Multi-lens projection lens, projector and optical equipment

Abstract

A multi-lens projection lens, a projector and an optical device are characterized in that the multi-lens projection lens comprises a first lens, a second lens, a third lens and a fourth lens which are sequentially arranged along an optical path; wherein the first lens is a biconvex positive lens; the second lens is a meniscus positive lens, the incident surface is a convex surface, and the emergent surface is a concave surface; the third lens is a biconcave negative lens; the fourth lens is a meniscus negative lens, the light-in surface is a concave surface, and the light-out surface is a convex surface. According to the utility model, the problems of speckle FOV, insufficient uniformity and distortion existing in the existing speckle projection scheme can be overcome, large FOV, high uniformity and low distortion speckle projection can be realized, and speckle projection with flexible pattern distribution can also be realized.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, specifically to a multi-lens projection lens, a projector, and an optical device. Background Technology

[0002] In the field of modern optical imaging, projection lenses are widely used in numerous optical display devices such as projectors, virtual reality (VR) devices, and augmented reality (AR) devices. With the continuous development of technology and people's increasing demands for display effects, more stringent standards are being set for the performance of projection lenses.

[0003] On the one hand, the demand for high-resolution and high-definition displays is constantly increasing. In traditional projection lens designs, due to the relatively simple optical structure, it is difficult to effectively correct optical problems such as aberrations. For example, in some low-quality projection lenses, phenomena such as blurred image edges and color distortion occur, seriously affecting the display effect. In order to achieve high-resolution and high-definition imaging, it is necessary to optimize the optical structure of the lens to reduce the impact of aberrations on image quality.

[0004] On the other hand, in certain specific applications, such as portable projectors and miniaturized VR / AR devices, there are strict limitations on the size and weight of the projection lens. However, traditional lens designs often struggle to achieve miniaturization while maintaining optical performance. This necessitates the development of novel lens structures to achieve better optical performance within limited space.

[0005] Furthermore, with the continuous innovation of optical display technology, such as the application of 3D display technology, higher requirements are being placed on the imaging accuracy and color reproduction capabilities of projection lenses. Traditional lenses are prone to problems such as inaccurate parallax and color deviation when processing complex 3D images, failing to meet users' needs for high-quality 3D displays.

[0006] The above background information is provided only to aid in understanding the inventive concept and technical solution of this utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Utility Model Content

[0007] Therefore, this utility model, by sequentially arranging a first lens, a second lens, a third lens, and a fourth lens along the optical path, and by rationally designing the type and shape of each lens, can effectively correct aberrations, improve the resolution and clarity of imaging, and meet the requirements of modern optical display devices for high-quality imaging. At the same time, the rational lens combination also helps to achieve lens miniaturization to a certain extent, adapting to the development trend of portable and miniaturized devices, and has important practical significance and application value.

[0008] In a first aspect, this utility model provides a multi-lens projection lens, characterized in that it comprises: a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical path; wherein...

[0009] The first lens is a biconvex positive lens;

[0010] The second lens is a meniscus lens, with a convex incident surface and a concave exit surface;

[0011] The third lens is a biconcave negative lens;

[0012] The fourth lens is a meniscus negative lens with a concave incident surface and a convex exit surface.

[0013] Optionally, the multi-lens projection lens is characterized by further comprising: an aperture stop located between the second lens and the third lens.

[0014] Optionally, the multi-lens projection lens is characterized in that the radius of curvature of the light-exiting surface of the first lens is greater than the radius of curvature of the light-incident surface of the first lens.

[0015] Optionally, the multi-lens projection lens is characterized in that the radius of curvature of the light-exiting surface of the second lens is greater than the radius of curvature of the light-incident surface of the second lens.

[0016] Optionally, the multi-lens projection lens is characterized by further including a spacer located between the first lens and the second lens for fixing the interval between the first lens and the second lens.

[0017] Optionally, the multi-lens projection lens is characterized in that the sum of the radii of curvature of the incident surface and the exit surface of the third lens is greater than the sum of the radii of curvature of the incident surface and the exit surface of any one of the first lens, the second lens, and the fourth lens.

[0018] Optionally, the multi-lens projection lens is characterized in that the radius of curvature of the light-incident surface of the fourth lens is smaller than the radius of curvature of the light-incident surfaces of the first lens, the second lens, and the third lens.

[0019] Optionally, the multi-lens projection lens is characterized in that the minimum distance between the first lens and the second lens is greater than the maximum distance between the light-emitting surface of the third lens and the light-incident surface of the fourth lens.

[0020] Secondly, this utility model provides a projector, characterized by a light source and a multi-lens projection lens as described in any of the preceding claims.

