Optical Module Substrate Design for Light Interference Reduction
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Solution Overview
Problem
Existing optical module configurations face challenges in miniaturization due to light interference between variable wavelength interference filters and light-receiving elements, leading to degraded measurement accuracy, and the use of bonding members like solder can cause inclination issues and increase component complexity.
Innovation Solution
An optical module design featuring a substrate with a flat surface and a hole portion, where the light-receiving element is positioned inside the hole, and an optical filter device with a translucent member is bonded to the substrate, setting the distance between the translucent member and the light-receiving element to avoid light interference, using the substrate thickness to secure this distance, and employing a lightproof bonding member to minimize stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical filter and light-receiving element are accommodated in the same package to miniaturize the device, then the package size is reduced, but light interference occurs between the variable wavelength interference filter and the light-receiving element, degrading measurement accuracy
Solution Approach 1:
A translucent member (light shield) is introduced as an intermediary component between the optical filter and the light-receiving element. This member blocks stray light from reaching the light-receiving element directly, preventing light interference while allowing the compact package configuration to be maintained. The translucent member is positioned to face the light-receiving element and block light paths that would cause interference.
2Measurement precision
If the package is bonded to the substrate using a bonding member like solder to secure the required distance, then the distance is maintained to prevent light interference, but the package inclines relative to the substrate
Solution Approach 1:
A lightproof bonding member is used as an intermediary that serves dual functions: bonding the optical filter package to the substrate and maintaining the required distance to prevent light interference. The lightproof material blocks stray light while providing mechanical support, eliminating the need for separate spacers and preventing package inclination.
Solution Approach 2:
The bonding member is designed to perform multiple functions simultaneously: mechanical bonding, distance maintenance, and light blocking. This multi-functional approach replaces the need for separate components (spacers and bonding agents) and ensures proper alignment while preventing light interference.
3Measurement precision
If a spacer is used to maintain the required distance between the package and substrate, then light interference is prevented, but the number of components increases
Solution Approach 1:
The lightproof bonding member is designed to perform multiple functions simultaneously: mechanical bonding, distance maintenance, and light blocking. This multi-functional approach replaces the need for separate components (spacers and bonding agents) and ensures proper alignment while preventing light interference.
Solution Approach 2:
The functions of the spacer and bonding member are merged into a single lightproof bonding member. This integration reduces the total component count while maintaining all necessary functions: mechanical support, precise positioning, and stray light blocking.
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 enhances measurement accuracy by preventing light interference, reduces the number of components, and simplifies the setup while maintaining high precision in light reception, even when the optical filter device is bonded using a minimal bonding member, thus supporting accurate light measurement without inclination issues.
Implementation Method 1
an interference filter which transmits light in a wavelength range of 780 nm to 850 nm
Implementation Method 2
a lightproof member which blocks stray light from reaching the light-receiving element
Data Source
AI summary
An optical module includes a circuit substrate that has a concave portion and a flat surface, an optical sensor that is disposed inside a space, and an optical filter device that has a base which accommodates a variable wavelength interference filter and has a light-through hole through which light emitted from the variable wavelength interference filter passes and a first glass member which is disposed in the light-through hole. The first glass member is positioned inside the space. The base is bonded to the flat surface. The distance between the first glass member and the optical sensor is set to a distance at which light emitted from the variable wavelength interference filter does not interfere between the first glass member and the optical sensor.