Laser Projection Optics Using Quantum Dots to Reduce Speckle
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Solution Overview
Problem
Laser projection devices suffer from speckle interference due to coherent light, which affects the imaging quality and visual display.
Innovation Solution
A laser projection device incorporating a quantum mechanism with differently sized quantum dots in red, blue, and green units, and a rotating reflecting mirror to convert coherent light into incoherent light, ensuring the light rays are transmitted in parallel directions to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If coherent light is used as light source, then color gamut coverage is improved (more than 90% of color space), but speckle interference occurs affecting imaging quality
Solution Approach 1:
The patent segments the coherent light beam into multiple separate light rays by using a rotating reflecting mirror with multiple reflective surfaces. Each light ray is directed to different quantum units (red, green, blue) at different times, effectively dividing the original coherent beam into multiple incoherent components that reduce speckle interference while maintaining color gamut coverage.
Solution Approach 2:
The patent employs a rotating reflecting mirror that dynamically changes the path of coherent light over time. The mirror rotates to sequentially direct different portions of the coherent light to different quantum units, creating temporal separation of light paths. This dynamic approach converts coherent light into incoherent light by varying the optical path length and phase relationships, thereby eliminating speckle while preserving the vibrant color reproduction.
2Object-affected harmful factors
If quantum mechanism with different particle sizes is used, then speckle is reduced, but device complexity increases
Solution Approach 1:
The patent integrates multiple quantum units (red, green, blue) with different quantum dot particle sizes into a single compact quantum mechanism. Each quantum unit serves multiple functions: it converts specific wavelengths of coherent light to different colors, acts as a spectral filter, and contributes to speckle reduction through its unique quantum dot size characteristics. This multi-functional design reduces overall device complexity compared to having separate systems for each function.
Solution Approach 2:
The patent employs a nested structure where quantum units with different sized quantum dots are arranged in a compact configuration within the optical path. The quantum units are positioned such that they are sequentially encountered by the rotating mirror's light rays, creating a space-efficient arrangement. This nesting approach allows the complex quantum mechanism to fit within a compact form factor while maintaining speckle reduction capabilities.
3Object-affected harmful factors
If rotating reflecting mirror is used to convert coherent light to incoherent light, then speckle eliminating performance is improved, but device complexity increases
Solution Approach 1:
The patent uses a rotating reflecting mirror that performs periodic action by continuously rotating through a fixed angular range. The mirror's rotation creates a periodic sequence of light ray directions, with each rotation cycle directing light to the same set of quantum units in the same order. This periodic motion simplifies the control mechanism compared to complex variable optical path systems, as the rotation speed and angle can be maintained at constant values while still achieving effective speckle elimination through the temporal variation in light paths.
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 speckles, enhancing the speckle eliminating performance and improving the clarity and fidelity of the image displayed.
Implementation Method 1
a quantum mechanism configured to convert the coherent light into incoherent light and including a red quantum unit, a blue quantum unit and/or a green quantum unit configured to receive the coherent light at different times, in which particle sizes of quantum dots included in the red quantum unit, the blue quantum unit and the green quantum unit are different
Implementation Method 2
The reflecting mirror may reflect the coherent light at a first position to form a first light ray, at a second position to form a second light ray, and/or at a third position to form a third light ray
Data Source
AI summary
Disclosed is a laser projection device which may include a laser light source configured to generate coherent light, a quantum mechanism configured to convert the coherent light into incoherent light and including a red, blue, and/or green quantum unit configured to receive the coherent light at different times, and/or a shaping mechanism configured to transmit the incoherent light from the red, blue, and/or green quantum unit in a same direction. Particle sizes of quantum dots included in the red, blue, and/or green quantum unit may be different. The red, blue, and/or green quantum unit may receive coherent light at different times and may convert it into incoherent light using quantum dots. This may avoid interference generated by the coherent light and may reduce speckles on the image formed by the laser projection device.