[0021] Thirdly, this utility model provides an optical device, characterized in that it includes a multi-lens projection lens as described in any of the preceding claims.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention features low high-order distortion in the projected light field, allowing speckle to concentrate in the effective area and reducing energy loss. Furthermore, the optical path is more uniform, resulting in a more even distribution of light. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Other features, objects, and advantages of this utility model will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0025] Figure 1 This is a schematic diagram of the optical path of a multi-lens projection lens in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of an array laser and the arrangement of light-emitting holes in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a speckle distribution in an embodiment of the present invention.

[0028] 1-Array laser;

[0029] 2-Projection lens;

[0030] 21-First lens;

[0031] 22-Second lens;

[0032] 23-Third lens;

[0033] 24 - Fourth Lens;

[0034] 25-spacer; Detailed Implementation

[0035] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0036] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this utility model 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 embodiments of the utility model described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] This utility model provides a multi-lens projection lens, which aims to solve the problems existing in the prior art.

[0038] The technical solutions of this utility model and this application solve the above-mentioned technical problems in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this utility model will now be described with reference to the accompanying drawings.

[0039] like Figure 1 As shown, in this embodiment of the present invention, a multi-lens projection lens includes, in sequence along the optical path, a first lens 21, a second lens 22, a third lens 23, and a fourth lens 24.

[0040] The first lens is a biconvex positive lens that converges the beam emitted by the array laser.

[0041] The second lens is a meniscus lens with a convex incident surface to further adjust the beam convergence angle, and a concave exit surface with a large radius of curvature to correct spherical aberration and distortion in the system.

[0042] The third lens is a biconcave negative lens, which works in conjunction with the second lens to correct spherical aberration and distortion in the system.

[0043] The fourth lens is a meniscus negative lens with a concave incident surface and a convex exit surface. Light rays are refracted at a large angle by this lens, thus expanding the projection angle.

[0044] In some embodiments, the first lens, the second lens, the third lens, and the fourth lens are all aspherical plastic lenses, and the refractive index nd of the lenses satisfies the following formula:

[0045] 1.52 <nd<1.69

[0046] Where nd is the refractive index of the lens at a wavelength of 587.6 nm.

[0047] The biconvex positive lens converges the speckle beam of the laser array, with a principal ray incident at an angle of 0°, into the projection lens, which helps to minimize the lens size of the meniscus positive lens and the biconcave negative lens. After being shaped by the meniscus positive lens and the biconcave negative lens, the light rays are incident on the surface of the meniscus negative lens. The outer convex surface of the meniscus negative lens redistributes the light rays to a larger angular range before they exit.

[0048] In some embodiments, an aperture stop is also included, located between the second lens and the third lens. Figure 1 The aperture stop is not shown. The second lens is a meniscus lens with a convex incident surface. The beam angle is further adjusted to allow the beam to enter the aperture stop. The exit surface is a concave surface with a large radius of curvature, which corrects spherical aberration and distortion of the system.

[0049] The radius of curvature of the light-exiting surface of the first lens is greater than the radius of curvature of the light-incident surface of the first lens.

[0050] The radius of curvature of the light-exiting surface of the second lens is greater than the radius of curvature of the light-incident surface of the second lens.

[0051] In some embodiments, a spacer 25 is also included, located between the first lens and the second lens, for fixing the interval between the first lens and the second lens.

[0052] The sum of the radii of curvature of the incident and exit surfaces of the third lens is greater than the sum of the radii of curvature of the incident and exit surfaces of any one of the first, second, and fourth lenses.

[0053] The radius of curvature of the incident surface of the fourth lens is smaller than that of the incident surfaces of the first lens, the second lens, and the third lens.

[0054] The minimum distance between the first lens and the second lens is greater than the maximum distance between the light-emitting surface of the third lens and the light-incident surface of the fourth lens.

[0055] This utility model also provides a projector. It should be noted that the descriptions in this embodiment are merely for the convenience of those skilled in the art and should not constitute any limitation on the rights of this utility model.

[0056] The projector includes an array laser for projecting an array of laser beams;

[0057] Projection lens 1; the focal plane of the projection lens is conjugate to the light-emitting surface of the array laser.

[0058] An array laser is a laser device composed of multiple laser emitting units arranged in a specific pattern. These laser emitting units can be common laser generating devices such as semiconductor lasers, which are arranged closely together to form an array structure. Each laser emitting unit generates laser light through stimulated emission. When a suitable electrical signal is applied to the array laser, electrons in these units transition between energy levels, generating stimulated emission and thus emitting a laser beam. Because multiple units operate simultaneously, they can collectively project an array laser with a specific distribution.

