Projection Display Diaphragm Angle Control for Lamp Heat Management
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Solution Overview
Problem
Projection type image display devices face challenges in achieving high contrast while minimizing noise from increased cooling fan rotation speeds and ensuring lamp reliability, particularly when increasing light source power and diaphragm control range, due to inaccurate temperature measurement of the lamp bulb and excessive return light causing heat damage.
Innovation Solution
A configuration that includes a diaphragm for adjusting light, a temperature sensor for ambient temperature detection, and a system to calculate and control the diaphragm angle based on video signal input, along with a fan control mechanism that adjusts rotation speed based on both temperature and estimated return light, allowing for precise temperature estimation and reduced fan noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the power of the lamp is increased to meet the demand for increased brightness, then the brightness of display video is improved, but return light reflected by the diaphragm increases causing heat damage to the lamp and peripheral parts
Solution Approach 1:
The patent dynamically adjusts the opening/closing angle of the diaphragm as a parameter to control the amount of light entering the display device. By changing this geometric parameter rather than simply increasing lamp power, the system achieves high contrast ratios while managing return light reflections that cause heat damage.
2Stability of the object's composition
If the diaphragm is closed sufficiently to improve contrast, then the contrast is improved, but return light from the diaphragm reaches 20% or more of the amount of incident light causing heat damage
Solution Approach 1:
The patent employs feedback control by detecting the characteristics of the input video signal and adjusting the diaphragm angle accordingly. This closed-loop system optimizes the balance between achieving high contrast and minimizing harmful return light reflections.
3Temperature
If the rotation speed of the cooling fan is increased to provide appropriate cooling capability, then the cooling performance is improved, but noise increases
Solution Approach 1:
The patent dynamically adjusts the rotation speed of the cooling fan based on real-time temperature detection and diaphragm angle control. This dynamic adjustment allows the system to provide adequate cooling only when and where needed, rather than operating at high speed continuously, thereby reducing noise.
4Device complexity
If the temperature sensor is disposed in the vicinity of the lamp to measure temperature, then the temperature detection is simplified, but the temperature of the lamp bulb itself cannot be measured accurately due to extreme heat
Solution Approach 1:
The patent uses the temperature in the vicinity of the lamp as an intermediary indicator to infer the temperature of the lamp bulb itself. Since directly measuring the bulb temperature is impractical due to extreme heat, the system uses the surrounding temperature as a proxy that correlates with the bulb temperature, enabling accurate temperature control without direct contact with the hot bulb.
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 solution enables accurate temperature control of the lamp bulb, reduces fan noise, and ensures lamp reliability by optimizing cooling fan speed, thereby improving contrast and extending lamp life without direct temperature measurement.
Implementation Method 1
a cooling fan for cooling the lamp
Implementation Method 2
an amount of return light reflected by the diaphragm increases
Data Source
AI summary
A diaphragm control angle calculating portion 2 calculates an angle at which a diaphragm is controlled to control an amount of light that reaches from a lamp 6 to a display device 10 according to distribution information of an input video signal, such as the maximum value, the minimum value, the average value and the histogram of the signal, and the control angle is inputted to a fan control signal generating portion 3 and a diaphragm driving portion 8 as control angle information. The diaphragm driving portion 8 controls the angle of the diaphragm 9 based on the control angle information. Light from the lamp 6 driven by a lamp driving portion 5 enters the diaphragm 9, and the amount of light according to the angle of the diaphragm 9 enters the display device 10. The fan control signal generating portion 3 controls the rotation speed of a cooling fan 4 according to a combination of the control angle information and the temperature detected by a temperature sensor. A high-contrast display image can be produced while noise resulting from an increase in the rotation speed of the cooling fan can be suppressed and the reliability of the lamp can be ensured by avoiding the influence of the temperature.