Strapped Integrating Rod Assemblies for Uniform Projector Illumination

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Solution Overview

Problem

Existing projector systems face challenges in improving image rendering performance and system efficiency, particularly in dual and multi-modulation display systems, where energy conservation and light recycling are desirable but not efficiently addressed.

Innovation Solution

The integration of multiple solid integrating rods joined by straps with a mismatched refractive index glue and reinforced by braces, allowing for longer lengths and varied orientations without disturbing internal reflectance, combined with light recycling modules to enhance illumination and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple solid integrating rods are joined together to extend length, then illumination uniformity is improved, but energy loss increases due to multiple bonding interfaces

Engineering Contradiction:
Improveillumination uniformityVSAvoidenergy loss
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent introduces an intermediary substance (adhesive or index-matching fluid) between the integrating rods to eliminate optical interfaces. This mediator has a refractive index matched to the rod material, creating an optically continuous path that prevents reflection and scattering at junctions, thereby maintaining energy efficiency while allowing extended rod lengths for improved illumination uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the optical parameter (refractive index) of the bonding medium to match the integrating rod material. By adjusting this parameter, the optical interface is eliminated, preventing energy loss at junctions while enabling the modular assembly of multiple rods to achieve the desired length for uniform illumination.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If integrating rod length is extended to improve illumination, then image uniformity is improved, but device complexity increases

Engineering Contradiction:
Improveimage uniformityVSAvoiddevice complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent segments the integrating rod into multiple modular sections that can be joined together. This segmentation allows the system to achieve extended effective length for improved illumination uniformity while maintaining manageable complexity through standardized connection interfaces and modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple integrating rod sections into a single functional unit through optical bonding. By combining these segments with proper index-matching adhesives, the system achieves the performance of a single long rod while benefiting from the modularity and ease of assembly of separate components.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If adhesive is used to bond integrating rods, then mechanical stability is improved, but optical performance deteriorates due to reflection at bonding interfaces

Engineering Contradiction:
Improvemechanical stabilityVSAvoidoptical performance
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent uses an intermediary bonding agent with specifically matched refractive index to bridge the mechanical and optical requirements. This mediator provides the necessary mechanical adhesion between rods while being optically transparent and index-matched to eliminate reflection, thus maintaining both structural stability and optical performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent carefully selects and adjusts the refractive index parameter of the bonding adhesive to match the integrating rod material. This parameter change ensures that the adhesive serves its mechanical bonding function without creating optical interfaces that would cause reflection and energy loss.

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 improves energy efficiency and cost-effectiveness by extending the length of integrating rods, maintaining optical integrity, and enabling flexible light recycling, resulting in enhanced image quality and reduced energy consumption.

Implementation Method 1

The straps are glued to the integrating rods by a glue having a substantially different (e.g. lower) index of refraction than the integrating rods, so as not to disturb the internal reflectance of the rods

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

integrating rod structure for a digital projector comprising a length of hollow integration rod and a length of solid integration rod, reflecting an incoming light beam to pass through to acquire a homogeneous light beam

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4002006B1Improved integration rod assemblies for image projectors
Publication Date: 2026.04.22 DOLBY LABORATORIES LICENSING CORP
  • EP4002006B1 patent drawingFigure 1
  • EP4002006B1 patent drawingFigure 2
  • EP4002006B1 patent drawingFigure 3

AI summary

Integrating rod modules are disclosed comprising a plurality of single and/or solid integrating rods that are mated together by straps. Such modules tend to comprise a greater length than the single and/or solid integrating rods and provide good illumination to a modulator that light from a light source is transmitted through the integrating rod module. The straps may comprise a material (e.g., glass) that has substantially same or similar thermal characteristics as the integrating rods. The straps may be glued to the integrating rods by a glue having a substantially different (e.g., lower) index of refraction than the integrating rods, so as not to disturb the internal reflectance of the rods. The straps may be reinforced by braces that may allow the integrating rod module to be set within a projection display system at an angle substantially different from horizontal.