Lighting Device Optical Path Shift for High-Density Flux
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Solution Overview
Problem
Existing lighting devices for projection display apparatus face limitations in high-density light flux gathering due to restricted close arrangement of light source units, which affects the achievement of high-luminance illumination.
Innovation Solution
A lighting device comprising a first and second light source unit with parallel laser elements and an optical path shift optical system, including reflecting surfaces, allows for high-density light flux gathering even with restricted arrangement by reflecting the second light flux to align it with the first light flux at a shorter distance, using a prism or mirror configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light fluxes from multiple light source units are densely gathered to achieve high-luminance illumination, then illumination luminance is improved, but the arrangement flexibility of light source units is restricted due to size and shape constraints
Solution Approach 1:
The patent introduces an optical path shift optical system that shifts the optical path of light fluxes in a direction orthogonal to the emission direction. This dimensional change allows light source units to be arranged in a matrix configuration where they can be spaced apart in the orthogonal direction while still achieving dense gathering of light fluxes through optical path shifting, thereby resolving the contradiction between high luminance and arrangement flexibility
Solution Approach 2:
The optical path shift optical system acts as an intermediary between the light source units and the light flux gathering process. It includes optical elements such as prisms or mirrors that shift the optical paths of light fluxes from differently arranged light source units, enabling flexible arrangement of light sources while maintaining high-density light flux gathering and high luminance output
2Quantity of substance
If light source units are arranged closely to enable high-density light flux gathering, then light flux density is improved, but the optional size and shape of light source units (including cooling devices) is restricted
Solution Approach 1:
By shifting optical paths in a direction orthogonal to the emission direction, the patent enables light source units to maintain larger optional sizes and shapes (including cooling devices) while still achieving high light flux density through optical path convergence at the target position, thus resolving the contradiction between light flux density and design flexibility of light source units
3Quantity of substance
If optical path shift optical system uses multiple reflecting surfaces to shift optical paths, then light flux gathering density is improved, but the number of optical elements increases
Solution Approach 1:
The patent merges multiple optical functions into a single optical path shift optical system that can shift optical paths of light fluxes from multiple light source units simultaneously. By integrating these functions and using efficient optical designs, the patent reduces the total number of optical elements while maintaining high light flux gathering density, thus resolving the contradiction between gathering density and device complexity
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 enhances light flux density and reduces luminance unevenness, enabling high-luminance illumination while allowing for a more compact optical element design and apparatus size reduction.
Implementation Method 1
a first reflecting surface that reflects the second light flux emitted from the second light source unit toward the first light flux
Implementation Method 2
a second reflecting surface that is parallel to the first reflecting surface and reflects the second light flux reflected by the first reflecting surface to be parallel to the first light flux
Data Source
AI summary
A lighting device includes: a first light source unit including a plurality of laser elements and emitting a first light flux in a first direction; a second light source unit including a plurality of laser elements and being arranged to emit a second light flux in the first direction and to be spaced apart from the first light source unit by a first distance in a second direction orthogonal to the first direction; and an optical path shift optical system including: a first reflecting surface that reflects the second light flux emitted from the second light source unit toward the first light flux; and a second reflecting surface that is parallel to the first reflecting surface and reflects the second light flux reflected by the first reflecting surface to be parallel to the first light flux at a second distance shorter than the first distance.