Surgery – Endoscope – With camera or solid state imager
Reexamination Certificate
1999-10-26
2001-11-13
Leubecker, John P. (Department: 3739)
Surgery
Endoscope
With camera or solid state imager
C600S131000, C600S110000, C600S132000, C600S182000
Reexamination Certificate
active
06315712
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. § 119 of French Patent Application No. 98/13708, filed on Oct. 27, 1998, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a video endoscopic probe with a distal color CCD sensor. The technical field of the invention is that of endoscopy devices.
The term “video endoscopy” designates an examination which allows one to obtain on a television monitor the image of a target situated inside of a dark cavity into which the distal end of a video endoscopic probe has been introduced.
2. Discussion of Background Information
Among the known devices pertaining to color video endoscopy, it is possible to distinguish two types of video endoscopes. The first type covers devices in which the image of the target observed inside of a cavity is transmitted by an endoscope or a fibroscope to a color CCD sensor situated outside of the cavity. This first type of video endoscope corresponds in particular to cameras are color CCD sensor equipped with a focussing objective and a mechanical connection device allowing the objective of said camera to be locked on the cup surrounding the eyepiece of an endoscope or fibroscope, this camera is connected by an umbilical cable to an external video processor which generates a video signal which signal can be viewed directly on a color monitor.
The second type of video endoscope covers devices in which the CCD sensor is housed directly in the distal end of the video endoscopic probe. The sensor is therefore introduced inside of the cavity in which the target to be examined is situated. Among the devices arising from this second type of embodiment, it is possible to distinguish two categories of video endoscopes with a distal CCD sensor capable of delivering color video images.
The first category covers devices in which the CCD sensor is a “monochromic” sensor (also called “black and white” sensor) which delivers an electrical signal containing only the luminance information. In this case, obtaining a video signal which can be viewed on a color monitor requires an illumination device which can sequentially deliver flashes corresponding to the three primary colors, a device for picking up the video signals generated sequentially by the monochromic distal CCD sensor during the flashes, and a processor which makes it possible to continually store the last three monochromic video frames in memory and to reconstitute a video signal which can be utilized directly on a color monitor from the three monochromic frames available in memory.
The second category of video endoscopes with distal CCD sensor covers devices in which the CCD sensor is a “trichromic sensor” (also called “color” sensor) which, in association with an illumination device which delivers a permanent and continuous white light, provides an electrical signal containing the luminance and chrominance information. This signal is transmitted to a processor which generates a video signal which can be directly viewed on a color monitor.
The difficulties in designing a video endoscope with a distal CCD sensor result essentially from the diversity of the applications requiring a range of probes whose useful lengths can range between 20 cm (for a dental probe) and 50 m (for a tubing inspection probe), and therefore from the need to adapt the characteristics of the video processor, as a function of the length of the electrical cable connecting the processor to the distal CCD sensor.
The joint functioning of a color CCD sensor, and of the video processor with which it is associated, in effect proceeds essentially from correct management of the phase shifts of the different high-speed clocks (14.2 MHZ in standard PAL) which are generated by the processor and described hereinafter.
“Pixel” clocks—This relates to clocks transmitted to the distal CCD sensor, in which they are used, on the one hand, for synchronizing the reading of the electrical voltages contained in the unit cells (called pixels) of the light-sensitive layer of the sensor and, on the other hand, for extracting from these unit voltages the significant information which, after integration, will constitute the electrical signal delivered by the CCD sensor and transmitted to the video processor.
“Sampling” clock—This relates to a clock used locally for synchronizing the sampling by the video processor of the electrical signal generated by the CCD sensor and transmitted to the processor. The proper functioning of the processor necessarily requires that the sampling clock be completely in phase with the incident electrical signal. Given the length of the electrical connections connecting the sensor to the video processor with which it is associated, misalignment of the color CCD sensor in the distal end of the video endoscopic probe introduces a redhibitory phase shift at the level of the processor between the sampling clock and the incident electrical signal. A phase shift results from the running total of the transmission delay to the CCD sensor of the pixel clocks generated by the video processor and the transmission delay to the video processor of the electrical signal generated by the CCD sensor. The method of remedying such a dysfunction consists of delaying either the sampling clock or the pixel clocks transmitted to the distal CCD sensor by the video processor, and in this way compensating for the overall phase shift mentioned above. The modalities of implementation of one or the other of these delay devices, and the connection problems proceeding from them, vary as a function of the integration mode of the video processor which can, depending on the architecture used, be external to the video endoscopic probe with distal CCD sensor or an integral part of the probe.
The video endoscopes arising from the first type of architecture utilize a case generally combining a light generator and a video processor. It is this case on which the connection device connected with the proximal end of the umbilical cable of the video endoscopic probes with distal CCD sensor is connected. The interchangeability of the different probe models which can be connected to the same processor obviously assumes a complete compatibility between the processor and the probes, and therefore integration in each probe of a specific delay device.
For example, the video endoscopic probes with distal monochromic CCD sensor described in U.S. Pat. No. 4,539,586 (Welch Allyn, September 1985) are equipped with a connection box allowing the probes to be connected on the case merging a generator of trichromic flashes and a video processor. This connection box contains two devices allowing adjustment of the characteristics of the two pixel clocks provided by the video processor and transmitted to the distal monochromic CCD sensor. An amplifier allows for adjustment of the level of the electrical signal generated by the distal monochromic CCD sensor, and transmitted to the video processor.
European Patent 0 218 226 B1 (Olympus, October 1986) describes a video processor which has a synchronization generator capable of delivering several sampling clock types corresponding to the number of endoscopic probe models having a distal CCD sensor, the connectors of the probes contain an electronic key which, when suitably decoded by the processor, allows the processor to select automatically the sampling clock suited to the connected probe.
U.S. Pat. No. 5,434,615 (Fuji Optical, July 1995) describes a video endoscopic probe with distal color CCD sensor having a control handle in which is housed the sampler, normally associated with the video processor, and an umbilical cable whose proximal end is equipped with a connection box in which the sampling clock generator is housed. The clock has a delay which is suited to the characteristics of the probe in consideration. The probe is connected to an external video processor which directly receives the electrical signal delivered by the sampler housed
Greenblum & Bernstein P.L.C.
Leubecker John P.
Tokendo ( Sarl)
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