Accessory Contact Layout Using Detection Grounding for Clock Noise

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Solution Overview

Problem

Existing contact arrangements in electronic apparatuses and accessories suffer from increased noise interference between clock signals and adjacent signals, leading to potential malfunctions, while also requiring a larger accessory shoe due to increased contact numbers.

Innovation Solution

The solution involves arranging attachment detection contacts next to clock contacts, with these detection contacts grounding to reduce noise interference without increasing the number of contacts, and utilizing a specific contact arrangement to ensure stable grounding and communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the contact arrangement pitch is made narrower to increase the number of contacts, then the accessory shoe can accommodate more contacts without increasing size, but noise interference between clock signals and adjacent signals increases

Engineering Contradiction:
Improvenumber of contactsVSAvoidnoise interference
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a ground contact as an intermediary element positioned between the clock signal contact and adjacent signal contacts. This ground contact acts as a mediator that absorbs or shields against electromagnetic noise, preventing direct interference between the clock signal and neighboring signals while maintaining compact contact spacing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the ground contact function from the traditional GND terminal arrangement and integrates it directly into the contact array between signal contacts. By taking out the shielding function and embedding it within the contact sequence, the design achieves noise reduction without requiring additional space or increasing the overall accessory shoe size.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-affected harmful factors

If GND contacts are arranged on both sides of the clock signal contact to prevent noise, then noise interference is reduced, but the number of contacts increases and the accessory shoe becomes larger

Engineering Contradiction:
Improvenoise interferenceVSAvoidaccessory shoe size
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent applies local quality by providing ground shielding only at the specific location where noise interference occurs - between the clock signal contact and adjacent signal contacts. Instead of uniformly arranging GND contacts on both sides of all signal contacts, the ground contact is strategically placed only where needed, achieving effective noise reduction while minimizing the increase in accessory shoe size.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs partial action by implementing ground shielding on only one side of the clock signal contact rather than both sides. This selective approach provides sufficient noise protection for the critical clock signal while avoiding the need for symmetric dual-sided GND arrangement, thus preventing excessive increase in the number of contacts and accessory shoe dimensions.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4134739B1Electronic device, and accessory
Publication Date: 2026.02.11 CANON KK
  • EP4134739B1 patent drawingFigure 1
  • EP4134739B1 patent drawingFigure 2A~2C
  • EP4134739B1 patent drawingFigure 3A~3B

AI summary

[SUMMARY] [PROBLEMS] To reduce the noise influence of a clock signal on a signal of an adjacent contact while suppressing an increase in the number of contacts. [SOLUTION MEANS] An accessory (200) is attachable to and detachable from an electronic apparatus (100). The electronic apparatus includes a plurality of contacts electrically connectable to the accessory and arranged in a row. The plurality of contacts include an attachment detection contact (TC6) that is used to detect an attachment of the accessory to the electronic apparatus, and a first clock contact (TC07) that is used to communicate a first clock signal in communication between the electronic apparatus and the accessory. A potential of the attachment detection contact changes from a predetermined potential to a grounded potential after the accessory is attached to the electronic apparatus. The attachment detection contact is disposed next to the first clock contact.