Zoom projection lens and projection system

Abstract

The utility model discloses a zoom projection lens which comprises a first lens assembly, a second lens assembly, a third lens assembly, a diaphragm, a fourth lens assembly and a fifth lens assembly which are sequentially arranged along a direction from an object space to an image space. A full-group linkage zoom design is adopted, and the first lens assembly is set as a zoom group for changing the focal length of the projection lens; the second lens assembly, the third lens assembly, the fourth lens assembly and the fifth lens assembly are arranged to be a compensation group used for offsetting the image surface position change caused by the movement of the zoom group. When zooming is carried out from the telephoto end to the wide-angle end, the distance between the second lens assembly and the third lens assembly is gradually increased. According to the utility model, the space occupied by the lens is reduced, so that the lens can adapt to the working condition of a compact installation space, the lens can maintain excellent imaging performance at different focal lengths within the working temperature range of a special application scene, and the flexible adaptability of the zoom projection lens is improved. The utility model also provides a projection system.

Description

Technical Field

[0001] This utility model relates to the field of projection technology, and in particular to a zoom projection lens and projection system. Background Technology

[0002] Zoom projection lenses are a core component of existing home and commercial projection systems, and their design typically focuses on balancing image quality and zoom capability. To ensure image quality, current lenses often employ multi-lens group combinations, which improves optical performance but also results in a larger overall size. This structure limits their application in space-constrained environments, such as compact electronic devices and embedded display systems.

[0003] Furthermore, in certain specialized applications, such as high-altitude aircraft, rail transportation systems, industrial manufacturing sites, outdoor mobile display devices, and unmanned systems, projection lenses need to operate continuously within a temperature range of -40°C to 100°C or even wider. However, traditional home or commercial projection lenses often struggle to maintain reliable imaging stability and structural integrity in such extreme temperature environments.

[0004] Taking in-vehicle projection systems as an example, due to limited working space and large temperature differences in the environment, higher requirements are placed on the projection lens in terms of structural compactness, thermal stability, and dynamic adjustment capabilities. Currently, some in-vehicle projection systems are still limited to static projection, with a fixed imaging range and content that cannot be adjusted in real time, making it difficult to meet the needs of complex and ever-changing real-world scenarios.

[0005] With the rapid development of technologies such as smart devices, unmanned systems, and augmented reality, the demand for optical modules with intelligent adjustment and dynamic projection capabilities is increasing across multiple fields. Future projection systems will tend towards zoom capabilities, adaptability to complex environments, and real-time response capabilities, thereby better serving diverse scenarios such as driver assistance, human-computer interaction, industrial monitoring, and flight navigation. Therefore, developing zoom projection lenses suitable for multiple industries, with broad environmental adaptability and compact structures, is a key innovative task in optical system design. Utility Model Content

[0006] The purpose of this invention is to provide a zoom projection lens and a projection system including the lens, in order to solve the problems of large lens size, poor environmental adaptability and insufficient dynamic adjustment capability in the prior art, especially in working environments with large temperature differences and limited space, to improve the imaging stability of the lens and the flexibility of system integration.

[0007] To achieve the above objectives, this utility model provides the following solution:

[0008] This utility model provides a zoom projection lens, comprising the following components arranged sequentially along the object-to-image direction:

[0009] A first lens assembly having negative optical power;

[0010] A second lens assembly having positive optical power;

[0011] A third lens assembly, the third lens assembly having positive optical power;

[0012] Aperture;

[0013] A fourth lens assembly having positive optical power;

[0014] A fifth lens assembly having positive optical power, and the distance between the fifth lens assembly and the image plane remains constant;

[0015] The first lens assembly, the second lens assembly, the third lens assembly, the aperture stop, and the fourth lens assembly are all capable of moving relative to the fifth lens assembly;

[0016] When the zoom projection lens zooms, during the zoom process from the telephoto end to the wide-angle end, the third lens assembly, the aperture stop, and the fourth lens assembly can all move toward the direction closer to the image plane.

[0017] Preferably, a zoom design with full group linkage is adopted, in which the first lens assembly is set as a zoom group to change the focal length of the projection lens; and the second lens assembly, the third lens assembly, the fourth lens assembly, and the fifth lens assembly are set as a compensation group to compensate for the change in image plane position caused by the movement of the zoom group.

[0018] Preferably, when the zoom projection lens zooms from the telephoto end to the wide-angle end, the distance between the second lens assembly and the third lens assembly gradually increases.

[0019] Preferably, the first lens assembly includes a first lens and a second lens arranged sequentially along the object-to-image direction, and both the first lens and the second lens have negative optical power; when the zoom projection lens zooms, the distance between the first lens and the second lens remains unchanged.

