Embedded LCD in Transmitter Housing for Hazardous Areas

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Solution Overview

Problem

Industrial process transmitters often lack effective and safe visual displays for process variables, particularly in potentially combustible environments, where traditional LCDs may pose fire risks and are not inherently intrinsically safe.

Innovation Solution

Embedding a liquid crystal display (LCD) within a transparent or translucent polymeric layer in the transmitter housing, which is sealed and powered through electrodes, allowing for safe and clear display of process information while being intrinsically safe for use in combustible environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional LCD display is installed in the transmitter housing, then visual display of process variables is achieved, but fire risk increases in combustible environments

Engineering Contradiction:

Improvevisual display capabilityVSAvoidfire risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A transparent or translucent polymeric layer is introduced as an intermediary between the LCD display and the external environment. This layer allows visual information to pass through while physically isolating the LCD from potential ignition sources in combustible atmospheres, thus enabling safe operation in hazardous environments.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The LCD display is sealed within a housing configuration that creates an intrinsically safe environment. The transparent polymeric layer acts as a barrier that maintains an inert separation between the electrical components and the combustible external atmosphere, preventing fire risks while preserving display functionality.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If a transparent polymeric layer is added to embed the LCD, then safety in combustible environments is improved, but device complexity increases

Engineering Contradiction:

Improveintrinsic safetyVSAvoidhousing structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The transparent polymeric layer is integrated directly into the housing structure, merging the safety barrier function with the existing housing components. This consolidation approach adds the necessary safety feature while minimizing increases in overall device complexity by combining multiple functions into a unified structure.

Inventive Principle:

Principle #5Merging (Combining)

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 embedded LCD provides a clear and safe visual output for process variables, including numeric values, set points, diagnostics, and alarms, without risking sparks in combustible environments, enhancing operational safety and usability.

Implementation Method 1

A LCD display is embedded within a transparent or translucent polymeric layer in the housing. The LCD display is coupled to the display output and is configured to display information through the polymeric layer.

Methodology Applied

Scientific EffectLiquid crystal display: Liquid Crystals

Data Source

PatentUS9612137B2Instrument housing with embedded liquid crystal display within plastic layer

Publication Date: 2017.04.04 ROSEMOUNT INC

AI summary

A process transmitter has a housing that contains transmitter circuitry. The transmitter circuitry is configured to provide a display output and is also configured to couple to a process control loop. A LCD display is embedded within a transparent or translucent polymeric layer in the housing. The LCD display is coupled to the display output and is configured to display information through the polymeric layer.