Photodetecting Device Positional Alignment Marks
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Solution Overview
Problem
In high-density photodetecting device arrangements, such as in telescopes, achieving accurate positional alignment of photodetecting elements with respect to installation bodies is challenging, particularly in buttable structures where close proximity and precise alignment are required.
Innovation Solution
A photodetecting device design featuring a positional alignment mark on the photodetecting element's surface, a wiring board with a window portion to expose the mark, and a base with a fitting portion that aligns accurately with the installation body using the mark, ensuring precise angular and positional alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If photodetecting devices are arranged in a buttable arrangement structure with small intervals to achieve high density, then the area utilization and detection coverage are improved, but the positional alignment accuracy between photodetecting elements and installation body becomes more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by pre-forming alignment marks on the photodetecting element and base before assembly, and pre-positioning the positioning portion on the base. This allows the fitting portion to be accurately positioned relative to the photodetecting element during assembly, ensuring high positional alignment accuracy even when devices are arranged in dense buttable configurations with small intervals of 100μm or less.
2Measurement precision
If the photodetecting element is thinned to improve light detection sensitivity, then the detection capability is improved, but the mechanical strength and structural integrity deteriorate
Solution Approach 1:
The patent applies the intermediary principle by introducing a support structure consisting of the wiring board and base that provides mechanical support to the thinned photodetecting element. The positioning portion and fitting portion create a stable mounting system that compensates for the reduced strength of the thinned semiconductor substrate, allowing the element to maintain both high light detection sensitivity and adequate mechanical integrity.
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 design allows for accurate positional alignment of photodetecting elements, enabling high-density arrangements without mechanical damage, even in 4-side buttable configurations, by utilizing alignment marks and a fitting mechanism that ensures precise positioning.
Implementation Method 1
a photodetecting element (11) which detects light made incident from one surface by a photodetecting section (16) being on a side of the other surface
Data Source
Figure 1
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Figure 3
AI summary
In a photodetecting device 3, positional alignment marks 18A, 18B to serve as positional references of a photodetecting element 11 are formed at the front surface side of the photodetecting element 11. Moreover, a pin base 13 is provided with a threaded fitting pin 32 to be fitted with a cold plate 2, and the threaded fitting pin 32 is accurately positionally aligned with respect to the photodetecting element 11 via a positioning portion 33 positioned with respect to the positional alignment marks 18A, 18B exposed from a slit portion 23 and a cutaway portion 24 of a wiring board 12. Accordingly, in the photodetecting device 3, by only fitting the threaded fitting pin 32 with a recess portion 4 of the cold plate 2, the photodetecting element 11 is accurately positionally aligned with respect to the cold plate 2.