Light Sensing Display with Dynamic LED Biasing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional touch-sensitive displays face challenges in capturing sufficient information due to inadequate design, which limits their ability to gather input effectively.
Innovation Solution
The display incorporates an array of pixels with light-emitting diodes that can be forward or reverse biased to emit and detect light, allowing for both image display and light sensing operations, with specific pixels temporarily deactivated to prevent interference during light sensing, using horizontal and vertical control lines for signal transmission and current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display uses light-emitting diodes for image display, then the display function is achieved, but the ability to sense light is compromised
Solution Approach 1:
The light-emitting diodes are dynamically switched between forward bias mode for light emission during display operations and reverse bias mode for light sensing during touch detection. This dynamic reconfiguration allows the same hardware components to serve multiple functions without compromising the reliability of either function.
Solution Approach 2:
The light-emitting diodes are designed to perform multiple functions: displaying images through light emission and sensing touch through light detection. By utilizing the bidirectional electrical characteristics of LEDs, the patent achieves multi-functionality without requiring separate dedicated sensing components, thereby improving adaptability while maintaining reliability through careful mode switching.
2Productivity
If all pixels remain active during light sensing, then the display is ready for immediate image display, but the light sensing measurements are interfered with by adjacent image pixels
Solution Approach 1:
The display screen is segmented into different operational zones during light sensing mode: some regions contain pixels that emit light to illuminate the touch surface, while other regions contain pixels that remain inactive to serve as pure sensors. This spatial segmentation prevents interference from adjacent emitting pixels and improves measurement precision without significantly reducing overall productivity.
Solution Approach 2:
The display alternates between display mode and sensing mode in periodic cycles. During sensing mode, pixels are selectively activated or deactivated based on their intended function (illumination or sensing). This periodic switching allows the system to maintain high productivity over time while achieving accurate measurements during dedicated sensing intervals.
3Adaptability or versatility
If the display incorporates touch sensors, then touch detection capability is added, but the ability to capture additional information through light sensing is limited
Solution Approach 1:
The patent merges the touch detection function with the light sensing function by using the same pixel array for both purposes. The light-emitting diodes serve as both display elements and touch sensors, eliminating the need for separate sensing layers. This merging allows the display to capture multiple types of information (touch location, pressure, ambient light, reflected light patterns) simultaneously, thereby improving adaptability without losing information.
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 enhances the display's ability to capture input by enabling efficient light sensing and touch detection without interfering with image display, improving the overall gathering of user interactions and environmental data.
Implementation Method 1
each pixel may contain a light-emitting diode and thin-film transistor circuitry that controls current flow through the organic light-emitting diode
Implementation Method 2
some of the light-emitting diodes may be reversed biased to detect the emitted light after the emitted light has reflected from an external object
Data Source
AI summary
A display may have an array of pixels. The pixels may contain light-emitting diodes. When it is desired to use the display to operate as a light sensor, some of the light-emitting diodes may be forward biased to emit light while some of the light-emitting diodes are reversed biased to detect the emitted light after the emitted light has reflected from an external object. During light sensing operations, one or more areas of the display may be temporarily deactivated so that the light-sensing pixels may measure the reflected light. Vertical lines may serve both as data loading lines and as current sensing lines. Currents may be sensed during drive transistor current compensation and during light sensing. The vertical lines may load signals into the pixels that forward bias the light-emitting diodes to emit light when it is desired to display images for a user.