Thermopile Infrared Detector Layout for Low Resistance Sensing
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Solution Overview
Problem
Infrared detectors face challenges in achieving high sensitivity due to increased resistance values and restricted light receiving area caused by multiple thermopile chips, making it difficult to improve sensitivity.
Innovation Solution
The infrared detector arranges thermopile chips in a specific configuration with series and parallel connections, optimized to minimize resistance and maximize light receiving area, using a package structure with lead pins and a light passing opening that avoids interference with lead pins, and employs wire connections to further optimize chip arrangement and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple thermopile chips are arranged on the main surface, then the light receiving area can be increased, but the resistance value of the circuit increases
Solution Approach 1:
The patent divides the thermopile chip arrangement into multiple groups (first group with first and second chips, second group with third chip) that are electrically connected in parallel. This segmentation allows the light receiving area to be increased by adding more chips while the parallel connection maintains low resistance, resolving the contradiction between area expansion and resistance increase.
Solution Approach 2:
The patent transitions from a single-dimensional series arrangement to a two-dimensional parallel arrangement of chip groups. By organizing chips in multiple groups connected in parallel rather than simply adding chips in series, the invention achieves both increased light receiving area and maintained low resistance, effectively using dimensional reorganization to resolve the technical contradiction.
2Area of stationary object
If multiple thermopile chips are arranged on the main surface, then the light receiving area can be increased, but the arrangement is restricted by the package structure with lead pins
Solution Approach 1:
The patent employs asymmetric arrangement of thermopile chips relative to the lead pins. The first and second chips are positioned at specific distances from the first lead pin, while the third chip is positioned relative to the second lead pin. This asymmetric positioning optimizes the light receiving area while avoiding interference with the lead pin structure, resolving the arrangement restriction issue.
Solution Approach 2:
The patent applies different positioning strategies to different chip groups based on their local environment. The first and second chips are arranged with specific spacing from the first lead pin, while the third chip is arranged with specific spacing from the second lead pin. This localized optimization allows maximum light receiving area within the constraints of the package structure.
3Use of energy by moving object
If a light passing opening is formed in the cap portion, then infrared rays can be efficiently incident on the thermopile chips, but the opening may cause irregular reflection and noise if it overlaps lead pins
Solution Approach 1:
The patent extracts the harmful element (lead pins) from the light path by positioning the light passing opening such that it overlaps the thermopile chips but does not overlap the lead pins. This selective extraction of the problematic component from the optical path eliminates the source of irregular reflection and noise while maintaining efficient infrared transmission to the chips.
Solution Approach 2:
The patent introduces the light passing opening as an intermediary structure that mediates between the need for efficient infrared transmission and the need to avoid noise. By carefully positioning this opening to overlap chips but not lead pins, it serves as a controlled aperture that allows beneficial infrared transmission while blocking harmful reflection paths.
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 reduces circuit resistance, ensures a large light receiving area, and enhances sensitivity by efficiently directing infrared rays to the thermopile chips while minimizing noise from reflections.
Implementation Method 1
an infrared detection element including a package having a base portion and a plurality of thermopile chips arranged on a main surface of the base portion
Data Source
AI summary
An infrared detector includes a package having a base portion, first to third lead pins, and a cap portion, and a plurality of thermopile chips. First and second thermopile chips are electrically connected in series, and a first chip unit and a second chip unit are electrically connected in parallel. The first and second lead pins are arranged side by side in a second direction via a first straight line, the first and third lead pins are arranged side by side in the first direction via a second straight line, the first thermopile chip is disposed on the second straight line and disposed on a straight line connecting the first and third lead pins, and the second and third thermopile chips are arranged side by side on the first straight line via a reference position.