JP5480929B2 - Endoscopic light projecting unit - Google Patents

Description

  The present invention relates to an endoscope light projecting unit that is provided at a distal end portion of an endoscope and irradiates illumination light toward a subject.

  In the medical field, diagnosis and treatment in a subject using an endoscope are widely performed. The endoscope includes an insertion portion that is inserted into the subject, and illumination light is irradiated toward the subject from an illumination window provided at a distal end portion of the insertion portion. Then, the subject illuminated with the illumination light is imaged with an imaging device such as a CCD provided at the distal end of the insertion portion, and an endoscopic image is displayed on the monitor based on the imaging signal obtained by this imaging. .

  White light such as a xenon lamp or a halogen lamp is often used for illumination in the subject, but the xenon lamp has a problem that it is relatively large and consumes a large amount of power. On the other hand, in Patent Documents 1 and 2, white light is generated by combining the blue light of a blue LED (Light Emitting Diode) and the fluorescence emitted by exciting the phosphor with the blue light. In this way, by generating white light using a blue LED and a phosphor, it is possible to achieve downsizing and power saving with respect to a xenon lamp or the like.

JP 2006-61685 A JP 2006-173498 A

  When white light is generated using a blue LED and a phosphor as in Patent Document 1, it is possible to reduce the size and power consumption, while the light diffusion characteristics of the phosphor have wavelength dependence. Therefore, there may be a difference between the divergence angle of blue light that is excitation light emitted from the phosphor and the divergence angle of fluorescence excited by the blue light. For example, when fluorescence is emitted from a phosphor with a blue laser beam having a central wavelength of 405 nm and a blue laser beam having a central wavelength of 445 nm, as shown in FIG. 11, the fluorescence spread angle is the widest and the central wavelength is 405 nm. The spread angle of the blue laser light and the blue laser light having a center wavelength of 445 nm is narrower than that of fluorescence. When the subject is irradiated with blue light and fluorescence in a state where there is a difference in the spread angle in this way, color unevenness occurs on the subject. Accurate diagnosis may not be performed on an image captured in a state where color unevenness has occurred.

  As one method for preventing the occurrence of uneven color, it is conceivable to add a filler that scatters the blue light emitted in a straight line to the phosphor (for example, see Patent Document 2). However, generally, mixing of the filler into the phosphor makes it difficult to separate the function of diffusing the blue light that is the excitation light from the function of emitting the fluorescence excited by the phosphor by the blue light. It is difficult to completely eliminate uneven color. Further, since the filler scatters blue light in all directions, the blue light that scatters only in the phosphor and does not exit the phosphor increases. Such an increase in blue light causes a decrease in luminous efficiency of the phosphor, and also causes a heat generation inside the phosphor and the emission end of the phosphor.

  In general, in order to ensure long-term stability of the phosphor, the phosphor and the illumination window that emits blue light and fluorescence from the phosphor toward the subject are sealed. Sometimes, a slight gap (also referred to as an air layer) is formed between the phosphor and the irradiation window. Due to the presence of this air layer, some blue light and fluorescence may not be emitted from the exit surface of the illumination window, but may be reflected from the entrance surface of the illumination window or reflected from the exit surface of the phosphor. Such reflection on the illumination window or the phosphor causes a reduction in fluorescence emission efficiency.

  With respect to this problem, by introducing an antireflection film (AR coating) on the incident surface of the illumination window, reflection on the incident surface of the illumination window can be prevented. However, since the phosphor cannot ensure the flatness of the emission surface in the manufacturing process, an antireflection film such as an illumination window cannot be introduced. Therefore, it is necessary to prevent reflection of blue light or fluorescence without using an antireflection film in the phosphor.

  The present invention is directed to irradiating a subject with blue light and fluorescence having different wavelengths when irradiating the subject with white light obtained by combining blue light and fluorescence excited and emitted from the phosphor with the blue light. An object of the present invention is to provide an endoscopic light projecting unit that can prevent the occurrence of color unevenness and suppress a decrease in the light emission efficiency of fluorescence in a phosphor.

