Telecentric Light Source Optics for Compact Virtual Image Display
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Solution Overview
Problem
Existing video display apparatuses are large in size due to the need for a substantial optical path length to form a virtual image, which limits their compactness and versatility.
Innovation Solution
A light source unit comprising a display device, a first prism sheet, and an imaging optical system with a telecentric property on the first image side, which reduces the size of the light source unit and the video display apparatus while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a substantial optical path length is used to form a virtual image, then image quality is maintained, but the device size increases
Solution Approach 1:
The patent introduces a telecentric optical system that changes the dimensional characteristics of light propagation. By making the chief rays parallel to the optical axis in the image space, the system effectively compresses the optical path in certain dimensions while maintaining image quality, allowing compact device design without sacrificing imaging performance
Solution Approach 2:
The patent changes the optical parameters by implementing a telecentric system where the numerical aperture and chief ray angles are specifically controlled. This parameter change allows the optical system to achieve both compact size and high image quality by optimizing the relationship between object distance, image distance, and aperture settings
2Volume of moving object
If the optical path length is reduced to decrease device size, then compactness is improved, but image formation quality deteriorates
Solution Approach 1:
The telecentric optical system utilizes dimensional transformation by making chief rays parallel to the optical axis, which allows the system to achieve effective optical path compression in the axial direction while maintaining transverse image quality. This dimensional change enables short optical path length without image degradation
Solution Approach 2:
By optimizing the telecentric parameters including object distance, image distance, and numerical aperture, the system achieves high image quality with reduced optical path length. The parameter optimization ensures that even with compact dimensions, the imaging performance remains excellent
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 proposed solution enables a significant reduction in the size of the light source unit and the video display apparatus while ensuring high-quality image formation, making them more compact and suitable for various applications.
Implementation Method 1
a first prism sheet on which light emitted from the display device is incident
Implementation Method 2
an imaging optical system including an input element on which light emitted from the first prism sheet is incident and an output element on which light that has passed through the input element is incident
Implementation Method 3
a reflection unit that is spaced apart from the light source unit and configured to reflect light emitted from the imaging optical system
Data Source
AI summary
A light source unit includes: a display device configured to emit light that has a substantially Lambertian light distribution and to display a picture; a first prism sheet on which the light emitted from the display device is incident; and an imaging optical system that includes an input element on which light emitted from the first prism sheet is incident and an output element on which light that has passed through the input element is incident, and configured such that light emitted from the output element forms a first image corresponding to the picture. The imaging optical system has a substantially telecentric property on a side of the first image.