Transmissive Display Light-Guiding System Brightness Uniformity
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Solution Overview
Problem
Existing transmissive image display devices, such as head-mounted displays, suffer from uneven external light transmittance within the viewing range, causing discomfort when observing external images due to abrupt changes in brightness.
Innovation Solution
Incorporating a first external light transmittance adjustment part with higher average transmittance than the first and second deflection parts, which are semi-transmissive and reflective volume hologram components respectively, to smoothly transition light transmission across the viewing area, reducing abrupt brightness changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If semi-transmissive mirrors are used in the first and second deflection parts to allow external light transmission, then the observer can view external images, but the transmittance of external light varies largely within the viewing range causing unpleasantness
Solution Approach 1:
The patent introduces a third deflection part with different optical properties (higher external light transmittance) to create a gradual transition zone. This local quality change in the optical system allows different regions to have different transmittance characteristics, smoothly connecting high-transmittance and low-transmittance areas to eliminate abrupt brightness changes
Solution Approach 2:
The third deflection part acts as an intermediary element between the first and second deflection parts. It mediates the transition of external light transmittance by having intermediate optical properties, thereby smoothing the brightness transition and reducing the harsh boundaries caused by direct transitions between high and low transmittance regions
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 reduces observer discomfort by gradually changing brightness across the viewing field, eliminating harsh boundaries and enhancing the viewing experience by maintaining consistent image quality and reducing unpleasantness.
Implementation Method 1
the first external light transmittance adjustment part has light absorbency or light reflectivity for the external light
Implementation Method 2
the first external light transmittance adjustment part has light absorbency or light reflectivity for the external light
Implementation Method 3
the first deflection part configured to deflect light emitted from the image generation part
Implementation Method 4
the second deflection part configured to further deflect light deflected by the first deflection part to guide the light to the position of the exit pupil while transmitting a portion of external light
Data Source
AI summary
A transmissive image display device includes an image generation part configured to emit a light, and a light-guiding optical system configured to guide the light. The light-guiding optical system includes a first deflection part configured to deflect the light, and a second deflection part configured to further deflect the light deflected by the first deflection part to guide the light to a position of the exit pupil while transmitting a portion of external light, a first external light transmittance adjustment part is provided outside an optical path of the light between the first deflection part and the second deflection part, and an average external light transmittance of the first external light transmittance adjustment part is higher than one of an average external light transmittance of the first deflection part and an average external light transmittance of the second deflection part lower than the other.