JP2007275153A - Illumination device for endoscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a compact illumination device for an endoscope for making radiated light emitted by a solid light emitting element enter a light guide efficiently by a simple mechanism. <P>SOLUTION: In the illumination device for an endoscope comprising the solid light emitting element and the light guide part for transmitting light emitted by the solid light emitting element, the light emitted by the solid light emitting element is efficiently taken in the light guide by mounting an incident plane of the light guide with a greater numerical aperture on a light emitting surface of the solid light emitting element in a manner to face directly, and simultaneously, the solid light emitting element is mounted inside the operational portion of an endoscope by reducing the size of the illumination device for an endoscope. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an illumination device for an endoscopic device suitable for observation inside a body cavity and internal observation of a mechanical device, and in particular, increases the light use efficiency of the illumination device, and at the same time makes the illumination device portion small and light. Thus, the present invention relates to an endoscope illuminating device that enables a solid-state light-emitting element to be mounted in an operation portion of an endoscope, thereby improving the operability of the endoscope.

Endoscopic devices used in a wide range of fields as rigid endoscopes, fiberscopes, and electronic endoscopes are widely used for observing inside the body cavity of a human body or inside equipment such as an engine.
Although these endoscopes have different means for forming and observing an image of the object to be observed, they all have an elongated cylindrical part called the tip part and the insertion part, and an operation whose outer shape is larger than the insertion part on the other end face of the insertion part It consists of a part that holds and manipulates an endoscope called a part, and an objective lens that captures an object to be observed is built into the tip provided at the tip of the insertion part. Depending on the case, the means for observing the image picked up by the objective lens as an image via the insertion section and the operation section differs.

In the rigid endoscope, as shown in FIG. 1, an image of an observation object imaged by an objective lens 104 provided at the distal end of the distal end portion 101 is used as an operation unit 103 by a relay lens group 105 incorporated in the insertion unit 102. And an enlarged observation through the eyepiece 106 provided in the operation unit 103. In the case of a rigid mirror, the insertion portion 102 is a non-flexible cylindrical pipe. Recently, even in rigid endoscopes, a small solid-state image sensor such as a CCD is placed on the imaging surface of an objective lens provided at the tip of the insertion section, and an image signal converted into an electrical signal by the solid-state image sensor can be provided outside A device having a structure for transmitting to a signal processing device and observing it as an image on a monitor has been put into practical use and is also called a rigid electronic endoscope.

In the fiberscope, in place of the relay lens 105 shown in FIG. 1, an image guide formed by a number of flexible optical fibers is mounted, and the image of the objective lens provided at the tip is operated by the image guide. It has a structure for transmitting to a part and magnifying observation through an eyepiece. In the case of a fiberscope, since the image guide is flexible, the insertion portion is also made of a flexible cylindrical material, and the bending operation means (Fig. (Not shown) so that it can be bent.

In the electronic endoscope, as shown in FIG. 2, a small solid-state image sensor 120 such as a CCD is arranged on the imaging surface of the objective lens 104 provided at the tip 101 and converted into an electric signal by the solid-state image sensor 120. The transmitted image signal is transmitted through the operation unit 103 via the cable 121 to the signal processing device 122 provided outside the operation unit 103, and the image signal is processed into a video signal by the signal processing device 122 and observed on the monitor 123. It has a structure for observing an object.

Although the specific structure is different, all of the so-called endoscopes require an illumination device that illuminates the observation object. The endoscope illumination device includes a light source device and a light guide that transmits light. The light source device 111 shown in FIG. 1 and FIG. 2 is prepared as a separate body outside the endoscope due to problems such as the shape of the lamp 113 serving as a light source and heat generation, and the light emitted from the lamp 113 is written by the condensing optical system 112. The light guide 110 has a structure to be incident on the end surface (incident surface) of the guide 110, the light guide 110 is inserted through the operation unit 103 and the insertion unit 102, and another end surface (exit surface) of the light guide 110 is disposed on the front surface of the distal end portion 101. Is generally used. Since the light guide is a bundle of many thin optical fibers with a diameter of 30 to 50 microns, the mechanical strength is weak. With such a lighting device, the light guide is relatively strong and flexible to protect it. Since the protective tube is required and the light source including the protective tube is connected between the light source device and the endoscope, the operability of the endoscope is impaired.

