Display Pixel Current Sink to Reduce Under-Display Artifacts
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Solution Overview
Problem
Electronic devices with full-face displays face issues of display artifacts due to non-visible-wavelength light emitted by sensors placed under the display, causing localized brightness or color differences that are more noticeable in dark environments.
Innovation Solution
Incorporating a current sink path in display pixels that overlap the light emitter to divert leakage current, using a shielding layer to block direct light exposure, and adjusting pixel design to mitigate artifacts by altering transistor control and anode size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sensors are placed under the full-face display, then the display coverage is improved, but display artifacts occur due to non-visible-wavelength light emission
Solution Approach 1:
The patent applies local quality by implementing different pixel structures in different display regions. Pixels in the light emitter overlap region (first display region) are equipped with additional transistors (seventh and eighth transistors) and configured with specific connectivity to prevent leakage current, while pixels in non-overlap regions use standard structures. This localized structural differentiation addresses the artifact problem only where light emitters are present, maintaining overall display coverage while resolving the harmful effect locally.
Solution Approach 2:
The patent introduces an intermediary current sink path mediated by the seventh and eighth transistors. This intermediary structure provides an alternative current pathway that intercepts and redirects leakage current before it can reach the light-emitting diode. The seventh transistor acts as a switch controlled by the light emitter's non-visible light, and the eighth transistor regulates current flow through the sink path, effectively mediating between the harmful light emission and the display pixel to prevent artifacts.
2Object-affected harmful factors
If a current sink path is added to divert leakage current, then display artifacts are reduced, but pixel circuit complexity increases
Solution Approach 1:
The patent segments the pixel circuit into distinct functional blocks with specialized transistors. The seventh transistor is dedicated solely to controlling the current sink path, while the eighth transistor manages current regulation. This segmentation allows each transistor to perform a specific function efficiently, making the complex circuit more manageable and manufacturable. The segmented approach also enables selective activation of the current sink path only in pixels overlapping light emitters, reducing overall complexity compared to a universal solution.
Solution Approach 2:
The patent implements partial action by applying the current sink path configuration only to pixels in the first display region that overlap with light emitters, rather than all pixels in the display. This partial implementation reduces the total number of additional transistors and circuit elements required, thereby limiting the increase in overall device complexity while still effectively addressing the artifact problem in the critical overlap regions.
3Stability of the object's composition
If the anode area is increased to compensate for light blocking, then display uniformity is improved, but pixel area and manufacturing complexity increase
Solution Approach 1:
The patent applies parameter changes by adjusting the anode area specifically in pixels located in the first display region that overlap with light emitters. These pixels are configured with larger anodes to compensate for the reduced light output caused by the shielding layer. The parameter change is localized and quantified, with the anode area in overlap-region pixels being greater than in non-overlap pixels, thereby restoring display uniformity without unnecessarily increasing the area of all pixels across the entire display.
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
Effectively reduces display artifacts by preventing current leakage through light-emitting diodes, maintaining consistent display quality across varying ambient light conditions.
Implementation Method 1
a light-emitting diode having an anode and a cathode
Implementation Method 2
a shielding layer that blocks the light from the light emitter
Data Source
AI summary
A light emitter that operates through a display may cause display artifacts, even when the light emitter operates using non-visible wavelengths. Display artifacts caused by a light emitter that operates through a display may be referred to as emitter artifacts. To mitigate emitter artifacts, a display pixel that overlaps the light emitter may include a transistor that provides a current sink to divert leakage current away from the light-emitting diode in that pixel. A shielding layer may be interposed between the light emitter and a display pixel. The shielding layer may block light from the light emitter. The shielding layer may have an opening that exposes one transistor in the pixel to the light from the light emitter. Pixels that overlap the light emitter may have larger anodes than pixels that do not overlap the light emitter.