Projector Light Combining Device Posture Adjustment
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Solution Overview
Problem
Existing projectors face issues with one-sided blurring due to improper placement of projection optical and light modulation devices, leading to increased complexity, power consumption, and manufacturing costs when attempting to address this with mechanisms that tilt the projection optical device, and current posture adjustment devices are costly and unreliable due to the use of absolute encoders or potentiometers with high detection variations.
Innovation Solution
A projector configuration that includes a lead screw for posture adjustment of the light combining device, a potentiometer for rotation detection, and a photosensor with a light shielding portion to accurately determine abnormalities and return the light combining device to its original position using a driver, such as a stepping motor, without the need for an absolute encoder, thereby reducing costs and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a mechanism tilting the projection optical device is employed to address one-sided blurring, then the one-sided blurring is suppressed, but the device complexity, power consumption, weight, and manufacturing cost increase
Solution Approach 1:
Instead of tilting the heavy projection optical device to correct one-sided blurring, the patent inverts the approach by tilting the lighter image formation unit (containing light modulation devices and light combining device) in the opposite direction. This achieves the same optical correction effect while avoiding the complexity and cost of tilting the entire projection optical device.
Solution Approach 2:
The patent creates a simplified copy of the tilting function by implementing posture adjustment on the image formation unit rather than the full projection optical device. The lead screw mechanism provides a simplified copying of the tilting capability needed to correct one-sided blurring without replicating the entire complex projection optical device structure.
2Measurement precision
If an absolute encoder is used in the posture adjustment device to detect position, then the position detection accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges multiple detection functions into a single integrated system. The potentiometer detects the shaft member rotation amount while the photosensor detects the light shielding state, and these are combined with the lead screw mechanism to achieve reliable position detection and abnormality detection without requiring an expensive absolute encoder.
Solution Approach 2:
The patent introduces intermediary detection elements (potentiometer and photosensor) that mediate between the mechanical position and the control system. These intermediaries provide sufficient detection accuracy for posture adjustment while being more cost-effective than absolute encoders, and they enable abnormality detection through their specific detection characteristics.
3Ease of manufacture
If a potentiometer is used instead of an absolute encoder for position detection, then the manufacturing cost is reduced, but the detection accuracy varies significantly
Solution Approach 1:
The patent implements feedback control using the potentiometer detection results. The control device continuously monitors the detected position and adjusts the lead screw-driven posture adjustment to achieve the target posture. This feedback mechanism compensates for the potentiometer's detection variations and ensures accurate positioning despite the lower inherent precision of the potentiometer.
Solution Approach 2:
The patent performs preliminary abnormality detection using the photosensor before relying on the potentiometer for position control. By detecting abnormalities in advance and using the photosensor to determine the original position, the system compensates for the potentiometer's detection variations and ensures reliable operation.
4Object-affected harmful factors
If the light combining device is tilted to suppress one-sided blurring, then the image quality is improved, but the power consumption and weight of the adjustment mechanism increase
Solution Approach 1:
The patent inverts which component is tilted: instead of tilting the heavy projection optical device, it tilts the lighter image formation unit containing the light combining device. This achieves the necessary optical angle adjustment to correct one-sided blurring while using a much lighter mechanism that consumes less power.
Solution Approach 2:
The patent creates a simplified copying of the tilting function on the image formation unit rather than implementing it on the full projection optical device. The lead screw mechanism provides a lightweight copy of the tilting capability that consumes minimal power compared to tilting the entire projection optical device.
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
The solution allows for reliable and cost-effective return of the light combining device to its original position, even in the event of abnormalities, using a relatively inexpensive potentiometer and photosensor, thereby addressing the issues of one-sided blurring and manufacturing cost while maintaining accurate posture adjustment.
Implementation Method 1
a photosensor including a light receiving portion that may be shielded according to a rotation of the shaft member by a light shielding portion provided in the shaft member
Data Source
AI summary
A projector includes light source, plurality of light modulation devices, light combining device integrated with the plurality of light modulation devices, projection optical device, posture adjustment device that adjusts posture of the light combining device, and control device that controls operation of the posture adjustment device, the posture adjustment device includes lead screw that changes posture of the light combining device, driver that rotates lead screw, shaft member to which rotation of lead screw is transmitted, potentiometer that detects amount of rotation of the shaft member, and photosensor that may be shielded by light shielding portion provided in the shaft member, and the control device includes abnormality determination unit that determines whether or not abnormality has occurred based on detection result by the potentiometer, and return operation unit that, if occurrence of abnormality is determined, returns the light combining device to original position based on detection result by the photosensor.