Antireflection Films on DMD Mirror and Electrode End Faces
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Solution Overview
Problem
Existing electronic devices with digital micromirror devices suffer from stray light generation due to unnecessary reflection, which degrades the quality of projected images, especially when mirrors are in the OFF position and their end portions are raised above the substrate.
Innovation Solution
The implementation of antireflection films on the end faces of mirrors and electrodes, specifically dielectric multilayer films, to suppress unwanted reflections and reduce stray light, thereby improving image quality by controlling the position of mirrors using electrostatic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the mirror is in the OFF position with its end portion raised above the substrate, then the light modulation function is achieved, but stray light is generated due to reflection at the end face
Solution Approach 1:
The patent applies antireflection films to the end faces of the mirrors to convert the harmful reflection into beneficial absorption. The antireflection film reduces the reflection coefficient at the end face, thereby minimizing stray light generation while maintaining the light modulation function. This transforms the previously harmful reflective surface into a beneficial absorptive surface.
2Object-generated harmful factors
If an antireflection film is provided on the end face of the mirror, then stray light generation is suppressed, but the structure becomes more complex
Solution Approach 1:
The patent uses thin film antireflection coatings on the end faces of the mirrors. These thin films provide the necessary antireflection functionality without significantly increasing the structural complexity. The thin film approach allows for effective stray light suppression while maintaining a relatively simple overall device structure.
3Ease of operation
If light is reflected by the end face of the mirror, then the light path is defined, but image quality degrades due to projected stray light
Solution Approach 1:
The antireflection film converts the end face from a reflective surface that generates stray light into an absorptive surface that minimizes unwanted reflections. This maintains the necessary light path control while eliminating the harmful effect on image 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 use of antireflection films effectively minimizes stray light generation, enhancing the quality of projected images by reducing unnecessary reflections and temperature increases associated with light absorption, thus maintaining the stability and performance of the electronic device.
Implementation Method 1
a first antireflection film is provided on the first incident end face... reflection of the light at the first incident end face is suppressed by the first antireflection film
Implementation Method 2
The electrode generates an electrostatic force between the mirror and the electrode so as to rotate the mirror
Data Source
AI summary
An electronic device includes an electro-optical device including a substrate, a mirror for optical modulation disposed above one surface side of the substrate, and electrodes including an elevated address electrode disposed between the mirror and the substrate. The light source emits light toward the mirror in a direction at an angle with respect to the direction perpendicular to the mirror. The mirror includes a first incident end face which is an end face of the mirror located at a side from which the light is radiated, and a first antireflection film is provided on the first incident end face. The elevated address electrode includes a second incident end face which is an end face of the elevated address electrode located at the side from which the light is radiated, and a second antireflection film is provided on the second incident end face.