Forward-on-forward DMD Architecture for HDR Projectors

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Solution Overview

Problem

Existing high dynamic range (HDR) projectors using digital micromirror devices (DMDs) operate the first DMD in a reverse configuration due to traditional projection optics, leading to inefficiencies and increased costs, size, noise, and power consumption due to diffractive effects, which are not optimal for achieving high contrast and black levels.

Innovation Solution

A forward-on-forward configuration for both DMDs with optics that tilt the subject plane of the first DMD to an equivalent tilted plane, ensuring all planes intersect at a Scheimpflug intersection, allowing for uniform focus and efficient light conveyance between the DMDs, using optical devices like prisms and lenses to achieve this configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the first DMD is operated in reverse configuration using traditional projection optics, then the Scheimpflug principle allows focusing two optical planes onto each other, but the system becomes significantly less optically efficient due to diffractive effects

Engineering Contradiction:
Improvefocus capabilityVSAvoidoptical efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent inverts the traditional configuration by operating both DMDs in forward configuration instead of reverse configuration. This inversion eliminates the need to rely on the Scheimpflug principle and reduces diffractive effects, thereby improving optical efficiency while maintaining focus capability through alternative optical design

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the operational parameters of the DMDs from reverse configuration to forward configuration. This parameter change fundamentally alters the optical path and eliminates the diffractive effects associated with reverse configuration, improving optical efficiency without sacrificing focus capability

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the first DMD is operated in reverse configuration, then traditional optics can achieve acceptable focus, but this increases projector cost, size, and power consumption

Engineering Contradiction:
Improvefocus capabilityVSAvoidprojector cost and size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By inverting the configuration to forward-on-forward, the patent eliminates the need for complex traditional optics required for reverse configuration operation, thereby reducing projector cost, size, and power consumption while maintaining focus capability

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts and removes the need for Scheimpflug-based optical systems from the design. By operating both DMDs in forward configuration, the system eliminates the requirement for complex traditional optics, simplifying the overall system and reducing cost and size

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the first DMD is operated in reverse configuration, then traditional projection optics can function, but diffractive effects lead to increased noise

Engineering Contradiction:
Improvefocus capabilityVSAvoidnoise from diffractive effects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the configuration to forward-on-forward, which eliminates the diffractive effects that occur in reverse configuration. This inversion removes the source of noise while preserving the ability to achieve proper focus through optimized optical design

Inventive Principle:
Principle #13The other way round (Inversion)

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 more efficient operation of HDR projectors by maintaining uniform focus and reducing inefficiencies, resulting in improved contrast and reduced costs, size, and power consumption, while maintaining high dynamic range capabilities.

Implementation Method 1

at least one optical device which tilt a subject plane of the first DMD to an equivalent tilted subject plane, an equivalent lens plane of the optics, the equivalent tilted subject plane and an image plane of the second DMD all intersecting at a Scheimpflug intersection

Methodology Applied
Scientific EffectScheimpflug principle:

Implementation Method 2

a first pre-modulator digital micromirror device ('DMD') and a second prime-modulator DMD, each operated in a forward configuration, such that each is illuminated at a respective non-normal angle and a respective output image is reflected at a normal angle

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

optics which convey light from the first DMD to the second DMD

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3364228B1Forward-on-forward high dynamic range architecture for digital micromirror devices
Publication Date: 2020.12.16 CHRISTIE DIGITAL SYSTEMS USA INC
  • EP3364228B1 patent drawingFigure 1
  • EP3364228B1 patent drawingFigure 2
  • EP3364228B1 patent drawingFigure 3

AI summary

A forward-on-forward high dynamic range architecture for digital micromirror devices device is provided. In particular, provided herein is a device that includes two digital micromirror devices (DMDs), each operated in a forward configuration, such that each is illuminated at a respective non-normal angle and a respective output image is reflected at a normal angle, a subject plane of a first DMD being parallel to the first DMD. Optics between the DMDs are configured to convey light reflected from the first DMD to illuminate an image plane at a second DMD in the forward configuration, the optics including an equivalent lens plane. At least one optical device between the DMDs is configured to: tilt the subject plane of the first DMD to an equivalent tilted subject plane, the equivalent lens plane, the equivalent tilted subject plane and the image plane all intersecting at a Scheimpflug intersection.