Device for acquiring information contained in a phosphor layer
AssigneeAgfa-Gevaert HealthCare GmbH
InventorsMartin Lind, Ralph Thoma, Georg Reiser, Christian Schulz
Life of this patent
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Abstract
A device for acquiring information that is contained in a phosphor layer which includes a light source (2) for irradiating and exciting the phosphor layer (1) to produce emission light (4) containing the information, a detector (6) for acquiring the emission light (4) produced in the phosphor layer (1) and a filter device (8), which is arranged between the phosphor layer (1) and the detector (6) and/or between the phosphor layer (1) and the light source (2). To increase the reliability in the acquisition of the emission light (4), the filter device (8) includes at least two filter elements structured as absorption filters and joined to each other.
Claims30
In a device for acquiring latent image information contained in a phosphor layer, said device comprising:
- (a) a light source for irradiating the phosphor layer with excitation light that is suitable for exciting emission light in the phosphor layer, said emission light having a first wavelength range (W1) and said excitation light having a second wavelength range (W2);
- (b) a detector for detecting the emission light that has been excited in the phosphor layer;
- and
- (c) a filter device, arranged between at least one of the (1) phosphor layer and the detector and (2) the phosphor layer and the light source,
- the improvement wherein the filter device comprises at least three absorption filter elements, which are joined to one another, and wherein at least two of the filter elements that are joined to one another exhibit differing coefficients of thermal expansion, the filter elements that are joined to one another being arranged such that:
- (i) at least two filter element pairs are each obtained from two filter elements with differing thermal expansion coefficients, wherein at least one second filter element with a second thermal expansion coefficient is arranged between at least two first filter elements, each with a first thermal expansion coefficient;
- and
- (ii) bending forces, which occur at temperature changes in the individual filter element pairs, work against each other and tend to cancel each other out;
- and wherein the thicknesses of the first filter elements are all the same order of magnitude.
In a device for acquiring latent image information contained in a phosphor layer, said device comprising:
- (a) a light source for irradiating the phosphor layer with excitation light that is suitable for exciting emission light in the phosphor layer, said emission light having a first wavelength range (W1) and said excitation light having a second wavelength range (W2);
- (b) a detector for detecting the emission light that has been excited in the phosphor layer;
- and
- (c) a filter device, arranged between at least one of the (1) phosphor layer and the detector and (2) the phosphor layer and the light source,
- the improvement wherein the filter device comprises at least three absorption filter elements, which are joined to one another, and wherein at least two of the filter elements that are joined to one another exhibit differing coefficients of thermal expansion, the filter elements that are joined to one another being arranged such that:
- (i) at least two filter element pairs are each obtained from two filter elements with differing thermal expansion coefficients, wherein at least one second filter element with a second thermal expansion coefficient is arranged between at least two first filter elements, each with a first thermal expansion coefficient;
- and
- (ii) bending forces, which occur at temperature changes in the individual filter element pairs, work against each other and tend to cancel each other out;
- and wherein the thicknesses of the second filter elements are all the same order of magnitude.
In a device for acquiring latent image information contained in a phosphor layer, said device comprising:
- (a) a light source for irradiating the phosphor layer with excitation light that is suitable for exciting emission light in the phosphor layer, said emission light having a first wavelength range (W1) and said excitation light having a second wavelength range (W2);
- (b) a detector for detecting the emission light that has been excited in the phosphor layer;
- and
- (c) a filter device, arranged between at least one of the (1) phosphor layer and the detector and (2) the phosphor layer and the light source,
- the improvement wherein the filter device comprises at least two absorption filter elements, which are joined to one another;
- wherein the filter device is substantially transparent in a first wavelength range (W1) of the emission light and is substantially non-transparent in a second wavelength range (W2) of the excitation light;
- and wherein the filter device is substantially non-transparent in at least a third wavelength range (W3) that is located at longer wavelengths than the second wavelength range (W2) of the excitation light.
Dependencies are inferred from the claim text.