Wavelength Tunable Interference Filter Hermetic Sealing
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Solution Overview
Problem
Existing wavelength tunable interference filters face challenges in maintaining a hermetically sealed environment while allowing voltage application to electrodes, which is essential for their operation, especially when using non-conductive substrates like glass, and are prone to deterioration due to foreign matter adhesion.
Innovation Solution
A configuration featuring a first and second substrate with reflection films, a gap changing section, and a third substrate with a top surface and sidewall portion, where the wiring portion extends both inside and outside the hermetically sealed space, enabling voltage application and reducing the filter's size by allowing hermetic sealing on a chip basis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hermetically sealed space is created to prevent foreign matter adhesion on reflection films, then reliability is improved, but voltage application to electrodes becomes difficult when using non-conductive substrates
Solution Approach 1:
The substrate is divided into two functional parts: a non-conductive glass substrate for optical transmission and hermetic sealing, and a conductive silicon substrate for electrical connection. The silicon substrate serves as an electrical extension of the glass substrate, allowing voltage application while maintaining the hermetic seal integrity.
Solution Approach 2:
The silicon substrate acts as an intermediary between the hermetically sealed optical components and the external electrical connections. It provides a conductive pathway without compromising the hermetic seal, enabling both protection and electrical operation simultaneously.
2Reliability
If a hermetic seal is implemented using conventional packaging methods, then protection from contamination is improved, but device size increases
Solution Approach 1:
The hermetic sealing function is merged with the substrate structure itself. The glass substrate forms an integral part of the hermetic seal, eliminating the need for separate packaging containers. This integration reduces overall device size while maintaining protection.
Solution Approach 2:
The optical components are nested within the glass substrate structure, which itself is nested within the hermetic seal. This multi-level nesting maximizes space utilization and minimizes external dimensions.
3Ease of operation
If complex wiring structures are used to apply voltage in hermetically sealed spaces, then ease of operation is improved, but manufacturing complexity increases
Solution Approach 1:
The electrical connection function is extracted from the hermetic seal structure and implemented through the silicon substrate extension. This eliminates complex external wiring while maintaining simple electrical connection points on the substrate surface.
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 allows for reliable voltage application to the electrodes within a hermetically sealed space, reduces the size of the wavelength tunable interference filter, and lowers manufacturing costs by simplifying the wiring process and ensuring a vacuum state is maintained.
Implementation Method 1
a first reflection film provided on the first substrate, the first reflection film reflecting part of incident light and transmitting part thereof, a second reflection film provided on the second substrate so that the second reflection film faces the first reflection film, the second reflection film reflecting part of incident light and transmitting part thereof
Implementation Method 2
wavelength tunable interference filter in which reflection films are disposed on the opposing surfaces of a pair of substrates so that the reflection films face each other and the dimension of the gap between the reflection films is changed to selectively extract light of a predetermined wavelength from incident light
Implementation Method 3
a gap changing section that changes the dimension of a gap between the first reflection film and the second reflection film
Implementation Method 4
the space in which the reflection films and electrodes that form an actuator are provided is exhausted into a vacuum and hermetically sealed
Implementation Method 5
An end surface of the sidewall portion of the third substrate that faces the first substrate is bonded to the first substrate so that a space surrounded by the top surface portion of the third substrate, the sidewall portion of the third substrate, and the first substrate is hermetically sealed
Data Source
AI summary
A wavelength tunable interference filter includes an electrostatic actuator that changes the dimension of a gap between a fixed reflection film and a movable reflection film, a fixed drawn electrode and a movable drawn electrode that are connected to the electrostatic actuator, and a third substrate having a top surface portion and a sidewall portion. An end surface of the sidewall portion is bonded to a first substrate so that a space surrounded by the top surface portion, the sidewall portion, and the first substrate is hermetically sealed. A second substrate and the electrostatic actuator are disposed in the space, and the fixed drawn electrode and the movable drawn electrode are disposed on the first substrate and extend both inside and outside the space.