Projection Display Device Compact Optical Path Design
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Solution Overview
Problem
Existing projection-type display devices using laser beams require large optical path spaces due to horizontal and vertical scanning, leading to enlarged device sizes and challenges in achieving compactness, ease of driving, and high light use efficiency.
Innovation Solution
A projection-type display device configuration that includes collimator and condenser lenses, a light diffusing element with a dynamic diffusing surface, integrator illumination systems, deflection units, and a transfer optical system to superimpose and deflect laser beams of different wavelengths, forming rectangular irradiation regions that are enlarged and scanned to a reflective light modulation element, ultimately projecting image light using a projection lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If optical scanning units with polygonal mirrors and galvanometer mirrors are used for horizontal and vertical scanning, then scanning function is achieved, but device size is enlarged
Solution Approach 1:
The patent extracts the scanning function from traditional mechanical scanning units (polygonal mirrors and galvanometer mirrors) and replaces it with a digital micromirror device (DMD) that performs scanning through electronic control of individual micromirors, thereby eliminating the need for large mechanical scanning components while maintaining the scanning capability
Solution Approach 2:
The patent replaces the mechanical scanning system (polygonal mirrors and galvanometer mirrors requiring large optical path spaces) with a digitally controlled DMD system that achieves scanning through electronic actuation of micromirors, substituting mechanical motion with electronic control to reduce device size
2Adaptability or versatility
If multiple laser beams of different wavelengths are superimposed, then color display capability is improved, but color regions may superimpose causing image quality degradation
Solution Approach 1:
The patent applies local quality by assigning different spatial positions to different color beams on the DMD surface, ensuring that red, green, and blue laser beams are directed to distinct regions of the DMD chip. This spatial separation prevents color region superimposition and maintains image quality while preserving color display capability
Solution Approach 2:
The patent resolves color superimposition issues by transitioning from temporal or spectral separation to spatial separation in the two-dimensional DMD plane. Each color channel is assigned a specific spatial region on the DMD, allowing simultaneous display of multiple colors without interference through dimensional separation in the spatial domain
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 enables a compact, easily drivable, and high-light-use-efficiency projection-type display device by reducing the optical path space and preventing superimposition of color regions, resulting in improved image quality and reduced component count.
Implementation Method 1
a first collimator lens configured to collimate a plurality of laser beams output from a plurality of semiconductor lasers
Implementation Method 2
a first condenser lens configured to condense the plurality of laser beams collimated by the first collimator lens
Implementation Method 3
a light diffusing element including a light diffusing surface having an area wider than any of an irradiation spot of the laser beams of the first wavelength condensed by the first condenser lens
Implementation Method 4
a first integrator illumination system configured to superimpose the laser beams of the first wavelength diffused by the light diffusing surface to form a rectangular irradiation region
Implementation Method 5
a first deflection unit disposed at a side of the first integrator illumination system with respect to a position where the rectangular irradiation region for the first wavelength is formed
Implementation Method 6
a transfer optical system configured to transfer the rectangular irradiation region for the first wavelength deflection-scanned by the first deflection unit and the rectangular irradiation region for the second wavelength deflection-scanned by the second deflection unit in an enlarged manner
Implementation Method 7
a projection lens configured to project image light output from the reflective light modulation element
Data Source
AI summary
A projection-type display device includes a first collimator lens configured to collimate a plurality of laser beams of a first wavelength, a first condenser lens, a second collimator lens configured to collimate a plurality of laser beams of a second wavelength, a second condenser lens, a light diffusing element, a first integrator illumination system configured to superimpose the laser beams of the first wavelength to form a rectangular irradiation region for the first wavelength, a second integrator illumination system configured to superimpose the laser beams of the second wavelength to form a rectangular irradiation region for the second wavelength, a first deflection unit, a second deflection unit, a transfer optical system configured to transfer the rectangular irradiation region for the first wavelength and the second wavelength to a reflective light modulation element, and a projection lens configured to project image light.