Integrated IR Sensor with Diffractive Optical Element
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Solution Overview
Problem
Existing infrared (IR) radiation sensors are large, expensive, fragile, and require costly packaging and precise alignment of discrete diffractive optical elements, limiting their sensitivity, accuracy, and robustness for applications like non-contact temperature measurement and gas concentration detection.
Innovation Solution
An integrated circuit IR sensor chip with thermally insulated temperature-sensitive elements and integrated diffractive optical elements, such as Fresnel lenses or diffraction gratings, on its back surface, which directs IR radiation to the sensitive elements, eliminating the need for external optics and reducing packaging costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If discrete diffractive optical elements are used to direct IR radiation, then measurement precision is improved, but device complexity and packaging cost increase
Solution Approach 1:
The patent integrates the diffractive optical element directly into the sensor chip structure, merging the optical directing function with the sensing element. This eliminates the need for separate discrete optical components and complex packaging, while maintaining the precision of IR radiation direction to the temperature-sensitive element
2Measurement precision
If discrete diffractive optical elements are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By integrating the diffractive optical element into the sensor chip during the semiconductor fabrication process, the patent eliminates separate manufacturing steps for assembling discrete optical components. This reduces overall manufacturing cost while achieving precise IR radiation direction through the integrated structure
Solution Approach 2:
The patent replaces mechanical assembly of discrete optical elements with a monolithic integrated circuit structure. The diffractive optical element is formed using standard semiconductor fabrication techniques rather than mechanical assembly, reducing manufacturing complexity and cost
3Measurement precision
If thermally insulated temperature-sensitive elements are used, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The patent segments the sensor chip into distinct functional regions: a thermally insulated region containing the temperature-sensitive element for high sensitivity measurements, and a thermally conductive region for reference measurements. This segmentation is achieved through localized thermal isolation structures rather than complex overall device architecture
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
The solution results in smaller, more sensitive, accurate, and robust IR sensors that provide precise IR radiation measurements at a lower cost, with improved alignment and reduced fragility, suitable for various applications without the need for expensive packaging.
Implementation Method 1
A diffractive optical element, such as a Fresnel lens or diffraction grating, is integrated in or on a back surface of the radiation sensor chip to direct infrared radiation toward the first temperature-sensitive element
Implementation Method 2
an integrated circuit radiation sensor chip including first and second temperature-sensitive elements connected within a dielectric stack of the chip, the first temperature-sensitive element being more thermally insulated from a substrate than the second temperature-sensitive element
Data Source
AI summary
An infrared (IR) radiation sensor device (27) includes an integrated circuit radiation sensor chip (1A) including first (7) and second (8) temperature-sensitive elements connected within a dielectric stack (3) of the chip, the first temperature-sensitive element (7) being more thermally insulated from a substrate (2) than the second temperature-sensitive element (8). Bonding pads (28A) on the chip (1) are coupled to the first and second temperature-sensitive elements. Bump conductors (28) are bonded to the bonding pads (28A), respectively, for physically and electrically connecting the radiation sensor chip (1) to corresponding mounting conductors (23A). A diffractive optical element (21,22,23,31,32 or 34) is integrated with a back surface (25) of the radiation sensor chip (1) to direct IR radiation toward the first temperature-sensitive element (7).