US3796916A
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-ray image viewer
Assignee: Agfa Gevaert NV
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Filing: 1971-01-12
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Granted: 1974-03-12
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Expires: 1991-01-12
Abstract
Abstract An X-ray viewer for coloured radiographic images. The apparatus comprises two groups of light sources with different colour temperature. The current through the groups can be progressively varied so as to increase or decrease the amount of irradiating light which lies in part of the visible spectrum which is complementary to the predominating wavelength in the image colour. The variation in the spectral composition causes no substantial change in the illumination of the image.
Inventors
- 👤 Belder M De
- 👤 R Bollen
- 👤 L Natens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:55
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/02; G02B27/022; G02B27/024
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
194 words
Light projecting apparatus for projecting light through a transparent image having a color predominantly within a given region of the visible spectrum and composed at least in part of juxtaposed image areas in which said color varies in color density, said apparatus comprising: a. two groups of electro-luminescent tubes, one group emitting light in a first spectral region containing the predominant color region of said image and the other group emitting light in a second spectral region substantially complementary to said predominant color region of said image, b. a diffusing screen for mixing the light emitted by said two groups of tubes to illuminate the said transparent image substantially uniformly, c. means for progressively varying the electric currents through the respective two groups of tubes in inverse proportion to one another to thus progressively vary the spectral composition of said illuminating light between said first and said second spectral region, and d. means for controlling the overall intensity of the emitted light to keep the intensity of illumination of the transparent image substantially constant independently of the variation of the spectral composition of the illuminating light between said first and said second spectral region.
Claim 2
Dependent Claim
194 words
Light projecting apparatus for projecting light through a transparent image having a color predominantly within a given region of the visible spectrum and composed at least in part of juxtaposed image areas in which said color varies in color density, said apparatus comprising: a. two groups of electro-luminescent tubes, one group emitting light in a first spectral region containing the predominant color region of said image and the other group emitting light in a second spectral region substantially complementary to said predominant color region of said image, b. a diffusing screen for mixing the light emitted by said two groups of tubes to illuminate the said transparent image substantially uniformly, c. means for progressively varying the electric currents through the respective two groups of tubes in inverse proportion to one another to thus progressively vary the spectral composition of said illuminating light between said first and said second spectral region, and d. means for controlling the overall intensity of the emitted light to keep the intensity of illumination of the transparent image substantially constant independently of the variation of the spectral composition of the illuminating light between said first and said second spectral region.
Claim 3
Dependent Claim
45 words
Light projecting apparatus according to claim 1 comprising at least one photoelectric cell for measuring the intensity of the emitted light and for controlling the current through at least one group of electro-luminescent tubes to keep the overall intensity of the emitted light substantially constant.
Claim 4
Dependent Claim
57 words
Light projecting apparatus according to claim 2 comprising a control amplifier with differential inputs, one input receiving an electric signal corresponding with the setting of said means for progressively varying the electric current through the two groups of tubes, and the other input receiving an electric signal corresponding to a predetermined level of overall intensity of illumination.
Claim 5
Dependent Claim
90 words
Light projecting apparatus according to claim 3 comprising an electric circuit for producing an electric signal having a saw-tooth pattern, and means for comparing said saw-tooth signal with the output signal of said controlling amplifier, the electric signal resulting from said comparison controlling an amplifier stage which produces a pulse width modulated output signal for controlling the current through said electro-luminescent tubes, the frequency of said output signal corresponding with the frequency of said sawtooth signal, and the pulse width of said output signal depending on said electric comparison signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |