Image Sensor Filter Recess Structure to Prevent Microparticle Light Spots
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Solution Overview
Problem
In image-capturing devices, the instability of short brackets and their flatness issues lead to microparticles being captured by the image sensor chip, causing light spots due to improper spacing between the filter and the image sensor chip.
Innovation Solution
An image-capturing device with a carrier substrate, image sensing chip, and lens assembly, where the filter element is accommodated in a recessed space of the carrier substrate, and the lens assembly includes a lens holder on the top side, maintaining a distance of 30 µm to 200 µm between the filter and the image sensing chip to prevent light spot capture from microparticles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the filter is supported by short brackets to be arranged on the image sensor chip, then the device complexity is reduced, but the stability and flatness of the filter cannot be controlled, and microparticles on the filter are captured by the image sensor chip causing light spots
Solution Approach 1:
The filter is moved from a horizontal arrangement on the image sensor chip to a vertical arrangement within a recessed space of the carrier substrate. This dimensional change allows the filter to be positioned below the optical axis, preventing microparticles from being captured while maintaining structural stability through the recessed space configuration.
Solution Approach 2:
The filter element is nested within the recessed space of the carrier substrate, with the recessed space acting as a housing that contains and stabilizes the filter. This nesting structure provides both mechanical support and precise positioning, eliminating the need for separate short brackets while ensuring filter stability and flatness.
2Object-affected harmful factors
If the short bracket is made too high to prevent microparticle capture, then image quality improves, but the filter and image sensor chip become too far apart, affecting optical performance
Solution Approach 1:
Instead of increasing the height of support brackets along the optical axis, the filter is repositioned in the vertical dimension within the recessed space. This allows sufficient distance from the image sensor chip surface to prevent microparticle capture while maintaining the optical path length through the carrier substrate thickness.
Solution Approach 2:
The carrier substrate acts as an intermediary structure that houses the filter in its recessed space. The substrate material and its thickness provide the necessary optical path and physical separation, mediating between the filter and image sensor chip to prevent microparticle capture while maintaining proper optical coupling.
3Length of stationary object
If the filter is placed close to the image sensor chip, then the optical path length is reduced, but microparticles on the filter are captured causing light spots in images
Solution Approach 1:
The filter is repositioned from a horizontal plane near the image sensor chip to a vertical position within the recessed space. This dimensional change increases the distance between the filter surface and the image sensor chip surface, preventing microparticle capture while the optical path length is maintained through the carrier substrate's thickness and refractive properties.
Data Source
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AI summary
A portable electronic device (Z), and an image-capturing device (S) and an assembly method thereof are provided. The image-capturing device (S) includes a carrier substrate (1), an image sensing chip (2), a filter element (3) and a lens assembly (4). The carrier substrate (1) has a through opening (1003) and a recessed space. The image sensing chip (2) is disposed on the bottom side (1002) of the carrier substrate (1). The filter element (3) is disposed in the recessed space of the carrier substrate (1), so that all or a part of the filter element (3) is accommodated in the through opening (1003). When at least one microparticle (P) with a maximum particle size between 5 µm and 25 µm is located on the filter element (3), a shortest distance (D) between the filter element (3) and the image sensing chip (2) is between 30 µm and 200 µm, so that the image sensing chip (2) cannot capture a light spot generated due to blocking of the microparticle (P).