Active LED Illumination for Viewfinder Frame Contrast
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Solution Overview
Problem
Conventional mixed-image viewfinder cameras face issues with overexposure and reduced contrast of image field limitation frames due to ambient light variability, and superimposition of scattered light on the viewfinder beam path, leading to low-contrast and flat images.
Innovation Solution
A lighting arrangement is placed in the viewfinder beam path before the image field limitation frame, using active LEDs with a diffuser and an opaque tube to ensure uniform backlighting without stray light, allowing for high-contrast display and mechanical separation from the viewfinder beam path, with adjustable LEDs for color and brightness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ambient light is used to illuminate the image field limiting frame, then the illumination is simple and passive, but the contrast and visibility of the frame deteriorate under varying ambient light conditions
Solution Approach 1:
The patent replaces the passive optical illumination system (relying on ambient light) with an active electronic illumination system using LEDs. This substitution enables controlled, consistent illumination of the image field limiting frame regardless of ambient light conditions, directly resolving the contradiction between system simplicity and frame visibility.
Solution Approach 2:
The patent changes the illumination parameter from passive ambient light to active LED light with controllable intensity. The LED illumination can be adjusted to provide optimal contrast for the image field limiting frame, ensuring consistent visibility across different shooting conditions while maintaining system simplicity through electronic control.
2Volume of stationary object
If a mirror-based illumination system is used, then the structure is compact, but stray light is directed into the viewfinder beam path causing low contrast and washed-out images
Solution Approach 1:
The patent extracts and removes the mirror component from the illumination system. By eliminating the mirror that causes stray light reflection into the viewfinder beam path, the system achieves clean, high-contrast illumination without the harmful optical interference, while maintaining compact dimensions through direct LED placement.
Solution Approach 2:
The patent eliminates the source of stray light (mirror) rather than trying to manage it. By removing the reflective surface that creates harmful reflections, the system converts the potential problem of light management into a benefit of clean, direct illumination that enhances image contrast and clarity in the viewfinder.
3Adaptability or versatility
If field-limiting frames are made mechanically adjustable for different focal lengths, then adaptability is improved, but the mechanical effort and complexity increase considerably
Solution Approach 1:
The patent replaces mechanical field-limiting frames with electronically controllable light-emitting elements (LEDs). This substitution eliminates the need for mechanical adjustment mechanisms while providing adaptability through electronic control, allowing different field-limiting configurations without physical movement or complex mechanics.
Solution Approach 2:
The patent creates a universal illumination system where LEDs can serve multiple functions: illuminating the image field limiting frame, providing focus indicators, and adapting to different focal lengths through electronic control. This multi-functional approach replaces specialized mechanical components for each function, reducing overall system complexity while maintaining versatility.
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 solution provides a constant, high-contrast display of image field limitation frames across varying ambient light conditions, preventing stray light superimposition and ensuring clear visibility of image edges, even during focus adjustments, while allowing for customizable color and brightness settings.
Implementation Method 1
The illumination arrangement (1) uses an active light source, in particular LEDs (14),
Implementation Method 2
which is surrounded by a diffuser element (20)
Implementation Method 3
The viewfinder beam path (3) is mechanically separated from the light source (13, 14) within the illumination device (1). This prevents light from the active light source from reaching the viewfinder beam path
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The lighting arrangement (1) is arranged in the viewer beam path (3) in light direction in front of the image area zoning frame (2). The lighting is formed by an active light source. The viewer beam path is mechanically differentiated within the lighting device opposite to the light source. The viewer beam path is surrounded by an opaque tube. The viewer beam path is pivotable against the observation beam path of the mixed image viewer camera. The light source consists of multiple light emitting diodes (14') arranged around the tube.