Head-Up Display Projection Optics for Compact Telecentric Imaging
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Solution Overview
Problem
Existing head-up display devices face challenges in achieving compact size while maintaining required performance, particularly due to large mirrors and unsatisfied telecentric properties in projection optical systems.
Innovation Solution
The use of a projection optical system comprising a concave lens, a free curved surface lens, and a free curved surface concave mirror to minimize optical configuration and enhance compactness, while ensuring telecentric property and distortion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional projection optical system with large mirrors is used, then the required optical performance is achieved, but the device volume becomes large and compactization is difficult
Solution Approach 1:
The patent introduces a field lens positioned between the liquid crystal display panel and the projection optical system. This additional optical element in a different spatial dimension (closer to the display panel) enables telecentric light flux without requiring larger mirrors, thus reducing device volume while maintaining optical performance
Solution Approach 2:
The field lens acts as an intermediary optical element that modifies the light flux before it enters the projection optical system. By placing this mediator component, the system achieves telecentricity and proper illumination without needing to enlarge the existing mirror components, resolving the contradiction between compact size and optical performance
2Length of moving object
If the light flux is folded in the horizontal direction to achieve a thin profile, then the device becomes thinner, but the reflecting mirror becomes large and compactization is hindered
Solution Approach 1:
The optical system is segmented into distinct functional zones: the image forming unit (liquid crystal display panel), the field lens positioned immediately behind it, and the projection optical system. This segmentation allows the field lens to handle light flux conditioning in a compact space, enabling the projection system to use smaller mirrors while maintaining the thin profile achieved through horizontal folding
3Volume of moving object
If a concave mirror is used for projection, then the optical path is folded and compactness is improved, but distortion arises that requires additional correction
Solution Approach 1:
The field lens serves as an intermediary that pre-corrects and conditions the light flux before it reaches the concave mirror. By positioning this lens between the display panel and the mirror, the system achieves distortion correction without needing to tilt the screen or add separate correction optics, thus maintaining compactness while improving image quality
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
This configuration allows for a compact head-up display device that maintains required performance by optimizing the eyepiece optical system, achieving improved telecentricity and distortion correction.
Implementation Method 1
the eyepiece optical system includes a concave lens, a free curved surface lens, and a free curved surface concave mirror disposed in order from the image forming unit side along the emission direction of the image light
Implementation Method 2
the eyepiece optical system includes a concave lens, a free curved surface lens, and a free curved surface concave mirror disposed in order from the image forming unit side along the emission direction of the image light
Implementation Method 3
the eyepiece optical system includes a concave lens, a free curved surface lens, and a free curved surface concave mirror disposed in order from the image forming unit side along the emission direction of the image light
Data Source
AI summary
An object of the present invention is to provide a vehicle that includes a display panel, a light source that irradiates light to the display panel, a first optical system that forms, onto a screen plate, a first optical image of a video on the display panel, and a second optical system that converts the first optical image into a second optical image that is a virtual image. The first and second optical systems are configured such that the first optical system's optical axis, at an incident surface side of the screen plate, is parallel to the second optical system's optical axis at an emission surface side of the screen plate. The first optical image formed on the screen plate is obtained by enlarging the video, and the virtual image is obtained by enlarging the first optical image formed on the screen plate by the second optical system.