refractive index of the first prism 130, so that some stray light incident from the first prism 130 towards the connecting adhesive layer can undergo total internal reflection. The refractive index of the connecting adhesive layer between the second prism 140 and the third prism 150 is less than the refractive index of the second prism 140, so that some stray light incident from the second prism 140 towards the third prism 150 can undergo total internal reflection.

[0058] like Figure 1 and Figure 2 As shown, the first prism 130, the second prism 140, and the third prism 150 have the same thickness. This arrangement ensures that the thickness of the reflective prism assembly formed by the first prism 130, the second prism 140, and the third prism 150 connected by a connecting adhesive layer is the same throughout, which is beneficial for controlling the light transmission path.

[0059] exist Figure 1 and Figure 2 In the specific embodiment shown, the first prism 130 is a first trapezoidal prism, the lower base of which includes an incident surface 10 and a second reflecting surface 40. The side of the first trapezoidal prism away from the second prism 140 has a first reflecting surface 30, and the side of the first prism 130 close to the second prism 140 has a first stray light total reflection surface 50. The second prism 140 is a second trapezoidal prism, the upper base of which is flush with the lower base of the first trapezoidal prism, and the lower base of the second prism 140 has a third reflecting surface 60. The side of the second trapezoidal prism away from the first prism 130 has a second stray light total reflection surface 70. The third prism 150 is a third trapezoidal prism, the lower base of which is flush with the upper base of the second trapezoidal prism, and the lower base of the third trapezoidal prism has a fourth reflecting surface 80 and an exiting surface 20. The side of the third trapezoidal prism away from the second prism 140 has a fifth reflecting surface 90.

[0060] Specifically, the first stray light total reflection surface 50 and the incident surface 10 have a first included angle β1, which is greater than or equal to 30° and less than or equal to 47°. By limiting the first included angle β1 to the range of 30° to 47°, some of the internal stray light in the folding prism assembly can satisfy the law of reflection when passing through the first stray light total reflection surface, thereby causing total internal reflection and reducing the amount of stray light entering the rear optical system, thus achieving the purpose of reducing internal stray light.

[0061] Specifically, the second stray light total reflection surface 70 and the incident surface 10 have a second included angle β2, which is greater than or equal to 133° and less than or equal to 150°. By limiting the second included angle β2 to the range of 133° to 150°, some of the internal stray light within the folding prism assembly can satisfy the law of reflection when passing through the second stray light total reflection surface, thereby achieving total internal reflection and reducing stray light entering the rear optical system, thus achieving the purpose of reducing internal stray light.

[0062] Specifically, the first stray light total reflection surface 50 has a first included angle β1 with the incident surface 10, and the second stray light total reflection surface 70 has a second included angle β2 with the incident surface 10. The first included angle β1 and the second included angle β2 are complementary. Setting the first included angle β1 and the second included angle β2 to be complementary is beneficial to the fabrication of the folding prism assembly and reduces the processing difficulty of the folding prism assembly.

[0063] Example 2

[0064] The difference from Embodiment 1 is that the shapes of the first prism 130, the second prism 140, and the third prism 150 are different.

[0065] Please see Figure 3 and Figure 4 In this embodiment, the first prism 130, the second prism 140 and the third prism 150 are all triangular prisms, and the bottom surface of the first prism 130, the top edge of the second prism 140 and the bottom surface of the third prism 150 are located on the same side, while the top edge of the first prism 130, the bottom surface of the second prism 140 and the top edge of the third prism 150 are located on the same side.

[0066] Other structures are similar to those in Embodiment 1, and no specific limitations are made here.

[0067] Example 3

[0068] The difference from Example 1 is that the number of prisms, the number of reflecting surfaces, and the number of stray light reflecting surfaces are different.

[0069] In this embodiment, please refer to Figure 5 The folding prism assembly consists of a first prism 130 and a second prism 140.

