Temperature Sensor Crystallinity Segmentation in Display Devices
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in maintaining high image quality due to heat generation from increased luminance, which affects temperature measurement accuracy, as the crystallinity of transistors in temperature sensors is similar to those in driving circuits, leading to lower temperature dependence and inaccurate temperature readings.
Innovation Solution
A display device with a temperature sensor circuit having different crystallinity than the peripheral circuit unit, disposed apart from heat-generating regions, and equipped with a light-shielding structure and electric shield, using delay circuits or ring oscillators with standby functions, to enhance temperature measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the ring oscillator is formed in parallel in the same process using the same material as those of a transistor for a driving circuit for which higher performance is required, then the manufacturing process is simplified, but the temperature dependence is reduced and temperature measurement accuracy deteriorates
Solution Approach 1:
The patent divides the transistor population into two distinct segments: high-crystallinity transistors for the driving circuit (peripheral circuit unit) and low-crystallinity transistors for the temperature sensor circuit. This segmentation allows each circuit to be optimized for its specific function - the driving circuit for performance and the temperature sensor for temperature dependence - while still using the same basic manufacturing process and materials.
Solution Approach 2:
The patent applies local quality by creating transistors with different crystallinity characteristics in different locations on the substrate. The peripheral circuit unit uses high-crystallinity transistors for optimal driving performance, while the temperature sensor circuit uses low-crystallinity transistors for enhanced temperature dependence. This local differentiation resolves the contradiction between manufacturing simplicity and measurement precision.
2Illumination intensity
If the luminance is enhanced and the amount of light from the light source is expanded, then the display brightness is improved, but the heat generation due to light absorption increases
Solution Approach 1:
The patent implements a feedback mechanism where the temperature sensor circuit continuously monitors the temperature of the liquid crystal panel, and this temperature information is fed back to the light source control system. Based on the detected temperature, the light source output is dynamically adjusted - reduced when temperature is high to prevent overheating, and increased when temperature is low to maintain brightness. This feedback loop resolves the contradiction between maintaining high luminance and controlling heat generation.
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 allows for precise temperature measurement and feedback control, improving image quality by reducing the impact of heat-generated noise and power consumption, while maintaining high performance of the peripheral circuit unit.
Implementation Method 1
a temperature sensor having a configuration in which a ring oscillator made up of an odd number of inverters connected in series is used and the temperature is sensed by a change in the oscillation frequency of the ring oscillator
Data Source
AI summary
In a display device including: a pixel array unit made up of pixels disposed on a substrate; a peripheral circuit unit that is disposed in a periphery of the pixel array unit and drives the pixels; and a temperature sensor circuit disposed on the same substrate as the pixels, the temperature sensor circuit is configured using an inverter circuit including a plurality of inverters made up of thin film transistors. Then, crystallinity of a channel portion of the thin film transistor of the temperature sensor circuit is different from crystallinity of a channel portion of a thin film transistor constituting the peripheral circuit unit.