Spatial Light Modulator Encapsulation with Light Absorbing Spacer

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Solution Overview

Problem

In the manufacturing of spatial light modulators, unwanted scattered light within micro chambers can compromise the optical performance by exiting through transparent windows, leading to reduced contrast and increased optical noise between the 'on' and 'off' states.

Innovation Solution

The encapsulation of spatial light modulators includes a spacer wall with a light absorbing material, such as zirconium compounds, to absorb unwanted light within the micro chambers, while the encapsulation cover is transparent to visible, UV, or IR light, and an aperture layer with chromium compounds is used to control light entry and exit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If transparent windows are used in micro chambers to allow light entry and exit, then optical signal transmission is enabled, but unwanted scattered light can exit the window causing reduced contrast and increased optical noise

Engineering Contradiction:

Improveoptical signal transmissionVSAvoidoptical noise and contrast reduction

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The spacer wall is selectively coated with light absorbing material only on its inner surface facing the chamber, while maintaining transparency elsewhere. This local application of light absorption creates different optical properties in different regions of the same component, allowing the transparent window to pass desired light while the coated inner surface absorbs scattered light.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The light absorbing material on the spacer wall acts as an intermediary element between the scattered light and the transparent window. Instead of letting scattered light directly exit through the window, the absorbing material intercepts it first, converting the harmful scattered light into heat and preventing it from degrading the optical signal.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If light absorbing material is added to the chamber to reduce scattered light, then optical contrast is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improveoptical contrastVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The spacer wall serves multiple functions: it maintains the physical separation between the encapsulation cover and substrate, provides structural support for the chamber, and when coated with light absorbing material, also functions as a light absorption element. This multi-functionality reduces the need for separate components and simplifies the overall device structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The light absorbing function is merged with the spacer wall structure rather than being implemented as a separate component. By coating the existing spacer wall with light absorbing material, the patent combines the mechanical support function and light absorption function into a single integrated element, reducing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If multiple spatial light modulators are fabricated on a semiconductor wafer and sealed in micro chambers, then manufacturing efficiency is improved, but unwanted scattered light within the chambers compromises optical performance

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidoptical performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The wafer-level fabrication process creates multiple identical micro chambers, each with its own spacer wall coated with light absorbing material. This segmentation allows the light absorption function to be implemented independently in each chamber while maintaining consistent optical performance across all devices produced in parallel on the wafer.

Inventive Principle:

Principle #1Segmentation

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 solution improves the optical performance by reducing optical noise and increasing the contrast between the 'on' and 'off' states of the spatial light modulators, while also enhancing manufacturing efficiency through a common process for encapsulating multiple spatial light modulators.

Implementation Method 1

a first light absorbing material on the inner surface of the spacer wall, the light absorbing material configured to absorb light in the chamber

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS7538922B2Encapsulated spatial light modulator having improved performance

Publication Date: 2009.05.26 SPATIAL PHOTONICS INC

AI summary

Devices and methods for forming a spatial light modulator with high contrast are described. Light absorbing materials are used within a chamber that houses a spatial light modulator. The light absorbing materials absorb reflected light that is not intended for forming a part of a display image. The light absorbing material can form an aperture layer, wherein light to form the display image is transmitted through an opening in the aperture layer. An array of spatial light modulators can be within the housing and dummy spatial light modulators may be formed to enable easy alignment of the array with the opening in the aperture layer.