[0020] Preferably, the second lens assembly includes a third lens with positive optical power; the third lens assembly includes a fourth lens with positive optical power; the fourth lens assembly includes a fifth lens with positive optical power and a sixth lens with negative optical power; and the fifth lens assembly includes a seventh lens with positive optical power.

[0021] Preferably, the fifth lens and the sixth lens are cemented doublet lenses.

[0022] Preferably, the aperture of the aperture is adjustable.

[0023] Preferably, the field of view of the zoom projection lens is 40° to 80° and the F-number is 1.9 to 2.1.

[0024] Preferably, at least one of the first lens, the second lens, or the third lens is a plastic aspherical lens.

[0025] This utility model also provides a projection system, including the above-mentioned zoom projection lens.

[0026] This invention achieves the following technical advantages over related technologies: The first lens assembly is mainly used to correct distortion and compress the incident light angle, allowing light to enter the second lens assembly at a smaller incident angle, thereby reducing the introduction of aberrations; the second and third lens assemblies work in conjunction with the first lens assembly to further correct aberrations, especially field curvature, ensuring consistent sharpness between the image edges and center; the aperture is used to control the light throughput entering the lens, thereby adjusting image brightness and sharpness; the fourth lens assembly corrects aberrations, especially chromatic aberration, after passing through the second and third lens assemblies, further improving image sharpness and color accuracy; the fifth lens assembly converges the light processed by all the preceding components onto the image plane, ensuring the principal ray is parallel to the optical axis when it reaches the image plane, further correcting aberrations, especially those related to field height, resulting in a more compact overall design and superior imaging performance. The principal ray originates from an off-axis point on the object side, passes through the center of the aperture, and finally reaches the corresponding image point on the image side, representing the center of the imaging beam.

[0027] This invention relates to a zoom projection lens that employs a fully interconnected zoom design. During zooming, the first lens assembly is configured as the zoom group to change the focal length of the projection lens; the second, third, fourth, and fifth lens assemblies are configured as the compensation group. Since moving the zoom group causes a significant shift in the image plane (focal point), the movement of the compensation group compensates for this change in image plane position. Through the linkage between the zoom group and the compensation group, it is ensured that the final clear image always accurately falls on the image plane as the focal length changes. Specifically, during the zoom process from the telephoto end to the wide-angle end, the third lens assembly, aperture, and fourth lens assembly can all move towards the image plane, and the distance between the second and third lens assemblies gradually increases. This invention reduces the space occupied by the lens, making it suitable for compact installation spaces, and maintaining excellent imaging performance at different focal lengths within the operating temperature range (-40℃ to 100℃) in special application scenarios.

[0028] This invention also provides a projection system, including the aforementioned zoom projection lens. The zoom projection lens is adaptable to various special application scenarios, including wide operating temperature ranges and confined spaces. These special application scenarios include, but are not limited to, intelligent vehicles, aerospace vehicles, rail transportation, special-purpose robots, industrial inspection devices, wearable devices, and outdoor interactive projection platforms. In these scenarios, equipment often faces operating conditions such as alternating high and low temperatures, limited space, continuous vibration, or the need for dynamic zoom response. The projection system of this invention effectively improves performance, reliability, and environmental adaptability. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the zoom projection lens disclosed in the embodiment of this utility model;

[0031] Figure 2 This is a schematic diagram of the zoom projection lens during zoom operation as disclosed in the embodiments of this utility model.

[0032] Figure 3 This is a dot plot of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3mm.

[0033] Figure 4 The modulation transfer function diagram of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3mm;

[0034] Figure 5 Distortion and field curvature diagrams of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3mm;

[0035] Figure 6 A dot plot of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3.6mm;

[0036] Figure 7 The modulation transfer function diagram of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3.6mm;

[0037] Figure 8 Distortion and field curvature diagrams of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 3.6mm;

[0038] Figure 9A dot plot of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 4.4mm;

[0039] Figure 10 The modulation transfer function diagram of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 4.4mm;

[0040] Figure 11 Distortion and field curvature diagrams of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 4.4mm;

[0041] Figure 12 A dot plot of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 5.45mm;

[0042] Figure 13 The modulation transfer function diagram of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 5.45mm;

[0043] Figure 14 The distortion and field curvature diagrams of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 5.45mm;

[0044] Figure 15 This is a dot plot of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 7mm.

[0045] Figure 16 The modulation transfer function diagram of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 7mm;

[0046] Figure 17 The distortion and field curvature diagrams of the zoom projection lens disclosed in this embodiment of the present invention when the focal length is 7mm.

[0047] In the diagram: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens. Detailed Implementation

[0048] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0049] The purpose of this invention is to provide a zoom projection lens and a projection system including the lens, in order to solve the problems of large lens size, poor environmental adaptability and insufficient dynamic adjustment capability in the prior art, especially in working environments with large temperature differences and limited space, to improve the imaging stability of the lens and the flexibility of system integration.

