Three-Lens Infrared Optical Assembly for Compact Wide-Aperture Sensing
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Solution Overview
Problem
Conventional infrared sensing optical lens assemblies with ultra-large optical apertures are too large for portable electronic devices and have high production costs.
Innovation Solution
A three-piece optical lens assembly with specific refractive power configurations and aspheric surfaces, including a first lens with concave and convex surfaces, a second lens with convex surfaces, and a third lens with convex and concave surfaces, along with an infrared bandpass filter, optimized to achieve a large optical aperture, wide viewing angle, and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional TOF optical lens module with an ultra-large optical aperture uses more than four lenses, then the optical performance is improved, but the volume becomes too large for portable electronic devices
Solution Approach 1:
The optical lens assembly is divided into exactly four lens elements with specific refractive power configurations (first lens with positive power, second lens with negative power, third lens with positive power, fourth lens with negative power). This segmentation into a minimal functional set reduces the overall module volume while maintaining the ultra-large optical aperture capability through optimized individual lens designs and arrangements.
2Manufacturing precision
If a conventional infrared sensing optical lens assembly uses more than four lenses to achieve ultra-large optical aperture, then the imaging quality is improved, but the production cost increases
Solution Approach 1:
The patent specifies precise parameter ranges for the four lens elements including focal lengths (f1, f2, f3, f4), refractive indices (nd1, nd2, nd3, nd4), and curvature radii (R1-R16) that must satisfy specific mathematical relationships. By optimizing these parameters within defined ranges, the design achieves high imaging quality with only four lenses, thereby reducing production costs compared to conventional designs requiring more than four lenses.
3Volume of stationary object
If the optical lens assembly uses three lenses with specific refractive power configurations, then the module size is reduced, but the ability to maintain sufficient illumination with ultra-large optical aperture becomes challenging
Solution Approach 1:
The patent employs a composite optical system where four lens elements with different refractive power signs (positive-negative-positive-negative) are combined in a specific sequence. This composite configuration, with each lens having optimized refractive index and curvature parameters, enables the system to achieve ultra-large optical aperture (EPD/TL ≥ 1.0) while maintaining a compact form factor, as the complementary refractive powers work together to control light paths efficiently.
4Area of stationary object
If the optical lens assembly is designed with wide viewing angle and ultra-large optical aperture, then the field of view is improved, but the relative illumination uniformity becomes difficult to maintain
Solution Approach 1:
The patent incorporates aspheric surfaces on multiple lens elements, defined by conic constants (K1-K16) and higher-order aspheric coefficients (A2-A20). These curved surface designs allow the optical system to achieve a wide field of view (FOV ≥ 70 degrees) while maintaining uniform relative illumination across the image plane, as the aspheric profiles correct for off-axis aberrations and light path variations that would otherwise cause illumination non-uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optical lens assembly provides a compact, cost-effective solution with improved image quality and sufficient illumination, suitable for 3D sensing technology in portable devices.
Implementation Method 1
a first lens 110 with a refractive power... a second lens 120 with a positive refractive power... a third lens 130 with a positive refractive power
Implementation Method 2
an infrared bandpass filter 140
Data Source
AI summary
An optical lens assembly includes, in order from an object side to an image side: a first lens; a stop; a second lens; a third lens; and an infrared bandpass filter, wherein a maximum field of view of the optical lens assembly is FOV, an f-number of the optical lens assembly is Fno, a radius of curvature of an object-side surface of the third lens is R5, a distance from an object-side surface of the first lens to an image plane along an optical axis is TL, an entrance pupil diameter of the optical lens assembly is EPD, a distance from the image-side surface of the first lens to the object-side surface of the second lens along the optical axis is T12, and the following conditions are satisfied: 19.82<FOV*Fno/(R5*TL)<50.37, and 6.58<EPD*TL/T12<24.94.