Composite pane having a hologram element and an optically highly-refractive layer
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Solution Overview
Problem
Existing composite panes with holograms for head-up displays face limitations in selecting the angle of inclination due to undesirable reflections and ghost images, which restrict the freedom of arrangement and image quality, particularly at larger angles of inclination.
Innovation Solution
Incorporating an optically highly-refractive layer with a refractive index greater than or equal to 2 on the interior surface of the inner pane, preferably made of materials like silicon nitride or titanium oxide, to minimize reflections and allow for greater freedom in selecting the angle of inclination while reducing ghost images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the angle of inclination of the composite pane is increased to allow for greater freedom in arrangement, then the adaptability of the display system is improved, but undesirable reflections and ghost images increase, degrading image quality
Solution Approach 1:
An intermediate layer with refractive index between the glass pane and the holographic material is introduced. This intermediate layer acts as a mediator to reduce optical impedance mismatch, minimizing reflections at the interface and enabling steeper angles of inclination without significant ghost images or artifacts.
Solution Approach 2:
The refractive index parameter of the layer between the glass pane and holographic material is optimized to be between 1.4 and 1.7. By adjusting this optical parameter, the system achieves reduced reflections and improved image quality at larger angles of inclination, resolving the contradiction between adaptability and image quality.
2Ease of manufacture
If the hologram is recorded before the lamination process, then the manufacturing process is simplified, but the optical properties of the hologram are degraded due to reflections during recording
Solution Approach 1:
The intermediate layer with optimized refractive index is introduced in advance during the lamination process setup. This preliminary preparation ensures that when the hologram is recorded after lamination, the optical conditions are favorable, preventing reflections and ghost images while maintaining manufacturing feasibility.
Solution Approach 2:
The intermediate layer serves as a mediator that improves optical conditions during hologram recording. By positioning this layer between the glass pane and holographic material, reflections are minimized, allowing high-precision hologram recording without compromising the simplicity of the manufacturing process.
3Object-affected harmful factors
If the refractive index of the intermediate layer is increased to reduce reflections, then the reduction of ghost images is improved, but the transmission of light may be affected
Solution Approach 1:
The refractive index of the intermediate layer is optimized within the range of 1.4 to 1.7. This parameter optimization balances two competing requirements: high enough refractive index to reduce reflections and ghost images, but not so high as to excessive impedance mismatch that would harm light transmission. The holographic material's refractive index (1.5-1.6) serves as a reference for this optimization.
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 enables the composite pane to be installed at steeper angles without undesirable reflections, maintaining good image quality and minimizing ghost images, suitable for industrial series production.
Implementation Method 1
Head-up displays in which the projected image is reflected in the direction of the viewer on the nearest glass surface of the composite glass pane that is inclined towards the viewer are subject to the law of reflection, according to which the angle of incidence and the angle of reflection are equal.
Implementation Method 2
Incorporating an optically highly-refractive layer with a refractive index greater than or equal to 2 on the interior surface of the inner pane to minimize reflections
Implementation Method 3
If the reference wave and the object wave have parallel wavefronts, the interference pattern corresponds to a parallel grating whose lamellae are angled below the angle bisector of reference wave and object wave. After recording, the holographic material is cured, thereby losing the ability to record further holograms. If the holographic material in which the hologram was recorded is again irradiated with the reference wave, the light at the recorded grating of the hologram is diffracted such that the diffracted wave corresponds to the object wave.
Implementation Method 4
To record a hologram, two, mutually-coherent light beams—the so-called reference beam—which can also be referred to as a reference wave, and the so-called object beam, which can also be referred to as an object wave, are directed onto a holographic material. The resulting interference pattern of the superimposed wave fronts is written to the holographic material as an alternating refractive index modulation.
Data Source
AI summary
A composite pane includes an outer pane having an outer surface and an interior surface, an inner pane having an outer surface and an interior surface, a first intermediate layer, and a hologram element having at least one hologram, wherein the first intermediate layer is arranged between the outer pane and the inner pane, the hologram element is arranged between the outer pane and the first intermediate layer or between the inner pane and the first intermediate layer, and wherein an optically highly-refractive layer is arranged on the interior surface of the inner pane.