Imaging Optical System with Intermediate Image for Wide Angle View

Solution Overview

Problem

Existing imaging optical systems for projection-type display apparatuses face challenges in achieving a wide angle of view with appropriate aberration correction while maintaining a small lens diameter, as they often result in either narrow angles of view, large lens diameters, or significant distortion.

Innovation Solution

The proposed imaging optical system consists of a first optical system and a second optical system, with specific conditional expressions to ensure a wide angle of view and correct various aberrations, incorporating a positive meniscus lens and a negative lens to optimize lens placement and curvature, thereby reducing lens diameters and maintaining optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the focal length is reduced to widen the angle of view in an optical system without intermediate imaging, then the angle of view is improved, but the lens diameter becomes excessively large

Engineering Contradiction:

Improveangle of viewVSAvoidlens diameter

Core Design Contradiction:

ShapeVSArea of stationary object

Solution Approach 1:

The optical system is divided into two separate systems: a first optical system (reduced-side) and a second optical system (magnified-side) with an intermediate image plane between them. This segmentation allows each system to be optimized independently, enabling the magnified-side system to have a shorter back focus and smaller lens diameter while maintaining a wide angle of view.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediate image is introduced as a mediator between the object plane and the final image plane. This intermediate image allows the optical system to achieve wide angle of view by reducing the focal length of the magnified-side system without requiring excessively large lens diameters, as the intermediate image acts as a virtual object for the first optical system.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Shape

If the focal length is reduced to widen the angle of view, then the angle of view is improved, but the lens diameter on the magnified side becomes excessively large

Engineering Contradiction:

Improveangle of viewVSAvoidmagnified-side lens diameter

Core Design Contradiction:

ShapeVSArea of stationary object

Solution Approach 1:

The optical system is divided into two separate systems: a first optical system (reduced-side) and a second optical system (magnified-side) with an intermediate image plane between them. This segmentation allows each system to be optimized independently, enabling the magnified-side system to have a shorter back focus and smaller lens diameter while maintaining a wide angle of view.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The introduction of the intermediate image plane adds a new dimension to the optical path, allowing the magnified-side system to operate with a shorter back focus distance. This dimensional addition enables the use of smaller lens diameters on the magnified side while still achieving wide angle of view through the reduced-side system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Shape

If the angle of view is widened by reducing focal length, then the angle of view is improved, but distortion increases and imaging performance becomes insufficient

Engineering Contradiction:

Improveangle of viewVSAvoidimaging performance

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The optical system is divided into two separate systems: a first optical system (reduced-side) and a second optical system (magnified-side) with an intermediate image plane between them. This segmentation allows each system to be optimized independently, enabling the magnified-side system to have a shorter back focus and smaller lens diameter while maintaining a wide angle of view.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system uses conditional expressions to precisely control optical parameters, including the ratio of the focal length of the first optical system to the overall focal length, and the position of the intermediate image. By optimizing these parameters, the system achieves wide angle of view while maintaining acceptable distortion and imaging performance.

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

This configuration allows for the projection of high-quality images with a wide angle of view while minimizing the size of the apparatus, effectively correcting aberrations and preventing excessive lens diameters, thus enhancing both optical performance and portability.

Implementation Method 1

an imaging optical system which is combined with the light valve has required satisfactory aberration correction appropriate for the resolution of the light valve

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12019223B2Imaging optical system, projection-type display apparatus, and imaging apparatus

Publication Date: 2024.06.25 FUJIFILM CORP

AI summary

The imaging optical system consists of a first optical system and a second optical system in order from a magnified side. The second optical system forms an image on an image display surface as an intermediate image, and the first optical system forms the intermediate image on a magnified-side conjugate plane. A height of a principal ray of light having a maximum angle of view becomes maximum on a lens surface of the whole system on the most magnified side, among heights of principal rays of light having a maximum angle of view on respective lens surfaces. The imaging optical system satisfies predetermined conditional expressions.