Mammography Compression Plate Projection Layout to Prevent Vignetting
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Solution Overview
Problem
Existing mammography apparatuses suffer from vignetting issues due to the projection of images onto compression plates, which are blocked by the side plates of the compression plate, leading to reduced visibility of the projected information.
Innovation Solution
The apparatus employs a projection optical system with a mirror positioned in front of an imaginary intersection to redirect the projection light, ensuring that the light beam paths avoid the rear end wall of the compression plate, thereby preventing vignetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the projector projects the image onto the compression plate, then the imaging condition information can be displayed for reference, but the side plate blocks part of the effective luminous flux causing vignetting and deteriorating image visibility
Solution Approach 1:
The patent introduces a mirror to redirect the projection light path from a direct horizontal projection to a reflected path that goes above the compression plate and then down to the target area. This dimensional change in the light path allows the projection to avoid the blocking side plate while still achieving the desired image display on the compression plate surface.
Solution Approach 2:
The mirror serves as an intermediary element that mediates between the projector and the compression plate. Instead of the projector directly projecting onto the plate (which gets blocked), the mirror intercepts and redirects the light, acting as a mediator that enables the projection to bypass the obstructing side plate structure.
2Ease of operation
If the compression plate has a box shape with side plates to compress and fix the breast, then the breast positioning is improved, but the side plate blocks the projection light causing reduced visibility of the projected image
Solution Approach 1:
By changing the dimensionality of the light path through mirror reflection, the system maintains the box-shaped compression plate structure for proper breast positioning while redirecting light through a different spatial route that avoids the blocking side plate, thereby preserving both the mechanical function and the optical function.
Solution Approach 2:
The mirror acts as an intermediary that allows the box-shaped compression plate to simultaneously fulfill its mechanical compression function and serve as a projection surface without the side plate interfering with the light path, thus maintaining both structural integrity and optical visibility.
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 maintains the visibility of projected imaging condition information on the compression plate by preventing light from being blocked by the rear end wall, ensuring clear and decipherable imaging.
Implementation Method 1
a mirror which reflects light incident from the projector to the imaging table; the optical element closest to the compression plate in the projection optical system is the mirror
Data Source
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AI summary
A mammography apparatus includes an imaging table (24); a radiation source (25); a stand (20); the compression plate (30) including a bottom plate that compresses the breast and side plates provided on at least two locations of a subject side and a stand side of the bottom plate; and a projector (14) that projects an image toward the compression plate and the imaging table, in which in a case where an intersection between an imaginary plane formed by extending the inner wall surface toward the projector and an imaginary horizontal line crossing the projector in a horizontal direction is defined as an imaginary intersection, an optical element closest to the compression plate on an optical path directed from the projector to the compression plate is located on the subject side with respect to the imaginary intersection.