Projection Illumination Homogenizing Element for HMD Brightness
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Solution Overview
Problem
Current head-mounted display (HMD) devices for augmented reality (AR) and virtual reality (VR) suffer from uneven brightness and chrominance due to skewed central optical paths of green, red, and blue light beams, leading to suboptimal display image quality.
Innovation Solution
A projection apparatus with an illumination system comprising a solid-state illuminating source array, a collimating lens element, and a light homogenizing element, where the solid-state illuminating sources include red, blue, and green LEDs arranged in arrays, and a light combining element to ensure uniform brightness and chrominance by aligning the center optical paths of the light beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If LEDs of two channels (green LEDs and red/blue LEDs) are adopted to provide illumination beam, then the volume is reduced, but the central optical paths of green, red and blue beams are skewed, resulting in uneven brightness and chrominance
Solution Approach 1:
The patent introduces a light homogenizing element as an intermediary component between the LED light sources and the display element. This element mediates the skewed optical paths by redistributing the light beams, ensuring that the central optical paths of green, red, and blue beams are aligned properly, thus achieving uniform brightness and chrominance while maintaining the compact two-channel LED structure
Solution Approach 2:
The patent modifies the optical parameters of the illumination system by using a light homogenizing element that changes the spatial distribution of light beams. This parameter change allows the skewed central optical paths to be corrected, transforming the non-uniform illumination into uniform brightness and chrominance across the display image
2Volume of moving object
If LEDs of two channels (green LEDs and red/blue LEDs) are adopted to provide illumination beam, then the volume is reduced, but the chrominance uniformity deteriorates
Solution Approach 1:
The light homogenizing element serves as a mediator that specifically addresses chrominance uniformity by aligning the central optical paths of different color beams (green, red, blue). This intermediary component ensures that each color channel's light is properly distributed, resulting in uniform chrominance across the display image while preserving the compact two-channel LED architecture
3Illumination intensity
If a light homogenizing element is added to align the central optical paths, then the brightness and chrominance uniformity are improved, but the device complexity increases
Solution Approach 1:
The light homogenizing element is designed to perform multiple functions simultaneously: it homogenizes the light intensity distribution, aligns the central optical paths of different color beams, and corrects chrominance uniformity. By consolidating these multiple functions into a single component, the patent improves brightness and chrominance uniformity while minimizing the increase in device complexity
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 achieves uniform brightness and chrominance in the display image provided by the projection apparatus, enhancing the overall image quality and reducing manufacturing costs by optimizing the optical design and alignment of light beams.
Implementation Method 1
light-emitting diodes (LEDs) of two channels (light transmission paths) are generally adopted to provide an illumination beam
Implementation Method 2
The first light source includes a first solid-state illuminating source array. The first solid-state illuminating source array includes a plurality of solid-state illuminating sources arranged in an array
Implementation Method 3
a first collimating lens element and a light homogenizing element. The first illumination beam passes through the light homogenizing element and is transmitted to the image device
Implementation Method 4
a first collimating lens element and a light homogenizing element. The first illumination beam passes through the light homogenizing element
Data Source
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AI summary
A projection apparatus (100A) including an image device (130) and an illumination system (150A) is provided. The image device (130) is configured to convert a first illumination beam (IL1) into an image beam (ML). The illumination system includes a light source (151), a collimating lens element (153A) and a light homogenizing element (157). The light source provides an illumination beam (IL1). The illumination beam sequentially passes through the collimating lens element and the light homogenizing element and is transmitted to the image device (130). The light source includes a solid-state illuminating source array. The solid-state illuminating source array includes a plurality of solid-state illuminating sources arranged in an array. The image beam exits the projection apparatus and is converged to a stop (ST) located outside the projection apparatus. Moreover, a head-mounted display device (10A) including the projection apparatus is also provided.