Patent Application
20080058602
Referring first to
Endoscopic device 12 includes a distal end 14 which during use is typically inserted into an orifice or body cavity and is directed at tissue 16 to inspect the tissue 16. As is known, there is typically very little light within the orifice or body cavity, such that illumination light 18 is required to be provided in order to illuminate tissue 16 for viewing. Typically, this illumination light 18 is provided by a high intensity light source 20 and passed to the distal end 14 of endoscopic device 12 through a light guide 22 that passes through the endoscopic device 12 to the distal end 14.
The light guide 22 may take the form of, for example, a fiber optic bundle coupled to a light cable 24 supplied light energy from light source 20 by way of an optical coupler 26 or the like. Of course, light guide 22 may take other forms.
Light source 20 may comprise any of numerous types of known or yet to be developed light sources. One type of known light source is a high intensity light source that utilizes an incandescent bulb (such as a xenon bulb, or other type), driven by an amplifier, which in turn is controlled by output control circuitry, to set the light intensity level of the light source. Of course, other types of light source intensity output control are known within the art, such as mechanical diaphragm or iris, liquid crystal shutter, rotary reed or slot devices, and the like. These various types of light source output controls may be utilized within the system of the present invention. All that is required is that the light source 20 for use in accordance with the present invention have a controller 28 that is capable of automatically controlling an intensity of illumination light 18 transmitted to light guide 22 of endoscopic device 12 in response to input signals (as described in more detail below).
Endoscopic device 12 includes at least one, but preferably a plurality of, temperature sensors 30 associated therewith sensing a temperature of at least a portion of endoscopic device 12 and producing a signal indicative of the sensed temperature. Preferably, temperature sensors 30 are disposed within endoscopic device, but if desired, they may be carried on an external surface thereof. It is also preferable that temperature sensors 30 be spaced apart at various locations along endoscopic device 12 so as to provide temperature readings at various locations thereof to ensure that the desired maximum temperature is not exceeded locally at any location thereof.
The signals indicative of the sensed temperature produced by temperature sensors 30 are transmitted to light source controller 28, which varies the intensity of illumination light 18 transmitted to light guide 22 based at least in part upon the signal indicative of the sensed temperature. More specifically, light source controller 28 varies the intensity of illumination light 18 transmitted to light guide 22 so as to maintain the sensed temperature below a threshold value. As discussed above, the threshold value is in some circumstances 50° C., but some other threshold value may be appropriate or dictated by appropriate standards.
Any of numerous algorithms may be employed by light source controller 28 to vary the intensity of illumination light 18 based at least in part upon the signal indicative of the sensed temperature. One simple algorithm employed may be to reduce the intensity of illumination light 18 transmitted to light guide 22 if the temperature sensed by any of temperature sensors 30 is above the threshold value (e.g., 50° C.), and then to increase the intensity of illumination light 18 again if the temperature sensed by all of temperature sensors 30 falls below another value (e.g., the threshold value minus 3° C., or 47° C.). Of course, one skilled in the art could easily and routinely program light source controller 28 with other control algorithms.
As discussed above in greater detail, known temperature sensors, such as thermocouples, suffer from a number of disadvantages which typically make them unsuitable for use in connection with endoscopic system 10 in accordance with the present invention. Referring now to
Each sensor 30 includes an optical fiber 32 having a proximal end 34, which is supplied with light energy, and a distal end 36. The light energy supplied to proximal end 34 may be supplied by light source 20, through, for example, optical coupler 26, or may be supplied by some other source. It should be understood that optical fiber 32 may comprise a single strand or a plurality of strands.
Each sensor 30 also includes a member 38 having a first end 40 disposed adjacent distal end 36 of optical fiber 32 and a second end 42 opposite the first end 40. Member 38 comprises a material with optical absorption/transmission properties that vary in a known relationship with respect to a temperature thereof. For example, member 38 may be formed from a material that allows different frequencies of light energy to pass therethrough at different temperatures thereof, different amounts of light energy to pass therethrough at different temperatures thereof, etc. The particular optical properties that vary with temperature are not important, so long as the relationship between the variance of the optical properties and temperature is known. One example of a material from which member 38 may be formed is boresilicate glass doped with neodymium, which material allows varying frequencies of light energy to pass therethrough at varying temperatures, the particular relationship therebetween having been well-documented.
A reflective surface 44 is disposed adjacent second end 42 of member 38, which acts to reflect a significant portion, and preferably substantially all, light energy striking reflective surface 44. Reflective surface 44 may comprise a mirror or any of numerous other reflective elements/materials known or later developed. Reflective surface 44 may comprise a separate element attached to second end 42 of member 38, may be painted, metallized, or otherwise applied directly onto second end 42 of member 38, may be positioned adjacent second end 42 of member 38, etc.
The light energy supplied to the proximal end 34 of optical fiber 32 (indicated by A), propagates to distal end 36 of optical fiber 32 (indicated by B), passes through member 38 from first end 40 to second end 42 thereof (indicated by C), is reflected by reflective surface 44, passes through member 38 from second end 42 to first end 40 thereof (indicated by D), enters distal end 36 of optical fiber 32 (indicated by E), propagates to proximal end 34 of optical fiber 32 (indicated by F), and exits proximal end 34 of optical fiber 32 (indicated by G). As indicated by the difference in size between arrows A, B representing the light energy before passing through member 38 and arrows E, F, G representing the light energy after passing through member 38, the light energy is altered by the optical properties of member 38 as it passes therethrough, and in a manner that is dependent upon the temperature of member 38, as discussed above.
The properties of the light energy exiting proximal end 34 of optical fiber 32 (indicated by G) is analyzed using a light energy analyzer 46, which generates a signal indicative of such properties. In the illustrated embodiment, light energy analyzer 46 comprises a spectrophotometer. Thus, in the case where member 38 is formed from a material which allows varying frequencies of light energy to pass therethrough at varying temperatures, the spectrophotometer could be used to measure the frequencies of the light energy exiting proximal end 34 of optical fiber 32 (indicated by G) and to generate a signal indicative of these frequencies.
A temperature analyzer 48 receives the signal indicative of the properties of the light energy exiting proximal end 34 of optical fiber 32 (indicated by G) generated by light energy analyzer 46, and determines the temperature of member 38 based at least in part upon the this signal, and based at least in part upon the known relationship between the optical absorption/transmission properties of member 38 and the temperature of member 38. Thus, temperature analyzer 48 has stored thereon, or otherwise has access to, data indicative of the known relationship between the variance of the optical properties and temperature for the material from which member 38 is made.
A temperature display 50 may optionally (indicated by dashed lines) be provided for displaying the sensed temperature of member 38. When multiple members 38 are provided, temperature display 50 may display all of the sensed temperatures, or may display only some of the sensed temperatures (e.g., the highest temperature).
Although light energy analyzer 46, temperature analyzer 48, temperature display 50 and controller 28 of light source 20 are shown as separate elements in
The present invention, therefore, provides an endoscopic system which provides enhanced safety and reduces the likelihood of patient burns, which ensures that the temperature of an endoscopic device does not exceed a threshold temperature, which automatically controls the intensity of an illumination light based upon a sensed temperature of some portion of the endoscopic device, which employs temperature sensors that can fit within the available volume within typical endoscopic devices, which employs temperature sensors that do not create voltage, and therefore do not compromise patient safety, and which employs temperature sensors that do not require a mechanical wire connection, so that the endoscopic device may be readily autoclaved.
Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.
