Balanced Light Valve TIR Modulator for Beam Steering Reduction
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Solution Overview
Problem
Conventional total internal reflection (TIR) modulators suffer from beam steering effects and improper formation of image pixels due to long-range electric fields and uneven electric potential differences between diffracting and non-diffracting regions, leading to reduced image quality and increased sensitivity to aberrations.
Innovation Solution
A balanced TIR modulator design with interdigitated electrode sets, where each pixel region is controlled by distinct electric potential values from two separate groups, reducing the electric potential difference between diffracting and non-diffracting regions and minimizing long-range electric fields, thereby improving image pixel placement and sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional TIR modulator uses single set of electrodes driven with binary voltage levels, then device complexity is reduced, but beam steering effects occur and image pixel placement precision deteriorates
Solution Approach 1:
The electrode system is segmented into two independent sets (first set and second set) instead of using a single electrode set. Each set can be independently addressed with different voltage levels, allowing separate control of diffracting and non-diffracting regions. This segmentation enables balanced electric potential distribution across the modulator, eliminating beam steering effects while maintaining precise image pixel placement.
2Ease of operation
If conventional TIR modulator uses binary voltage levels (0 and V), then ease of operation is improved, but long-range electric fields are generated causing beam steering
Solution Approach 1:
The voltage control scheme is changed from binary levels (0 and V) to multi-level parameters including 0, +V/2, and -V/2. The first set of electrodes can be driven at +V/2 while the second set is driven at -V/2, creating a balanced electric potential distribution. This parameter change eliminates the generation of long-range electric fields that cause beam steering, while maintaining straightforward voltage control through the balanced configuration.
3Device complexity
If conventional TIR modulator uses interdigitated electrodes with common ground, then device complexity is reduced, but electric potential difference between diffracting and non-diffracting regions increases
Solution Approach 1:
The modulator achieves equipotentiality by balancing the electric potential distribution across the first and second electrode sets. When the first set is driven at +V/2 and the second set at -V/2, the average electric potential at the boundary between diffracting and non-diffracting regions is equalized. This eliminates unwanted electric potential differences that would otherwise deflect output radiation and cause beam steering effects.
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 balanced modulator design reduces beam steering effects, enhances image pixel sharpness, and improves exposure profiles, resulting in higher resolution and better-defined image features by effectively utilizing the imaging system's pupil and illumination.
Implementation Method 1
Electro-optic materials are those whose optical properties change in accordance with the strength of an electric field established within them.
Implementation Method 2
The application of the voltage alters the refractive index of the electro-optic material, thereby changing a birefringent state of the pixel region.
Implementation Method 3
The arrangement of electrodes 15 and 16 in each of the electrode groups S1, S2, S3, S4 . . . S causes each of the electrode groups to behave in a manner similar to a diffraction grating.
Implementation Method 4
Surfaces 20 and 22 are arranged to cause input radiation 25 to refract and undergo total internal reflection at surface 18.
Implementation Method 5
Surfaces 20 and 22 are arranged to cause input radiation 25 to refract and undergo total internal reflection at surface 18.
Data Source
AI summary
Radiation from an illumination source (102) is directed to a total internal reflector (TIR) modulator (10). The modulator includes a an electro-optic member (213) with a plurality of individually addressable pixel regions (210) comprised of a plurality of electrodes arranged in a first and second set. At least one electrode of the first set is adjacent to at least one electrode of the second set and at least one of the pixel regions is controlled to form at least one image pixel on a surface. A first electric potential is imposed on the first set of electrodes selected from a first predetermined group of electric potential values. A second electric potential is imposed on the second set of electrodes selected from a second predetermined group of electric potential values. The first and second predetermined groups of electric potential values together comprise at least three different electric potential values.