Projection Display Thermal Preheating for Stable Startup Images
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Solution Overview
Problem
Projection display devices using reflective liquid crystal display elements face instability in image performance immediately after startup due to the time required for the liquid crystal display element to heat up to the desired temperature.
Innovation Solution
Incorporation of a first temperature sensor and a heating unit via a heat sink, along with a second temperature sensor and a blower fan, controlled by a control unit to maintain the liquid crystal display element at a target temperature before and during activation, ensuring stable image performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater is used to heat the liquid crystal display element, then the temperature can be maintained at a target level, but it takes time for the element to heat up after startup, resulting in unstable image performance
Solution Approach 1:
The heating unit is activated during the standby state to preheat the liquid crystal display element to the target temperature before the device is actually used. This preliminary heating action ensures that when the device transitions from standby to active use, the liquid crystal display element is already at the appropriate operating temperature, eliminating the delay and instability that would otherwise occur during startup heating.
2Reliability
If the heater operates continuously to maintain temperature, then stable image performance is achieved, but power consumption increases
Solution Approach 1:
The heating control is implemented periodically rather than continuously. The control unit activates the heating unit based on temperature sensor feedback, applying heat only when the liquid crystal display element temperature falls below the target temperature. This periodic heating approach maintains stable image performance while significantly reducing overall power consumption compared to continuous operation.
3Measurement precision
If power is supplied to the liquid crystal display element during standby, then temperature control is accurate, but power consumption increases
Solution Approach 1:
The power supply to the liquid crystal display element is extracted or separated during the standby state. Instead of continuously powering the element, the system only activates power supply when the device transitions to active use. This extraction of unnecessary power consumption during standby maintains the ability to control temperature accurately when needed, while dramatically reducing overall energy usage during idle periods.
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
Achieves stable image performance immediately after startup by accurately controlling the liquid crystal display element's temperature, reducing power consumption, and minimizing defects such as fringes.
Implementation Method 1
a heating unit disposed on the liquid crystal display element via a heat sink
Implementation Method 2
a blower fan that air-cools the heat sink
Data Source
AI summary
A projection display device includes a third display element embedded with a band-gap type temperature sensor, a heater, a temperature sensor, a fan, and a control unit that controls operations of the third display element, the heater, and the fan based on temperatures detected by the temperature sensors. In a case where the projection display device is in a standby state, the control unit operates the heater to control the third display element to have a target temperature based on the temperature detected by the temperature sensor without supplying power to the third display element. When the projection display device is activated, the control unit supplies power to the third display element and operates at least one of the heater and the fan to control the third display element to have the target temperature based on the temperature detected by the temperature sensor.