Integrated Light-Combining Prism for LCOS Projection Displays

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Solution Overview

Problem

Existing projection display apparatuses with liquid crystal on silicon modulators have a complex structure due to the use of multiple polarizing beam splitters and light-combining prisms, leading to a large number of component parts.

Innovation Solution

A projection display apparatus with a simplified structure that uses a light-combining prism and LCOS modulators, omitting polarizing beam splitters, and incorporates a uniform light prism to reduce speckle, while utilizing laser light sources for polarized light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If multiple polarizing beam splitters and light-combining prisms are used to combine beams in the modulation module, then the beam combining function is achieved, but the number of component parts increases and the structure becomes complex

Engineering Contradiction:
Improvestructure complexityVSAvoidnumber of component parts
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The patent merges multiple polarizing beam splitters and light-combining prisms into a single integrated light-combining prism component. This integration maintains the beam combining function while significantly reducing the number of discrete parts and simplifying the overall structure, directly resolving the technical contradiction between achieving beam combining and avoiding structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated light-combining prism performs multiple functions that were previously distributed across separate components: it combines beams from different LCOS modulators, manages polarization states, and integrates the optical path routing. This multi-functionality reduces the quantity of component parts while maintaining the required beam combining capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If multiple polarizing beam splitters and light-combining prisms are used in the modulation module, then the beam combining function is achieved, but the apparatus size increases

Engineering Contradiction:
Improveapparatus sizeVSAvoidstructure complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

By consolidating multiple optical components into a single integrated light-combining prism, the patent reduces the total volume occupied by the modulation module. The integrated structure eliminates the need for multiple separate components that would require additional space for mounting, alignment, and optical path routing, thereby reducing apparatus size while maintaining beam combining function

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If a uniform light prism is added to reduce speckle, then speckle reduction is achieved, but the number of component parts increases

Engineering Contradiction:
ImprovespeckleVSAvoidnumber of component parts
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent converts the harmful speckle effect into a beneficial outcome by introducing a uniform light prism that scatters and redistributes the light. The prism transforms the coherent laser light into a more uniform distribution, eliminating speckle patterns while maintaining the overall light intensity and quality for projection display

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

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

Reduces the number of component parts and manufacturing costs, minimizes the apparatus size, and enhances light utilization and speckle reduction.

Implementation Method 1

The light emitting module includes a light source that is configured to emit linearly polarized light

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 2

The light-combining prism includes four rectangular prisms. The light-combining prism has four sides and four intersection planes formed by the four rectangular prisms

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

At least two of the four intersection planes are configured to split light emitted from the light source in the light-combining prism. At least two of the four intersection planes are configured to combine light emitted from the light source in the light-combining prism

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

The modulation component includes a light-combining prism and an LCOS modulator. The LCOS modulator is configured to generate modulated light and unmodulated light

Methodology Applied
Scientific EffectLiquid crystal modulation: Liquid Crystals

Data Source

PatentEP4130872B1Projection display device
Publication Date: 2025.09.24 HUAWEI TECH CO LTD
  • EP4130872B1 patent drawingFigure 1
  • EP4130872B1 patent drawingFigure 2~3
  • EP4130872B1 patent drawingFigure 4~5

AI summary

A projection display apparatus is provided, including an optical machine module (1). The optical machine module (1) includes a light emitting module (11) and a modulation module (12). The light emitting module (11) includes a light source (111) configured to emit linearly polarized light. The modulation module (12) includes a modulation component. The modulation component includes a light-combining prism (122a) and an LCOS modulator. The light-combining prism (122a) includes four rectangular prisms. The light-combining prism (122a) has four sides and four intersection planes formed by the four rectangular prisms. The LCOS modulator includes a first LCOS modulator (122c), a second LCOS modulator (122d), and a third LCOS modulator (122e). The first LCOS modulator (122c), the second LCOS modulator (122d), and the third LCOS modulator (122e) are respectively disposed on light emitting sides of three different sides. At least two of the four intersection planes are configured to split light emitted from the light source (111) in the light-combining prism (122a). At least two of the four intersection planes are configured to combine light emitted from the light source (111) in the light-combining prism (122a). The projection display apparatus can resolve a problem that the modulation module (12) has a large quantity of component parts and a complex structure.