CN-121995607-A - Light-weight large-aperture heat difference eliminating tele lens for unmanned aerial vehicle and electronic equipment

CN121995607ACN 121995607 ACN121995607 ACN 121995607ACN-121995607-A

Abstract

The invention discloses a tele lens for a light-weight large-aperture athermal unmanned aerial vehicle and electronic equipment. The lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and a seventh lens, wherein the first lens is sequentially arranged from an object side to an image side along an optical axis from the object side to the fourth side, the first lens is positive in refractive index, the object side is a convex surface, the image side is a concave surface, the second lens is positive in refractive index, the object side is a convex surface, the image side is a concave surface, the third lens is negative in refractive index, the object side is a convex surface, the image side is a concave surface, the fourth lens is positive in refractive index, the object side is a convex surface, and the image side is a concave surface. The lens group of the invention effectively corrects monochromatic aberration such as spherical aberration, coma and the like and inhibits curvature of field and distortion by combining positive-negative-positive focal power distribution and convex-concave surface shape. This configuration is advantageous for large aperture (e.g., F1.1) designs, where the introduction of negative lenses reduces advanced aberration sensitivity, allowing for larger clear apertures without sacrificing image quality, thus supporting high light input requirements in low light environments.

Inventors

XIE XIAONA
CAO LAISHU
ZHANG JUNGUANG

Assignees

厦门力鼎光电股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260305

Claims (9)

1. A long-focus lens for a lightweight large-aperture athermal unmanned aerial vehicle is characterized in that the lens sequentially comprises a first lens and a fourth lens from an object side to an image side along an optical axis, wherein, The first lens has positive refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has positive refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the third lens has negative refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the fourth lens element has positive refractive index, wherein the object-side surface thereof is convex, and the image-side surface thereof is concave.
2. The tele lens for the lightweight large-aperture athermal unmanned aerial vehicle according to claim 1, wherein, The first lens and the second lens are made of high-refractive-index infrared glass materials, the third lens and the fourth lens are made of low-refractive-index infrared glass materials, and at least one lens of the first lens, the second lens, the third lens and the fourth lens is aspheric.
3. The tele lens for the lightweight large-aperture athermal unmanned aerial vehicle according to claim 2, wherein, The lens satisfies the following conditional expression: Nd 1 =Nd 2 Where Nd 1 is the first lens refractive index and Nd 2 is the second lens refractive index.
4. A tele lens for a lightweight large aperture athermal unmanned aerial vehicle as defined in claim 2 or 3, wherein, The lens satisfies the following conditional expression: Nd 3 =Nd 4 Where Nd 3 is the third lens refractive index and Nd 4 is the fourth lens refractive index.
5. The tele lens for the lightweight large-aperture athermal unmanned aerial vehicle according to claim 1, wherein, The lens satisfies the following conditional expression: 60mm < f 1 < 75mm; 40mm < f 2 < 50mm; -25mm < f 3 < -20mm; 50mm < f 4 < 60mm; Where f 1 is the focal length of the first lens, f 2 is the focal length of the second lens, f 3 is the focal length of the third lens, and f 4 is the focal length of the fourth lens.
6. The tele lens for the lightweight large-aperture athermal unmanned aerial vehicle according to claim 1, wherein, The lens barrel of the lens adopts a combined structure lens barrel, and the combined structure lens barrel comprises at least two metal materials with different thermal expansion coefficients.
7. The tele lens for a lightweight large aperture athermal unmanned aerial vehicle as recited in claim 6, wherein, The lens barrel is in a hollowed-out design.
8. The tele lens for the lightweight large-aperture athermal unmanned aerial vehicle according to claim 1, wherein, The lens satisfies the following conditional expression: TTL<39; F#≤1.1; Wherein TTL is the total optical length of the lens, and F# is the F-number of the lens.
9. An electronic device characterized in that a lightweight large aperture athermal unmanned aerial vehicle is provided with a tele lens according to any one of claims 1-8, and An image sensor configured to receive an image formed by the tele lens for the lightweight large aperture athermal unmanned aerial vehicle.

Description

Light-weight large-aperture heat difference eliminating tele lens for unmanned aerial vehicle and electronic equipment Technical Field The invention relates to the technical field of unmanned aerial vehicle lenses, in particular to a tele lens for a light-weight large-aperture athermal unmanned aerial vehicle and electronic equipment. Background Unmanned aerial vehicle's wide application in fields such as survey and drawing, control, agriculture, rescue and national defense have put forward comprehensive and harsh performance requirement to airborne optical system. These demands are focused on aspects of light weight and miniaturization, high resolution, large aperture, wide temperature environment adaptability, and long focal length. The unmanned aerial vehicle has the advantages that the limited load capacity of the unmanned aerial vehicle requires a compact structure and light weight, the high resolution is a basis for ensuring the ground detail capture from high altitude, the large aperture (such as F number smaller than 1.1) can improve the light incoming quantity and shorten the exposure time in the morning and evening or low light environment so as to inhibit motion blur, the wide working temperature range (-40 ℃ to 80 ℃) needs to overcome the problems of defocusing, lens opening, image quality degradation and the like which are easily caused by a common lens, the long focus design is particularly critical for long-distance observation and avoiding target interference, and the high-grade aberration is usually corrected by reasonable focal power distribution and aspherical lenses so as to improve the imaging quality. However, it is generally difficult to combine all of the above properties with the current unmanned aerial vehicle lenses on the market, especially in the tele section. Common situations include insufficient weak light imaging performance caused by large aperture (such as F2.0 or more), incapability of maintaining image plane stability and imaging definition under severe temperature change, or overdetermined volume and weight caused by pursuing long focal length, and difficulty in adapting to unmanned aerial vehicle loading limit. These contradictions reflect the existence of significant technical tension between the multiple objectives of achieving long focal length, large aperture, high image quality, and high thermal stability under limited size and weight constraints. Therefore, there is a strong need to develop a new optical system integrating long focal length, large aperture, high resolution, miniaturization and high environmental stability. Such designs typically require high refractive index glass, aspherical lenses (including plastic aspheres introduced for weight reduction), and low coefficient of thermal expansion materials to address both aberration correction and thermal drift control issues. However, the introduction of such materials also brings about a significant increase in material and processing (coating, assembly, calibration) costs, especially differences in coefficient of thermal expansion between plastic aspherical lenses and glass materials, which in turn presents additional optomechanical matching challenges in wide temperature applications. How to realize comprehensive performance breakthrough on the premise of controlling cost and ensuring reliability becomes a key subject of the development of the current unmanned aerial vehicle optical lens. Disclosure of Invention In view of the above, an object of the present invention is to provide a tele lens for a lightweight large aperture unmanned aerial vehicle and an electronic device. The lens can solve at least one technical disadvantage mentioned in the background art. According to one aspect of the invention, there is provided a tele lens for a lightweight large aperture athermal unmanned aerial vehicle, the lens comprising, in order from an object side to an image side, a first lens to a fourth lens along an optical axis, wherein, The first lens has positive refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the second lens has positive refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the third lens has negative refractive index, the object side surface is a convex surface, and the image side surface is a concave surface; the fourth lens element has positive refractive index, wherein the object-side surface thereof is convex, and the image-side surface thereof is concave. In the above technical scheme, aiming at the optical performance requirement of the unmanned aerial vehicle-mounted tele lens, a four-lens structure is provided, and the four-lens structure sequentially comprises a positive refractive index convex-concave first lens, a positive refractive index convex-concave second lens, a negative refractive index convex-concave third lens and a positive refractive index convex-concave