Hybrid Viewfinder Light Shielding Plate Pupil Tracking
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Solution Overview
Problem
In optical/electronic hybrid viewfinders, the shielded region shifts significantly when the observer's pupil moves, causing the displayed image on the liquid crystal display unit to misalign with the optical image, leading to excessive protrusion or overlap.
Innovation Solution
A camera with a virtual finder using a concave lens as the objective lens and a convex lens as the eyepiece lens, equipped with a deflecting optical system, a movable light shielding plate, a position detection device, and a control system that adjusts the light shielding plate and display to maintain a constant shielded region regardless of pupil movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light shielding plate is inserted to block part of the emergent light from the objective lens, then the optical image and the displayed image can be viewed side by side simultaneously, but the shielded region shifts greatly when the pupil of the observer moves
Solution Approach 1:
The light shielding plate is made movable along the optical axis to dynamically adjust its position. A drive unit responds to detected pupil position changes by moving the light shielding plate forward or backward, maintaining the shielded region's stability despite pupil movement. This dynamic adjustment resolves the contradiction by allowing the system to adapt to varying observation conditions while preserving both simultaneous viewing capability and shielded region stability.
Solution Approach 2:
A pupil position detection device continuously monitors the observer's pupil position and provides feedback to the control system. Based on this feedback, the drive unit adjusts the light shielding plate's position to compensate for pupil movement. This feedback mechanism ensures that the shielded region remains stable and properly aligned with the displayed image, resolving the technical contradiction between ease of operation and manufacturing precision.
2Manufacturing precision
If the shielded region shifts when the pupil moves, then the displayed image misaligns with the optical image, but maintaining a fixed shielded region requires additional control mechanisms
Solution Approach 1:
A drive unit acts as an intermediary between the pupil position detection device and the light shielding plate. This intermediary component translates detection signals into precise mechanical adjustments of the light shielding plate, achieving accurate image alignment without requiring a overly complex control system. The drive unit serves as a simple yet effective mediator that resolves the contradiction between alignment accuracy and system complexity.
Solution Approach 2:
The system achieves automatic adjustment through the interaction of the pupil position detection device, drive unit, and movable light shielding plate. Once these components are in place, the system self-regulates to maintain proper alignment without requiring external intervention or complex control algorithms. This self-service approach maintains image alignment accuracy while minimizing device complexity.
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
Ensures that the shielded region remains constant, preventing misalignment and overlap of the displayed image with the optical image, allowing for simultaneous and accurate viewing of both images side by side.
Implementation Method 1
a deflecting optical system, provided between the object lens and the eyepiece lens, for introducing the portion of the image, which is being displayed on the display screen of the display unit, to the eyepiece lens
Implementation Method 2
a light shielding plate for blocking a portion of light emergent from the objective lens
Data Source
AI summary
An image of a subject formed optically by a objective lens (concave lens) and an eyepiece lens can be seen by a pupil. A light shielding plate is provided in front of part of the objective lens and a shielded region is formed by the light shielding plate. When the image of a subject is captured on a portion of the display screen of an electronic viewfinder, the image of the subject is reflected by a prism and can be seen superimposed upon the shielded region. If the pupil moves away from the optical axis of the virtual finder unit, the extent of the shielded region also shifts. In order to solve this problem, the light shielding plate is moved in accordance with the position of the pupil so that the extent of the shielded region is rendered constant despite movement of the pupil.