Color Combining Prism Unit for Bright Projection Display
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Solution Overview
Problem
Existing two-plate-type projection display apparatuses with reflective elements face challenges in achieving bright image projection with complex configurations.
Innovation Solution
A projection display apparatus using two reflective display elements, a color separating mirror, and a color combining prism unit with four prisms and dichroic coating, which separates and combines light efficiently to produce bright images with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a two-plate-type configuration with reflective display elements is used, then the device complexity is reduced, but the illumination intensity (brightness) is insufficient
Solution Approach 1:
The patent combines multiple optical functions (color separation, total internal reflection, and light combination) into a single integrated color combining prism unit. This merging of functions maintains the simplicity of the two-plate-type configuration while improving light efficiency and projection brightness through optimized optical paths and multiple reflection surfaces.
2Illumination intensity
If traditional color separation and combination methods are used, then the illumination intensity can be improved, but the device complexity increases
Solution Approach 1:
The color combining prism unit serves multiple functions simultaneously: it acts as a color separator, a total internal reflector, and a light combiner. This multi-functionality eliminates the need for separate optical components for each function, thereby maintaining device simplicity while achieving high projection brightness through efficient light management.
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 apparatus achieves bright projection with a simplified optical system by optimizing the angle of incidence and using dichroic coatings for efficient color separation and combination, resulting in a compact and effective display solution.
Implementation Method 1
a color separating mirror that separates light emitted from the light source part into a first color light and a second color light
Implementation Method 2
two air gap faces that totally reflect or transmit light depending on the angle of incidence
Implementation Method 3
a color combining prism unit that combines the first color light modulated by the first light modulation element and the second color light modulated by the second light modulation element
Data Source
AI summary
The projection display apparatus according to the present disclosure includes: a light source part; a color separating mirror that separates light emitted from the light source part into a first color light and a second color light; a first light modulation element that modulates the first color light; a second light modulation element that modulates the second color light; a color combining prism unit that combines the first color light modulated by the first light modulation element and the second color light modulated by the second light modulation element; and a projection unit that projects combined light emitted from the color combining prism unit. The color combining prism unit includes four prisms and has two air gap faces that totally reflect or transmit light depending on the angle of incidence.