Viewing direction independent single-layer, pixelated light dimming filter

Abstract

A system included in a wearable viewing device (10) prevents reduction in legibility of a near-eye image display for observation in combination with an observer's visual exterior view. The system includes a near-eye image source (14) from which emanates near-eye image-carrying light and which is positioned out of the observer's direct visual exterior view. A dimming matrix display (12) including multiple pixels is positioned so that the observer (22) can see though them a scene (30, 32) in an exterior view. A partly transparent optical element (20) is positioned so that the observer can see the scene in the exterior view and reflect the near-eye image-carrying light to provide an image for observation by the observer. A dimming controller (34) controls amounts of scene-carrying light propagating through the multiple pixels from the locations in the scene and thereby prevents wash-out of the near-eye image when outside illumination is very bright.

Description

RELATED APPLICATION[0001]This application claims benefit of U.S. Patent Application No. 62 / 662,040, filed Apr. 24, 2018.COPYRIGHT NOTICE[0002]©2019 LC-TEC Displays AB. A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 37 CFR § 1.71(d).TECHNICAL FIELD[0003]This disclosure relates to a high dynamic range, electrically controllable, single-layer, pixelated light dimming filter for use in combination with a near-eye digital image display in wearable viewing devices.BACKGROUND INFORMATION[0004]Augmented reality headsets and glasses are wearable computers that add virtual information to a real world scene by displaying translucent content that can be viewed by the user, while at...

AI Technical Summary

Benefits of technology

The disclosed patent is about a new way to make viewing devices that can show images on a small screen without confusing the person wearing them with external light. It uses a special kind of display that has a special matrix of pixels that can show the outside world and the image at the same time. This is made possible through a see-through optical element that allows the person to see the outside world and the display simultaneously. The device also uses a controller to adjust the amount of light from the outside world that reaches the display so that the image doesn't get washed out when the person is in a very bright environment. This new technology solves the problem of previous devices that made it difficult to see the images without being blinded by external light.

Problems solved by technology

As environmental lighting conditions change, for example, when the user goes from indoors to outdoors, the brightness ratio of the two worlds also changes, something that can result in significantly reduced legibility.

However, this AR headset design has the disadvantage of over-dimming darker indoor scenes, requiring the neutral density filter to be manually changed to a less dense one.

However, electrochromic cells operate at relatively slow switching speeds and exhibit inherent coloration, so, in order to achieve a neutral filter, at least three electrochromic layers are required.

The addition of three electrochromic layers adds complexity and cost.

Furthermore, electrochromic displays work by electrochemical processes of charging and discharging, and much like a battery, they are limited by the number of charge and discharge cycles before operational failure.

The transmission of liquid crystal devices is, however, strongly dependent on viewing direction and thereby results in angular dependent dimming that is accompanied by viewing discomfort in wearing the AR headset.

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