Image Projection Unit Resolving Registration Deviation via Resin Intermediary
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing image projection apparatuses face issues with registration deviation due to the weaker coupling intensity of total reflection prisms, which can lead to breakdown or positional deviation of digital mirror devices and color synthesis prisms, especially under impact or thermal expansion, resulting in poor image quality.
Innovation Solution
An image projection unit is designed with a color synthesis prism, total reflection prisms having an air gap, and digital mirror devices, where a holding member supports the digital mirror devices to prevent load on the total reflection prisms, and a base member securely supports both the color synthesis and total reflection prisms, using materials with matching linear expansion coefficients to minimize thermal stress and external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the total reflection prism is used to guide light with an air gap structure, then the device complexity is reduced and manufacturing is simplified, but the coupling intensity becomes weaker leading to breakdown under impact or thermal expansion
Solution Approach 1:
A resin layer is introduced as an intermediary substance between the total reflection prism and the digital mirror device. This resin layer acts as a mediator that transfers and distributes mechanical stress, preventing direct stress concentration at the air gap interface. The resin's viscoelastic properties allow it to absorb impact forces and thermal expansion stresses, thereby maintaining the structural integrity of the air gap prism while securing the digital mirror device in position.
Solution Approach 2:
The patent employs a composite structure combining the total reflection prism (optical element), resin layer (bonding material), and digital mirror device (display element). This composite assembly leverages the complementary properties of each material: the prism provides optical functionality with minimal internal stress, the resin provides mechanical cushioning and stress distribution, and the digital mirror device provides display functionality. The composite structure achieves both manufacturing simplicity and structural reliability.
2Manufacturing precision
If the digital mirror device is fixed by bonding to the total reflection prism, then the registration can be adjusted, but the positional relation may deviate due to expansion of the air gap layer under thermal stress
Solution Approach 1:
The patent changes the physical parameters of the bonding interface by replacing a direct rigid bond with a resin layer that has specific viscoelastic properties. The resin's damping coefficient and shear modulus are selected to match the thermal expansion characteristics of the adjacent components. This parameter matching allows the resin to compensate for thermal expansion differences, maintaining the positional relationship between the digital mirror device and total reflection prism under varying temperature conditions.
Solution Approach 2:
The resin layer is positioned beforehand between the total reflection prism and digital mirror device to provide preemptive cushioning against thermal expansion and contraction. This pre-positioned cushioning layer absorbs dimensional changes before they can cause misalignment or damage to the bonded components, thereby maintaining registration precision across different operating temperatures.
3Strength
If the color synthesis prism and total reflection prisms are bonded together, then the structural integration is improved, but the air gap planes are prone to breakdown under impact and thermal expansion
Solution Approach 1:
The resin layer serves as a protective intermediary between the color synthesis prism and total reflection prism at the air gap interfaces. This intermediary layer distributes impact forces across a larger area and prevents stress concentration at the fragile air gap planes. The resin's compliance allows it to deform under impact, absorbing energy and preventing catastrophic failure of the bonded optical elements.
Solution Approach 2:
The resin bonding material provides beforehand cushioning at the air gap planes by being applied during assembly before any thermal or mechanical stress occurs. This pre-applied cushioning layer is designed to accommodate anticipated thermal expansion and impact loads, protecting the air gap interfaces from harmful stress concentrations that would otherwise lead to breakdown.
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 reduces the likelihood of registration deviation, ensuring stable alignment and high-quality image projection by distributing loads effectively and absorbing thermal and external shocks.
Implementation Method 1
total reflection prisms each having an air gap, and configured to guide light emitted from the light source unit to the corresponding reflection-type image display element and to emit the light reflected from the corresponding reflection-type image display element
Data Source
AI summary
An image projection unit includes: a light source unit; a plurality of reflection-type image display elements; a plurality of total reflection prisms configured to guide lights of multiple colors emitted from the light source unit to the reflection-type image display elements and to emit the lights reflected from the reflection-type image display elements; a color synthesis prism configured to receive the lights emitted from the total reflection prisms, synthesize the lights, and emit the synthesized lights; a holding member fixed to the color synthesis prism and holding the reflection-type image display elements; and a base member supporting the color synthesis prism and the plurality of total reflection prisms