Viewfinder Eye Imaging Layout Without a Light-Splitting Prism

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Solution Overview

Problem

Existing camera configurations with a line-of-sight input function face challenges in capturing the user's eye without increasing apparatus size or cost when the optical axes of the eyeball-imaging and finder optical systems are made independent, leading to pupil center position changes and potential eye movement out of the imaging range.

Innovation Solution

A display apparatus with a nonparallel optical axis configuration between the imaging and display systems, using a rectangular imaging plane for the eyeball image sensor, and a projected optical axis parallel to the long side of the imaging plane, eliminating the need for a light-splitting prism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the light-splitting prism is removed and the optical axis of the eyeball-imaging optical system and the optical axis of the finder optical system are made independent from each other, then the apparatus size and cost are reduced, but it becomes more difficult to capture the user's eye with the eyeball image sensor

Engineering Contradiction:

Improveapparatus sizeVSAvoideye capture reliability

Core Design Contradiction:

Volume of stationary objectVSReliability

Solution Approach 1:

The patent introduces a new spatial dimension by making the optical axis of the eyeball-imaging optical system nonparallel to the optical axis of the display optical system. This dimensional change allows the eyeball image sensor to capture the user's eye effectively without requiring a light-splitting prism, thus reducing apparatus size while maintaining eye capture reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a composite optical system design where the imaging optical system and display optical system are integrated with nonparallel optical axes. This composite configuration enables both finder optical performance and line-of-sight input function to coexist without requiring separate light paths through a prism

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the light-splitting prism is removed and the optical axis of the eyeball-imaging optical system and the optical axis of the finder optical system are made independent from each other, then the cost is reduced, but it becomes more difficult to capture the user's eye with the eyeball image sensor

Engineering Contradiction:

Improvemanufacturing costVSAvoideye capture reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts and removes the light-splitting prism from the optical system, eliminating the need for this expensive component. The functionality previously achieved through the prism is replaced by a nonparallel optical axis configuration that is simpler and less costly to manufacture while maintaining the ability to capture the user's eye

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical light-splitting prism with an optical axis configuration approach. Instead of using a physical component to separate light paths, the invention uses the spatial relationship and angular orientation between optical axes to achieve the same functional separation, reducing manufacturing complexity and cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the optical axis of the eyeball-imaging optical system is made nonparallel to the optical axis of the display optical system, then the eye can be captured more easily without increasing apparatus size, but the optical performance of the finder optical system may be affected

Engineering Contradiction:

Improveeye capture reliabilityVSAvoidoptical performance

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the angular parameter of the optical axis orientation, making it nonparallel to the display optical system axis. This parameter change optimizes the eye capture angle while maintaining finder optical performance, achieving a balance between reliability and precision requirements

Inventive Principle:

Principle #35Parameter changes

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

Facilitates easier capture of the user's eye without enlarging the apparatus or increasing costs, reducing vignetting, and maintaining optical performance.

Implementation Method 1

an imaging optical system for forming an optical image of the eye on the imaging plane

Methodology Applied

Scientific EffectOptical imaging: Lens

Data Source

PatentUS20250365486A1Display apparatus, finder apparatus, and imaging apparatus

Publication Date: 2025.11.27 CANON KK

AI summary

A display apparatus according to the present invention, includes: a display panel; a display optical system for looking at the display panel; an image sensor for capturing an eye of an user looking at the display panel, the image sensor having a rectangular imaging plane; and an imaging optical system for forming an optical image of the eye on the imaging plane, wherein the imaging optical system has an optical axis that is nonparallel to an optical axis of the display optical system, and a projected line of the optical axis of the display optical system on the imaging plane is substantially parallel to a long side of the imaging plane.