[0059] Compared to a single laser, an array laser can provide higher laser power output. By rationally designing the arrangement and number of cells, different laser intensity distributions and beam characteristics can be achieved to meet various application requirements. For example, this characteristic of array lasers is very useful in applications requiring large-area illumination or high-precision measurement.

[0060] A projection lens is an optical element whose main function is to focus, collimate, or modify the propagation direction and shape of a laser beam in a specific way. In this system, the focal plane of the projection lens is conjugate to the emitting surface of the array laser, a crucial optical condition. When the focal plane of the projection lens is conjugate to the emitting surface of the array laser, it means that the light emitted from the emitting surface of the array laser, after refraction or reflection by the projection lens, can form a clear image on the focal plane (or in other words, the beam can propagate and distribute in the expected way). This conjugate relationship ensures the quality and propagation characteristics of the laser beam, enabling the projected array laser to accurately reach the target location and maintain a good beam shape and energy distribution.

[0061] To achieve this conjugate relationship, the design of the projection lens needs to consider multiple parameters, such as focal length, aperture, and aberration correction. Focal length determines the lens's ability to focus light, aperture affects the amount of light passing through the lens, and aberration correction ensures beam quality and avoids problems such as image blur. Through precise optical design and manufacturing processes, the projection lens can meet the system's requirements for laser projection.

[0062] Through the projection lens, the speckle pattern of the array laser is projected into space with near-proportional magnification. The light emitted from array laser 1 is symmetrical and all emitted perpendicularly. Each beam emitted from array laser 1 exits uniformly after passing through projection lens 2. The optical path in the center of array laser 1 has a zero field of view, and after passing through projection lens 2, it ultimately diffuses out. The exit angle of the main field of view in the center of the optical path exiting from projection lens 2 is 0 degrees, while the others are oblique exits.

[0063] The array laser used in this embodiment is directly projected, which overcomes the defect of inconsistent brightness between the zeroth and higher orders in the replicated spot of DOE devices.

[0064] This embodiment uses an array laser for direct projection, and the number and arrangement of the output ports can be customized according to the application requirements. This overcomes the limitation of the traditional VCSEL+DOE solution, where the array laser must be designed in a specific shape to ensure that it can be connected after replication.

[0065] This embodiment employs a telecentric object-side lens for projection, overcoming the drawback of large high-order distortion in the projected light field inherent in the traditional VCSEL+DOE scheme. Speckle patterns are concentrated in the effective area, reducing energy loss.

[0066] In this embodiment, the focal plane of the projection lens is conjugate to the emitting surface of the array laser. This conjugate relationship has been carefully designed and calculated. It enables the beam of the array laser to be accurately focused on the focal plane of the projection lens, forming a clear, stable, and intensity-distributed zero-order speckle pattern. This precise focusing and speckle formation method effectively avoids blurring and distortion of the speckle, improving the quality and usability of the speckle.

[0067] This utility model also provides an optical device. It should be noted that the description in this embodiment is only for the convenience of those skilled in the art and should not constitute any limitation on the optical device.

[0068] The structure and working principle of a multi-lens projection lens:

[0069] Composition: A multi-lens projection lens is composed of multiple lenses of different types. These lenses may include convex lenses, concave lenses, aspherical lenses, etc. Different types of lenses have different optical properties; convex lenses are used to converge light rays, concave lenses are used to diverge light rays, and aspherical lenses can more effectively correct aberrations. By combining these lenses appropriately, precise control of light can be achieved.

[0070] Principle: The working principle of a multi-lens projection lens is based on the law of refraction of light. When light enters from one lens to another, due to the different refractive indices and curvatures of the different lenses, the light is refracted, thereby changing its propagation direction and focusing characteristics. Through the synergistic effect of multiple lenses, light can be refracted and adjusted multiple times to eliminate aberrations, improve image quality, or precisely control the propagation of the light beam.

[0071] Overall functions of optical equipment:

[0072] Laser projection and imaging: If the optical device is used for laser-related applications, a multi-lens projection lens can precisely project the laser emitted from a laser source (such as the array laser mentioned earlier). For example, in laser display devices, a multi-lens projection lens can project a laser beam onto a screen to form a clear image. In laser processing equipment, it can focus the laser onto the workpiece surface to achieve high-precision processing operations.

[0073] Optical Detection and Sensing: In some optical detection and sensing devices, multi-lens projection lenses can collect and focus light reflected or emitted by a target object onto the detector. By precisely focusing and imaging the light, the detector's sensitivity and resolution can be improved, thereby enabling accurate detection and analysis of the target object. For example, in optical imaging sensors, multi-lens projection lenses can focus light from a scene onto an image sensor to form a clear image for subsequent image analysis and processing.

