Projection Display Light Loss Reduction via Dielectric Color Filter
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Solution Overview
Problem
Existing projection-type video-image-displaying devices suffer from significant light loss, which reduces the efficiency of image display and increases costs.
Innovation Solution
The device incorporates a light multiple reflecting element with a dielectric multilayer film that reflects visible light efficiently and a color wheel with six fan-shaped transmission type color filters, along with a TIR prism and relay lenses to minimize light divergence and reflection, optimizing light distribution and reducing spoke time and infrared component reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional projection-type video-image-displaying device is used, then image display function is provided, but light loss is significant and light use efficiency is low
Solution Approach 1:
The patent converts harmful infrared light that would otherwise cause heat and light loss into useful illumination by reflecting it back through the color filter and onto the light modulation element. The dielectric multilayer film on the color filter reflects infrared light while allowing visible light transmission, transforming what was previously waste energy into contributing light for the projection process.
Solution Approach 2:
The patent employs a composite structure combining a color filter with a dielectric multilayer film deposited on its surface. This composite material allows selective wavelength manipulation - the color filter transmits visible light while the dielectric multilayer film reflects infrared light, creating a multi-functional optical component that addresses both color separation and infrared management.
2Illumination intensity
If the light source operates at high intensity to improve image brightness, then illumination intensity increases, but light source temperature increases and lifetime decreases
Solution Approach 1:
The patent converts harmful infrared radiation into useful visible light illumination. By reflecting infrared light back through the color filter and onto the modulation element, the system recovers what would otherwise be waste heat energy, converting it into contributing light that improves brightness without requiring increased light source power.
Solution Approach 2:
The patent recovers infrared light that would otherwise be discarded as waste heat. The dielectric multilayer film reflects infrared light back into the optical path, allowing this previously wasted energy to be reused for illumination, thereby reducing the need for high light source intensity and extending light source lifetime.
3Ease of manufacture
If a rotary color filter is used to achieve high resolution with one liquid crystal panel, then manufacturing yield improves and costs reduce, but light loss occurs at color filter boundaries
Solution Approach 1:
The patent converts light that would otherwise be lost at color filter boundaries into useful illumination. By reflecting infrared light and redirecting it through the color filter, the system ensures that light passing through or near boundary regions still contributes to the final image, reducing the impact of boundary losses.
Solution Approach 2:
The patent maintains continuous useful light action by reflecting infrared light back through the color filter and onto the modulation element. This ensures that light paths that might otherwise be interrupted or lost at color filter boundaries continue to contribute to image formation, maintaining continuous illumination efficiency throughout the rotation cycle.
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 use efficiency, reduces costs, and extends the life of the light source by minimizing light loss and temperature increase, resulting in improved image display quality and reduced device expenses.
Implementation Method 1
a light multiple reflecting element with a dielectric multilayer film that reflects visible light efficiently
Implementation Method 2
a TIR prism and relay lenses to minimize light divergence and reflection
Implementation Method 3
a color wheel with six fan-shaped transmission type color filters
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3(A)~3(B)
AI summary
The objective of the present invention is to provide a projection-type video-image-displaying device capable of efficiently displaying an image by reducing the loss of light in the device, the device also being suitable for reducing costs associated therewith. A projection-type image-displaying device is provided with a light source radiating white light, a rod lens, a rotary color filter (4), a DMD (10), illumination optical elements (5, 12, 18), a projection lens and a control device. The rod lens collects light from the light source and emits the light. The rotary color filter (4) is disposed in the vicinity of the emitting surface of the rod lens, and selectively transmits or reflects, from the white light, light of a specific color. The DMD (10) includes a plurality of pixels and modulates incident light in accordance with an image signal. The illumination optical elements (5, 12, 18) collect the emitted light from the rotary color filter and form illumination light for projection onto the DMD. The projection lens projects an image formed using the DMD. The control device controls the rotation of the rotary color filter to be synchronized with the image display by the DMD. The rotary color filter forms, on a part thereof, a light-emitting surface using light from the emitting surface of the rod lens. The DMD is disposed in a substantially conjugate relationship with the light-emitting surface on the rotary color filter.