Projector Driving Device Backlash Control via Sensor Inversion

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Solution Overview

Problem

In projector driving systems where the location sensor is not near the motor, backlash compensation methods used in traditional configurations are ineffective due to the reversed location relationship between the driving target and the location sensor, leading to insufficient control over backlash.

Innovation Solution

A driving device with a control unit that performs two distinct controls: one based on the detected driving state and another for a predetermined amount, allowing efficient backlash management without relying on location sensor detection results, especially in configurations where the backlash of the location sensor is larger than the driving target.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the location sensor is provided nearer to the motor than the driving target, then the backlash can be compensated based on detection results, but the device complexity increases and miniaturization becomes difficult

Engineering Contradiction:

Improvebacklash compensation accuracyVSAvoidsensor arrangement complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional sensor arrangement by placing the location sensor nearer to the driving target rather than near the motor. This reversal changes the detection relationship: instead of detecting motor position to infer target position, the sensor directly detects the driving target's position, eliminating the need for complex backlash compensation algorithms and reducing overall system complexity while maintaining miniaturization capability

Inventive Principle:

Principle #13The other way round (Inversion)

2Speed

If the driving target is moved before the location sensor detects the location, then the response speed increases, but the measurement precision deteriorates due to smaller detected movement amount

Engineering Contradiction:

Improveresponse speedVSAvoidmovement detection accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent introduces a gear mechanism as an intermediary between the motor and the location sensor. This gear acts as a mechanical amplifier that translates the small movement of the driving target into a larger, more easily detectable movement at the sensor side, thereby improving measurement precision without sacrificing response speed

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the location sensor is placed nearer to the driving target, then the miniaturization is facilitated, but the backlash control becomes insufficient due to reversed location relationship

Engineering Contradiction:

Improvedevice sizeVSAvoidbacklash control accuracy

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces complex mechanical backlash compensation mechanisms with a simplified sensor-based detection system. By positioning the location sensor near the driving target and using gear-based mechanical advantage, the system achieves effective backlash control through direct position feedback rather than complex mechanical pre-loading or anti-backlash gears, enabling miniaturization

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS9261667B2Driving device, projector, and driving method

Publication Date: 2016.02.16 SEIKO EPSON CORP

AI summary

A driving device includes: a driving state detection unit which detects a driving state of a driving unit which drives a driving target; and a control unit which performs a first control for driving the driving unit for an amount based on the driving state of the driving unit detected by the driving state detection unit and a second control for driving the driving unit for a predetermined amount.