JP2006087764A - Led fiber light source device and endoscope using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the mechanical movement of a sub-lamp by putting the sub-lamp in alignment with a main lamp so that the light can be concentrated on the same light path as a backup configuration and to develop a method for collimating a plurality of LEDs (light emitting diodes) each having a different wavelength in order to raise the brightness and change the light source wavelength. <P>SOLUTION: The subject device is provided with a plurality of fixed LEDs, a collimation means which includes a collimating lens or a reflecting mirror for collimating each outputted light from the LEDs, an optical focusing means which includes a condensing lens or a condensing mirror for focusing the outputted light from the collimating means, and an optical fiber with one end disposed near the focal point of the optical focusing means, and a main lamp consisting of some LEDs for regular use among the plurality of LEDs, and a sub-lamp consisting of the other LEDs that can be substituted for the main lamp. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is an LED fiber light source device for industrial or medical use and an endoscope using the same. Used as a medical endoscope illumination light source having a main lamp and a sub lamp.

  Medical endoscopes illuminate the inside of the body with white light (illumination optical system) and obtain an in-vivo image with a CCD camera or the like. The illumination optical system is a high-intensity lamp such as a xenon lamp, a condensing lens (including a reflection mirror) that condenses the lamp output, a light guide composed of an optical fiber that guides the collected light into the body, and a light It consists of an illumination lens for irradiating the body with the output from the guide.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a method that enables the examination of the endoscopic examination to be continued by turning on the sub lamp even when power is not supplied from a commercial power source due to a power failure or the like. Although not shown, the main lamp is a xenon lamp or a halogen lamp. The sub lamp is an LED, and the sub lamp is retracted from the optical path of the main lamp, and is configured to be used by moving the sub lamp onto the optical path of the main lamp during a power failure.

  As described above, high-intensity lamps used in illumination optical systems also propose illumination optical systems that use LEDs in accordance with the development status of high-power LEDs due to problems such as heat generation, large power consumption, and large shapes. It is being done.

  Patent Document 2 proposes an endoscope illumination light source using a plurality of LEDs. There has been proposed an assembling method in which a plurality of LEDs are arranged and light emitted from the LEDs is introduced into an optical glass fiber using a reflecting mirror. As described above, attempts have been made to increase the output by using a plurality of LEDs, but it is considered that the light collection efficiency is very bad, and no measures are taken against power failure.

  FIG. 8 shows an endoscope light source device using three-color LEDs disclosed in Patent Document 3.

  If you prepare three (31R, 31G, 31B) optical fibers corresponding to each of the three colors R (red) 30R, G (green) 30G, and B (blue) 30B as the LED light emitting unit, It can be used for an endoscope apparatus. A field sequential endoscope is an apparatus that switches R, G, and B illumination light, sequentially irradiates the subject, images and observes the subject, and provides a high-quality image.

  For example, when a purple or blue light is applied, normal tissue emits fluorescence, but a cancerous portion is difficult to emit fluorescence and is difficult to see in the dark. Cancer can be found by comparing an image obtained by applying blue light with an image obtained by combining images obtained by applying three colors (corresponding to an image obtained by white light).

Further, according to Non-Patent Document 1, Narrow Band Imaging (NBI) of an endoscope is discussed, and the light source wavelength dependency of endoscopy is described. An endoscope is a skin inspection of a part to be measured, and it is important to have means that can change the wavelength of the light source in order to facilitate the skin inspection.
JP 2002-72106 A Japanese Patent Laid-Open No. 2003-23596 Japanese Patent No. 3088165 “Current Status and Future Prospects of Biomedical Optical Research” p43-51, Optoelectronic Industry and Technology Promotion Association, March 2004

  A light source for an endoscope is required to have a backup configuration in which a sub lamp is lit even when a main lamp is not lit, or a high-intensity light source and a light source wavelength that can be changed.

  The conventional backup configuration is complicated because the sub lamp is moved mechanically. Although LEDs are advantageous for miniaturization, in the current LED output, a plurality of LEDs are used to increase the luminance. In Patent Document 2 of a light source device using a conventional LED, the output of a plurality of LEDs is not collimated, and a large light source of the entire LED is condensed, so the light collection efficiency is very poor. In Patent Document 3, R (red), G (green), and B (blue) LEDs are prepared to change the light source wavelength. However, since three optical fibers are prepared, the insertion portion is thick. turn into.

  In order to solve the above-described requirements, it is an object to develop a structure that eliminates mechanical movement of a sub lamp by first laying out a main lamp and a sub lamp so as to collect light on the same optical path as a backup configuration.

