Integrated Photosensor Package Layout for Optical Crosstalk Isolation
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Solution Overview
Problem
Miniaturization and high-functionality of photosensors are desired while reducing optical crosstalk caused by diffused light, and integrating light emitting and receiving elements in a single package is challenging.
Innovation Solution
A photosensor design with a substrate, conductive layers, a conductive via layer, and a translucent covering member that includes a groove between the light emitting element and integrated circuit, allowing for electrical connection through separate mounting portions and via layers, reducing crosstalk while enabling miniaturization and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting element and light receiving element are integrated in a single package, then miniaturization and high-functionality are achieved, but optical crosstalk increases due to diffused light
Solution Approach 1:
The package is segmented into distinct mounting portions for the light emitting element and light receiving element, separated by a groove structure. This spatial segmentation prevents diffused light from the emitting element from reaching the receiving element, thereby reducing optical crosstalk while maintaining integration in a single package.
Solution Approach 2:
Different regions of the package are assigned different functions with specific structural characteristics. The groove region acts as an optical isolation zone with specific geometric properties that block diffused light paths, while the mounting portions are optimized for their respective elements. This local differentiation resolves the crosstalk issue without compromising overall integration.
2Adaptability or versatility
If the light emitting element and light receiving element are integrated in a single package, then functionality is enhanced, but device complexity increases
Solution Approach 1:
The package structure serves multiple functions simultaneously: it provides mechanical support for both elements, establishes electrical connections through conductive layers and vias, and creates optical isolation through the groove structure. This multi-functionality reduces the need for separate components and simplifies the overall system while maintaining high integration.
Solution Approach 2:
The mounting portions for the light emitting element and light receiving element are merged into a single package substrate with shared conductive layers and via structures. This merging reduces the number of separate components and interfaces, thereby reducing device complexity while achieving enhanced functionality through integration.
3Object-generated harmful factors
If mounting portions are separated by a groove, then optical crosstalk is reduced, but electrical connection complexity increases
Solution Approach 1:
The electrical connection structure transitions from a two-dimensional planar layout to a three-dimensional layered architecture. Conductive vias extend vertically through the substrate to connect conductive layers on different sides of the groove, enabling electrical connections without requiring horizontal paths that would compromise optical isolation. This dimensional transition resolves the conflict between crosstalk reduction and electrical connectivity.
Solution Approach 2:
The conductive vias act as intermediary elements that bridge the electrical connection across the optical isolation groove. These vias provide a dedicated electrical pathway through the substrate without requiring the light emitting and receiving elements to be in direct electrical contact, thereby maintaining both optical isolation and electrical connectivity.
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 achieves both miniaturization and high-functionality by reducing crosstalk, allowing for efficient electrical connection and enhanced light extraction efficiency, while supporting larger integrated circuits and reducing wire length on the substrate.
Implementation Method 1
a light emitting element (20), mounted on the first conductive layer (60)
Implementation Method 2
a covering member (90) being translucent, disposed on the substrate (50), covering the light emitting element (20) and the integrated circuit (30) together with the first conductive layer (60), and including a groove (92) between the light emitting element (20) and the integrated circuit (30)
Implementation Method 3
a first conductive layer (60), disposed on a main surface of the substrate (50); a second conductive layer (70), disposed on a back surface of the substrate (50); a conductive via layer (80), disposed between the first conductive layer (60) and the second conductive layer (70)
Data Source
AI summary
A photosensor including first and second conductive layers disposed on a main surface and a back surface of a substrate is provided. A conductive via layer is disposed between the conductive layers. A light emitting element and an integrated circuit (IC) including a light receiving element are mounted on the first conductive layer. The photosensor includes a translucent covering member that covers the light emitting element and the IC together with the first conductive layer. The covering member includes a groove between the light emitting element and the IC in a plan view. The first conductive layer includes a first mounting portion on which the light emitting element is mounted and a second mounting portion on which the IC is mounted. The light emitting device is electrically connected to the IC via the first mounting portion, the conductive via layer, the second conductive layer and the second mounting portion.