Prism Sheet Light Source Apparatus for Compact Optical Systems
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Solution Overview
Problem
Conventional light source apparatuses using dichroic prisms are costly and suffer from significant light loss, while those employing linear prisms require increased space and result in beam width expansion, making them bulky and inefficient in terms of size and light utilization.
Innovation Solution
A light source apparatus utilizing a prism sheet with fine elongated prisms and bandpass mirrors to combine and mix light from multiple sources, reducing the optical system's thickness and eliminating the need for additional spacing between components, thereby enhancing light utilization efficiency and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dichroic prisms are used to combine light from multiple sources, then light combining function is achieved, but the apparatus cost increases and light loss increases
Solution Approach 1:
The patent replaces expensive dichroic prisms with inexpensive linear prism sheets that can be easily manufactured and disposed of. The linear prism sheets achieve the same light combining function at a fraction of the cost, eliminating the need for costly optical components while maintaining system performance.
Solution Approach 2:
The patent changes the optical path parameters by using linear prism sheets with specific refractive indices and prism angles to optimize light combining efficiency. By adjusting the prism geometry and material properties, the system achieves high light utilization without the losses associated with dichroic prism coatings.
2Device complexity
If linear prisms are used to combine multiple lights into a single beam, then light combining is achieved, but the apparatus size increases and beam width expands
Solution Approach 1:
The patent uses multiple linear prism sheets arranged in sequence, where each sheet performs a portion of the light combining task. This distributed approach allows the system to achieve the same light combining function as a single large prism while reducing the overall apparatus volume and preventing excessive beam width expansion.
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 a compact, cost-effective light source apparatus with improved light combining performance and efficiency, allowing for the combination of multiple light sources into a single, thin optical system that maintains effective light utilization and reduces beam expansion issues.
Implementation Method 1
a bandpass mirror disposed between each of the light sources and the prism sheet to transmit light in a wavelength region emitted from a corresponding light source and to reflect light in the other wavelength regions
Implementation Method 2
a prism sheet having a plurality of mutually parallel fine elongated prisms on at least one surface thereof. The prism sheet is configured to receive lights from the plurality of light sources through a light entrance surface thereof at predetermined angles and emit the lights from an exit surface thereof as color-mixed exiting light
Data Source
AI summary
The present invention provides a light source apparatus less costly, capable of being reduced in size and thickness and superior in light combining performance and a display apparatus having the light source apparatus. The light source apparatus has a plurality of light sources different in emission wavelength from each other and a prism sheet having a plurality of mutually parallel fine elongated prisms on at least one surface thereof. Lights from the light sources enter the prism sheet through a light entrance surface of the prism sheet at a predetermined angle and output from an exit surface thereof as color-mixed exiting light. A bandpass mirror is disposed between each light source and the prism sheet to transmit light in a wavelength region emitted from the associated light source and to reflect light in the other wavelength regions.