[0050] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] This embodiment provides a zoom projection lens; please refer to [reference needed]. Figures 1-17 The system includes a first lens assembly, a second lens assembly, a third lens assembly, an aperture stop, a fourth lens assembly, and a fifth lens assembly arranged sequentially along the object-to-image direction. The first lens assembly has negative optical power; the second lens assembly has positive optical power; the third lens assembly has positive optical power; the fourth lens assembly has positive optical power; and the fifth lens assembly has positive optical power, with a constant distance between the fifth lens assembly and the image plane. The first, second, third, aperture stop, and fourth lens assemblies are all movable relative to the fifth lens assembly. During zooming from the telephoto end to the wide-angle end, the third lens assembly, aperture stop, and fourth lens assembly are all movable towards the image plane, and the distance between the second and third lens assemblies gradually increases.

[0053] The zoom projection lens of this invention comprises a first lens assembly primarily used to correct distortion and compress the incident light angle, allowing light to enter the second lens assembly at a smaller incident angle, thereby reducing the introduction of aberrations. The second and third lens assemblies work in conjunction with the first lens assembly to further correct aberrations, particularly field curvature, ensuring consistent sharpness between the image edges and center. An aperture stop controls the light throughput entering the lens, adjusting image brightness and sharpness. A fourth lens assembly corrects aberrations, particularly chromatic aberration, after passing through the second and third lens assemblies, further improving image sharpness and color accuracy. A fifth lens assembly converges the light processed by all the preceding components onto the image plane, ensuring the principal ray reaches the image plane parallel to the optical axis, further correcting aberrations, especially those related to field height, resulting in a more compact overall design and superior imaging performance. The principal ray originates from an off-axis point on the object side, passes through the center of the aperture stop, and finally reaches the corresponding image point on the image side; it represents the center of the imaging beam.

[0054] This invention relates to a zoom projection lens that employs a fully interconnected zoom design. During zooming, the first lens assembly is configured as the zoom group to change the focal length of the projection lens; the second, third, fourth, and fifth lens assemblies are configured as the compensation group. Since moving the zoom group causes a significant shift in the image plane (focal point), the movement of the compensation group compensates for this change in image plane position. Through the linkage between the zoom group and the compensation group, it is ensured that the final clear image remains precisely on the image plane regardless of the focal length. Specifically, during the zoom process from the telephoto end to the wide-angle end, the third lens assembly, aperture, and fourth lens assembly can all move towards the image plane, and the distance between the second and third lens assemblies gradually increases. This invention reduces the space occupied by the lens, making it suitable for compact installation spaces. Furthermore, within the operating temperature range (-40℃ to 100℃) of special application scenarios, the lens maintains excellent imaging performance at different focal lengths, greatly improving the flexibility and adaptability of the zoom projection lens. It should also be explained here that the first lens assembly, second lens assembly, third lens assembly, aperture, fourth lens assembly and fifth lens assembly in the zoom projection lens of this utility model are all arranged along the optical axis.

[0055] The first lens assembly includes a first lens 1 and a second lens 2 arranged sequentially along the object-to-image direction. Both the first lens 1 and the second lens 2 have negative optical power, so that the first lens assembly has negative optical power. There is a certain distance between the first lens 1 and the second lens 2. When the zoom projection lens zooms, the distance between the first lens 1 and the second lens 2 remains unchanged, which is used to compress the angle of the incident light.

[0056] In this specific embodiment, the first lens 1 is a meniscus lens and the second lens 2 is a biconcave lens, so as to meet the requirement that the first lens assembly has negative optical power.

[0057] Specifically, the second lens assembly includes a third lens 3, which is a biconvex lens with positive optical power.

[0058] More specifically, the third lens assembly includes a fourth lens 4, which is a plano-convex lens with positive optical power. The zoom projection lens of this invention utilizes the fourth lens 4, the third lens 3, and the second lens 2 in conjunction to further correct aberrations, particularly field curvature, thereby ensuring consistent sharpness between the image edges and center.

[0059] Accordingly, the fourth lens assembly includes a cemented doublet consisting of a fifth lens 5 with positive optical power and a sixth lens 6 with negative optical power, used to correct aberrations, especially chromatic aberration, in the light after passing through the fourth lens 4, thereby further improving image clarity and color accuracy.

[0060] In this specific embodiment, the fifth lens assembly includes a seventh lens 7, which is a plano-convex lens with positive optical power. It is used to converge the light rays processed by all the preceding lenses onto the image plane, so that the main ray is parallel to the optical axis when it reaches the image plane, further correcting aberrations, especially aberrations related to the field of view height, making the overall design more compact and the imaging performance better.

[0061] In this specific embodiment, at least one of the first lens 1, the second lens 2, and the third lens 3 is a plastic aspherical lens, and the remaining lenses are glass lenses.

