Prism Sheet Unit Light Source for Compact Color Mixing
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Solution Overview
Problem
Conventional light source apparatuses face challenges such as high costs due to the use of costly components like dichroic prisms, significant light loss, and increased size and thickness due to the need for spaced linear prisms to combine light from multiple sources, particularly in color projectors and liquid crystal display systems.
Innovation Solution
A light source apparatus utilizing a prism sheet unit with two mutually parallel prism surfaces, where the prism rows on one surface intersect those on the other at a predetermined angle, allowing for efficient light combination and color mixing without the need for additional spacing, thereby reducing the overall size and cost while maintaining superior optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dichroic prisms are used to combine light from multiple sources, then light combining capability is improved, but cost increases and light loss increases
Solution Approach 1:
The patent replaces expensive dichroic prisms with inexpensive linear prism sheets that can be mass-produced. The linear prism sheets achieve the same light combining function through refraction at inclined surfaces, eliminating the need for costly dichroic coating materials while maintaining optical performance.
Solution Approach 2:
The patent substitutes the complex dichroic prism optical system with a simpler linear prism sheet system that uses geometric refraction rather than dichroic interference. This mechanical/optical substitution reduces light loss by eliminating the complex internal reflections and coatings required in dichroic prisms.
2Adaptability or versatility
If linear prisms are used to combine light beams, then light combining is achieved, but apparatus size and thickness increase due to required spacing
Solution Approach 1:
The patent merges multiple linear prism sheets into a single integrated sheet structure where the inclined surfaces of different prism rows are positioned adjacent to each other. This allows light from multiple sources to be combined in a single pass through the sheet without requiring spacing between separate prism components, thereby reducing apparatus thickness.
Solution Approach 2:
The patent arranges linear prism rows in different orientations (e.g., perpendicular to each other) within the same planar sheet, allowing light combining to occur in multiple dimensions simultaneously. This dimensional arrangement enables compact integration of multiple light combining functions without increasing the thickness of the apparatus.
3Adaptability or versatility
If dichroic prisms are used for light combination, then light combining performance is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive dichroic prisms with inexpensive linear prism sheets that can be mass-produced using conventional plastic injection molding or extrusion techniques. The linear prism sheets achieve the same light combining function through geometric refraction rather than costly dichroic interference coatings, significantly reducing material and manufacturing costs.
Solution Approach 2:
The patent changes the optical mechanism from dichroic interference (wavelength-dependent reflection) to geometric refraction (angle-dependent direction change). This parameter change allows the use of simple transparent materials with standard refractive indices instead of expensive dichroic-coated glass, improving ease of manufacture and reducing device cost.
4Adaptability or versatility
If multiple linear prism plates are used to combine light from three or more sources, then light combining capability is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple separate linear prism plates into a single integrated prism sheet containing multiple sets of linear prism rows with different orientations. This integration reduces the number of discrete components from multiple separate plates to a single multi-functional sheet, thereby reducing assembly complexity while maintaining the capability to combine light from three or more sources.
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 and color mixing capabilities, achieving efficient light emission with reduced beam expansion and aspect ratio changes, suitable for applications in projectors and liquid crystal display systems.
Implementation Method 1
Light P51a and P51b incident on the light entrance surface 51 of the linear prism plate 50 from two different oblique directions are refracted by the light entrance surface 51 and thereafter respectively refracted by two exit surfaces 52 and 53 of each prism to exit as light P52 and P53 traveling in the same direction.
Data Source
AI summary
A light source apparatus capable of being reduced in size and thickness and superior in light combining performance includes a prism sheet unit having two mutually parallel prism surfaces each having a plurality of mutually parallel fine prism rows. The prism rows on the two prism surfaces intersect each other at a predetermined angle in plan view. A plurality of light sources are disposed at the light entrance surface side of the prism sheet unit to emit light so that the light is incident on the light entrance surface of the prism sheet unit at a predetermined angle thereto. The lights from the light sources are combined or color-mixed together by passing through the two prism surfaces, and the resulting combined or color-mixed light is emitted as exiting light.