Image Displaying Apparatus Using Volume Hologram Grating

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Solution Overview

Problem

Conventional image displaying apparatuses require large diameter lenses in the image formation apparatus, leading to increased size and weight, and result in decreased display contrast and picture quality due to the long optical path length and varying number of reflections in the light conduction plate, which affects the aperture stop width and light flux distribution.

Innovation Solution

The image displaying apparatus incorporates a first light conduction section with a reflection type volume hologram diffraction grating and a second light conduction section with internal total reflection and multiple deflection sections, allowing for beam expansion and reduced aperture stop diameter, eliminating the need for large lenses and optimizing light flux distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional light conduction plates with long optical paths are used, then the apparatus can achieve basic light conduction function, but the number of reflections varies causing non-uniform light intensity distribution and decreased picture quality

Engineering Contradiction:

Improvelight intensity distribution uniformityVSAvoidoptical path length

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent divides the light conduction function into two separate sections: a first light conduction section with a reflection type volume hologram diffraction grating that provides a fixed number of reflections, and a second light conduction section with internal total reflection. This segmentation ensures uniform light intensity distribution while maintaining a compact overall optical path length.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If large diameter lenses are used in the image formation apparatus, then sufficient light flux can be achieved, but the size and weight of the apparatus increase

Engineering Contradiction:

Improvelight flux efficiencyVSAvoidapparatus weight

Core Design Contradiction:

Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The patent changes the optical parameters by introducing a reflection type volume hologram diffraction grating in the first light conduction section. This grating efficiently redirects light with a fixed number of reflections, improving light flux efficiency without requiring large diameter lenses, thereby reducing apparatus weight.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If large diameter lenses are used in the image formation apparatus, then sufficient light flux can be achieved, but the apparatus size increases

Engineering Contradiction:

Improvelight flux efficiencyVSAvoidapparatus size

Core Design Contradiction:

Use of energy by moving objectVSLength of moving object

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If the optical path length is increased, then light flux distribution can be adjusted, but display contrast decreases due to varying reflections

Engineering Contradiction:

Improvelight flux distributionVSAvoiddisplay contrast

Core Design Contradiction:

Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent segments the light conduction into two distinct sections with different reflection mechanisms. The first section uses a reflection type volume hologram diffraction grating with a fixed number of reflections to ensure uniform light intensity, while the second section uses internal total reflection. This segmentation maintains high display contrast by preventing the non-uniform light distribution that would otherwise occur with varying reflection numbers in a single long optical path.

Inventive Principle:

Principle #1Segmentation

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 reduces the size and weight of the apparatus, maintains high display contrast, and prevents picture quality degradation by ensuring uniform light intensity and efficient light propagation, while allowing for good observation of the external world with a head-mounted display.

Implementation Method 1

a first light conduction section with a reflection type volume hologram diffraction grating

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 2

reflection type volume hologram diffraction grating

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

a second light conduction section with internal total reflection

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

multiple deflection sections

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9279984B2Image displaying apparatus and optical apparatus

Publication Date: 2016.03.08 SONY GROUP CORP

AI summary

The image displaying apparatus includes an image production apparatus, a first light conduction section and a second light conduction section. The first light conduction section includes a first light conduction plate which propagates part of incident light thereto by total reflection in the inside thereof and emits the propagated light, and a reflection type volume hologram diffraction grating disposed on the first light conduction plate. The second light conduction section includes a second light conduction plate, a first deflection section and a second deflection section.