Eyepiece Lens Configuration for Wide Visual Angle

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Solution Overview

Problem

There is a demand for an observation optical system that enables wider visual angles while maintaining favorable performance, as existing systems face challenges in achieving both a wider field of view and high resolution without significant aberrations such as field curvature and lateral chromatic aberration.

Innovation Solution

The proposed observation optical system consists of an eyepiece lens configuration with a combination of lenses having positive and negative optical powers, specifically including a first lens with positive power, a second lens with negative power, and a third lens, where the lenses are arranged to satisfy specific conditional expressions to optimize focal lengths and curvature radii, allowing for diopter adjustment and aberration correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional eyepiece lens configuration is used, then the structure is simple, but the visual angle is narrow and aberrations occur

Engineering Contradiction:

Improvevisual angleVSAvoideyepiece lens structure

Core Design Contradiction:

Area of stationary objectVSDevice complexity

Solution Approach 1:

The eyepiece lens is divided into multiple lens units (first lens unit with positive power, second lens unit with negative power, third lens unit with positive power) arranged in sequence. Each lens unit contributes differently to the overall optical function, allowing the system to achieve a wide visual angle while correcting aberrations through the combined effect of segmented components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each lens unit has specifically designed local optical properties (different focal lengths, curvature radii, and optical powers) to address specific optical requirements. The first lens unit provides positive convergence, the second lens unit provides negative divergence for wide angle, and the third lens unit provides additional positive correction, with each unit optimized for its local function within the overall system.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If lenses are added to widen visual angle, then the visual angle increases, but aberrations like field curvature and lateral chromatic aberration worsen

Engineering Contradiction:

Improvevisual angleVSAvoidaberrations

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent uses negative-powered lens units (which inherently introduce certain aberrations) in a controlled manner to achieve the wide visual angle, then compensates for the resulting aberrations using positive-powered lens units. The harmful aberrations introduced by the negative lens are converted into manageable corrections through the subsequent positive lens units, ultimately achieving both wide angle and aberration control.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent employs specific parameter relationships between lenses, including conditional expressions for focal lengths (f1, f2, f3), curvature radii (R1r, R1f, R2r, R2f, etc.), and optical powers. These parameter changes are carefully controlled to satisfy specific mathematical relationships that simultaneously achieve wide visual angle and minimize aberrations through optimized optical path management.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If multiple lenses are used to correct aberrations, then aberration correction improves, but the device complexity increases

Engineering Contradiction:

Improveaberration correctionVSAvoidnumber of lenses

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Each lens unit in the eyepiece is designed to serve multiple functions simultaneously. The positive-powered lens units not only correct field curvature and lateral chromatic aberration but also contribute to the overall focal length and visual angle. The negative-powered lens units provide both wide-angle capability and serve as part of the aberration correction system, reducing the need for additional dedicated correction elements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This configuration enables a wider visual angle while effectively suppressing aberrations like field curvature and lateral chromatic aberration, achieving high optical performance and improved image quality.

Implementation Method 1

an eyepiece lens disposed on an eyepoint side of the display element, in which the eyepiece lens includes a first lens having positive optical power, a second lens having negative optical power, and a third lens

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS20230194852A1Observation optical system and optical apparatus

Publication Date: 2023.06.22 FUJIFILM CORP

AI summary

An observation optical system includes a display element and an eyepiece lens disposed on an eyepoint side of the display element. The eyepiece lens includes a first lens having positive optical power, a second lens having negative optical power, and a third lens consecutively in order from closest to a display element side to the eyepoint side. In a case where a half value of a longest diameter of a display region in the display element is denoted by H, and a focal length of the eyepiece lens in a state where diopter is −1 diopter is denoted by f, the observation optical system satisfies a conditional expression represented by 0.35<H/f<0.6.