[0070] like Figure 5As shown, the folding prism assembly sequentially includes an incident surface 10, a first reflecting surface 30, a first penetrating surface (first stray light total internal reflection surface 50), a second penetrating surface 110, a second reflecting surface 40, a third reflecting surface 60, and an exit surface 20 along the optical path. A first gap is formed between the first penetrating surface and the second penetrating surface 110, with the first penetrating surface serving as the first stray light total internal reflection surface 50. Imaging light can pass through the first penetrating surface and enter the second penetrating surface 110. The first gap between the first and second penetrating surfaces 110 causes a change in refractive index when light enters the second penetrating surface 110 from the first penetrating surface, altering the light's transmission path. Simultaneously, the refractive index relationship on both sides of the first penetrating surface satisfies the total internal reflection condition, allowing some stray light incident on the first penetrating surface to undergo total internal reflection.

[0071] Example 4

[0072] The difference from Example 1 is that the number of prisms, the number of reflecting surfaces, and the number of stray light total reflection surfaces are different.

[0073] In this embodiment, please refer to Figure 6 The folding prism assembly consists of a first prism 130, a second prism 140, a third prism 150, and a fourth prism 160, and has three stray light total reflection surfaces.

[0074] like Figure 6As shown, the reflecting prism assembly, along the optical path, sequentially includes an incident surface 10, a first reflecting surface 30, a second reflecting surface 40, a first penetrating surface (first stray light total reflection surface 50), a second penetrating surface 110, a third reflecting surface 60, a fourth reflecting surface 80, a third penetrating surface (second stray light total reflection surface 70), a fourth penetrating surface 120, a fifth reflecting surface 90, a sixth reflecting surface 100, a fifth penetrating surface (third stray light total reflection surface 170), a sixth penetrating surface 210, a seventh reflecting surface 180, an eighth reflecting surface 190, a ninth reflecting surface 200, and an exit surface 20. A first gap is formed between the first penetrating surface and the second penetrating surface 110, with the first penetrating surface serving as the first stray light total reflection surface 50. A second gap is formed between the third penetrating surface and the fourth penetrating surface 120, with the third penetrating surface serving as the second stray light total reflection surface 70. A third gap is formed between the fifth penetrating surface and the sixth penetrating surface 210, with the fifth penetrating surface serving as the third stray light total reflection surface 170. Imaging light rays can pass through the first penetrating surface and enter the second penetrating surface 110. A first gap exists between the first and second penetrating surfaces 110, causing a change in refractive index when light enters the second penetrating surface 110, thus altering the light's transmission path. Simultaneously, the refractive index relationship on both sides of the first penetrating surface satisfies the condition for total internal reflection, ensuring that some stray light incident on the first penetrating surface undergoes total internal reflection. Similarly, imaging light rays can pass through the third and fourth penetrating surfaces 120, with a second gap between them. This second gap causes a change in refractive index when light enters the fourth penetrating surface 120, altering the light's transmission path. Furthermore, the refractive index relationship on both sides of the third penetrating surface satisfies the condition for total internal reflection, ensuring that stray light incident on the third penetrating surface undergoes total internal reflection. Similarly, imaging light can pass through the fifth and sixth penetration surfaces 210. There is a third gap between the fifth and sixth penetration surfaces 210 so that when light enters the sixth penetration surface 210 from the fifth penetration surface, the refractive index changes, which can change the transmission path of the light. At the same time, the refractive index relationship on both sides of the fifth penetration surface satisfies the condition for total internal reflection, so that stray light can undergo total internal reflection when it is incident on the fifth penetration surface.

[0075] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0076] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0077] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0078] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A folding prism assembly, characterized in that, The folding prism assembly has an incident surface (10), multiple reflecting surfaces and an exit surface (20) in sequence along the optical path. There is at least one stray light total reflection surface between the multiple reflecting surfaces. The stray light total reflection surface is used to reflect stray light generated in the folding prism assembly and transmit imaging light.

2. The folding prism assembly according to claim 1, characterized in that, The folding prism assembly includes multiple prisms, with adjacent prisms spaced apart, and at least one of the adjacent prisms has a stray light total reflection surface on its critical surface.

3. The folding prism assembly according to claim 2, characterized in that, There is an air gap between two adjacent prisms; or There is a connecting adhesive layer between two adjacent prisms, and the refractive index of the connecting adhesive layer is less than the refractive index of the prism.