In order to achieve the above object, the present invention absorbs a part of light having a predetermined wavelength in an endoscope projection unit that is provided at the distal end portion of an endoscope and irradiates illumination light toward a subject. The wavelength conversion member generates the fluorescence by converting the wavelength and transmits the remaining light, thereby emitting the light of the predetermined wavelength and the illumination light including the fluorescence, and the illumination light emitted from the wavelength conversion member Are spread by a scattering member mixed in a transparent substrate to widen the spread angle of the illumination light, and an illumination window that irradiates the scattered illumination light toward the subject The wavelength conversion member and the divergence angle widening portion, and the divergence angle widening portion and the illumination window are configured to be in close contact with each other, and the refractive index of the base material of the divergence angle widening portion is the wavelength conversion. Ri value der between the refractive index and the refractive index of the illumination window of the member The wavelength conversion member and the divergence angle increasing unit has a substantially cylindrical shape, the diameter of the spread angle increasing unit may be greater than the diameter of the wavelength conversion member.

The scattering member before Symbol wavelength conversion member is preferably not mixed.

The refractive index of the wavelength conversion member is in the range of 1.46 to 2.0, the refractive index of the illumination window is in the range of 1.40 to 1.9, and the refractive index of the substrate is The wavelength conversion member and the illumination window are preferably selected from the range of 1.40 to 2.0 depending on the combination of the refractive index values of the illumination window and the wavelength conversion member. The refractive index of the base material is preferably a mean square value of the refractive index of the wavelength conversion member and the refractive index of the illumination window.

The substrate is preferably an organic material such as epoxy. The substrate is preferably a inorganic materials.

It is preferable to provide a metal sleeve that holds the ferrule that holds the wavelength conversion member and the divergence angle widening portion .

  According to the present invention, the divergence angle of the illumination light is expanded by scattering the illumination light after exiting the wavelength conversion member, so compared with the case where the illumination light is scattered within the wavelength conversion member. Further, it is possible to more reliably prevent the uneven color of the illumination light and to further suppress the decrease in the light emission efficiency at the wavelength conversion member.

  Further, when the divergence angle widening portion and the illumination window are configured separately, the divergence angle widening portion includes a base material having an intermediate refractive index between the refractive index of the wavelength conversion member and the refractive index of the illumination window. By doing so, the illumination light is prevented from reflecting on the exit surface of the wavelength conversion member, the entrance surface of the illumination window, and the like. Thereby, the loss of the illumination light in a wavelength conversion member or an illumination window can be suppressed. In addition, the wavelength conversion member and the divergence angle widening portion are brought into close contact with each other, and the divergence angle widening portion and the illumination window are brought into close contact with each other, thereby preventing reflection at each boundary surface such as the emission surface of the wavelength conversion member. Also by this, the loss of illumination light can be suppressed.

  When the divergence angle widening part and the illumination window are integrated, the wavelength conversion member and the illumination window are brought into close contact so that the illumination light is reflected on the exit surface of the wavelength conversion member or the entrance surface of the illumination window. Is prevented. Thereby, the loss of illumination light can be suppressed.

  In addition, since the divergence angle widening portion is held by a metal sleeve, heat generated by scattering of illumination light in the divergence angle widening portion can be released to the sleeve. Moreover, the effect of releasing the heat generated by the wavelength conversion member to the outside can be enhanced by making the diameter of the divergence angle widening portion larger than the diameter of the wavelength conversion member.

