Projection Device Light Sensor Calibration for Color Stability
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Solution Overview
Problem
Conventional projectors experience color point shifting due to long-time use of plastic lenses in the light-combining or illumination modules turning yellow, leading to a failure of the color point calibration function.
Innovation Solution
A light sensor is disposed between a prism and a digital micromirror device in the imaging module of the optical engine, allowing for dynamic adjustment of the setting current to calibrate the color points of the light beam based on brightness data received from the light sensor, thereby preventing color point shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light sensor is disposed in the light combining module or the illumination module, then the color point calibration can be performed initially, but the plastic lenses turn yellow due to long-time use, causing calibration failure and color point shifting
Solution Approach 1:
The light sensor is extracted from the light combining module or illumination module and relocated to the imaging module. This separation removes the light sensor from the environment where plastic lenses are present, preventing the yellowing issue from affecting calibration while maintaining the calibration functionality.
Solution Approach 2:
The patent introduces an intermediate optical path through the prism in the imaging module. The prism acts as an intermediary to guide light from the light combining module to the light sensor without requiring the sensor to be in direct contact with the plastic lenses, thus isolating the sensor from the harmful environmental factors.
2Measurement precision
If the light sensor is disposed in the light combining module, then calibration can be performed, but reflected light from the digital micromirror device interferes with the light sensor
Solution Approach 1:
The light sensor is extracted from the light combining module and placed in the imaging module, physically separating it from the digital micromirror device. This spatial separation eliminates the reflected light interference issue while maintaining the sensor's ability to measure brightness for calibration purposes.
Solution Approach 2:
The patent uses the prism and optical path design in the imaging module as an intermediary mechanism. The prism directs light from the light combining module to the light sensor through a controlled path that avoids reflection from the digital micromirror device, thus eliminating interference.
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 effectively maintains accurate color point calibration by dynamically adjusting the light source settings, ensuring consistent image quality over time by isolating the light sensor from the effects of yellowed plastic lenses.
Implementation Method 1
The prism is configured to receive the illumination beam and transmit a portion of the illumination beam to the light sensor
Implementation Method 2
The light sensor receives the portion of the illumination beam transmitted from the prism to generate a brightness data
Implementation Method 3
The digital micromirror device is configured to receive the other portion of the illumination beam transmitted from the prism and convert the other portion of the illumination light beam into an image beam
Data Source
AI summary
A projection device includes a light source, an optical engine and a controller. The light source provides a light beam according to a setting current. The optical engine includes a light combining module, an imaging module and a projection lens. The light combining module receives the light beam to generate an illumination beam. The imaging module includes a prism, a digital micromirror device and a light sensor. The prism transmits a portion of the illumination beam to the light sensor. The digital micromirror device converts the other portion of the illumination light beam into an image beam. The light sensor disposed between the prism and the digital micromirror device receives the portion of the illumination beam to generate a brightness data. The projection lens projects the image beam. The controller dynamically adjusts the setting current to calibrate a color point of the light beam according to the brightness data.