[0074] Optical communication: In optical communication equipment, multi-lens projection lenses can be used to collimate and focus light signals to achieve long-distance transmission and accurate reception. By precisely controlling the propagation direction and focusing characteristics of the light signal, the transmission efficiency and reliability of the optical communication system can be improved.

[0075] The impact of multi-lens projection lenses on the performance of optical equipment:

[0076] Image quality: The design and manufacturing quality of multi-lens projection lenses directly affect the image quality of optical equipment. By accurately correcting aberrations (such as spherical aberration, chromatic aberration, coma, etc.), optical equipment can obtain clearer and more accurate images. High-quality multi-lens projection lenses can reduce image distortion and blur, and improve image contrast and resolution.

[0077] Beam control accuracy: For optical devices requiring precise control of beam propagation, the beam control accuracy of multi-lens projection lenses is crucial. By rationally designing the curvature, refractive index, and arrangement of the lenses, precise focusing, collimation, and shaping of the beam can be achieved, thereby meeting the beam characteristic requirements of different applications.

[0078] Equipment stability and reliability: The structure and material selection of multi-lens projection lenses also affect the stability and reliability of optical equipment. High-quality lens materials and precise manufacturing processes can improve the lens's resistance to wear, corrosion, and temperature changes, thereby ensuring the stable operation of optical equipment under different environmental conditions.

[0079] Application areas:

[0080] Consumer electronics: such as smart projectors, virtual reality (VR) and augmented reality (AR) devices. In these devices, multi-lens projection lenses are used to project images or virtual scenes into the user's field of vision, providing an immersive visual experience.

[0081] Industrial manufacturing: In industrial applications such as laser processing, optical inspection and measurement, multi-lens projection lenses can achieve high-precision laser focusing and beam control, improving production efficiency and product quality.

[0082] In the medical field, such as ophthalmic surgical equipment and medical imaging equipment, multi-lens projection lenses can be used for precise laser focusing during surgical procedures or for high-quality medical imaging, assisting doctors in disease diagnosis and treatment.

[0083] Aerospace: In the aerospace field, optical equipment needs to operate under extreme environmental conditions. The high precision and high reliability of multi-lens projection lenses can meet the stringent requirements of aerospace optical systems for image quality and beam control, such as in astronomical observation and remote sensing applications.

[0084] In summary, optical devices containing multi-lens projection lenses achieve a variety of functions through precise control of light, are widely used in many fields, and their performance largely depends on the design and manufacturing quality of the multi-lens projection lens.

[0085] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0086] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this utility model.

Claims

1. A multi-lens projection lens, characterized in that, include: A first lens, a second lens, a third lens, and a fourth lens are arranged sequentially along the optical path; wherein, The first lens is a biconvex positive lens; The second lens is a meniscus lens, with a convex incident surface and a concave exit surface; The third lens is a biconcave negative lens; The fourth lens is a meniscus negative lens with a concave incident surface and a convex exit surface.

2. The multi-lens projection lens according to claim 1, characterized in that, Also includes: An aperture stop is located between the second lens and the third lens.

3. The multi-lens projection lens according to claim 1, characterized in that, The radius of curvature of the light-exiting surface of the first lens is greater than the radius of curvature of the light-incident surface of the first lens.

4. The multi-lens projection lens according to claim 1, characterized in that, The radius of curvature of the light-exiting surface of the second lens is greater than the radius of curvature of the light-incident surface of the second lens.

5. The multi-lens projection lens according to claim 1, characterized in that, It also includes a spacer located between the first lens and the second lens, used to fix the interval between the first lens and the second lens.

6. The multi-lens projection lens according to claim 1, characterized in that, The sum of the radii of curvature of the incident and exit surfaces of the third lens is greater than the sum of the radii of curvature of the incident and exit surfaces of any one of the first, second, and fourth lenses.

7. A multi-lens projection lens according to claim 1, characterized in that, The radius of curvature of the incident surface of the fourth lens is smaller than that of the incident surfaces of the first lens, the second lens, and the third lens.

8. A multi-lens projection lens according to claim 1, characterized in that, The minimum distance between the first lens and the second lens is greater than the maximum distance between the light-emitting surface of the third lens and the light-incident surface of the fourth lens.

9. A projector, characterized in that, The light source and the multi-lens projection lens according to any one of claims 1-8.

10. An optical device, characterized in that, Includes the multi-lens projection lens as described in any one of claims 1-8.

Images