It is a figure shown in the endoscope system of 1st Embodiment. It is a figure which shows the cross section of the front-end | tip part of the electronic endoscope of 1st Embodiment. It is a figure which shows the front end surface of the front-end | tip part of the electronic endoscope of 1st Embodiment. It is a figure showing the relationship between the divergence angle and light intensity of the 1st blue laser beam at the time of fluorescent substance incidence, and the relationship between the divergence angle and light intensity of 1st blue laser beam and fluorescence after radiating | emitting a divergence angle expansion part. is there. It is a figure for demonstrating the color nonuniformity prevention effect at the time of integrating an excitation light diffusion function and a fluorescence emission function. It is a figure for demonstrating the color nonuniformity prevention effect at the time of isolate | separating an excitation light diffusion function and a fluorescence emission function. It is a figure for demonstrating the fall inhibitory effect of the luminous efficiency at the time of integrating an excitation light diffusion function and a fluorescence emission function. It is a figure for demonstrating the reduction inhibitory effect of luminous efficiency at the time of isolate | separating an excitation light diffusion function and a fluorescence emission function. It is a figure for demonstrating the manufacturing method of the 1st light projection unit of 1st Embodiment. It is a figure which shows the cross section of the front-end | tip part of the electronic endoscope of 2nd Embodiment. It is a figure for demonstrating the manufacturing method of the 1st light projection unit of 2nd Embodiment. The relationship between the divergence angle of the first and second blue laser light and the light intensity at the time of the incidence of the phosphor, and the fluorescence after exiting the divergence angle widening portion and the divergence angle and light intensity of the first and second blue laser light It is a figure showing these relationships. It is a figure showing the relationship between the divergence angle of fluorescence and blue laser light (405 nm, 445 nm), and light intensity in the case of not using scattering members, such as a filler.

  As shown in FIG. 1, the endoscope system 2 of the first embodiment is provided with an electronic endoscope 10 that images a subject, a processor device 12 that generates an endoscope image, and the processor device 12. A light source device 13 for supplying illumination light for illuminating the subject, a monitor 14 for displaying an endoscopic image, and a water supply tank 16 for storing water to be fed into the subject.

  The electronic endoscope 10 includes an insertion unit 20 that is inserted into a body cavity of a patient, an operation unit 22 that is connected to a proximal end portion of the insertion unit 20 and that is operated by a surgeon such as a doctor or a technician, It consists of a universal cord 24 extending from the operation unit 22. The insertion portion 20 includes a distal end portion 26, a bending portion 27, and a flexible tube portion 28 in order from the distal end. The tip portion 26 is formed of a hard resin material. The flexible tube portion 28 is formed in a thin and long tubular shape and has flexibility, and connects the operation portion 22 and the bending portion 27.

  The bending portion 27 is configured to bend up, down, left, and right according to the rotation operation of the up / down operation knob 30 and the left / right operation knob 31 provided in the operation unit 22. When the up / down operation knob 30 is rotated, the bending portion 27 is bent in the up / down direction, and when the left / right operation knob 31 is rotated, the bending portion 27 is bent in the left / right direction.

  The universal cord 24 is provided with a connector 36 used for taking in light and air supplied from the processor device 12 and transmitting power and various control signals. The electronic endoscope 10 is detachably connected to the processor device 12 via a connector 36.

  The light source device 13 includes a first laser light source 13a that emits a first blue laser beam having a center wavelength of 445 nm. The first blue laser light emitted from the first laser light source 13 a is guided to the distal end portion 26 of the electronic endoscope through ride guides 24 a and 24 b in the universal cord 24. The first blue laser light guided is partly absorbed by the phosphor 50 provided at the distal end portion 26 to excite and emit green to yellow fluorescence, and at the phosphor 50 (wavelength conversion member). The light that has not been absorbed passes through the phosphor 50 as it is. Accordingly, the tip portion 26 irradiates the subject with white light (illumination light) obtained by combining the first blue laser light and the fluorescence. Return light from the subject is imaged as an image of the subject by the imaging element 42 (see FIG. 3) in the electronic endoscope 10. The light guides 24a and 24b are made of a light guide member such as an optical fiber.

  The processor device 12 receives an imaging signal obtained by imaging of the electronic endoscope 10 via the signal cable 24 c in the universal cord 24. The processor device 12 generates image data by performing various types of image processing on the received imaging signal. An endoscopic image of the subject is displayed on the monitor 14 based on the generated image data.

