Rear-mounted Semi-transmitting Mirror Optical Path for Wide Visual Field
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Solution Overview
Problem
Existing image display devices, such as head-mounted displays, restrict the viewer's visual field due to the placement of optical systems, making it difficult to recognize outdoor scenes over a wide range.
Innovation Solution
The image display device positions the first deflection unit, formed by a semi-transmitting reflecting mirror, on the rear side of the viewer's head, with the optical axis forming an acute angle with the exit pupil, allowing the viewer to see outdoor scenes through both the first and second deflection units, which are designed to minimize obstruction and enhance the visual field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical systems are disposed on the sides of the head portion to enable image display, then image display function is achieved, but the visual field for viewing outdoor scenes is narrowed
Solution Approach 1:
The patent repositions optical components from a lateral arrangement (affecting the front visual field) to a rearward arrangement along the optical path. The image generating unit is disposed behind the first deflection unit, and the exit pupil is positioned behind the second deflection unit, allowing light to traverse forward through deflection units while components remain rearward. This dimensional reorganization separates the optical system from the visual field obstruction zone.
Solution Approach 2:
Instead of placing optical components in front of the viewer where they block the visual field, the patent inverts the arrangement by positioning the image generating unit and exit pupil behind the deflection units. This backward-facing configuration allows the optical path to extend forward through the deflection units while keeping bulky components rearward, non-obstructive to the viewer's forward vision.
2Adaptability or versatility
If multiple optical components are arranged to achieve image display, then display functionality is improved, but the device size and complexity increase
Solution Approach 1:
The patent combines multiple optical functions into an integrated optical path sequence. The first deflection unit and second deflection unit work together in series to guide light from the image generating unit through the exit pupil to the viewer's eye. This merged optical path, with components arranged sequentially along the light trajectory, reduces the need for separate, dispersed optical subsystems and simplifies the overall configuration.
3Adaptability or versatility
If optical components are positioned to enable image generation and display, then image display capability is achieved, but obstruction of outdoor scene viewing occurs
Solution Approach 1:
The patent extracts the bulky optical components (image generating unit and exit pupil) from the forward visual field zone and relocates them to the rearward zone. By separating the functional optical components from the visual field obstruction zone, the design allows uninterrupted viewing of outdoor scenes through the deflection units while maintaining full image display capability.
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 enables the viewer to recognize outdoor scenes over a wide range while maintaining a thin and unobstructed visual field, reducing the device's size and minimizing interference with the head, and correcting for image distortion.
Implementation Method 1
The first deflection unit is formed of a mirror. According to this configuration, it is possible to realize a thin image display device. The mirror is a semi-transmitting reflecting mirror which reflects a portion of incident light and transmits another portion of the incident light.
Implementation Method 2
The mirror is a semi-transmitting reflecting mirror which reflects a portion of incident light and transmits another portion of the incident light.
Data Source
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AI summary
A display device of the embodiment includes an image generating unit which emits a light including an image information, and a light guide optical system which generates an image from the light which is emitted from the image generating unit at a position of an exit pupil, in which the light guide optical system is provided with a first mirror (a first deflection unit) which deflects the light which is emitted from the image generating unit, and a second mirror (a second deflection unit) which further deflects the light which is deflected by the first mirror to guide the light to the position of the exit pupil and transmits a portion of external light, and in which an optical axis of the light which propagates from the first mirror toward the second mirror and an optical axis of the exit pupil form an acute angle.