  Next, it is an object to develop a method of bundling a plurality of LEDs having different wavelengths in order to change the light source wavelength with high brightness.

  The present invention has been made to solve these problems, and includes a plurality of fixed LEDs, a collimating means comprising a collimating lens or a reflecting mirror for collimating each output light from the LEDs, and an output from the collimating means. A condensing lens or a condensing means for condensing light, one end of an optical fiber is arranged near the focal point of the condensing means, and a part of the plurality of LEDs that are always used It has the main lamp which consists of LED, and the sub lamp which consists of other LED which can be switched and used for the said main lamp.

  Further, the apparatus has means for detecting a malfunction of the main lamp, and means for automatically switching to lighting of the sub lamp according to the malfunction.

  Moreover, it has a light guide means via an optical fiber between the plurality of LEDs and the collimator means.

  The main lamp and the sub lamp include a red LED and a white LED that excites a yellow phosphor with a blue LED.

  In addition, the main lamp and the sub lamp include three or more colors among red LED, blue LED, green LED, orange LED, and cyan LED.

  In addition, a wavelength combining mirror for combining the output lights from the plurality of LEDs is disposed between the collimating unit and the condensing unit.

  Further, the LED fiber light source device is used as a light source.

  According to the present invention, there is no moving part when switching between the main lamp and the sub lamp, and the light source device for endoscope can be reduced in size and improved in reliability.

  A high-luminance endoscope in which the wavelength of the light source can be changed by bundling red LEDs and LEDs mainly containing blue or LEDs of several colors with a condensing lens or a wavelength synthesis mirror. A light source device can be provided.

  FIG. 1 is a block diagram showing a first embodiment of the present invention.

  FIG. 1A is an overall configuration diagram, and FIG. 1B shows the layout of LEDs 1a and 1b in detail.

  First, according to the present invention, a plurality of fixed LEDs, a collimating means including a collimating lens or a reflecting mirror for collimating each output light from the LED, a condenser lens for collecting the output light from the collimating means, or a collecting lens. A main lamp formed of a part of the plurality of LEDs that is always used, and one end of an optical fiber disposed near the focal point of the light collecting means. And a sub lamp made of other LEDs that can be used by switching.

  Furthermore, it is preferable to have light guide means via an optical fiber between the plurality of LEDs and the collimating means.

  Since the LED 1a is used as the main lamp and the LED 1b is used as the sub lamp, and the LED of FIG. 1 (a) represents the cross-sectional view of FIG. 1 (b), only two LEDs are shown.

  1A includes LEDs 1a and 1b, a collimator lens 2, a condenser lens 3, an optical fiber 4, an LED driver 5, an LED abnormality detection circuit 6, and optical fibers 7a and 7b.

  The LEDs 1a and 1b emit white light and become light close to parallel light by the collimator lens 2 via the optical fibers 7a and 7b, respectively, and are collected by the condenser lens 3 and guided to one end of the optical fiber 4 and output to the optical fiber 4 White light is output from the side.

The LED used here requires a heat sink or the like for its heat generation countermeasure, and assumes an outer diameter of 10 mm or more. When the outer diameter of the LED is large, the output light of the LEDs 1a and 1b is collected by the optical fibers 7a and 7b, and the fibers 7a and 7b are placed close to each other and placed in the collimator lens 2, thereby reducing the light beam in the condenser lens It is preferable that the present invention has means for detecting a malfunction of the main lamp and means for automatically switching to lighting of the sub lamp according to the malfunction.

  The LED driver 5 is supplied with a commercial power supply (not shown) and turns on the LED 1a as a normal main lamp. However, when the LED abnormality detection circuit 6 detects a failure of the LED 1a, the LED 1b as a sub lamp is turned on and the LED 1a is turned on. Turn off the light.

  In addition, with this configuration, it is possible to switch between the main lamp and the sub lamp without mechanical operation.

  Although detailed explanation of the LED abnormality detection circuit 6 is omitted, it can be determined from the luminance signal of the CCD camera built in the endoscope, or a circuit for monitoring a part of the light amount of the LED 1 can be added. Is possible.

  In the above embodiment, the collimator lens 2 is used as the collimator means, but it is also possible to increase the light collection degree by adding a parabolic reflecting mirror.

  In the present invention, the main lamp and the sub lamp preferably include a red LED and a white LED that excites a yellow phosphor with a blue LED.

  In the present invention, it is preferable that the main lamp and the sub lamp include three or more colors among red LED, blue LED, green LED, orange LED, and cyan LED.