  As shown in FIG. 2, at the distal end portion 26 of the electronic endoscope, two first and second light projecting units 38 and 39 for irradiating illumination light toward the subject, an observation window 40 and An imaging unit 43 is provided that captures an image of a subject received through the imaging lens 41 with an imaging element 42 such as a CCD.

  As shown in FIG. 3, the first and second light projecting units 38 and 39 are provided at positions symmetrical with respect to the imaging unit 43 on the distal end surface 26 a of the distal end portion 26. In addition to the first and second light projecting units 38 and 39 and the imaging unit 43, the distal end portion 26 has cleaning air toward the treatment instrument outlet 46 and the observation window 40 that expose a treatment instrument such as a snare. An air / water supply nozzle 48 for discharging water is provided.

The first light projecting unit excites the phosphor 50 with the first blue laser light from the light guide 24 a to emit white light from the phosphor 50, and spreads the divergence angle of the emitted white light at the angle expanding unit 51. spread. The white light that has passed through the divergence angle widening portion 51 has biocompatibility among glass members such as quartz glass and sapphire glass (for example, “K-LaSFn17” (“http://www.sumita-opt.co.jp”). (See page 120 of /data/glassdata.pdf))). The phosphor is preferably YAG or BAM (BaMgAl ₁₀ O ₁₇ ).

In the first and second light projecting units 38 and 39, the illumination window 52 and the divergence angle widening portion 51 and the divergence angle widening portion 51 and the phosphor 50 are in contact with each other without a gap. There is no air layer between them. Here, when an air layer is sandwiched between the illumination window 52 and the divergence angle widening portion 51 and between the divergence angle widening portion 51 and the phosphor 50, light incidence is made as compared with a case where no air layer is sandwiched. -The number of boundary surfaces such as reflecting surfaces can be reduced (when the air layer is sandwiched, the number of boundary surfaces is “5”, whereas when the air layer is not sandwiched, the number of boundary surfaces is “3”. "). Therefore, the number of boundary surfaces can be reduced by closely contacting each member and eliminating the air layer. Thereby, since reflection at the boundary surface can be prevented, it is possible to irradiate the subject with the first blue laser light and fluorescence while maintaining high light intensity.

  The phosphor 50 has a substantially cylindrical shape having a constant outer diameter D1. The phosphor 50 is mixed with a fluorescent material, and part of the first blue laser light is absorbed by the fluorescent material to emit green to red fluorescence, while the light that is not absorbed by the fluorescent material is It passes through the phosphor 50 as it is. Thus, the fluorescence emitted from the fluorescent material and the first blue laser light are combined, and white light is emitted from the phosphor 50.

  The divergence angle widening part 51 is a translucent member formed by mixing a filler 51a, which is a light scattering member that scatters fluorescence and first blue laser light, into a base material 51b (see FIG. 4) made of a transparent material. . As the base material 51b, for example, an organic material such as a resin is used, and a material whose refractive index is between the refractive index of the phosphor 50 and the refractive index of the illumination window 52 is used.

  The divergence angle widening portion 51 has a substantially cylindrical shape, and its outer diameter D2 is larger than the outer diameter D1 of the phosphor 50. Therefore, the leakage light that does not enter the divergence angle widening portion 51 of the light emitted from the phosphor 50 is reduced, so that the optical loss can be reduced. Further, since the entire emission surface of the phosphor 50 is in contact with the divergence angle widening portion 51, heat generated in the phosphor 50 is spread and transmitted to the angle magnifying portion 51. In addition, it is preferable that the outer diameter D1 of the fluorescent substance 50 is 0.8 mm, for example, and the outer diameter D2 of the divergence angle expansion part 51 is 1.1 mm, for example.

