Projection Device Mirror for Zero-Order Light Extraction
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Solution Overview
Problem
Existing projection devices using phase modulation type spatial modulators face challenges in removing zero-order light without adding extra modulation elements or pixels, which can lead to image distortion and reduced luminance.
Innovation Solution
A projection device configuration that includes a phase modulator, a Fourier transform lens, a mirror, and a projection lens, where the mirror guides zero-order light away from the projection path, allowing only light excluding zero-order light to be projected, thus eliminating distortion and maintaining luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a light shielding member is used to shield high-order images, then the high-order image is removed, but the device complexity increases
Solution Approach 1:
The patent extracts and removes only the harmful zero-order light component from the projected image using a mirror, while leaving the useful first-order images intact. This selective extraction approach eliminates the need for complex light shielding members that would block all light, thereby reducing device complexity while maintaining image quality.
Solution Approach 2:
The patent introduces a mirror as an intermediary element between the spatial modulator and the projection lens. This mirror acts as a simple mediator that selectively reflects away only the zero-order light component, avoiding the need for complex shielding structures while achieving the desired separation of harmful and useful light components.
2Object-generated harmful factors
If zero-order light is completely removed, then image quality improves, but luminance decreases
Solution Approach 1:
The patent selectively extracts only the harmful zero-order light component from the total light flux using a mirror, while allowing the useful first-order images to pass through unchanged. This selective extraction ensures that luminance is maintained at the level of the first-order images while removing only the problematic zero-order light.
Solution Approach 2:
The patent applies different optical paths to different components of the light: the zero-order light is reflected away by the mirror, while the first-order images continue through to the projection lens. This local differentiation of optical paths ensures that each light component receives the appropriate treatment without affecting overall luminance.
3Object-generated harmful factors
If asymmetric lens system is used to shift zero-order light, then zero-order light is removed, but image distortion increases
Solution Approach 1:
The patent extracts and removes only the harmful zero-order light component using a mirror, avoiding the need to distort the entire image field. This selective removal approach prevents the image distortion that would result from using asymmetric lens systems to shift all light components.
Solution Approach 2:
The patent uses a mirror as an intermediary element that selectively interacts with only the zero-order light component, leaving the first-order images unaffected. This approach avoids the image distortion that would be introduced by asymmetric lens systems that would need to manipulate the entire image field.
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
Enables the projection of images without zero-order light, without additional modulation elements or pixels, preventing image distortion and maintaining luminance, regardless of the screen position or distance.
Implementation Method 1
a phase modulator that modulates a phase of incident laser light
Implementation Method 2
a Fourier transform lens that performs Fourier transformation on laser light, whose phase is modulated by the phase modulator
Implementation Method 3
a mirror that reflects Fourier-transformed laser light transformed by the Fourier transform lens, the mirror being disposed on an image formation surface on which an image is formed by the Fourier transform lens
Implementation Method 4
a projection lens that enlarges light reflected by the mirror and projects the light as projected light
Data Source
AI summary
In order to project an image excluding zero-order light without adding extra modulation elements or pixels, without applying distortions, and without reducing luminance, a projection device includes: a phase modulator that modulates the phase of incident laser light; a Fourier transform lens that performs Fourier transformation on laser light, whose phase is modulated by the phase modulator; a mirror disposed on an image formation surface by the Fourier transform lens, and configured to reflect the laser light subjected to Fourier transformation by the Fourier transform lens; and a projection lens that enlarges the light reflected by the mirror and projects the light as projected light. The mirror guides zero-order light included in the Fourier-transformed laser light in a direction different from a direction of the projection lens, and reflects the light excluding zero-order light toward the projection lens.