Cab Projection Display for Cautions Without Window Obstruction

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Solution Overview

Problem

The increasing number of decals on working machine windows obstructs the operator's view, making it difficult to properly alert the operator to cautions.

Innovation Solution

A working machine equipped with a projection device that projects image light to form caution images on a combiner display, controlled by a controller that adjusts the display based on the machine's state, allowing for unobstructed viewing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If decals are attached to window glass to alert operators to cautions, then safety information is provided to the operator, but the operator's view is obstructed

Engineering Contradiction:
Improvesafety information deliveryVSAvoidview obstruction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a projection device to create a virtual image copy of caution information on the window glass rather than attaching physical decals. This optical copy conveys the same safety information without the physical obstruction of actual decal materials blocking the operator's view.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical approach of attaching physical decals to the window with an optical projection system. Instead of using material substances (decals) that physically block light, the system uses projected light to create visible caution information that does not obstruct the view.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Loss of information

If the number of decals is increased to cover more caution information, then more safety warnings are provided, but the complexity of the display increases and view obstruction worsens

Engineering Contradiction:
Improvecaution information completenessVSAvoiddisplay complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The projection device serves multiple functions: it can display various caution information, adjust display positions, control display timing, and modify display characteristics all through a single integrated system. This replaces the need for multiple separate decals with different positions and characteristics.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The projection system dynamically adjusts the display of caution information based on the working machine's state. The controller activates specific caution projections based on detected operational conditions, allowing the system to display only relevant information rather than all possible decals simultaneously.

Inventive Principle:
Principle #15Dynamics

3Reliability

If decals are attached to ensure all cautions are visible, then complete caution coverage is achieved, but the ease of operation is reduced due to view obstruction

Engineering Contradiction:
Improvecaution coverageVSAvoidoperator ease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The virtual image projection creates caution information that is visible to the operator without requiring physical decals that would block the view. The optical copy provides complete caution coverage while maintaining unobstructed visibility of the work area.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The projection system displays caution information in the optical space in front of the window rather than attaching materials to the window surface itself. This dimensional shift allows caution information to be visible without physically occupying the window surface and blocking the view.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Effectively alerts operators to cautions without obstructing their view by dynamically adjusting the display of caution images based on the machine's state.

Implementation Method 1

a projection device that projects image light to form an image

Methodology Applied
Scientific EffectLight projection: Light

Data Source

PatentEP3936671B1Work machine
Publication Date: 2026.02.11 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3936671B1 patent drawingFigure 1
  • EP3936671B1 patent drawingFigure 2
  • EP3936671B1 patent drawingFigure 3

AI summary

The present invention provides a working machine that makes it possible to alert its operator to cautions properly without obstructing the view of the operator. The working machine includes a cab for its operator to ride in, a projection device that projects image light to form an image of cautions to an operator who operates the working machine, a display unit that displays image light projected by the projection device, state detection element to detect a state of the working machine, and a controller that controls the projection device so that a manner of displaying the cautions on the display unit will change depending on the state of the working machine detected by the state detection element.