Single Projection Display Device Optical Axis Alignment
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Solution Overview
Problem
Existing handheld projection display devices are not suitable for being held in one hand due to their large size, primarily because they use multiple reflective light valves or have optical axes that are not aligned, making them bulky and difficult to miniaturize.
Innovation Solution
A single projection display device design that utilizes a reflective light valve, a polarized light separation plane, and a reflection optical unit with a phase-rotating quarter-wave plate to align the optical axes, allowing for a compact, straight-type device that can be held like a flashlight or penlight, using a single reflective light valve and optimizing the projection lens for size and portability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three reflective liquid crystal display devices and a color quad are used to improve image quality and resolution, then the projection display device can achieve high resolution and illuminance, but the width of the intermediate part is significantly increased, making the device too large to be held in one hand
Solution Approach 1:
The patent merges the functions of multiple light valves and color separation optics into a single reflective liquid crystal display device that directly receives illumination light and modulates it for projection, eliminating the need for separate red, green, and blue light valves and the color quad, thereby significantly reducing device width while maintaining image quality
Solution Approach 2:
The patent extracts and eliminates the color quad (wavelength-selective polarization rotator and PBS prism) from the optical path by using a single reflective liquid crystal display device that can directly modulate illumination light across the visible spectrum, removing the complex color separation and recombination subsystem
2Device complexity
If a single reflective liquid crystal display device is used to reduce device complexity, then the device structure is simplified, but the optical axis of the illumination optical unit must be bent at a right angle with respect to the projection lens, preventing a straight-type compact design
Solution Approach 1:
The patent repositions the single reflective liquid crystal display device in the optical path and introduces a projection lens with specific focal length characteristics, enabling the illumination optical unit and projection lens to be arranged along substantially the same optical axis (straight-type configuration) rather than requiring perpendicular bending, thus achieving both simplified structure and compact straight-type form factor
3Illumination intensity
If multiple light valves are used to improve projection performance, then image quality is enhanced, but the intermediate part width increases significantly, making miniaturization difficult
Solution Approach 1:
The patent combines the color separation, modulation, and recombination functions that were previously distributed across three separate light valves into a single reflective liquid crystal display device, allowing all color channels to be modulated simultaneously by one device, thereby maintaining high projection illuminance while dramatically reducing the width of the intermediate part
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, portable single projection display device that can project images onto a screen while maintaining high resolution and illuminance, allowing for easy handling and alignment of optical components, thus achieving a handheld device with improved portability and image quality.
Implementation Method 1
The polarized light separation plane reflects the illumination light, which is in a predetermined linear polarization state, in a direction perpendicular to a traveling direction of the illumination light
Implementation Method 2
The reflective light valve is illuminated with illumination light emitted from the light source and emits modulated light corresponding to a predetermined image signal
Implementation Method 3
rotating a phase of the linearly polarized illumination light by 180 degrees
Data Source
AI summary
Linearly polarized illumination light that is emitted from a light source unit and then reaches a polarized light separation plane along the optical axis of an illumination optical unit is reflected from the polarized light separation plane at a right angle and reaches a reflection optical unit. The reflection optical unit reverses the phase of the linearly polarized illumination light and reflects the illumination light to the polarized light separation plane. The illumination light passes through the polarized light separation plane and reaches a reflective liquid crystal display device. The reflective liquid crystal display device converts the illumination light into modulated light having image information thereon. In this case, the phase of the linearly polarized light is reversed again and reflected from the polarized light separation plane at a right angle to reach a projection lens. The light is enlarged and projected onto a screen.