Optical Sensor Package With Transparent Substrate
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Solution Overview
Problem
Conventional optical sensor packages are thick and suffer from reduced optical sensitivity due to the space between the optical device dies and the target object, leading to degradation of optical signals, especially in wearable devices where thickness and sensitivity are critical.
Innovation Solution
An optical sensor package design featuring a transparent substrate that allows light to pass through, with an integrated optical device die and a processor die mounted on the substrate, and a frame that is optically opaque to block unwanted light, reducing package thickness and enhancing optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional optical device dies are used with spacing from the target object, then the device structure is simplified and easier to manufacture, but the package thickness increases and optical sensitivity degrades
Solution Approach 1:
The patent merges the optical device die with the package substrate by mounting the optical device die directly onto the substrate, eliminating the need for separate spacing structures. This integration reduces the overall package thickness while maintaining manufacturability through standard mounting processes.
Solution Approach 2:
The patent transitions from a three-dimensional spaced arrangement to a two-dimensional planar integration by mounting the optical device die flush against the substrate surface. This dimensional change eliminates the thickness contribution from spacing structures while preserving the optical detection function.
2Ease of manufacture
If conventional optical device dies with spacing are used, then the device is easier to assemble, but optical sensitivity degrades due to increased distance from target object
Solution Approach 1:
The optical device die is merged with the substrate through direct mounting, eliminating spacing and bringing the optical detection surface as close as possible to the target object. This integration maintains assembly simplicity while maximizing optical sensitivity by minimizing the detection distance.
3Measurement precision
If transparent substrate is used for light transmission, then optical sensitivity is improved, but ambient light interference increases
Solution Approach 1:
The substrate is designed with localized optical properties: transparent in the specific wavelength range required for optical detection to maximize sensitivity, while the frame provides localized opacity to block ambient light from reaching the optical device die from unwanted directions. This spatial differentiation of optical properties resolves the contradiction between detection efficiency and interference rejection.
Solution Approach 2:
The frame structure, which could be seen as adding complexity, is utilized to convert harmful ambient light into a blocked signal, preventing interference while allowing the transparent substrate to maintain its beneficial light transmission properties for the desired optical wavelength range.
4Measurement precision
If frame structure is added to block ambient light, then optical sensitivity is improved by reducing interference, but device complexity increases
Solution Approach 1:
The frame structure serves multiple functions simultaneously: it provides mechanical support for the optical device die, defines the package boundary, and blocks ambient light interference. By combining these functions into a single structural element, the patent reduces overall device complexity while maintaining optical signal quality.
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 design results in a compact, high-performance optical sensor package that improves light transmission and detection efficiency, reducing thickness and minimizing interference from ambient light, making it suitable for wearable vital signs monitoring systems.
Implementation Method 1
a substrate that passes light at an optical wavelength
Implementation Method 2
a frame that is disposed at least partially around the side wall and at least partially over a back side of the optical device die. The frame is opaque to at least the optical wavelength
Data Source
AI summary
An optical device package is disclosed. The optical device package includes a substrate that passes light at an optical wavelength. The optical device package also includes an optical device assembly that is mounted to the substrate. The optical device assembly comprises an optical device die. The optical device die has a first surface that is mounted to and facing the substrate and a second surface that is opposite the first surface. The optical device package further includes a molding compound that is disposed at least partially over the second surface of the integrated device die.