Telecentric Optics for Uniform Head-Up Display Projection
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Solution Overview
Problem
Existing projection systems, including head-up display systems, suffer from speckle patterning and uneven light distribution due to diffusers, leading to compromised image quality and increased costs with larger diffusers required for larger images.
Innovation Solution
Incorporating a telecentric optical component between the laser source and light diffusing means to ensure light rays are output as parallel rays, allowing for controlled diffusion and uniform light distribution across the display screen, along with a vibrating means to reduce speckle patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If diffusers are used to increase field of view, then field of view is improved, but light distribution uniformity deteriorates
Solution Approach 1:
The patent applies local quality by using a telecentric optical component that creates a localized region of parallel light rays incident on the diffuser. This ensures that only light rays within a specific angular range (telecentric condition) are uniformly diffused, while maintaining overall field of view. The telecentric lens creates a narrow cone of parallel rays that hit the diffuser at consistent angles, achieving uniform light distribution in the projected image while still providing adequate field of view for the display application.
2Area of stationary object
If larger diffusers are used to project larger images, then image size is improved, but cost deteriorates
Solution Approach 1:
The patent introduces a telecentric optical component as an intermediary between the light source and diffuser. This intermediary creates parallel light rays that allow a smaller diffuser to effectively illuminate a larger area uniformly. The telecentric lens acts as a mediator that decouples the relationship between diffuser size and projected image size, enabling cost-effective projection of larger images without requiring proportionally larger (and more expensive) diffusers.
3Adaptability or versatility
If light rays are incident on diffusers at various angles, then field of view is increased, but brightness uniformity deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the angular parameter of light rays incident on the diffuser. The telecentric optical component ensures that light rays incident on the diffuser maintain a consistent angle (telecentric condition), rather than varying angles. This parameter control (maintaining constant incident angle) achieves uniform brightness in the projected image while still allowing the system to provide adequate field of view through the overall optical design.
4Illumination intensity
If TFT projectors use diffusers to ensure perpendicular light incidence, then brightness uniformity is improved, but device size deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of TFT projectors (which use large physical components to ensure perpendicular light incidence) with an optical approach. Instead of relying on the physical size and mechanical alignment of TFT elements, the patent uses a telecentric optical component to create parallel light rays that naturally incident on the diffuser at consistent angles. This substitution of mechanical constraints with optical principles achieves brightness uniformity while reducing overall device 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
Achieves even light distribution and reduced speckle patterning, resulting in improved image quality and cost-effectiveness by minimizing the size and number of components needed.
Implementation Method 1
a telecentric optical component which is disposed along said optical path between the laser source and the light diffusing means, so that the telecentric optical component receives light projected from the laser source and outputs light comprising parallel rays to the light diffusing means
Implementation Method 2
a light diffusing means which can diffuse light; wherein the laser source and the light diffusing means are arranged to be in optical communication along an optical path
Implementation Method 3
along with a vibrating means to reduce speckle patterns
Data Source
AI summary
The present invention provides a projection system (10), preferably for a head-up display e.g. on board a vehicle, comprising a laser source (1), a diffuser (3) and telecentric optics (2) disposed between the laser and the diffuser so that the telecentric optics outputs parallel rays to the diffuser, the diffused light being thus independent from the incidence angle; each pixel of the projected image has the same brightness, regardless of the angle or of the position from which it is viewed.