In recent years, high-intensity light-emitting diodes (LEDs) have come into practical use as solid-state light-emitting devices due to remarkable progress in semiconductor technology. In particular, as a high-intensity white diode is put into practical use, proposals have been made to use it as a light source for an endoscope.

When a solid state light emitting device is used for an endoscope light source device, the structure used as an alternative light source for the lamp of the light source device prepared outside the endoscope as in the past, or the tip of the endoscope Various proposals have been made, such as a structure in which a light emitting diode is directly disposed on the screen, and a structure in which a light emitting diode is disposed in an operation portion of an endoscope.

Among these, the proposal of using a light emitting diode as a light emitter of a light source device prepared outside the endoscope has an effect of reducing power consumption, but as described above, a light is provided between the light source device and the endoscope. Since the guide connection is used, a flexible protective tube is required in the same manner as in the conventional illumination device, and improvement in the operability of the endoscope cannot be expected. Further, various types of condensing optical systems have been studied and proposed in order to make light emitted from the light emitting surface of the light emitting diode efficiently enter the light guide, but sufficient effects have not been obtained.

In addition, the structure in which the light emitting diode is directly arranged at the distal end portion of the endoscope has advantages such as simple mechanism and efficient use of light emitted from the light emitting diode, but there is a difficulty in solving the problem of heat generation. .

As a proposal for solving the above-described problems, a configuration in which a light emitting diode is arranged in an operation portion of an endoscope and light emitted from the light emitting diode is transmitted to a required position at the distal end of the insertion portion by a light guide has been proposed.

In this case as well, a structure in which a condensing optical system is arranged between the light emitting surface of the light emitting diode and the incident surface of the light guide has been proposed in order to efficiently take in the light emitted from the light emitting diode. However, the condensing optical system has a problem that it has not yet been put into practical use because it requires a considerable space and the utilization rate of light is not sufficient.
Japanese Patent Laid-Open No. 2003-126034 JP 2003-255236 A Japanese Patent Laying-Open No. 2005-312829 Gastrointestinal endoscope Vol. 17 No. 6 2005 p. 759

  As described above, various types of condensing optical systems have been studied and proposed in order to efficiently cause light emitted from the light emitting surface of the solid light emitting element to enter the light guide. Efficient incorporation into the light guide is an important issue.

The present invention has been made paying attention to the above-mentioned problems, and in particular, an endoscope having a structure capable of efficiently incorporating light emitted from a solid state light emitting device into a light guide in a minimum mechanical space. The purpose of the present invention is to provide an illuminating device, and further to protect the light guide connecting the light source device and the endoscope by enabling a solid light emitting element corresponding to the light source unit of the illuminating device to be mounted in the operation unit. The flexible protective tube can also take an unnecessary structure, and the operability of the endoscope can be improved.

In order to achieve the above object, an invention according to claim 1 is directed to an endoscope illumination apparatus including a solid light emitting element and a light guide portion that transmits light emitted from the solid light emitting element. Is mounted in the endoscope operation section, and the endoscope illumination device has a structure in which the incident surface of the light guide having a large numerical aperture directly faces the light emitting surface of the solid state light emitting device.

The invention according to claim 2 is characterized in that the numerical aperture of the light guide is larger than 0.8.

According to a third aspect of the present invention, the light guide mounting portion is provided on a part of the heat dissipating member provided in the solid light emitting element so that the incident surface of the light guide can be mounted facing the light emitting surface of the solid light emitting element. It is provided.

  The invention according to claim 4 is characterized in that the incident surface of the light guide is branched into a plurality of portions, and the light emitting surface of the solid state light emitting element is directly mounted on the branched incident surface.

  More specifically, when a solid light emitting element such as a light emitting diode is incorporated in the operation unit, heat generation of the solid light emitting element becomes a problem. When the amount of light emitted from the light emitting diode increases, the amount of heat generation also increases. When the light emitting diode is mounted in the operation unit, local heat generation increases and heat dissipation becomes a problem. In this case, a plurality of light emitting diodes with a small amount of emitted light but a small amount of heat generation are provided, and each light emitting diode is mounted on the incident surface of the light guide branched into a plurality, so that the mounting position of the light emitting diode within the operation unit can be determined. It can be dispersed and local heat generation can be kept small.

