Single-Sided Wafer-Level Optics Alignment
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Solution Overview
Problem
Conventional wafer-level optics manufacturing techniques face challenges in achieving precise alignment of lenses, limiting the production of high-resolution images in cameras, especially for devices with image sensors of 8 megapixels or more, due to difficulties in replicating and aligning lens surfaces to sub-micron precision.
Innovation Solution
The use of single-sided wafer-level optics (WLOs) with lens surfaces on one side of the wafer, allowing for precise alignment and manufacturing of lens stacks with improved precision, enabling the use of machines and tools specifically designed for single-sided WLOs, and facilitating atomic or molecular bonding without adhesives to enhance optical system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double-sided wafer level optics are manufactured using standard semiconductor techniques, then manufacturing complexity is reduced, but alignment precision deteriorates (cannot achieve sub-micron precision)
Solution Approach 1:
The patent divides the optical system into separate single-sided WLO components rather than manufacturing double-sided WLOs as a single unit. This segmentation allows each component to be manufactured independently with standard techniques, then precisely aligned and bonded together, achieving sub-micron precision without the complexity of double-sided manufacturing.
Solution Approach 2:
The patent performs preliminary alignment and bonding of single-sided WLO components before final assembly. By pre-aligning components to sub-micron precision during the bonding process and maintaining this alignment through spacer design, the system achieves high precision without requiring complex real-time alignment during final assembly.
2Manufacturing precision
If double-sided WLOs are used, then manufacturing process is simpler, but lens alignment for high-resolution images deteriorates
Solution Approach 1:
The patent segments the optical system into multiple single-sided WLO components that can be manufactured using standard, well-established semiconductor techniques. This avoids the experimental and complex double-sided manufacturing process while enabling precise control over each component's lens alignment through independent fabrication and subsequent precision bonding.
Solution Approach 2:
The patent changes the manufacturing parameter from double-sided to single-sided WLOs, which fundamentally alters the manufacturing approach. This parameter change enables the use of standard semiconductor techniques with proven precision capabilities, while the spacer design and bonding process maintain ease of manufacture through modular assembly.
3Manufacturing precision
If single-sided WLOs are used with precise alignment, then image quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary alignment and bonding of single-sided WLO components with precision spacers in place before final assembly. This preliminary action establishes sub-micron alignment precision that is maintained through the final assembly process, avoiding the need for complex real-time alignment equipment while achieving high precision.
Solution Approach 2:
The patent introduces precision spacers as intermediary elements between WLO components. These spacers serve as mechanical mediators that maintain precise alignment and spacing during bonding and assembly, enabling sub-micron precision without requiring complex alignment machinery or procedures.
4Manufacturing precision
If double-sided WLOs are manufactured, then fewer components are needed, but alignment precision for 8MP+ sensors deteriorates
Solution Approach 1:
The patent segments the optical system into multiple single-sided WLO components rather than using fewer double-sided components. This segmentation increases the number of components but enables precise alignment of each component to meet the stringent requirements of 8MP and higher resolution sensors, achieving the necessary sub-micron precision that double-sided components cannot provide.
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
This approach enables the production of high-resolution images with improved f-number specifications and increased design flexibility, allowing for lens shapes and configurations previously unfeasible with double-sided WLOs, while reducing manufacturing defects and improving optical quality.
Implementation Method 1
An adhesive layer may be disposed between the second surfaces of each glass wafer of two single-sided WLO's, such that the adhesive layer is configured to facilitate substantially precise alignment between the two single-sided WLO's
Implementation Method 2
a lens surface replicated onto a transparent material deposited on the first side of the glass wafer... arranged to propagate light received at a first surface of the lens assembly, through the two or more single-sided WLO lenses and to the image sensor
Data Source
AI summary
An optical system may include a lens assembly that has two or more single-sided wafer level optics (WLO) lenses arranged to propagate light. The optical system can further include an image sensor, wherein the lens assembly is arranged relative to the image sensor to propagate light received at a first surface of the lens assembly, through the two or more single-sided WLO lenses and to the image sensor. In some embodiments, the optical system further includes a camera which includes the lens assembly and the image sensor. In various embodiments, a smart phone, a tablet computer, or another mobile computing device may include such a camera. In some embodiments, the at least two single-sided wafer level optics (WLO) lenses are each separated by a gap G, wherein the gap may be different between each of the single-sided lenses, and the gap G may be zero.