Fingerprint Sensor Integrated Into Display Panel Using Pixel Light Sources
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Solution Overview
Problem
The integration of fingerprint sensors into display devices, such as smartphones and tablets, increases device thickness and production costs due to the need for separate light sources and complex optical systems.
Innovation Solution
A photo-sensing type fingerprint sensor is integrated into the display device, where the pixels function as light sources, and a pinhole array layer is used to control light paths, reducing thickness and cost by eliminating the need for external light sources and complex optical systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate light source and optical system are installed for fingerprint sensing, then fingerprint sensing capability is achieved, but device thickness increases and production cost increases
Solution Approach 1:
The patent merges the light source function into the display panel by using pixel circuits that can emit light for fingerprint sensing. The fingerprint sensor is integrated within the display structure, combining multiple functions (display and biometric authentication) into a single device, thereby eliminating the need for separate light sources and reducing overall device thickness
Solution Approach 2:
The pixel circuits in the display panel serve dual purposes: displaying visual information and providing light for fingerprint sensing. This multi-functionality approach allows the same structural elements to perform multiple roles, reducing the need for additional dedicated components and minimizing device thickness
2Reliability
If a separate light source and optical system are installed for fingerprint sensing, then fingerprint sensing capability is achieved, but production cost increases
Solution Approach 1:
The patent combines the fingerprint sensor manufacturing process with the existing display panel fabrication process. By integrating the fingerprint sensing function into the display structure using the same pixel circuits and manufacturing steps, the need for separate production lines and additional assembly is eliminated, thereby reducing production costs
Solution Approach 2:
The display panel's pixel circuits serve their own additional function as light sources for fingerprint sensing, eliminating the need for separate dedicated light source components and their associated manufacturing and assembly costs
3Illumination intensity
If openings are separated from sensors and not in a conductive layer, then light guidance is achieved, but device thickness increases
Solution Approach 1:
The patent positions the openings (pixel circuits) and sensors in overlapping spatial relationships across different layers of the display structure. By utilizing the vertical dimension and overlapping arrangement, light guidance is achieved without requiring additional horizontal space or increasing device thickness
Solution Approach 2:
The fingerprint sensor openings are nested within the display panel structure, with the sensor array positioned behind the pixel circuits. This nested arrangement allows light to pass through the pixel circuits and be detected by the sensors without requiring separate external optical components, thereby maintaining thin device profile
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 integration reduces the module thickness and production costs while maintaining reliable fingerprint sensing capabilities, and prevents moiré effects by adjusting the resolutions of the pinhole array and photo sensor arrays.
Implementation Method 1
a pinhole array layer disposed between the pixel array and the photo sensor array and including a plurality of pinholes
Implementation Method 2
a photo sensor array disposed on a second surface of the first substrate and overlapping with the pinhole array in a plan view
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~3D
AI summary
A display device may include: a first substrate including pixel areas; a circuit element layer disposed on a first surface of the first substrate, and including at least one conductive layer; a light emitting element layer disposed on the circuit element layer; pixels each including a circuit element and a light emitting element disposed on the circuit element layer and the light emitting element layer in a corresponding one of the pixel areas; a first light transmitting hole array layer including first light transmitting holes distributed in the circuit element layer; and a photo sensor array layer disposed on a second surface of the first substrate and configured to overlap with the first light transmitting hole array layer, the photo sensor array layer comprising photo sensors. The first light transmitting holes may include openings distributed in the at least one conductive layer.