Photostimulable Plate Reader Optical Filter

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Solution Overview

Problem

Current photostimulable plate reading devices are inefficient due to scattered red laser light interfering with the detection of blue light, leading to prolonged reading times and reduced efficiency.

Innovation Solution

A photostimulable plate reading device with a filtering means, such as a block of optical fibers and a thin multilayered filter, is used to prevent scattered red light from passing while allowing blue light to be detected, utilizing a two-dimensional array of pixels for improved image data collection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser beam is used to illuminate the phosphor layer, then the latent image can be stimulated to emit blue light, but scattered red light interferes with the detection of blue light by the PMT

Engineering Contradiction:
Improvedetection precisionVSAvoidlight interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

An interference filter is introduced as an intermediary component between the phosphor layer and the PMT. This filter selectively transmits blue light (wavelength range 380-480 nm) while blocking red light (wavelength range 600-680 nm), thereby mediating the interaction between the stimulated phosphor and the detector to eliminate harmful interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The interference filter is positioned specifically in the optical path between the phosphor layer and the PMT, creating a localized filtering zone. This allows the filter to affect only the relevant portion of the optical path where red light interference occurs, without affecting other parts of the system.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If an interference filter is used to block red light, then the PMT can detect blue light more accurately, but the reading time increases due to the need for sequential scanning

Engineering Contradiction:
Improvesignal discriminationVSAvoidreading time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the sequential mechanical scanning system with a parallel optical detection system. Instead of moving the laser beam or PMT step-by-step across the plate, the entire phosphor layer is illuminated simultaneously and the complete image is captured in one exposure, substituting mechanical motion with optical parallelism.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transitions from one-dimensional sequential scanning (moving the laser or detector along a line) to two-dimensional parallel detection (capturing the entire plate area simultaneously). This dimensional change allows all pixels to detect their respective positions at the same time, eliminating the time loss associated with sequential scanning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Loss of information

If the whole PSP is read by sequential scanning, then complete image data can be obtained, but the reading process takes several seconds

Engineering Contradiction:
Improveimage data completenessVSAvoidreading efficiency
Core Design Contradiction:
Loss of informationVSProductivity

Solution Approach 1:

The system implements two-dimensional parallel detection where the entire phosphor layer is illuminated and detected simultaneously across the plate surface. This converts the one-dimensional sequential scanning process into a two-dimensional parallel operation, capturing all image data points at once and dramatically improving reading efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The illumination and detection occur continuously across the entire plate surface in a single exposure event, rather than discontinuously scanning through different regions sequentially. This continuous action eliminates the time losses associated with step-by-step scanning and maintains productive detection throughout the entire reading process.

Inventive Principle:
Principle #20Continuity of useful action

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 significantly increases reading efficiency, reduces the time required to read a photostimulable plate, and facilitates the reading process by allowing substantially more blue light to pass through, enhancing image data capture.

Implementation Method 1

The laser beam illuminates a surface spot and stimulates the phosphor layer according to the well known photostimulated luminescence principle. Following this principle, a portion of incident red laser light is converted into stimulated blue light

Methodology Applied
Scientific EffectPhotostimulated luminescence: Photoluminescence

Implementation Method 2

the interference filter is used to filter red light out, with a rejection ratio of for example greater than 10exp-6

Methodology Applied
Scientific EffectOptical interference filtering: Interference

Data Source

PatentEP3168685B1A photostimulable plate reading device
Publication Date: 2018.10.31 CARESTREAM DENTAL TECH TOPCO LTD
  • EP3168685B1 patent drawingFigure 1~4
  • EP3168685B1 patent drawingFigure 5~6
  • EP3168685B1 patent drawingFigure 7~8

AI summary

A photostimulable plate reading device (10) including at least one photostimulable plate (12) carrying image data and having two opposite surfaces, an illuminator (20) for homogeneously illuminating a first one of the two opposite surfaces of the at least one photostimulable plate (12) with light emitted in a first wavelength range, the illumination causing the at least one photostimulable plate both to emit light in a second wavelength range by photostimulated luminescence and to scatter light in the first wavelength range; a filter (22) for preventing the light scattered in the first wavelength range from passing and for allowing the light emitted in the second wavelength range to pass, the filter facing a second one of the two opposite surfaces of the at least one photostimulable plate (12); and a detector (24) composed of a two dimensional array of pixels for detecting the light allowed to pass and for obtaining image data therefrom.