In the endoscope illuminating device according to the present invention, the light guide and the protective tube connected to the light source unit prepared outside the endoscope are not required by mounting the solid light emitting element in the endoscope operation unit. It can be expected to improve the operability of the endoscope, and the light emitting surface of the solid state light emitting device and the light guide incident surface with a large numerical aperture are directly facing each other, so there is no need for a large space for incorporating the condensing optical system. In addition, the light emitted from the solid state light emitting element can be efficiently taken into the light guide and used for illumination.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings used in the description of the embodiments, the size of the light guide, the solid state light emitting element, etc. are shown on an exaggerated scale so that the endoscope illumination apparatus can be easily understood and understood, and the present invention is further illustrated. The mechanism etc. not directly related to is omitted. A solid light emitting element will be described as a light emitting diode.

Many commercially available light-emitting diodes have a convex lens disposed on the front surface of the light-emitting surface in order to match the light distribution characteristics of the light-emitting diode with the intended use. However, the light distribution characteristic of the light emitting diode from the light emitting surface has a light distribution characteristic of a wide angle with respect to the front of the light emitting surface, and the structure in which the convex lens is arranged in front of the light emitting surface cannot sufficiently utilize the light from the light emitting surface. There are many. FIG. 3 shows an example of the light distribution characteristic of a light emitting diode that does not have a convex lens on the front surface of the light emitting surface. The Y axis indicated by the vertical axis 201 in the drawing stands vertically to the light emitting surface of the light emitting diode. The X axis indicated by the horizontal axis 202 indicates the light emission direction from the central axis (vertical axis) as an angle. As shown in FIG. 3, the light distribution characteristic of the light emitting diode has a wide angle. When the light distribution angle is within 70 ° (± 35 °), only about 60% of the total light emission amount can be used, but the light distribution angle is 110 °. When using within (± 55 °), about 80% of the total amount of emitted light can be used, and when using within the light distribution angle of 120 ° (± 60 °), about 90% of the total amount of emitted light can be used.

On the other hand, the optical fiber constituting the light guide is composed of a cylindrical transparent core material 205 and a transparent clad material 206 covering the outer periphery thereof as shown in FIG. For the optical fiber of this structure, if the refractive index of the core material is n1, the cladding material is selected to be a material having a refractive index lower than that of the core material, that is, a clad material having a refractive index n2 of n1> n2, and one end (incident end) of the optical fiber is selected. ) Light is incident on the core, the light is repeatedly reflected at the interface with the clad and transmitted to multiple ends (exit ends).

The incident angle θ (light receiving angle is 2θ) of light that can be transmitted by the optical fiber is determined by the numerical aperture (NA), and NA = sin θ = ((n1) ² − (n2) ² ) ^1/2 as shown in FIG. Indicated by In a light guide that is usually used, an optical fiber composed of a core material having a refractive index of n1 = 1.62 and a clad material having a refractive index of n2 = 1.52 is used, and the numerical aperture is NA. = 0.57 (light receiving angle 2θ = 70 degrees). Further, in order to give flexibility to the diameter of the optical fiber, those having a diameter of 30 to 50 microns are often used, and the light guide is a bundle of many such optical fibers.

In the case where an endoscope illumination device is configured using a light emitting diode and a light guide, a means for effectively making light emitted from the light emitting diode incident on the light guide is required. Considering the case of using a light guide with a numerical aperture of NA = 0.57, the light guide has a light receiving angle of about 70 °. Therefore, even if the light guide is arranged directly on the light emitting surface of the light emitting diode, as described above. Only about 60% of the amount of light emitted from the light emitting diode can be transmitted.

In general, many commercially available light emitting diodes are provided with a convex lens that changes the light distribution characteristic in front of the light emitting surface, and the light distribution characteristic is relatively narrow. For this reason, in many endoscope illumination devices, a configuration in which a condensing optical system is arranged between a light emitting diode and a light guide has been proposed. It is difficult to sufficiently incorporate the light emitted from the light emitting diode within the light receiving angle of the optical fiber.

