Light-Emitting Device Transistor Region Switching for Flash Illumination
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Solution Overview
Problem
Conventional light-emitting devices for electronic devices, such as those used in portable cameras, face issues with insufficient subject illumination due to high power consumption and the need for high voltage to maintain luminance, leading to display uniformity problems and image burn-in when used as both display and flash sources.
Innovation Solution
A light-emitting device with a transistor that operates in a saturation region for displaying text or images and switches to a linear region for high-luminance illumination, allowing for independent control of current flow to manage power consumption and prevent deterioration, enabling dual functionality as a display and flash.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light-emitting element operates with constant current drive to prevent deterioration, then display uniformity is improved, but the source-drain voltage of the transistor increases and power consumption increases when high luminance is needed
Solution Approach 1:
The transistor operation region is dynamically switched between saturation region (for display function with constant current drive) and linear region (for flash function with high luminance). This dynamic adjustment allows the system to optimize between display uniformity and power consumption/luminance output based on the operational mode.
Solution Approach 2:
The operation region parameter of the transistor is changed based on the functional requirement. In saturation region, the transistor provides constant current drive for uniform display. In linear region, the transistor allows high current flow for high-luminance flash illumination, reducing the need for extremely high source-drain voltage and thus reducing power consumption.
2Reliability
If the transistor operates in saturation region for constant current drive, then display uniformity is maintained, but the source-drain voltage increases and high voltage is needed for high luminance
Solution Approach 1:
The transistor operation region is dynamically switched between saturation region (for display function with constant current drive) and linear region (for flash function with high luminance). This dynamic adjustment allows the system to optimize between display uniformity and power consumption/luminance output based on the operational mode.
3Illumination intensity
If the light-emitting element is used for high-luminance illumination, then subject illumination is improved, but the transistor operates in saturation region requiring extremely high source-drain voltage
Solution Approach 1:
The operation region parameter of the transistor is changed based on the functional requirement. In saturation region, the transistor provides constant current drive for uniform display. In linear region, the transistor allows high current flow for high-luminance flash illumination, reducing the need for extremely high source-drain voltage and thus reducing power consumption.
4Adaptability or versatility
If the light-emitting device is used for both display and flash functions, then versatility is improved, but display uniformity deteriorates and image burn-in occurs
Solution Approach 1:
The transistor operation region is dynamically switched between saturation region (for display function with constant current drive) and linear region (for flash function with high luminance). This dynamic adjustment allows the system to optimize between display uniformity and power consumption/luminance output based on the operational mode.
Solution Approach 2:
The light-emitting element operates in different modes periodically - constant current drive mode for display function and high current mode for flash function. This periodic switching between operational modes allows the device to perform both functions while managing the deterioration issues through proper mode selection.
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 provides high-luminance illumination with reduced power consumption and minimizes display uniformity issues and image burn-in, allowing the device to effectively function as both a display and a flash source while maintaining efficient operation.
Implementation Method 1
a light-emitting device including a pixel, and the pixel includes a transistor and a light-emitting element
Data Source
AI summary
Provided is a display device or the like which can illuminate a subject with high-luminance illumination light. Another embodiment of the present invention provides a display device which can be used as a light source for a subject, or a display device which can be used as a light source for a subject, can display images and texts, and can switch these functions. The transistor of the light-emitting device is configured to operate in a saturation region in a period during which the light-emitting device displays text or an image, and is configured to operate in a linear region in a period during which the light-emitting device emits illumination light to a subject.