LED Light Converging System Using Virtual Image Formation
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Solution Overview
Problem
Conventional light source systems for projectors, particularly those using LEDs, face challenges in effectively converging and homogenizing light due to the large angular range of LED source light, leading to issues such as increased size, damage to optical components, and difficulty in using LEDs as a point light source.
Innovation Solution
An LED light converging system comprising an LED light source, a first lens unit with a specific focal length and spacing to form a virtual image, and a second lens unit with a different focal length and spacing to form a real image, eliminating the need for integration rods and transmission lenses, thereby reducing system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light source systems use ultra-high pressure arc lamps with array of lenses to converge and homogenize light, then light homogenization is achieved, but the system size increases due to large-sized reflector and additional optical components
Solution Approach 1:
The patent extracts and eliminates unnecessary optical components (large reflector, integration rod, transmission lenses) from the conventional light source system. By using LED as a self-luminous element with built-in hemispherical lens, the system removes multiple separate components while maintaining light homogenization function, thus reducing overall system size.
Solution Approach 2:
The patent merges the light source and the first lens into a single integrated LED component with hemispherical lens. This integration eliminates the need for separate reflectors and multiple lenses, achieving both light convergence and homogenization in a compact structure that reduces system volume.
2Illumination intensity
If conventional light source systems use integration rods for light homogenization, then light homogenization efficiency is improved, but the system size increases due to sufficiently long integration rod and additional transmission lenses
Solution Approach 1:
The patent removes the integration rod and transmission lenses from the optical path by using LED's inherent light emission characteristics. The LED with hemispherical lens directly provides homogenized light that can be focused by a single condensing lens, eliminating the need for long integration rods and additional transmission lenses.
Solution Approach 2:
The patent replaces the mechanical light homogenization system (integration rod with multiple reflections) with an optical approach using LED's direct light emission and a single condensing lens. This substitution eliminates the need for long mechanical structures while achieving the same homogenization effect.
3Use of energy by moving object
If conventional light source systems use large reflector to collect diverging LED light, then light collection is improved, but the system size increases and ultraviolet and infrared light damage optical components
Solution Approach 1:
The patent converts the harmful effect of diverging LED light (which contains UV and IR) into a beneficial focused beam by using a condensing lens positioned at the focal point. The lens collects and converges the diverging light rays into a parallel beam, eliminating the need for large reflectors while maintaining light collection efficiency and protecting optical components from UV and IR damage.
4Volume of stationary object
If LED is used as point light source, then system size can be reduced, but the large angular range of source light makes it difficult to use
Solution Approach 1:
The patent introduces a condensing lens as an intermediary element between the LED and the optical system. The lens acts as a mediator that converts the LED's large angular range diverging light into a focused parallel beam, making the LED effectively function as a point light source while maintaining ease of operation and reducing system size.
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 system effectively converges and collects diverging LED light without the need for large reflectors or integration rods, allowing for a smaller size and adjustable illumination area, overcoming the limitations of conventional systems.
Implementation Method 1
The first lens unit has a first focal length, and is disposed forwardly of and is spaced apart from the LED light source by a first distance less than the first focal length such that a virtual image of the source light provided by the LED light source is formed rearwardly of the LED light source
Implementation Method 2
The second lens unit has a second focal length, is disposed forwardly of the first lens unit, and is spaced apart from the virtual image of the source light by a second distance larger than the second focal length such that a real image of the source light provided by the LED light source is formed forwardly of the second lens unit
Implementation Method 3
The source light emitted by the array 22 of the light-emitting diodes exits the hemispherical lens 23 after being refracted
Data Source
AI summary
An LED light converging system includes an LED light source, and first and second lens units aligned in sequence along an optical axis. The LED light source provides source light. The first lens unit has a first focal length, and is disposed forwardly of and is spaced apart from the LED light source by a first distance less than the first focal length such that a virtual image of the source light provided by the LED light source is formed rearwardly of the LED light source. The second lens unit has a second focal length, is disposed forwardly of the first lens unit, and is spaced apart from the virtual image of the source light by a second distance larger than the second focal length such that a real image of the source light provided by the LED light source is formed forwardly of the second lens unit.