Dichroic Prism Layout for Stray-Light-Controlled Projection
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Solution Overview
Problem
Existing projection devices using dichroic prisms with self-luminous display devices suffer from stray light due to light reflection and diffusion, leading to reduced image quality and increased device size and weight.
Innovation Solution
A projection device incorporating a dichroic prism with a specific configuration and additional angle limiting filters or light absorbing members to minimize stray light, combined with self-luminous display devices that emit different wavelengths, allowing for high-quality image projection without a separate light source, enabling a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light passes through the dichroic prism to combine images from three self-luminous display devices, then image combination is achieved, but stray light is generated due to reflection and diffusion
Solution Approach 1:
The patent extracts and removes stray light from the optical path by introducing a light absorbing member that selectively absorbs reflected and diffused light before it reaches the emission surface, thereby eliminating the harmful effect while preserving the main image light
Solution Approach 2:
The light absorbing member acts as an intermediary element placed within the dichroic prism to intercept and absorb stray light generated by reflections and diffusions, preventing it from reaching the emission surface while allowing the primary image light to pass through
2Device complexity
If self-luminous display devices are used without a separate light source, then device complexity is reduced, but light efficiency is lowered due to diffusion and reflection
Solution Approach 1:
The patent converts the harmful effect of light diffusion and reflection into a beneficial outcome by using the light absorbing member to selectively remove only the stray light components, thereby recovering light efficiency without adding complex external light sources or restructuring the self-luminous display system
3Adaptability or versatility
If the dichroic prism is used for image combination, then three display devices can be integrated, but the device size and weight increase
Solution Approach 1:
The patent merges the light absorbing function directly into the dichroic prism structure by placing the light absorbing member inside the prism, thereby achieving stray light reduction without adding separate external components that would increase device weight and size
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
The solution effectively reduces stray light, enhances image quality, and allows for a portable and versatile projection system that can be integrated into various devices, including smartphones and wearable glasses, while maintaining high luminance and reduced size and weight.
Implementation Method 1
a dichroic prism 10 for combining first image light LG having a first wavelength emitted from the first self-luminous display device 21, second image light LB having a second wavelength emitted from the second self-luminous display device 22, and third image light LR having a third wavelength emitted from the third self-luminous display device 23
Implementation Method 2
The light emitted from each of the self-luminous display devices passes through the dichroic prism to be superimposed on each other
Implementation Method 3
The first self-luminous display device 21 includes a plurality of first light-emitting elements configured to emit light of a first wavelength... The second self-luminous display device 22 includes a plurality of second light-emitting elements configured to emit light of a second wavelength... The third self-luminous display device 23 includes a plurality of third light-emitting elements configured to emit light of a third wavelength
Data Source
AI summary
A projection device includes a dichroic prism, a first self-luminous display device, a second self-luminous display device, a third self-luminous display device, and a projection optical system. The dichroic prism has a first surface, a second surface, a third surface, and a fourth surface, and is configured to emit combined image light from the fourth surface. The first self-luminous display device is configured to use light of a first wavelength to emit first image light to the first surface. The second self-luminous display device is configured to use light of a second wavelength to emit second image light to the second surface. The third self-luminous display device is configured to use light of a third wavelength to emit third image light to the third surface. The projection optical system is configured to project, onto a projection target, the combined image light emitted from the dichroic prism.