Thermal Infrared Sensor Reference Pixel Shielding
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Solution Overview
Problem
Conventional infrared image sensing devices face challenges in maintaining a stable output level due to temperature drift and self-heat generation, leading to differences in signal levels between pixel and reference-pixel elements, which complicates signal processing and miniaturization.
Innovation Solution
A thermal-type infrared image sensing device with pixel elements and reference-pixel elements arranged on a semiconductor substrate, where the reference-pixel elements are thermally insulated and shielded from incident infrared light using a light reflector, ensuring equivalent heat transport characteristics and preventing unnecessary signal generation from incident infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If reference-pixel elements are configured without heat-insulated structure, then device complexity is reduced, but output level stability deteriorates due to temperature drift and self-heat generation
Solution Approach 1:
The patent applies local quality by providing heat-insulated structures specifically to reference-pixel elements while pixel elements have different thermal characteristics. This localized differentiation allows reference pixels to maintain stable output levels despite self-heat generation, resolving the contradiction between simplified structure and output stability.
Solution Approach 2:
The patent introduces a light reflector as an intermediary component that shields reference-pixel elements from incident infrared light. This mediator prevents unnecessary signal generation in reference pixels while maintaining their thermal insulation, thus stabilizing output levels without adding significant structural complexity.
2Reliability
If reference-pixel elements are completely shielded from incident infrared light using light-shielding plate, then unnecessary signal generation is prevented, but device size increases due to isolation requirements
Solution Approach 1:
The patent merges the light reflector function with the existing package structure by forming the reflector as a reflective film on the inner surface of the package cavity. This integration achieves complete light shielding for reference pixels without requiring separate isolation structures, thus preventing unnecessary signal generation while avoiding device size increase.
Solution Approach 2:
The patent transitions from planar light shielding to three-dimensional cavity-based shielding by utilizing the package cavity space. The light reflector is positioned on the cavity wall to reflect infrared light away from reference pixels, achieving effective shielding without occupying additional device area.
3Productivity
If pixel elements and reference-pixel elements have different heat transport characteristics, then reference signals can be generated, but signal processing complexity increases
Solution Approach 1:
The patent applies equipotentiality by equalizing the heat transport characteristics of pixel elements and reference-pixel elements through identical heat-insulated structures. This creates equivalent thermal conditions for both element types, simplifying signal processing by eliminating the need to compensate for thermal differences while maintaining the ability to generate reference signals.
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 configuration stabilizes the output level of the reference-pixel element, allowing it to serve as an ideal reference voltage, reducing signal processing complexity and enabling miniaturization without the need for additional light-shielding structures.
Implementation Method 1
an infrared-light absorber, supported above the first detector apart therefrom through a connector thereon, for absorbing incident infrared light and converting the light into heat
Implementation Method 2
a light reflector for shielding the second detector from incident infrared light
Implementation Method 3
a first support for supporting the first detector apart from the semiconductor substrate
Data Source
AI summary
A thermal-type infrared image sensing device and method of producing a thermal-type infrared image sensing device are provided. The thermal-type infrared image sensing device includes pixel elements that are two-dimensionally arranged on a semiconductor substrate. Each pixel element includes a detector that detects temperature, an infrared-light absorber that absorbs incident infrared light and that converts the light into heat, and a support that supports the detector apart from the semiconductor substrate. The thermal-type infrared image sensing device also includes reference-pixel elements that are arranged adjacent to and along a row of the pixel elements. Each of the reference pixels generates a reference signal, and each of the reference pixels includes a structure that shields a detector from incident infrared light. The detectors of the pixel elements and the reference-pixel elements are each connected to the semiconductor substrate through the respective supports.