FIG. 5 shows an example in which the condensing optical system 212 is disposed between the light emitting diode 211 and the light guide 210. Since the incident angle that the light guide 211 can transmit is about 35 °, the light quantity of the light emitting diode 211 is effectively increased. Is incident on the light guide 210, the effective F number of the condensing optical system on the incident end side of the light guide is required to be about 0.9 (F = 1/2 NA), which is brighter on the light emitting diode side. A valid F number is required. When considering such a bright lens system as the condensing optical system, it is impossible to effectively incorporate the light emitted from the light emitting diode into the light guide in consideration of aberrations. It is not realistic to use.

FIG. 6 shows how the numerical aperture of the optical fiber changes depending on the refractive index of the core material when the refractive index n2 = 1.52 of the clad material. The horizontal axis indicates the refractive index n1 of the core material. The left vertical axis indicates the numerical aperture (NA), the right vertical axis indicates the incident angle at which transmission is possible, the change in NA is indicated by a solid line, and the change in incident angle is indicated by a dotted line. For example, an optical fiber using the refractive index n1 = 1.75 of the core material and the refractive index n2 = 1.52 of the clad material has NA = 0.87, the transmittable incident angle is 60 °, and the receiving angle is about 120 °. It becomes.

FIG. 7 shows a basic configuration of an endoscope illumination apparatus according to the present invention, in which 210 is a light guide, 211 is a light emitting diode, 215 is a heat dissipation material of the light emitting diode, and 216 is an electrode of the light emitting diode. . As described above, by using the optical fiber constituting the light guide 210 having a large numerical aperture such as NA = 0.87, nearly 90% of the light emitted from the light emitting diode is taken into the light guide. Is possible. If an optical fiber having a numerical aperture of about NA = 0.8 is used for the light guide, nearly 80% of the light emitted from the light emitting diode can be taken into the light guide. It is desirable to use a light guide.

In such a light guide using an optical fiber having a large numerical aperture (NA), the light guide is disposed so that the incident surface of the light guide directly faces the light emitting surface of the light emitting diode. I can take it in. Further, in order to effectively capture the light emitted from the light emitting diode 211 into the light guide 210, it is desirable that the distance d between the light emitting surface of the light emitting diode 221 and the incident surface of the light guide be as small as possible, and the light emitting surface of the light emitting diode 221. It is also possible to bond the incident surface of the light guide 210.

In addition, since the light emitting surface of the light emitting diode is often rectangular (including square), the shape of the incident end of the light guide is not the round shape often used in the past, but by matching the shape of the light emitting surface of the light emitting diode, Light emitted from the light emitting diode can be used for illumination more efficiently.

In this way, the use of a light guide having a large numerical aperture eliminates the need for a condensing optical system, allows the light emitted from the light-emitting diode to be effectively taken into the light guide, and provides a condensing lens system. Since it is not provided, the mechanical space can be reduced, so that the light emitting diode can be easily installed in the operation unit.

FIG. 8 shows a specific example in which a light guide is coupled to a light-emitting diode that constitutes the endoscope illumination device shown in FIG. 7. In FIG. 8, reference numeral 210 denotes a light guide. A guide base 219 is attached. As already described, when a light-emitting diode is used as a light source, heat is generated, so it is necessary to attach a heat dissipation member 217 to the light-emitting diode 211. As shown in the figure, a light guide coupling portion 218 that can couple a light guide base 219 is provided on a part of the heat radiating member 217. By combining the light guide and the light emitting diode in such a structure, the light emitting diode and the light guide can be mounted in a small space in the endoscope operation portion, and the heat dissipation member 217 is connected to a part of the metal portion constituting the operation portion. Therefore, it is easy to improve the heat dissipation effect.

FIG. 9 shows a specific embodiment in which the endoscope illumination device according to the present invention is applied to an electronic endoscope. As in FIG. 2, a small solid-state imaging device 120 such as a CCD is connected to the tip portion. An image signal, which is arranged on the imaging surface of the objective lens 104 provided in 101 and converted into an electrical signal by the solid-state imaging device 120, is connected to the outside of the operation unit 103 via the insertion unit 102 and the operation unit 103 by the cable 121. The image signal is transmitted to the signal processing device 122 provided by the cable 124, the image signal processed by the signal processing device 122 is transmitted to the monitor 123, and the monitor 123 observes the observation object. In this case, the light emitting diode 221 serving as a light source is mounted inside the operation unit 103 together with the heat dissipation member 222 with the structure shown in FIG. It is attached to. As shown in FIG. 8, since the structure for coupling the light emitting diode 221 and the light guide 220 is simple and does not require a large space, the conventional endoscope operation unit is not greatly changed. The lighting device can be incorporated in the operation unit. Note that power for driving the light emitting diode is supplied from the signal processing device 122 via the cable 223, but it is also easy to incorporate a battery into the operation unit to make the power.