  As shown in FIG. 4, the first blue laser light incident on the phosphor 50 has a relatively narrow divergence angle at a portion where the light intensity is high. Along with this, the spread angle of the fluorescence excited by the phosphor 50 by the first blue laser light is also narrowed. Therefore, the first blue laser light and the fluorescence emitted from the phosphor 50 are scattered by the filler 51a, so that the spread angle of each light is expanded. In this way, by expanding the divergence angles of both the first blue laser light and the fluorescence, there is no portion where the respective lights do not overlap, so that the occurrence of color unevenness can be prevented.

  In addition, as a filler, although silica, quartz, etc. are preferable, if it has a light-diffusion function, it will not be limited to this. In addition, the organic material is preferably a resin such as epoxy. However, when considering deterioration due to irradiation with the first blue laser light having a short wavelength, an inorganic material such as silicon is used instead of the organic material. May be.

  In the phosphor 50, the filler 51a contained in the divergence angle widening portion 51 is not mixed. In this way, the filler 51a is not mixed in the phosphor 50, but is mixed in the divergence angle widening portion 51 that is separate from the phosphor 50, thereby exciting the first blue laser light that is the excitation light. The light diffusion function and the fluorescence emission function for emitting fluorescence excited by the phosphor 50 by the first blue laser light can be separated. Therefore, for the reason described below, compared with the case where the filler 51a is mixed in the phosphor 50 (when the excitation light diffusion function and the fluorescence emission function are integrated), the effect of preventing color unevenness and the luminous efficiency can be reduced. An effect capable of suppressing the decrease can be obtained with certainty.

  Regarding the effect of preventing color unevenness, there are the following differences between the case where the excitation light diffusion function and the fluorescence emission function are integrated and the case where they are separated. When both functions are integrated, as shown in FIG. 5A, a part of the first blue laser light diffused by the filler 51a in the phosphor 50 is emitted from the phosphor 50, but the others are phosphors. 50 is absorbed by the fluorescent material 50a in the gas 50 and consumed for excitation emission of fluorescence. Thereby, since the diffusion effect of the first blue laser beam is reduced, the spread angle expansion effect by the filler 51a is reduced. Then, the effect of preventing color unevenness is reduced by the reduction of the effect of widening the spread angle.

  On the other hand, as shown in FIG. 5B, when the excitation light diffusion function and the fluorescence emission function are separated, the filler 51a has a diffusion effect on the first blue laser light after being emitted from the phosphor 50. Is granted. Since the first blue laser light to which the diffusion effect is given is irradiated as it is toward the subject through the illumination window 52, it is not used for fluorescence excitation emission as described above. Therefore, the diffusion effect due to the filler 51a is used to expand the spreading angle by almost 100%. Therefore, compared with the case where the excitation light diffusion function and the fluorescence emission function are integrated, an effect of preventing color unevenness can be obtained with certainty.

  Further, regarding the effect of suppressing the decrease in luminous efficiency, there are the following differences between the case where the excitation light diffusion function and the fluorescence emission function are integrated and the case where they are separated. When both functions are integrated, as shown in FIG. 6A, the light emitted to the fluorescent material 50a of the phosphor 50 is irradiated to the fluorescent material 50a as it is without colliding with the filler 51a. Not only the laser beam but also the first blue laser beam that collides with the filler 51a and scatters is included. Since the energy of the first blue laser light colliding with the filler 51a is attenuated by the collision, a part of the first blue laser light does not contribute to the excitation light emission of the fluorescence even when irradiated to the fluorescent material 50a. In some cases, the light is lost without being emitted. The energy of the lost light is converted into heat and disappears in the phosphor 50. When there is much loss light, luminous efficiency will fall and the heat generation of the phosphor 50 will also increase.

  On the other hand, as shown in FIG. 6B, when the excitation light diffusing function and the fluorescence emission function are separated, since the phosphor 51 does not contain the filler 51a, the first blue laser that has entered the phosphor 50 In light, there is no energy attenuation by the filler 51a. Therefore, since the first blue laser light is applied to the fluorescent material 50a of the phosphor 50 while maintaining relatively high energy, the excitation light rate of the fluorescence can be improved. Further, most of the first blue laser light that is not absorbed by the fluorescent material 50a is emitted from the phosphor 50 because it retains relatively high energy. Therefore, the loss of light that is consumed only in the phosphor 50 is reduced.

