Monolithic MEMS SLM Driver with Integrated DACs
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Solution Overview
Problem
Existing spatial light modulators (SLMs) face issues with size, operating speed, and cost due to the need for separate substrates for SLMs and their drivers, which include external digital-to-analog converters (DACs) that introduce delays and increase complexity.
Innovation Solution
A monolithic SLM module is developed with integrated drivers and DACs fabricated on a single substrate, eliminating the need for external DACs and reducing capacitances, ESD protection, and in-band noise, while incorporating internal DACs and test circuitry for improved performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external DACs are used to drive the SLM, then the SLM can be operated, but the module size increases and wire bonding delays are introduced
Solution Approach 1:
The patent merges the SLM and DACs into a single integrated circuit fabricated on one substrate. The driver circuit includes multiple DACs that are directly integrated within the same chip as the SLM array, eliminating the need for separate external DACs and wire bonding connections. This integration reduces module size while maintaining full operational capability.
2Ease of operation
If external DACs with wire bonds are used, then the SLM can be driven, but operating speed decreases due to signal transmission delays
Solution Approach 1:
By integrating the DACs directly into the same substrate as the SLM, the patent eliminates wire bonding delays and reduces signal transmission path length. The driver circuit is positioned adjacent to the SLM array, enabling direct signal delivery without external connections, thereby significantly improving operating speed.
3Ease of operation
If external DACs are used, then the SLM can be controlled, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple functions (SLM array and DACs) into a single integrated circuit, reducing system complexity by eliminating separate external DAC components and their associated wiring. The driver circuit is fully integrated within the same chip, simplifying the overall system architecture while maintaining complete control capability.
4Ease of manufacture
If separate substrates are used for SLM and drivers, then fabrication can be performed, but manufacturing complexity and cost increase
Solution Approach 1:
The patent integrates both the SLM and DACs onto a single substrate, allowing both components to be fabricated simultaneously in one manufacturing process. This eliminates the need for separate substrate fabrication and subsequent assembly operations, reducing manufacturing complexity while maintaining fabrication capability.
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 solution reduces module size, increases pixel densities and switching speeds, decreases complexity and power consumption, and enhances reliability by integrating all necessary components on a single substrate, improving overall performance and reducing costs.
Implementation Method 1
GLVs are ribbon-type SLM that use electrostatic forces to move actuators or ribbons to produce diffraction between light reflected from adjacent actuators, thereby modulating light incident thereon
Data Source
AI summary
A spatial light modulator (SLM) module and methods of designing, manufacturing and using the same are provided. In one embodiment, the SLM module comprises a diffractive, diffractive SLM formed on a substrate, the SLM including a plurality of pixels each including a plurality of electrostatically deflectable actuators, and a driver including a number of drive channels each coupled to one of the plurality of electrostatically deflectable actuators. Each of the drive channels include at least one internal digital-to-analog converter (DAC) integrally formed on the same substrate as the SLM. In one embodiment, the DAC is a multi-slope charge integrating DAC. In other embodiments, the driver includes circuitry to test each of the drive channels, and a spare drive channel that can be switched in to replace a defective drive channel.