Virtual Image Display Device with Intermediate Image Formation Unit
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Solution Overview
Problem
Existing head-up display systems require a large number of components to present virtual images at multiple positions in the direction of depth, which increases complexity and cost.
Innovation Solution
A virtual image display device with an intermediate image formation unit that includes a substrate with transmission-type and reflection-type screens, and a reflective part, allowing for the projection of image display light to create virtual images at different depths using a smaller number of components by optimizing the arrangement of these elements on a reference surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate projection systems are used to present virtual images at different depths, then the depth presentation capability is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple projection functions into a single projection unit by using different screen types (transmission-type and reflection-type) within one intermediate image formation unit. This allows first display light to pass through transmission screens and second display light to reflect off reflection screens, both processed by the same projection unit to create virtual images at different depths, thereby reducing component count while maintaining multi-depth capability
Solution Approach 2:
The intermediate image formation unit serves multiple functions simultaneously by incorporating both transmission-type screens and reflection-type screens. This single unit handles both transmitted light paths and reflected light paths, enabling the projection system to present virtual images at multiple depth positions without requiring separate projection systems for each depth level
2Device complexity
If a single projection unit is used to present virtual images at multiple depths, then the device complexity is reduced, but the image quality may deteriorate
Solution Approach 1:
The patent applies different screen types at different locations within the intermediate image formation unit. Transmission-type screens are positioned for first display light while reflection-type screens are positioned for second display light. This local differentiation ensures that each light path receives the appropriate screen type optimized for its specific function, maintaining high image quality for both virtual images at different depths while using a single projection unit
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
Enables the presentation of virtual images at multiple depths with reduced component count, improving manufacturing efficiency and cost-effectiveness while maintaining a natural depth perception for the user.
Implementation Method 1
the first area is provided with a transmission-type screen on which a first display light that is a portion of the image display light forms an image
Implementation Method 2
a reflective part that reflects a portion of the image display light transmitted through the reference surface toward the reference surface
Implementation Method 3
the third area is provided with a reflection-type screen on which a second display light that is another portion of the image display light forms an image, the second display light is reflected by the reflection-type screen and output toward the projection mirror
Data Source
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Figure 3
Figure 4~5
AI summary
A virtual image display device 10 includes: a projection unit 12 that projects an image display light; an intermediate image formation unit 14 on which a real image based on the image display light is formed; and a projection mirror 16 that reflects the image display light output from the intermediate image formation unit 14 toward a virtual image presentation plane. The intermediate image formation unit 14 includes a principal surface 21 on which a first area W1, a second area W2, and a third area W3 are arranged in a stated order in a predetermined direction, and a reflective part 28, the first area W1 is provided with a transmission-type screen 31 on which a first display light that is a portion of the image display light forms an image, and the third area W3 is provided with a reflection-type screen 33 on which a second display light that is another portion of the image display light forms an image. The first display light is transmitted through the transmission-type screen 31, reflected by the reflective part 28, transmitted through the second area W2, and output toward the projection mirror 16, and the second display light is reflected by the reflection-type screen 33 and output toward the projection mirror 16.