Projector Distance Sensor Positioning for Close-Range Focus
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Solution Overview
Problem
Conventional projectors with distance measuring sensors face challenges in focus adjustment when the screen is close, as the sensors cannot detect distances within a non-detection range, leading to ineffective focus adjustment.
Innovation Solution
The projector design includes a distance measuring sensor with a detection range and a non-detection range, where the sensor is positioned to allow detection even at close distances by shifting the exit port of the projection system behind the sensor, and the sensor is housed in an enclosure with a recess or exposed configuration to prevent noise and allow detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the projection distance is shortened to reduce the distance between projector and screen, then the projector can discourage persons from walking between projector and screen, but the distance measuring sensor cannot measure the distance because it falls within the non-detection range
Solution Approach 1:
The patent introduces a second direction (opposite to the detection signal direction) and positions the exit port in this different spatial dimension. This dimensional separation allows the projection system and distance measuring system to coexist without interfering with each other's operational ranges, enabling both short projection distance and accurate distance measurement
2Length of stationary object
If the distance measuring sensor is positioned close to the screen for short-focal-length projection, then the projection distance is reduced, but the sensor cannot detect the distance as it falls within the non-detection range
Solution Approach 1:
The patent segments the projector structure into distinct functional zones: the distance measuring sensor is positioned in one location while the exit port is positioned in another location (shifted in the second direction). This spatial segmentation allows each component to operate independently within its optimal range, with the sensor able to measure distances that would otherwise be too short for detection
3Device complexity
If the exit port is positioned at the same location as the distance measuring sensor, then the structure is simplified, but the detection signal is interfered with by the projection system
Solution Approach 1:
The patent extracts the exit port from the sensor location and positions it in a separate location (shifted in the second direction). This separation removes the harmful projection light from the sensor's detection path, eliminating noise interference while maintaining structural efficiency
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 focus adjustment even when the screen is close to the projector, reducing the focal length and preventing noise interference, thus ensuring accurate projection.
Implementation Method 1
a distance measuring sensor that measures the distance between the screen and the projector
Data Source
AI summary
A projection apparatus includes a projection system, a distance measuring sensor that is used to adjust the focal point of the projection system and outputs infrared light in the frontward direction, and an enclosure that houses the projection system and the distance measuring sensor. An exit port of the projection system is disposed at a position which is shifted from the distance measuring sensor in a second direction opposite the first direction. The enclosure has a detection opening via which the infrared light exits. The distance measuring sensor has a detection range over which distance detection is allowed and a non-detection range over which no distance detection is allowed and which is shifted from the detection range toward the distance measurement sensor, and the distance measuring sensor is disposed at a distance from the detection opening, the distance including the non-detection range of the distance measuring sensor.