Optical Sensing Array in Display Black Matrix
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Solution Overview
Problem
Conventional optical sensors embedded in display devices face challenges such as limited aperture size due to shared active areas with display emission elements, non-selective wavelength sensitivity leading to excessive signal processing, and crosstalk between display elements and sensors, resulting in inefficient operation and incorrect readings.
Innovation Solution
An optical sensing array is positioned within the black matrix of a display device, independent of display element addressing lines, utilizing a sensing diode and blocking diode configuration with a partial spectrum pass filter and quantum-dot film for selective wavelength sensitivity, allowing larger aperture size and reduced signal processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical sensors are formed in the same active area as display emission elements, then the display device can integrate sensing functionality, but the aperture of the optical sensors is reduced and display brightness is compromised
Solution Approach 1:
The display device is segmented into distinct functional zones: an active display area for light emission and a separate inactive area for optical sensing. This spatial segmentation allows the optical sensor to have a large aperture without compromising display brightness, as the sensor occupies the black matrix region rather than competing for active pixel space.
Solution Approach 2:
The inactive area of the display, traditionally unused for image production, is given a new function by embedding the optical sensing array there. This multi-functional use of the inactive area allows the device to provide both display and sensing capabilities without reducing the active display area or sensor aperture.
2Device complexity
If conventional optical sensors are used without wavelength selectivity, then the sensor structure is simpler, but excessive signal processing power is required to extract signals from ambient light noise
Solution Approach 1:
Wavelength-selective filters are applied locally at each optical sensor position within the inactive area. These filters are specifically designed to match the wavelength of the light source (e.g., infrared LEDs), enabling the sensor to selectively detect the desired signal while rejecting ambient light noise, thereby reducing processing power requirements.
Solution Approach 2:
The optical sensors are configured with specific wavelength sensitivity parameters through the use of wavelength-selective filters. By changing the spectral response parameter of the sensors to match the light source wavelength, the system achieves high signal-to-noise ratio without requiring complex signal processing or excessive power consumption.
3Device complexity
If address lines are shared by optical sensors and display elements, then the device uses fewer control lines, but concurrent reading of sensors and writing of display elements cannot occur
Solution Approach 1:
The addressing system is segmented into separate control line sets: one set for display element addressing and another set for optical sensor reading. This segmentation enables independent and concurrent operation of display writing and sensor reading processes, significantly improving processing efficiency without requiring a large number of control lines.
Solution Approach 2:
Optical sensor readings are performed in advance during the inactive period between display refresh cycles. By completing sensor readings beforehand, the system prepares sensing data without interfering with display writing operations, enabling efficient concurrent processing and improving overall productivity.
4Area of moving object
If display emission elements and optical sensors share the same active area, then space utilization is maximized, but crosstalk between display elements and sensors occurs
Solution Approach 1:
The device is divided into spatially separate regions: the active display area for light emission and the inactive area for optical sensing. This physical segmentation eliminates crosstalk between display elements and sensors by ensuring that light from display elements cannot reach the optical sensors, guaranteeing accurate optical readings.
Solution Approach 2:
The traditionally harmful inactive area, which would otherwise be wasted space, is converted into a beneficial region for optical sensing. By placing sensors in the inactive area, the system turns a structural limitation into an advantage, achieving both accurate sensing and high display brightness without crosstalk interference.
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
The solution enables a larger optical sensor aperture without compromising display area, improves sensitivity with selective wavelength detection, and allows concurrent operation with display elements, reducing crosstalk and enhancing processing efficiency.
Implementation Method 1
a sensing diode configured to generate current in response to light incident on the sensing diode
Implementation Method 2
utilizing a sensing diode and blocking diode configuration with a partial spectrum pass filter and quantum-dot film for selective wavelength sensitivity
Implementation Method 3
utilizing a sensing diode and blocking diode configuration with a partial spectrum pass filter
Data Source
AI summary
A display device includes a pixel array comprising a plurality of pixels, each of the pixels comprising a plurality of sub-pixels; a black matrix located between the sub-pixels; and an optical sensing array at the black matrix, the optical sensing array comprising a row conductor, and a column conductor that crosses the row conductor at a crossing region.