[0062] In other specific embodiments achievable by this utility model, the aperture of the aperture can be adjusted to adjust the light flux passing through the aperture, thereby meeting various imaging requirements and improving the flexibility and adaptability of the zoom projection lens.

[0063] Example 2

[0064] This embodiment provides a zoom projection lens. In this specific implementation, the zoom projection lens achieves zooming through the movement of the aforementioned lens assembly, with a focal length range of 3mm to 7mm. Simultaneously with the movement of each lens assembly, the total optical length (TTL) of the zoom projection lens changes accordingly. In this embodiment, within the focal length variation range, the field of view (FOV) of the zoom projection lens ranges from 40° to 80°, the F-number (aperture factor) ranges from 1.9 to 2.1, the total optical length (TTL) is within 100mm, and the geometric relationship between the field of view (FOV) and the total optical length (TTL) is tan(FOV / 2) / TTL > 0.0036mm. -1 .

[0065] This embodiment analyzes the imaging effect and athermalization performance of the lens at different focal lengths. The results show that the zoom projection lens of this embodiment maintains excellent imaging performance at characteristic focal lengths of 3.0mm, 3.6mm, 4.4mm, 5.45mm, and 7.0mm within an operating temperature range of -40℃ to 100℃. The MTF value is higher than 0.5 at a spatial frequency of 66lp / mm, the relative illumination exceeds 90%, the overall distortion is controlled within 3%, and the field curvature is less than 0.05mm. Furthermore, the tolerance results meet the assembly reliability requirements in an automotive environment. For detailed dot plots, modulation transfer function (MTF) diagrams, distortion and field curvature diagrams of the projection lens at each focal length (3.0mm, 3.6mm, 4.4mm, 5.45mm, 7.0mm), please refer to... Figures 3-17 .

[0066] Example 3

[0067] This utility model also provides a projection system, including a zoom projection lens of Embodiment 1 or Embodiment 2.

[0068] This invention's zoom projection lens can adapt to various special application scenarios, including those with a wide operating temperature range and confined spaces. These applications include, but are not limited to, smart cars, aerospace vehicles, rail transportation, special-purpose robots, industrial inspection devices, wearable devices, and outdoor interactive projection platforms. In these scenarios, equipment often faces operating conditions such as alternating high and low temperatures, limited space, continuous vibration, or the need for dynamic zoom response. This invention's projection system effectively improves performance, reliability, and environmental adaptability.

[0069] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of ​​this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A zoom projection lens, characterized in that, Including those arranged sequentially along the object-to-image direction: A first lens assembly having negative optical power; A second lens assembly having positive optical power; A third lens assembly, the third lens assembly having positive optical power; Aperture; A fourth lens assembly having positive optical power; A fifth lens assembly having positive optical power, and the distance between the fifth lens assembly and the image plane remains constant; The first lens assembly, the second lens assembly, the third lens assembly, the aperture stop, and the fourth lens assembly are all capable of moving relative to the fifth lens assembly; When the zoom projection lens zooms, during the zoom process from the telephoto end to the wide-angle end, the third lens assembly, the aperture stop, and the fourth lens assembly can all move toward the direction closer to the image plane.

2. The zoom projection lens according to claim 1, characterized in that: The system employs a fully integrated zoom design, with the first lens assembly configured as a zoom group to change the focal length of the projection lens; and the second, third, fourth, and fifth lens assemblies configured as a compensation group to compensate for changes in the image plane position caused by the movement of the zoom group.

3. The zoom projection lens according to claim 1, characterized in that: When the zoom projection lens zooms from the telephoto end to the wide-angle end, the distance between the second lens assembly and the third lens assembly gradually increases.

4. The zoom projection lens according to claim 1, characterized in that: The first lens assembly includes a first lens and a second lens arranged sequentially along the object-to-image direction. Both the first lens and the second lens have negative optical power. When the zoom projection lens zooms, the distance between the first lens and the second lens remains unchanged.

5. The zoom projection lens according to claim 1, characterized in that: The second lens assembly includes a third lens with positive optical power; the third lens assembly includes a fourth lens with positive optical power; the fourth lens assembly includes a fifth lens with positive optical power and a sixth lens with negative optical power; the fifth lens assembly includes a seventh lens with positive optical power.

6. The zoom projection lens according to claim 5, characterized in that: The fifth lens and the sixth lens are cemented doublet lenses.

7. The zoom projection lens according to claim 1, characterized in that: The aperture of the aperture can be adjusted.

8. The zoom projection lens according to claim 1, characterized in that: The zoom projection lens has a field of view of 40° to 80° and an F-number of 1.9 to 2.

1.

9. The zoom projection lens according to claim 4, characterized in that: At least one of the first lens, the second lens, or the third lens is a plastic aspherical lens.

10. A projection system, characterized in that: Includes the zoom projection lens as described in any one of claims 1-9.

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