Lighting Device Air Gap Right-Angle Prism Beam Combination
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Solution Overview
Problem
Existing projection type display apparatuses face inefficiencies in combining light beams from multiple sources, leading to suboptimal brightness and light loss due to issues with light source image size and converging angles, particularly when using LEDs or discharge lamps with large arc lengths.
Innovation Solution
A lighting device comprising multiple light sources, converging lenses, right-angle prisms made of high refractive materials, and a composite rod integrator, with a predetermined air gap between the prisms and the integrator, allowing for efficient beam combination and minimizing light loss by optimizing the focal points and angles of incidence and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light sources are used to improve brightness, then the brightness of projected images is improved, but light loss increases due to inefficient beam combination
Solution Approach 1:
A right-angle prism is introduced as an intermediary optical element between the light source and the rod integrator. The prism receives light beams from the light source, reflects them 90 degrees, and directs them onto the rod integrator's incident surface. This intermediary structure enables efficient coupling of multiple light beams while minimizing light loss at interfaces.
Solution Approach 2:
The patent optimizes the air gap distance between the right-angle prism and the rod integrator to a specific range (0.1-10mm). This parameter optimization ensures that light beams maintain appropriate convergence angles after reflection, maximizing the effective light utilization and minimizing loss during the beam combination process.
2Illumination intensity
If light sources with large arc lengths or high output are used, then brightness is improved, but light source image size becomes too large causing light loss at the periphery
Solution Approach 1:
The right-angle prism utilizes its inclined surface to reflect and redirect light beams, effectively controlling the spatial distribution of the light source image. The geometric configuration of the prism transforms the light path, ensuring that even large light source images are properly directed onto the rod integrator without peripheral light loss.
3Device complexity
If conventional beam combination methods are used, then device complexity is reduced, but light use efficiency deteriorates due to large light source images and improper converging angles
Solution Approach 1:
The right-angle prism serves as a compact intermediary element that efficiently redirects light beams without requiring complex optical systems. By placing the prism at a 45-degree angle to the light source, the system achieves effective beam combination with minimal additional complexity while significantly improving light use efficiency.
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 high-output lighting with uniform luminance distribution, effectively utilizing light beams from sources of varying sizes and angles, thereby enhancing the brightness of projected images while reducing heat generation and manufacturing costs.
Implementation Method 1
a converging lens 103 is arranged so that parallel light beam emitted from the light source 101 are focused on the incident surface 115 of the right-angle prism 111
Implementation Method 2
the light beam emitted from the light source 101 enters through the incident surface 115 of the right-angle prism 111, is reflected by an inclined surface 113, and forms a spot on the incident surface 121 of the composite rod integrator 120
Implementation Method 3
The light beams emitted from the light sources 101 and 104 are repeatedly reflected inside the composite rod 120, and thereby combined together
Data Source
AI summary
A lighting device configured to efficiently combine light beams emitted from a plurality of light sources, and to emit high output light while minimizing light loss, and a projection type display apparatus including the lighting device. The lighting device includes: a first light source and a second light source; two converging lenses for converging light beams emitted from the first and second light sources; two right-angle prisms for bending the light beams emitted from the first and second light sources; and a composite rod integrator for combining the light beams emitted from the first and second light sources. Between an exit surface of each right-angle prism and an incident surface of the composite rod integrator, a predetermined air gap is provided. The focal point of each converging lens is located on an incident surface of each right-angle prism.