Optical Device Thermal Management for Registration Shift Reduction
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Solution Overview
Problem
Front projectors using reflective liquid crystal panels face registration shifts due to thermal stress and linear expansion, which are not adequately addressed by existing solutions, leading to blurred images.
Innovation Solution
An optical device with a light synthesis prism, a light modulation unit including an optical compensation element and a reflective light modulation device, and a fixing member that incorporates a light blocking member and a heat insulating member to reduce thermal stress and linear expansion, thereby minimizing registration shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the color synthesis prism, reflective polarization element, and reflective liquid crystal panels are fixed using adhesive or fixing plates, then the three images can overlap correctly on the screen, but thermal stress and linear expansion cause registration shifts leading to blurred images
Solution Approach 1:
The invention divides the fixing structure into multiple independent fixing plates (first fixing plate for the color synthesis prism, second fixing plate for the reflective liquid crystal panels) rather than using a single rigid fixing structure. This segmentation allows each fixing plate to independently accommodate thermal expansion and stress, preventing cumulative registration shifts that would occur in a unified rigid structure.
Solution Approach 2:
The invention introduces a light blocking plate as an intermediary component between the light source and the reflective liquid crystal panels. This light blocking plate serves multiple functions: it blocks stray light, reduces thermal stress on the panels, and acts as a thermal barrier that prevents direct heat transmission to the adhesive and fixing structures, thereby maintaining registration precision under thermal conditions.
2Manufacturing precision
If a fixing plate with low linear expansion coefficient is used to fix the polarization element to the color synthesis prism, then registration shift is prevented, but the structure becomes more complex
Solution Approach 1:
The fixing plates in the invention serve multiple functions simultaneously: they provide mechanical support and positioning, accommodate thermal expansion through their material properties and design, block stray light when positioned appropriately, and distribute thermal stress. This multi-functionality eliminates the need for separate specialized components for each function, maintaining registration accuracy without significantly increasing structural complexity.
3Temperature
If the wave plate holder uses a transmission window smaller than the aperture to block unnecessary light, then temperature increase is reduced, but the device complexity increases
Solution Approach 1:
The invention extracts and separates the light blocking function from the structural support function by introducing a dedicated light blocking plate. This light blocking plate is positioned to block unnecessary light paths without requiring complex aperture designs in the wave plate holder or other structural components. The extraction of this specific function into a separate element simplifies the overall structure while achieving the temperature control objective.
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 registration shifts caused by heat reception in reflective liquid crystal devices, improving image clarity and projector performance while maintaining cost-effectiveness and assembly strength.
Implementation Method 1
a heat insulating member that is in contact with the light blocking member and the fixing member
Implementation Method 2
a light blocking member that blocks light from reaching the light modulation unit and that limits light to be irradiated on the optical compensation element and the reflective light modulation device to light passing an aperture portion
Implementation Method 3
a fixing member that fixes a reflective polarization element and the light modulation unit to the light synthesis prism so as to correspond to one of incidence surfaces
Data Source
AI summary
An optical device includes: a light synthesis prism that synthesizes incident light beams which are incident to a plurality of incidence surfaces and outputs the synthesized light beams; a light modulation unit that includes an optical compensation element and a reflective light modulation device; and a fixing member that fixes a reflective polarization element and the light modulation unit to the light synthesis prism so as to correspond to one of the incidence surfaces, wherein the light modulation unit includes a light blocking member that blocks light from reaching the light modulation unit and limits light with which the optical compensation element and the reflective light modulation device are irradiated, to light passing an aperture portion; and a heat insulating member that comes into contact with the light blocking member and the fixing member.