Photocopying – Projection printing and copying cameras – Focus or magnification control
Reexamination Certificate
2001-06-19
2003-03-11
Nguyen, Henry Hung (Department: 2851)
Photocopying
Projection printing and copying cameras
Focus or magnification control
C355S040000, C355S072000
Reexamination Certificate
active
06532058
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to scanners for the capturing of photographic image information from photographic media, especially scanners for the scanning of films, or to photographic printers for the projection of individual image originals (frames) contained in a photographic film onto photographic paper. In particular, the present invention relates to the control or adjustment of the focus of the projection of a photographic medium (for example a film, transparent foil with image, photographic paper with image) onto a detection element (for example a photoelectric converter such as, for example, CCD or for example a photochemical converter, such as, for example, photographic paper) in such a photographic scanning arrangement.
BACKGROUND ART
Focussing of the projection is normally carried out in conventional photographic scanning arrangements (scanners) or in conventional photographic copier apparatus (printers) by way of a test film or a test negative which is mounted in place of a film on a film stage and in a preselected reference position. An operator must thereby manually position the test film into the film transport arrangement or must manually position and fasten a test negative on the film stage. The focus of the test image produced with the test film or the test negative is then judged by an operator and the position of the lens adjusted until a satisfactory result is achieved.
SUMMARY OF THE INVENTION
It is now an object of the invention to provide a photographic scanning arrangement where the focus testing or focussing is simplified and reproducable.
This object is achieved with a photographic capturing device in accordance with the invention including a sample or pattern for controlling the focus of the projection and a positioning mechanism for selectively positioning the sample or pattern in a reference position for projection of the sample or pattern onto a detection means.
The capturing device in accordance with the invention can be constructed as a photographic scanner, whereby a photoelectric converter (CCD) is used as the detection means. It can also be constructed as a photographic copier (printer) whereby a photochemical converter (photographic paper) is used as the detection means.
The photographic capturing apparatus includes a light source, such as, for example, a halogen lamp or light emitting diodes. The light of the light source is preferably focussed and directed by way of light conducting elements (object lenses, lenses, mirrors, shutters, etc.) to a stage which serves for the positioning of a photographic medium to be exposed. The spectrum of the light can be changed, for example, by way of filters or by activating light emitting diodes of different color. The light transmitted by the photographic medium is preferably measured by projecting the photographic medium onto a detector, however, the reflected light can also be captured by way of a projection optics. The detection means is suited to detect the light modulated by transmission or reflection in order to so capture the image information stored on the photographic medium. As already mentioned, a CCD and photographic paper are suitable detection elements.
The photographic capturing device preferably includes an arrangement for testing the focus of the projection and especially for adjusting the focus of the projection. This arrangement in accordance with the invention includes a so called sample or pattern carrier with a sample or pattern and a positioning mechanism for moving the sample carrier into a desired reference position. The mechanism is constructed such that the sample carrier is positioned at the same reference position for each measurement process for testing the focus. It is especially preferred to position the sample carrier each time in the same object plane (plane in which the object to be exposed is located). This provides a significant advantage compared to the use of test negatives and test films. Conventional test films or test negatives can curve towards the illumination means or the detection means whereby they leave a preselected object plane. The curvature can vary in direction and extent with the surrounding temperature, the orientation of the test negative or the type of test film or test negative. The sample or pattern carrier with sample in accordance of the invention is preferably constructed to be so stiff that the sample does not curve. For example, the sample carrier is constructed as a rigid metal mesh, whereby the shape of the grid represents the sample. The sample carrier preferably has a non-flexible or non-elastic or rigid substrate which carries, forms or surrounds the sample and in this way prevents a curving of the sample. The sample or pattern which is used for the testing of the focus of the exposure is constructed with sufficient contrast that it can be recognized by the detection means at least upon focussed projection. It can be, for example, a grid, circles or other geometric shapes. The substrate which carries the sample is preferably transparent, while the sample itself is not transparent, or vice-versa, in order to achieve the strongest light/dark contrast in the plane of projection. The sample carrier is preferably positioned at the same reference position in which the photographic medium is positioned for the scanning in the conventional operation of the capturing device. The reference position is selected such that the sample is located in the preselected object plane.
In the following, the expression “sample carrier” is used as a synonymous for the expressions sample, pattern, pattern carrier and sample carrier.
The mechanism for the positioning of the sample carrier allows the selective movement of the sample carrier to the reference position or away therefrom. The sample carrier is thereby removed sufficiently far that it does not impede the exposure of a photographic medium or the detection means. In order to achieve a defined positioning of the sample carrier at a reference position, the mechanism preferably includes positioning means, such as, for example, tracks, pivot arms, rotors. Stop means such as, for example, notches or pawls, are preferably also provided. Step motors, especially in connection with a transmission (gears) can also be provided.
The mechanism especially preferably serves a double purpose, namely the positioning of the sample carrier and the positioning of a pressure mask for the pressing of a photographic medium (film) onto a stage (film stage) at the preselected reference position. The films to be captured conventionally rest in film guides along their edges which carry no image. The films are pressed by way of a pressure mask against these edges so that the film image (frame) lies as much as possible in a defined plane, which represents the object plane in the projection geometry. Since the mask is not needed or not necessarily needed when the focus of the exposure is tested by way of the sample carrier, the mechanism is preferably constructed such that it enables the exchange between a mask and the sample carrier. For example, the sample carrier can be on a sled together with one or more masks, whereby either the mask or the sample carrier can be brought into the reference position as desired. The exchange or the positioning of the sample carrier and especially also of the mask is preferably carried out automatically and is controlled by a control arrangement.
Preferably at least one mask is positioned together with the sample carrier on a carrier member, such as, for example, a sled, so that the at least one mask and the sample carrier have a fixed position relative to one another. The carrier member is preferably guided along a preselected path, for example, by way of tracks, or by way of a rotor supported on an axis. The path preferably extends transverse to the transport direction of the film. The positioning along the path can be monitored by way of sensors. If a photoelectric converter is used as the detection means, the detection result, ie. the position of the detection sample detected
Kobel Peter
Koch Willy
Lehmann Mathias
Rotach Hansjorg
Schaub Heiner
Gretag Imaging Trading AG
Nguyen Henry Hung
Weingarten Schurgin, Gagnebin & Lebovici LLP
LandOfFree
Photographic scanner with focus control does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photographic scanner with focus control, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photographic scanner with focus control will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3058201