Display Control Device for Minimizing EVF Delay

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Solution Overview

Problem

In mirror-less SLR digital cameras, there is a significant delay from image capture by the image sensor to displaying the image on the electronic viewfinder, making it difficult to follow moving subjects and capture intended still images, especially when using a fast-moving subject, due to complex circuit configurations and inefficiencies in handling image signal delays.

Innovation Solution

A display control device that uses a counter to synchronize image signals with a horizontal synchronization signal and a control signal indicating validity, allowing for flexible adjustment of the vertical scanning period and simplifying the circuit configuration by distinguishing between valid and invalid image signals, thereby minimizing delay times and accommodating changes in display unit size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the horizontal scanning period is adjusted to shorten delay time, then the delay from imaging to displaying is reduced, but the circuit configuration becomes complicated and dedicated controllers are required for different display sizes

Engineering Contradiction:

Improvedelay time from imaging to displayingVSAvoidcircuit configuration complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent changes the parameter being adjusted from the horizontal scanning period to the vertical scanning period. By counting the number of valid lines in the vertical scanning period and comparing it with the total number of lines, the system can synchronize the next frame's imaging start timing without requiring complex horizontal timing adjustments. This parameter change simplifies the circuit configuration while achieving the same delay reduction effect.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal display control device that can handle different display unit sizes without requiring dedicated controllers. By using a line counter and comparator that work with the vertical scanning period, the system becomes size-independent and can adapt to various display configurations through software parameters rather than hardware changes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the horizontal scanning period is extended to reduce delay, then frame-rate synchronization is improved, but a dedicated EVF controller is required for each display size causing waste

Engineering Contradiction:

Improveframe-rate synchronizationVSAvoidadaptability to different display sizes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs a universal control device that can work with different display unit sizes by counting vertical scanning lines. The line counter and comparator logic remain the same regardless of display size, making the system adaptable to various configurations without requiring dedicated controllers for each size, thus eliminating waste.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a feedback mechanism where the line counter continuously monitors the number of valid lines and compares it with the expected total. This feedback allows the system to automatically adjust the next frame's imaging start timing based on actual line count, ensuring reliable frame-rate synchronization across different display sizes without manual configuration.

Inventive Principle:

Principle #23Feedback

3Device complexity

If simple line counting is used to detect end of valid image signal, then the circuit is simplified, but accurate detection fails when number of lines varies in vertical scanning period

Engineering Contradiction:

Improvecircuit simplicityVSAvoiddetection accuracy of valid signal end

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10347171B2Imaging device including timing generator that generates vertical synchronization signal after number of lines of valid image signal reaches number of valid lines of vertical scanning period

Publication Date: 2019.07.09 SEIKO EPSON CORP

AI summary

A display control device controls an image displayed on a display unit based on an image signal synchronized with a horizontal synchronization signal and a control signal indicating that the image signal is valid or invalid. The device includes: an input unit that inputs a valid image signal based on the control signal; an output unit that outputs the input valid image signal to the display unit; and a comparison unit that compares the number of lines of which the image signal becomes valid with the number of valid lines of one frame.