Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2001-10-24
2004-05-04
Peffley, Michael (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C362S555000, C362S574000, C600S182000
Reexamination Certificate
active
06730019
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an endoscope, comprising a shaft, an imaging system arranged in the shaft, and an illuminating system which allows light emitted by a light source to emerge at the distal end of the shaft, wherein the light source comprises at least one light emitting diode.
Such an endoscope is known from the German utility model 299 22 755.
Endoscopes are used both in the technical field and in the medical field.
Examples of application of a technical endoscope are the inspection of difficultly accessible cavities in machines, motors, turbines, reaction spaces etc. which are, thus, not observable with the naked eye.
In medical endoscopy, endoscopes are used in minimal-invasive surgery, if necessary, in combination with surgical instruments for purposes of examination or for operations with visual control or for application of diagnostic or therapeutic light.
A first component of such endoscopes is the imaging system. The imaging system serves for receiving observation light from the observation space or the operation space, respectively, and for transmitting image information from distally to proximally.
The imaging system may, conventionally, consist in an optical image transmission system which comprises an objective in the distal end of the shaft, a lens system proximally adjoining to same, e.g. in the form of rod lenses, or an ordered fiber bundle and a proximal eyepiece, by which it is possible to observe with the eye, or onto which a camera can be connected.
The imaging system may, however, in the distal end of the shaft, also comprise a camera module with an imaging optic and an imager chip, e.g. in the form of a CCD-chip which transforms the light signals into electric signals which are transmitted to proximal via electric lines and which are visually presented, as a real image, on an image reproduction unit outside the endoscope.
A second component of such endoscopes the present invention refers to is the illuminating system. The illuminating system serves for transmitting light from proximally to distally in order to illuminate the observation space or the examination space, respectively, with light. For a bright illumination, white light is usually used, whereas for other applications, e.g. examinations with excitation light, colored light is also used.
For endoscopes used at present, the illuminating system comprises an external light source, commonly on the basis of a xenon or halogen lamp. The endoscope is then connected with the external light source via a light conducting cable.
Apart from that such xenon or halogen light sources are very cost-intensive apparatus, another disadvantage of such common endoscopes is that the connection of the endoscope with the light source via a light conducting cable is disturbing during the use of the endoscope. Due to the long transmission path from the light source to the distal tip of the endoscope that can be 2 through 3 m, besides, losses in the light intensity of the light emerging from the distal end of the endoscope may occur which have to be balanced by a suitably luminous light source with a corresponding cost effort.
The endoscope known from the utility model mentioned above does not operate with an external light source by integrating at least one light emitting diode (LED) in the endoscope. As light emitting diodes are, in the meanwhile, available with a high light intensity, the observation space or the examination space can be illuminated sufficiently brightly with a light emitting diode as light source. Thus, an external cost-intensive light source can be saved. In addition, light emitting diodes have the advantage in the case of the application of colored light, that the color quality of the light of an LED is better than if a white light source with a color filter is used. Moreover, the light conducting cable which would be disturbing during the applications of the endoscope between the external light source and the endoscope becomes superfluous, whereby, on the one hand, further costs are saved, and, on the other hand, the handling of the endoscope is improved.
Light emitting diodes would be generally suitable for the application in endoscopy due to their structural shape and their efficiency, both for a continuous and for a pulsed illumination. The disadvantage of light emitting diodes, however, is that the power density of the light emitted by light emitting diodes is not very high and that light emitting diodes that are stronger in power radiate in a relatively narrow-band. For example, diodes exist that are stronger in power and that radiate in a narrow band particularly in the red and infrared region. In comparison to that, there are requirements in the endoscopy that always faithfully colored images and no “one color” (e.g. red) or black-and-white images, respectively, are required.
It is therefore the object of the present invention to improve an endoscope of the type mentioned at the outset such that as faithfully colored images as possible can be observed through the endoscope.
SUMMARY OF THE INVENTION
According to the invention, this object is achieved by an endoscope, comprising:
a shaft having a distal end and a proximal end;
an imaging system arranged in said shaft;
a light source;
an illuminating system allowing light emitted by said light source to emerge at said distal end of said shaft,
wherein said light source comprises at least two light emitting diodes which emit light in different spectral ranges, and wherein said light of said at least two light emitting diodes emerges spectrally additively mixed from said illuminating system.
By means of the additive color mixture of the light of at least two light emitting diodes provided according to the invention, an endoscopic image as faithful as possible with respect to the colors of the image is achieved because it is possible due to the invention to mix the light of two spectrally narrow band light emitting diodes such that it results in white light by an additive mixture of colors. If the examination space or the observation space, respectively, is illuminated with white light, a faithful endoscopic image with respect to the colors of the image can be achieved. This measure allows it, in particular, to use high power light emitting diodes, wherein their naturally spectral narrow-bandness (“monochromatic”) by the additive mixture of light emitted by the LED's can be balanced in order to achieve a faithful endoscopic image with respect to the colors of the image. Furthermore, the effect is used that the light intensities of the at least two LED's are added to a high light intensity.
To this end, it is particularly preferred if the at least two light emitting diodes emit light in spectral regions that are spectrally complementary to each other.
By this measure, due to the additive color mixture of the light emitted by the at least two light emitting diodes, exact white light of high light intensity is generated. For example, a light emitting diode having a maximal radiation power in the frequency range of the spectral color blue together with a light emitting diode having a maximal radiation power in the spectral range of the color orange, or, for instance, a light emitting diode radiating in the red spectral range can be used together with a light emitting diode radiating in the green spectral range.
In another preferred embodiment, the light source comprises at least three light emitting diodes which emit light preferably in the blue, green, and red spectral region.
Such a light emitting diode arrangement comprising at least three light emitting diodes in the blue, green, and red spectral range does not only offer advantageously the possibility of generating white light that is even stronger in intensity, but also offers the possibility of a modulation in color and/or intensity with corresponding well-aimed drive of the three individual light emitting diodes and a corresponding mixture of the light emitted by the individual light emitting diodes.
In another preferred embodiment, the at least two
Karl Storz GmbH & Co. KG
Peffley Michael
St. Onge Steward Johnston & Reens LLC
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