Projector Sensor Timing Control for Illuminance Accuracy
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Solution Overview
Problem
When a projector is equipped with both an obstacle sensor and an illuminance sensor, the light emitted by the obstacle sensor interferes with the illuminance detection, leading to improper image quality adjustment due to heat accumulation issues.
Innovation Solution
A projector design that includes a window for light passage, a projection section, an illuminance sensor, an obstacle sensor with a light emitting and receiving section, and a control section that disables illuminance detection during obstacle sensor operation, allowing accurate illuminance detection without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an obstacle sensor with a light emitting section is provided close to the projection window to detect obstacles causing heat accumulation, then projector reliability is improved, but the light from the light emitting section interferes with illuminance sensor detection, worsening measurement precision
Solution Approach 1:
The control section alternates the operation timing between the obstacle sensor and illuminance sensor. The obstacle sensor operates during specific periods to detect obstacles, while the illuminance sensor operates during other periods to measure illuminance without interference from the obstacle sensor's light emitting section. This periodic alternation resolves the contradiction by ensuring both sensors function accurately at different times.
2Reliability
If the obstacle sensor operates continuously to ensure reliable obstacle detection, then projector reliability is improved, but the illuminance sensor cannot accurately detect illuminance due to continuous light interference, worsening measurement precision
Solution Approach 1:
Instead of continuous operation, the obstacle sensor operates periodically under control of the control section. The control section determines appropriate operation periods for the obstacle sensor that ensure reliable obstacle detection while allowing the illuminance sensor to operate during periods when the obstacle sensor is inactive, thus avoiding light interference and maintaining measurement precision.
3Measurement precision
If the illuminance sensor operates continuously to ensure accurate illuminance detection, then measurement precision is improved, but the obstacle sensor cannot detect obstacles reliably due to light interference from the illuminance sensor, worsening detection reliability
Solution Approach 1:
The control section coordinates the operation timing of both sensors to alternate their active periods. When the illuminance sensor operates to ensure accurate illuminance detection, the obstacle sensor remains inactive. Conversely, when the obstacle sensor needs to detect obstacles, the illuminance sensor is deactivated. This periodic alternation eliminates mutual light interference and ensures both sensors maintain their respective detection accuracies.
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
Enables reliable detection of obstacles causing heat accumulation and prevents incorrect illuminance measurements, ensuring stable and precise image quality adjustment by separating the operation periods of the obstacle and illuminance sensors based on the projector's attitude.
Implementation Method 1
an obstacle sensor that has a light emitting section and a light receiving section, the light emitting section emitting second light, the light receiving section receiving the second light, the obstacle sensor detecting an obstacle based on an output from the light receiving section
Implementation Method 2
an illuminance sensor that detects illuminance in a space where the image is projected
Data Source
AI summary
Illuminance in a space where a projector projects an image is accurately detected with failure of the projector due to heat accumulation prevented. The projector includes a window that allows light to pass therethrough, a projection section that projects light through the window to project an image, an illuminance sensor that detects illuminance in a space where the image is projected, an obstacle sensor that has a light emitting section and a light receiving section, the light emitting section emitting second light, the light receiving section receiving the second light, the obstacle sensor detecting an obstacle based on an output from the light receiving section, and a control section that disables the detection of the illuminance during a period for which the light emitting section emits the light.