  In the above embodiment, the LED uses a white LED. However, the number of LEDs is increased, a combination of a plurality of colors, for example, a red LED and a white LED that excites a yellow phosphor with a blue LED, a red LED, and a green LED. Since LEDs and blue LEDs can be used and the lighting of red, green and blue LEDs can be sequentially switched and used as a surface-sequential type endoscope light source, the application is advantageous depending on the application.

  In this way, the main lamp and the sub lamp are guided by the optical fiber 7 and are condensed on one end of the optical fiber 4 by the condensing lens 3, so that the LED 1 light is easily collected on the optical fiber 4, When the main lamp 1a breaks down, there is no moving part for switching to the sub lamp 1b, and there is an effect of downsizing the device and improving reliability.

  In addition, the output of a plurality of LEDs can be bundled, the output (brightness) of the light source device can be increased, the wavelength of the light source can be changed by selecting the LED to be turned on, and a surface sequential light source having no moving parts can be provided. effective.

  FIG. 2 is a block diagram showing the second embodiment.

  In the present invention, it is preferable that a wavelength combining mirror for combining the output lights from the plurality of LEDs is disposed between the collimating unit and the condensing unit.

  The LEDs 10a and 10b, collimator lenses 11a and 11b, a wavelength combining mirror 12, and an optical fiber 4 are included. LED10a and LED10b arrange | position two LED of the same wavelength (color) next to each other. One of them is used as a main lamp and the other as a sub lamp. However, it is assumed that the LEDs used here are small in size and can be arranged side by side.

  The wavelengths of the LED 10a and the LED 10b are different. The wavelength combining mirror 12a has a wavelength characteristic that transmits the wavelength of the LED 10a and reflects the wavelength of the LED 10b.

  The light output from the LEDs 10a and 10b becomes substantially parallel light by the collimator lenses 11a and 11b, and is combined by the wavelength combining mirror 12a and condensed on one end surface of the optical fiber 4 through the condenser lens 10a and output from the output end. The

  FIG. 3 is a block diagram showing a third embodiment of the present invention.

  FIG. 3 is an extension of the configuration of FIG. 2, and an LED 10c and a wavelength combining mirror 12b having different wavelengths are further added. The wavelength multiplexing mirror 12b has a wavelength characteristic that reflects the wavelength of the LED 10c and transmits the wavelengths of the LEDs 10a and 10b. By comprising in this way, the wavelength of LED10a, 10b, 10c can be synthesize | combined and it can be made to radiate | emit from the output end of an optical fiber.

  The LEDs 10 can be turned on at the same time, but a necessary illumination wavelength can be obtained by turning on an arbitrary LED.

  However, the reason why the optical fiber 7 in FIG. 1 is not used in FIGS. 2 and 3 is that the size of the LED 10 is small (about 2 mm), and therefore it is not necessary to use the optical fiber 7.

  With this configuration, the outputs of a plurality of LEDs can be bundled, and the output (luminance) of the light source device can be increased.

  Furthermore, since the wavelength of the light source can be changed by selecting the LED to be lit, a high-intensity light source can be provided as the light source for the endoscope, and the illumination wavelength can be easily changed, and there is no moving part and high reliability. There is an effect that it is possible to provide the endoscope sequential light source for frame sequential type or the above-described narrowband imaging light source.

  An example will be described based on the embodiment of FIG.

  FIG. 4 shows the emission spectrum waveform of the white LED used.

  The LED 1 is a blue LED coated with a yellow phosphor and outputs white light. The output of one LED is a 120 lumen high luminous flux LED, but the output beam divergence angle from LED 1 is omnidirectional (120 degrees or more). Here, the optical fiber 7 is a plaque fiber (POF) having an outer diameter of 2 mm, and is disposed directly on the end face of the LED 1 and led to the collimator lens 2.

  The LED 1 is a bullet type, and a heat sink (φ20 mm) is attached to the bullet type lens portion (φ5 mm). For this reason, the LEDs are arranged at intervals of 20 mm.

  The collimator lens 2 and the condenser lens 3 also use plano-convex lenses.

  The optical fiber 4 is a multi-component glass bundle fiber for a light guide having a diameter of 2 mm and has a length of 3 m. Accordingly, this optical system is a lens system having a light source size of 4 mm in which two fibers 7 having a diameter of 2 mm are bundled, and the image side is a 2 mm size of the fiber 4 and a lens system having a magnification of 0.5.

  When the optical fiber 7 is not used as a comparative example, the light source size is 20 mm, the lens system magnification is 0.1, the magnification difference is 5 times, and the amount of light that can be condensed on the end face of the fiber 4 is 1/25 (fiber 7 If there is no loss of

  That is, since it is equivalent to arranging the LEDs 1a and 1b close to the optical fiber 7, the size of the collimator lens 2 and the condenser lens 3 can be reduced, and as a result, there is an effect that the optical fiber 4 can be easily condensed.