In the embodiment of FIG. 9, the power for driving the light emitting diode 221 is supplied from a signal processing device provided outside by a cable 223. However, since the cable is thinner and stronger than the light guide, a flexible protective tube is used. This is not always necessary, and in particular, when a battery is incorporated in the operation section, no cable is required, and the operability of the endoscope can be remarkably improved.

FIG. 10 shows another embodiment in which the endoscope illumination apparatus according to the present invention is applied to an electronic endoscope. The basic configuration is the same as that of the embodiment of FIG. In the case of this embodiment, the light incident end of the light guide 220 is branched into two systems as indicated by 225 and 226 in the operation unit 103, and the incident ends of the branched light guides 225 and 226 are shown in FIG. In this structure, the light emitting diodes 227 and 228 are coupled together with the heat dissipating members 229 and 230 and mounted in the operation unit.

In this way, by splitting the incident end of the light guide 110 into a plurality of systems and attaching a light emitting diode to each branched incident end, it becomes possible to use a small light emitting diode with a small amount of heat generation. Since the coupling part between the light guide and the light guide is also small, the degree of freedom in selecting a space for mounting the light emitting diode in the operation part is increased, and the light emitting diodes for obtaining the required light quantity can be distributed and arranged. It is possible to dissipate more heat in the operation unit.

In the above description, the light guide incident end is branched into two. However, depending on the purpose, the light guide incident end can be branched into two or more and a light emitting diode can be attached to each incident end. It is.

As described above, the endoscope illumination device according to the present invention has been described as being mounted on an electronic endoscope. However, this endoscope illumination device is applicable to all endoscopes having various forms.

It is a schematic explanatory drawing which shows the basic structure of the conventional rigid endoscope which provided the illuminating device outside. It is a schematic explanatory drawing which shows the basic structure of the conventional electronic endoscope which provided the illuminating device outside. It is explanatory drawing which shows the light distribution of the light which a light emitting diode light-emits. It is explanatory drawing which shows the structure of the optical fiber which comprises a light guide. It is explanatory drawing of the structure which used the condensing optical system between the light emitting diode and the light guide. It is explanatory drawing which showed how the numerical aperture of an optical fiber changes with the refractive index of a core material, when the refractive index n2 = 1.52 of a clad material is used. It is a schematic explanatory drawing explaining the illuminating device using the light guide and light emitting diode with a large numerical aperture by this invention. It is a schematic explanatory drawing which shows one example of the structure which couple | bonds the light guide and light emitting diode by this invention. It is a schematic block diagram which shows the specific Example of the illuminating device for endoscopes by this invention. It is a schematic block diagram which shows the other Example of the illuminating device for endoscopes by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Tip part 102 Insertion part 103 Operation part 104 Objective lens 105 Relay lens 106 Eyepiece lens 110,210,220 Light guide 111 Light source device 112,212 Condensing optical system 113 Lamp 211,221,227,228 Light-emitting diode 120 Solid-state image sensor 122 Signal processor 123 Monitors 215, 217, 222, 229, 230 Heat radiation member 225, 226 Light guide branch

Claims (4)

In an endoscope illuminating device including a solid light emitting element and a light guide part that transmits light emitted from the solid light emitting element, the solid light emitting element is mounted in an endoscope operation unit, and a light emitting surface of the solid light emitting element An endoscope illumination device characterized in that the light guide having a large numerical aperture is mounted so that the incident surface of the light guide faces directly. The endoscope illumination device according to claim 1, wherein the numerical aperture of the light guide is larger than 0.8. The light guide mounting portion is provided on a part of the heat radiating member provided in the solid light emitting element so that an incident surface of the light guide can be mounted facing the light emitting surface of the solid light emitting element. The endoscope illumination device according to claim 1 or 2. 4. The structure according to claim 1, wherein the light guide surface of the light guide is branched into a plurality of portions, and the light emitting surface of the solid state light emitting device is directly attached to each of the branched light entrance surfaces. The endoscope illumination device described.

Images