Display Substrate Layout Using Oxide Transistors for Under-Screen Cameras
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Solution Overview
Problem
The challenge of integrating a front camera under the screen in OLED displays is hindered by opaque driving circuits and wires, leading to low overall transmittance and the need for design compromises like monobrow, notch, or waterdrop designs, which occupy screen space.
Innovation Solution
Incorporating oxide transistors in the first display region of the display substrate, along with specific configurations of pixel circuits and light-emitting elements, to enhance transparency and allow for direct placement of optical sensors under the screen without additional design modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional pixel circuits with polycrystalline silicon transistors are used, then the driving capability is sufficient, but the transparency of the display region is reduced
Solution Approach 1:
The patent changes the material parameter of the transistor from polycrystalline silicon to oxide semiconductor, which fundamentally alters the electrical and optical properties. Oxide transistors have lower light absorption coefficients, directly improving transparency while maintaining adequate driving capability through optimized channel dimensions and device architecture
Solution Approach 2:
The patent applies different transistor types in different display regions: oxide transistors in the first display region for high transparency, and polycrystalline silicon transistors in the second display region for standard performance. This local differentiation allows each region to have optimized properties for its specific function
2Area of stationary object
If the front camera is placed under the screen, then the screen-to-body ratio is increased, but the optical sensor cannot receive light due to opaque driving circuits
Solution Approach 1:
By changing the transistor material to oxide semiconductor, the optical properties of the driving circuit are fundamentally altered. The oxide transistor's lower light absorption enables sufficient light transmission (greater than 40% in the first display region) for the optical sensor to receive external light while the camera remains positioned under the screen
Solution Approach 2:
The oxide transistor acts as an intermediary element that mediates between the need for functional driving circuits and the requirement for light transmission. It provides the necessary electrical functionality while simultaneously allowing light to pass through to the optical sensor below
3Ease of operation
If monobrow, notch, or waterdrop designs are used to accommodate the front camera, then the camera can be positioned, but the screen space is reduced and aesthetic appeal is compromised
Solution Approach 1:
The patent extracts the transparency requirement from the traditional camera placement solutions. By making the driving circuit itself transparent through oxide transistors, the need for separate camera cutouts (monobrow, notch, waterdrop designs) is eliminated, allowing the entire screen area to be utilized without compromises
Data Source
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AI summary
The present application relates to a display substrate and a display device. The display substrate comprises: at least one first display area; a second display area located on at least one side of the at least one first display area, the light transmittance of the second display area being smaller than that of the at least one first display area; and a plurality of first sub-pixels located in the at least one first display area, the first sub-pixels each comprising a first light-emitting element and a first pixel circuit, the first pixel circuit being configured to drive the first light-emitting element to emit light, wherein the first pixel circuit comprises a plurality of transistors, and at least one transistor among the plurality of transistors is an oxide transistor. In this way, the light transmittance of the first display area can be improved.