  Further, although the LED 10a is normally lit, if the luminance signal of a CCD camera (not shown) is reduced by the LED abnormality detection circuit, it is determined that there is an abnormality and the LED 1b is switched.

  As a comparative example, in Patent Document 1, since the main lamp and the sub lamp are switched using mechanical means, the apparatus becomes complicated. However, this method can be switched only by an electric signal, and has high luminance and high reliability. There is an effect of providing a light source.

  Next, an example will be described based on the embodiment of FIG.

  The LED 10a is a white LED obtained by applying a yellow phosphor to a blue LED, and the LED 10b is a red LED.

  FIG. 4 shows the spectrum of the LED 10a, and FIG. 5 shows the spectrum of the LED 10b.

  The wavelength synthesizing mirror 12a is a dichroic mirror formed by depositing a dielectric multilayer film on a glass substrate.

  FIG. 6 shows the wavelength characteristics of the wavelength combining mirror.

  The wavelength band of 650 to 750 nm including the red component is reflected, and the wavelength band of 450 to 560 nm including the blue to yellow components has a transmitted wavelength characteristic. The optical fiber 4 is a φ2 mm multicomponent glass bundle fiber.

  FIG. 7 shows a light output spectrum output from the end face of the optical fiber 4 when the LEDs 10a and 10b are turned on simultaneously.

  In the spectrum of the LED used for the LED 10a, as shown in FIG. In FIG. 7, the spectral intensity in the vicinity of red with a wavelength of 600 nm is enhanced, and light closer to the sunlight spectrum (natural light) can be obtained. Endoscopic observation with light close to natural light in medical applications and observation by changing the illumination wavelength, as represented by the surface sequential method, or obtaining new knowledge It contributes to medical care.

  As a comparative example, the method disclosed in Patent Document 3 uses three optical fibers, so the insertion portion of the endoscope becomes thick. In this method, the insertion portion is a single fiber. Therefore, there is an effect that the operability is improved with less burden on the subject.

  Further, since the main lamp and the sub lamp are also incorporated, there is no mechanical moving part as described above, and the reliability is improved.

It is a schematic diagram which shows 1st Embodiment of the LED fiber light source device in this invention. It is a schematic diagram which shows 2nd Embodiment of the LED fiber light source device in this invention. It is a schematic diagram which shows 3rd Embodiment of the LED fiber light source device in this invention. It is a graph which shows the emission spectrum of the used white LED. It is a graph which shows the emission spectrum of the used red LED. It is a graph which shows the transmission / reflection wavelength characteristic of the used wavelength synthetic | combination mirror. It is a graph which shows the output spectrum of the light source device in this invention. It is a graph which shows the output spectrum of the light source device in the light source device of a prior art.

Explanation of symbols

1a, 1b: LED
2: Collimator lens 3: Condensing lens 4: Optical fiber 5: LED driver 6: LED abnormality detection circuit 7a, 7b: Optical fiber 10a, 10b, 10c: LED
11a, 11b, 11c: Collimator lenses 12a, 12b: Wavelength combining mirrors

Claims (7)

A plurality of fixed LEDs, collimating means comprising a collimating lens or a reflecting mirror for collimating each output light from the LED, and a collecting lens comprising a condenser lens or a collecting mirror for condensing the output light from the collimating means. One end of an optical fiber is arranged in the vicinity of the focal point of the light collecting means, and can be used by switching between the main lamp consisting of some LEDs that are always used among the plurality of LEDs and the main lamp. LED fiber light source device characterized by having a sub lamp made of other LED. 2. The LED fiber light source device according to claim 1, further comprising means for detecting a malfunction of the main lamp and means for automatically switching to lighting of the sub lamp according to the malfunction. The LED fiber light source device according to any one of claims 1 to 3, further comprising a light guide unit via an optical fiber between the plurality of LEDs and the collimator unit. 4. The LED fiber light source device according to claim 1, wherein the main lamp and the sub lamp include a red LED and a white LED that excites a yellow phosphor with a blue LED. The LED fiber light source device according to any one of claims 1 to 3, wherein the main lamp and the sub lamp include three or more colors among red LED, blue LED, green LED, orange LED, and cyan LED. . 6. The LED fiber light source device according to claim 1, wherein a wavelength combining mirror for combining output lights from the plurality of LEDs is disposed between the collimating unit and the condensing unit. An endoscope using the LED fiber light source device according to any one of claims 1 to 6 as a light source.

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