Folded Optical Path Display Mitigating Stray Light Artifacts

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Solution Overview

Problem

Surgical display systems with folded optical paths often produce undesired image artifacts due to stray image light, which can distort the visualization of surgical images during minimally invasive procedures.

Innovation Solution

The implementation of a display system with a display panel, a first reflector, and a second reflector, where the second reflector is positioned to absorb stray image light by orienting it at the Brewster angle and using a light control device to control the distribution angle of image light, thereby mitigating image artifacts and improving image contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the optical path is folded to position the display panel to the side of or above the user eyepiece, then the user input devices can be positioned in front of the user, but image artifacts are produced when image light follows paths other than the intended optical path

Engineering Contradiction:

Improveuser input device positioningVSAvoidimage artifacts

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies the Brewster angle principle to convert the harmful stray light into a beneficial effect. By positioning the second reflector at the Brewster angle, the system causes stray light to be transmitted rather than reflected, effectively eliminating the image artifacts while maintaining the folded optical path configuration for ease of operation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Illumination intensity

If the second reflector is positioned to reflect image light toward the eyepiece, then the displayed image is viewable through the eyepiece, but stray image light is also reflected causing image artifacts

Engineering Contradiction:

Improveimage light transmissionVSAvoidstray light reflection

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the angular parameter of the second reflector to the Brewster angle. This parameter change fundamentally alters the optical behavior, causing the reflector to transmit p-polarized light (the intended image light) while blocking s-polarized stray light, thus eliminating artifacts without compromising image transmission

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system converts the potentially harmful stray light into a beneficial filtering mechanism. By orienting the second reflector at the Brewster angle, stray light that would normally create artifacts is now transmitted through the reflector while the desired image light is reflected toward the eyepiece, effectively using the same optical path for both purposes

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 significantly reduces image artifacts and enhances image clarity by minimizing the reflection of stray light, providing a clearer view of the surgical area for the surgeon during computer-assisted surgical procedures.

Implementation Method 1

the second reflector is positioned relative to the second image light and a polarization direction of the second image light incident on the second reflector has a first orientation such that reflectance of a portion of the second image light from the second reflector is approximately zero

Methodology Applied

Scientific EffectBrewster angle: Brewster's Angle

Implementation Method 2

the first reflector reflects the first image light from the display panel toward the second reflector

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

the second reflector reflects the first image light from the first reflector toward an eyepiece

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS20250020919A1Image artifact mitigation in a display system having a folded optical path

Publication Date: 2025.01.16 INTUITIVE SURGICAL OPERATIONS INC

AI summary

A display system includes a display panel, a first reflector, and a second reflector. The display panel provides first image light representative of a displayed image to the first reflector and provides second image light representative of at least a portion of the displayed image to the second reflector without first being reflected by the first reflector. The first reflector reflects the first image light toward the second reflector. The second reflector reflects the first image light toward an eyepiece. The second reflector is positioned relative to the second image light and a polarization direction of the second image light incident on the second reflector has a first orientation such that reflectance of a portion of the second image light from the second reflector is approximately zero. A light control device behind the display panel may control a distribution angle of image light from the display panel.