Reflecting Layer CMOS Sensor Light Collection
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Solution Overview
Problem
CMOS image sensors have low emission light collection efficiency due to un-detected light emitted in the opposite direction from the photodiode, limiting their effectiveness in biological or chemical analysis.
Innovation Solution
Incorporating a reflecting layer above the micro-lens structure to redirect emission light back to the photodiode, along with a second reflecting layer and waveguide structure to enhance light collection, and using a filter and passivation layer to improve light detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional CMOS image sensor structure is used, then the device complexity is low and manufacturing is easy, but the emission light collection efficiency is low (lower than 50%)
Solution Approach 1:
The sensor structure is segmented into multiple functional layers including a micro-lens structure with opening, interlayer with filter, passivation layer, and two reflecting layers at different positions. Each layer performs a specific function in the light collection pathway, dividing the light management task into discrete segments that work together to improve overall efficiency
Solution Approach 2:
The patent introduces vertical layering (z-dimension) with multiple reflecting layers positioned at different heights above the photodiode. The first reflecting layer is positioned between the micro-lens structure and passivation layer, while the second reflecting layer is positioned between the interlayer and micro-lens structure, creating a multi-dimensional light management architecture that captures light from multiple angles and directions
2Measurement precision
If light emitted in the opposite direction from the photodiode is not detected, then the device structure remains simple, but the light collection efficiency is limited
Solution Approach 1:
The patent converts the harmful loss of oppositely directed emission light into a beneficial signal by introducing reflecting layers that redirect this previously wasted light back toward the photodiode. The first reflecting layer reflects light from the micro-lens structure region, while the second reflecting layer reflects light from the interlayer region, both converting energy loss into detectable signals
Solution Approach 2:
The reflecting layers act as intermediary elements between the emission light and the photodiode. These intermediaries redirect light that would otherwise be lost, mediating the interaction between the sample fluorescence and the detector to improve overall detection efficiency
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
Significantly improves the sensitivity and performance of the sensor device by increasing the collection of emission light, enhancing the detection of fluorescence or chemiluminescence from biological samples.
Implementation Method 1
a reflecting layer disposed above the micro-lens structure. The reflecting layer may increase the collection of emission light by reflecting the emission light toward the at least one sensor element
Implementation Method 2
a micro-lens structure disposed on the passivation layer... the micro-lens structure may have a parallel light or a single focus point corresponding to one sensor element
Implementation Method 3
CMOS image sensors usually include integrated circuits and photodiodes and therefore they may capture light and convert it into electrical signals
Implementation Method 4
The at least one sensor unit may further comprise a waveguide structure disposed above the second reflecting layer... the filter may comprise a uniform filter, a pixelated filter, a rejection filter
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~4
AI summary
A sensor device (10A) is provided. The sensor device includes at least one sensor unit (100U). The sensor unit includes at least one sensor element (102), an interlayer (104), a passivation layer (106), a micro-lens structure (108), an opening (108p), and a first reflecting layer (110). The interlayer is disposed on the sensor element. The passivation layer is disposed on the interlayer. The micro-lens structure is disposed on the passivation layer. The opening is disposed in the micro-lens structure. The first reflecting layer is disposed on the micro-lens structure. In addition, the first reflecting layer extends from the opening to the passivation layer.