HUD Projection Shutter Control for External Light Heating
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Solution Overview
Problem
Conventional head-up display (HUD) devices experience a temperature increase in the image emission unit due to external light, leading to deterioration and reduced luminance in image projection.
Innovation Solution
An image projection device equipped with a shutter unit that switches between transmission and shielding modes, allowing for the selection of modes based on the pulse drive of the light source unit, thereby controlling the amount of external light reaching the image emission unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a wavelength cut filter is disposed on the optical path to cut infrared light and ultraviolet light, then temperature increase is suppressed, but visible light is partially attenuated causing decrease in luminance
Solution Approach 1:
The harmful infrared and ultraviolet components are extracted and removed from the external light path using a wavelength cut filter, while allowing the useful visible light to pass through to maintain image luminance
Solution Approach 2:
The wavelength cut filter is applied selectively to specific wavelength ranges (infrared and ultraviolet) while maintaining high transmittance in the visible light range, achieving local quality differentiation in light transmission properties
2Illumination intensity
If the shutter unit is in transmission mode to allow image light passage, then image projection is enabled, but external light reaches the image emission unit causing temperature increase
Solution Approach 1:
The shutter unit operates periodically, switching between transmission mode (allowing image light) and shielding mode (blocking external light), synchronized with the pulse drive of the light source to prevent temperature increase while maintaining image projection capability
Solution Approach 2:
The shutter unit dynamically changes its light transmission state based on operational requirements, transitioning between transparent and opaque states to control external light entry and prevent overheating
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 effectively suppresses temperature increases in the image emission unit, maintaining luminance and preventing deterioration caused by external light.
Implementation Method 1
a shutter unit that is disposed on an optical path for the image light between the image emission unit and the display unit and switches between a transmission mode for transmitting light and a shielding mode for shielding light
Implementation Method 2
the external light reaching the image emission unit via the projection optical system is condensed by the optical power of the projection optical system, leading to a problem that the external light causes deterioration due to a temperature increase
Data Source
AI summary
Provided is an image projection device capable of suppressing a temperature increase in an image emission unit due to external light. An image projection device for emitting a projection image to a display unit for displaying a virtual image, which includes an image emission unit (20) that emits image light, a projection optical unit (40) that emits the image light as the projection image in a direction of a point of view via the display unit, and a shutter unit (30) that is disposed on an optical path for the image light between the image emission unit (20) and the display unit and switches between a transmission mode for transmitting light and a shielding mode for shielding light.