  Further, the first blue laser light after being emitted from the phosphor 50 passes through the phosphor 50, so that the spread angle is slightly expanded. As described above, since the phosphor 50 itself also has a spread angle widening effect, the mixing rate of the filler 51a in the spread angle widening portion 51 can be set by subtracting the spread angle widening effect of the phosphor 50. That is, the mixing ratio of the filler 51a in the divergence angle widening portion 51 can be reduced as compared with the case where the first blue laser light is directly incident on the phosphor 50. Although the spread angle widening effect by the widening angle widening portion 51 is reduced by the amount of reduction of the mixing rate, the decrease is compensated by the widening angle widening effect of the phosphor 50. From the above, when the excitation light diffusion function and the fluorescence emission function are separated, the light emission efficiency and the heat generation suppression effect can be enhanced as compared with the case where these both functions are integrated.

  When the excitation light diffusion function and the fluorescence emission function are separated, the fluorescence emission efficiency and the first blue laser light scattering efficiency can be considered separately. In addition, it is easy to design the mixing rate of the filler 51a in the divergence angle widening portion 51. This is because when fillers are mixed in the phosphor, the mixing ratio must be determined in consideration of the interaction between the fluorescent substance and the filler in the phosphor. Since the rate can be adjusted independently, it is easy to select the optimal combination of both mixing rates.

  In addition, the divergence angle widening part 51 configured as a separate body is added to the phosphor 50, and the both are brought into close contact with each other, so that the divergence angle widening part 51 is compared with the case of the phosphor 50 alone. As heat is added, the heat capacity and surface area increase. For this reason, the heat generation of the phosphor 50 can be spread and escaped to the angle widening portion 51, so that the heat dissipation effect is also improved.

  In addition, since the filler 51a is provided in the divergence angle widening portion 51 that is separate from the phosphor 50, the first blue laser light scattered by the filler 51a is mostly directed toward the illumination window 52 side. The part becomes return light toward the phosphor 50. The return light reenters the phosphor 50 and is used again for fluorescence excitation light emission. As a result, the amount of emitted fluorescence can be increased, so that the return light is effectively used. On the other hand, when the filler 51a is provided in the phosphor 50, if the first blue laser light is scattered by the filler 51a on the side opposite to the illumination window 52 (the ferrule 55 side), much of the scattered light Is emitted from the phosphor 50 and becomes a loss. In this case, the scattered light is not used effectively because it is not used for fluorescence excitation light emission like the return light.

The first blue laser light passes through each medium in the order of the phosphor 50, the divergence angle widening portion 51, the illumination window 52, and the air layer, and the fluorescence passes through each medium in the order of the divergence angle widening portion 51, the illumination window 52, and the air layer. To do. As described above, the smaller the difference in the refractive index between the light transmitting media, the smaller the reflection. Therefore, in order to reduce the optical loss due to the reflection, the air layer having the smallest refractive index (refractive index: 1.0) is in contact. The refractive index ny of the illumination window 52 is minimized so as to approach 1.0, and the refractive index nx of the phosphor 50, the refractive index nk of the divergence angle widening portion 51, and the refractive index ny of the illumination window 52 are sequentially set. It is preferable to decrease the refractive index of the medium stepwise. Therefore, the refractive index nk of the base material 51b of the divergence angle widening portion 51 is set to an intermediate value between the refractive index nx of the phosphor 50 and the refractive index ny of the illumination window 52, and the phosphor 50 and the divergence angle widening portion. The materials are selected so that the refractive index of each medium decreases in the order of 51 and the illumination window 52 (nx> nk> ny). Thereby, the light loss of the first blue laser light and the fluorescence is reduced, so that the illumination light irradiated on the subject has high light intensity.