4. The folding prism assembly according to claim 1, characterized in that, The folding prism assembly, along the optical path, sequentially includes: the incident surface (10), the first reflecting surface (30), the second reflecting surface (40), the first stray light total reflection surface (50), the third reflecting surface (60), the second stray light total reflection surface (70), the fourth reflecting surface (80), the fifth reflecting surface (90), and the exit surface (20). The imaging light beam travels through the incident surface (10) to the first reflecting surface (30), whereby the first reflecting surface (30) reflects the imaging light beam to the second reflecting surface (40), the second reflecting surface (40) reflects the imaging light beam to the third reflecting surface (60), the third reflecting surface (60) reflects the imaging light beam to the fourth reflecting surface (80), the fourth reflecting surface (80) reflects the imaging light beam to the fifth reflecting surface (90), and the fifth reflecting surface (90) reflects the imaging light beam to the exit surface (20). In this process, a portion of the stray light generated within the folding prism assembly is totally reflected by the first stray light total reflection surface (50) and cannot be incident on the third reflection surface (60). The imaging light then passes through the first stray light total reflection surface (50) and is incident on the third reflection surface (60). Another portion of the stray light generated within the folding prism assembly is totally reflected by the second stray light total reflection surface (70) and cannot be incident on the fourth reflection surface (80). The imaging light then passes through the second stray light total reflection surface (70) and is incident on the fourth reflection surface (80).

5. The folding prism assembly according to claim 4, characterized in that, The incident surface (10), the second reflecting surface (40), the fourth reflecting surface (80), and the exit surface (20) are located on the same plane; and / or The first reflective surface (30), the third reflective surface (60), and the fifth reflective surface (90) are located on different planes.

6. The folding prism assembly according to claim 4, characterized in that, The folding prism assembly includes, in sequence along the optical path: the incident surface (10), the first reflecting surface (30), the second reflecting surface (40), the first penetrating surface, the second penetrating surface (110), the third reflecting surface (60), the third penetrating surface, the fourth penetrating surface (120), the fourth reflecting surface (80), the fifth reflecting surface (90), and the exiting surface (20). The first penetrating surface and the second penetrating surface (110) are spaced apart to form a first gap, and the third penetrating surface and the fourth penetrating surface (120) are spaced apart to form a second gap. The first penetrating surface serves as the first stray light total reflection surface (50), and the third penetrating surface serves as the second stray light total reflection surface (70).

7. The folding prism assembly according to claim 6, characterized in that, The folding prism assembly includes a first prism (130), a second prism (140), and a third prism (150) arranged in sequence. The first prism (130) and the second prism (140) have a first gap, and the second prism (140) and the third prism (150) have a second gap. A connecting adhesive layer is provided at the first gap and the second gap.

8. The folding prism assembly according to claim 7, characterized in that, The first prism (130), the second prism (140), and the third prism (150) have the same thickness.

9. The folding prism assembly according to any one of claims 4 to 8, characterized in that, The folding prism assembly satisfies at least one of the following: The first stray light total reflection surface (50) and the incident surface (10) have a first included angle β1, which is greater than or equal to 30° and less than or equal to 47°; The second stray light total reflection surface (70) and the incident surface (10) have a second included angle β2, which is greater than or equal to 133° and less than or equal to 150°; The first stray light total reflection surface (50) has a first included angle β1 with the incident surface (10), and the second stray light total reflection surface (70) has a second included angle β2 with the incident surface (10). The first included angle β1 and the second included angle β2 are complementary.

10. The folding prism assembly according to any one of claims 1 to 8, characterized in that, The stray light total reflection surface is not parallel to the side surface of the folding prism assembly.

11. The folding prism assembly according to any one of claims 1 to 8, characterized in that, The incident surface (10) has a first central axis, and the exit surface (20) has a second central axis. The distance t between the first central axis and the second central axis and the refractive index n of the prism assembly satisfy the following condition: 14.07mm≤t / n≤19.41mm.

12. The folding prism assembly according to any one of claims 1 to 8, characterized in that, The refractive index n of the folding prism assembly satisfies: 1.5≤n≤1.

55.

13. An optical lens, characterized in that, Includes the folding prism assembly as described in any one of claims 1 to 12.

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