Stacked Display Panels with Different Color Filter Thicknesses

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Solution Overview

Problem

Conventional head-up displays (HUDs) face challenges in reducing the decrease in transmitted light quantity, particularly when display regions of stacked display panels overlap, leading to reduced luminance and compromised image quality.

Innovation Solution

The proposed display device comprises a backlight, a first image display panel, and a second image display panel with a gap between them. The first image display panel includes a first polarizing plate and a first color filter, while the second image display panel includes a second polarizing plate and a second color filter. The thickness of the first color filter is different from that of the second color filter, and no polarizing plate is provided between the two image display panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If display regions of multiple display panels are arranged to overlap, then the quantity of transmitted light is significantly reduced, but the ability to superimpose virtual images at different distances is improved

Engineering Contradiction:

Improveability to superimpose virtual imagesVSAvoidquantity of transmitted light

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by making the color filters of different display panels have different spectral characteristics. Specifically, the first display panel uses a color filter with a first spectral transmittance characteristic while the second display panel uses a color filter with a second spectral transmittance characteristic. This allows each panel to transmit light efficiently in its optimized wavelength range, reducing overall light loss while enabling overlapping display regions for virtual image superposition.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If display panels are stacked vertically spaced apart, then virtual images at different distances can be displayed, but the device complexity increases

Engineering Contradiction:

Improvedisplay of virtual images at different distancesVSAvoidstacked panel structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple display panels with different focal requirements into a single stacked structure. The first and second display panels are positioned at different vertical distances from the viewer, with each panel's display region overlapping the other. This combined structure enables simultaneous display of virtual images at different distances without requiring separate HUD systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes the vertical dimension (z-axis) to create depth separation between display panels. By stacking panels at different vertical positions rather than arranging them side-by-side in the horizontal plane, the system achieves multiple virtual image distances while maintaining a compact footprint. The spectral differentiation of color filters further adds a wavelength dimension to distinguish between panels.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If the same color filter is used in both display panels, then manufacturing is simplified, but the transmitted light quantity decreases when panels overlap

Engineering Contradiction:

Improvecolor filter consistencyVSAvoidtransmitted light quantity

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

Inventive Principle:

Principle #3Local 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 increased luminance of the displayed images by reducing the decrease in transmitted light quantity, while maintaining the ability to superimpose virtual images from both display panels, enhancing the overall visibility and quality of the HUD.

Implementation Method 1

a first polarizing plate configured to transmit light polarized in a first direction and block light polarized in a direction different from the first direction

Methodology Applied

Scientific EffectPolarisation: Polarisation

Implementation Method 2

a second polarizing plate configured to transmit light polarized in a second direction different from the first direction and block light polarized in a direction different from the second direction

Methodology Applied

Scientific EffectPolarisation: Polarisation

Implementation Method 3

The thickness of the first color filter is different from the thickness of the second color filter

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Data Source

PatentUS20250138312A1Display device and head-up display

Publication Date: 2025.05.01 MAGNOLIA WHITE CORP

AI summary

According to an aspect, a display device includes: a backlight, first and second image display panels. The first image display panel includes: a first polarizing plate configured to transmit light polarized in a first direction and block light polarized in a direction different from the first direction; and a first color filter provided between the first polarizing plate and the second image display panel. The second image display panel includes: a second polarizing plate configured to transmit light polarized in a second direction and block light polarized in a direction different from the second direction; and a second color filter provided between at least the second polarizing plate and the first image display panel. The thickness of the first color filter is different from the thickness of the second color filter. Another polarizing plate is not provided between the first image display panel and the second image display panel.