Lens Position Adjustment Eliminating Backlash via Preliminary Inversion

Solution Overview

Problem

Existing lens position adjustment mechanisms in projectors and similar devices face challenges in accurately adjusting lens positions due to backlash in transmission mechanisms, leading to user dissatisfaction and inaccuracies, especially when the registered position is near the end of the movable range, causing delays and feelings of incorrect adjustments.

Innovation Solution

A lens position adjustment apparatus that includes a transmission unit, a conversion unit, a drive control unit, a position detection unit, and a storage unit, which controls the drive source to adjust the final displacement direction based on the registered direction and position, eliminating backlash and ensuring synchronized movement with user adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the lens is returned to the registered position by moving in the registered direction, then the lens position accuracy is improved, but when the registered position is near the endpoint, the user experiences a delay feeling during fine adjustment

Engineering Contradiction:

Improvelens position accuracyVSAvoiduser adjustment responsiveness

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The system performs preliminary action by moving the lens beyond the registered position in the opposite direction before returning to the registered position. This preliminary movement in the opposite direction ensures that the transmission mechanism's backlash is eliminated in the direction the user will likely adjust, making the lens respond immediately to user adjustments without delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies inversion by moving the lens in the opposite direction of the registered direction as a preliminary step. Instead of directly returning to the registered position from any direction, the system intentionally moves beyond it in the opposite direction first, then returns, ensuring the backlash is eliminated in the direction the user will likely adjust.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If the lens is moved beyond the registered position to eliminate backlash, then the lens position accuracy is improved, but the transmission mechanism complexity increases

Engineering Contradiction:

Improvelens position accuracyVSAvoidtransmission mechanism control complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system applies self-service by automatically determining and executing the preliminary movement beyond the registered position based on stored registration direction information. The control unit autonomously calculates the required overshoot distance and direction, eliminating the need for manual intervention or complex external control mechanisms.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system uses feedback by storing the registration direction information and using it to automatically determine the preliminary movement direction and distance. The control unit receives feedback from the encoder about the current lens position and compares it with the registered position to execute the appropriate preliminary movement before returning to the registered position.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the registered position is near the endpoint of the movable range, then the lens can reach extreme positions, but the backlash elimination becomes problematic causing user dissatisfaction

Engineering Contradiction:

Improvelens movable rangeVSAvoidfine adjustment responsiveness

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The system performs preliminary action by moving the lens beyond the registered position in the opposite direction before returning to the registered position. This preliminary movement in the opposite direction ensures that the transmission mechanism's backlash is eliminated in the direction the user will likely adjust, making the lens respond immediately to user adjustments without delay.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system applies inversion by moving the lens in the opposite direction of the registered direction as a preliminary step. Instead of directly returning to the registered position from any direction, the system intentionally moves beyond it in the opposite direction first, then returns, ensuring the backlash is eliminated in the direction the user will likely adjust.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS9007699B2Lens position adjustment apparatus, projector, lens position adjustment method, and lens position registration method

Publication Date: 2015.04.14 SEIKO EPSON CORP

AI summary

A lens position adjustment apparatus includes: a transmission unit that is displaced in a first direction oriented from one end point toward the other end point or a second direction oriented from the other endpoint toward the one endpoint to transmit power of a drive source; a conversion unit that moves a lens by using the power supplied from the transmission unit; a drive control unit that controls the drive source; a position detection unit that detects a current position of the transmission unit; and a storage unit that stores a registered position and a registered direction, wherein the drive control unit controls the drive source in such a way that a final displacement direction is the second direction in case that the registered position is within a predetermined amount of displacement from the one end point, and that the final displacement direction is the registered direction otherwise.