  The value of the refractive index nk of the base material 51b of the divergence angle expanding portion 51 is preferably in the range of 1.40 to 2.0 (intermediate refractive index range). The refractive index nx of the generally used phosphor 50 material is about 1.46 to 2.0, the refractive index ny of the illumination window 52 is about 1.40 to 1.9, and intermediate refraction. The range of the rate is defined by the maximum value of the refractive index nx of the phosphor 50 and the minimum value of the refractive index ny of the illumination window 52. The value of the refractive index nk of the substrate 51b of the divergence angle widening portion 51 is an intermediate value depending on the combination of the refractive index nx of the phosphor 50 and the refractive index ny of the illumination window 52 used in the product. From the range of the intermediate refractive index, it is appropriately selected. Even when an inorganic material is used as the material of the substrate 51b, the preferable refractive index range of the inorganic material is the same as that of the organic material.

Further, the refractive index nk of the base material 51b is a mean square value of the refractive index nx of the phosphor and the refractive index ny of the illumination window (nk = (0.5 × (nx ² + ny ² )) ^1/2 ). Is preferred. For example, when nx is 1.46 and ny is 1.4, nk is 1.43. Further, ny is preferably a value between 1.3 and 1.4.

  In the 1st light projection unit 38, the light guide 24a, the fluorescent substance 50, the divergence angle expansion part 51, and the illumination window 52 are arrange | positioned as follows. The phosphor 50 and the light guide 24a are held by the ferrule 55 in an optically connected state. The ferrule 55 is a hollow cylindrical member, and holds the light guide 24a through a through hole 55a extending in the axial direction. In addition, the ferrule 55 fixes the phosphor 50 with an adhesive 56 in a substantially cylindrical or rectangular parallelepiped tip storage portion 55 b having an opening on the tip side.

  Further, the ferrule 55 and the illumination window 52 are held by a metal sleeve 60, and a spread angle widening portion 51 is provided between the ferrule 55 and the illumination window 52 in the metal sleeve 60. In the divergence angle widening portion 51, heat is generated because the first blue laser light and fluorescence are scattered by the filler 51a. However, since the divergence angle widening portion 51 is in direct contact with the metal sleeve 60, the heat generation occurs. Can be released to the sleeve 60. Thereby, the heat dissipation effect can be enhanced.

  The first light projecting unit 38 is preferably manufactured by the following method. First, as shown in FIG. 7, after the illumination window 52 is attached to the illumination window installation part 60a of the sleeve 60, the filler 51a is added to the base material 51b in the space formed in a part of the illumination window installation part 60a. The divergence angle widening portion 51 is formed by filling the organic material mixed with the slag. Next, the ferrule 55 in which the phosphor 50 is fixed to the tip storage portion 55 b is inserted into the ferrule insertion hole 60 b of the sleeve 60. When the phosphor 50 fixed to the ferrule 55 is inserted to a position where it is in contact with the divergence angle widening portion 51, the organic material and the filler are cured. By completing this process, the first light projecting unit 38 in which the divergence angle widening portion 51 is formed between the illumination window 52 and the phosphor 50 is completed. In the first light projecting unit 38 after manufacture, the lighting window 52 and the spread angle widening portion 51 and the widening angle widening portion 51 and the phosphor 50 are in close contact with each other without any gap. It has become.

  The second light projecting unit 39 includes the same phosphor 50 as the first light projecting unit 38, a divergence angle widening portion 51, an illumination window 52, a ferrule 55, and a sleeve 60. The arrangement and manufacturing method of each member of the second light projecting unit 39 is the same as that of the first light projecting unit 38. Therefore, detailed description is omitted.

  As shown in FIG. 8, the 1st and 2nd light projection unit 100,101 of 2nd Embodiment provided the divergence angle expansion function in the illumination window 52, and the example which integrated the illumination window 52 and the divergence angle expansion part. It is. The illumination window 52 is formed by using a transparent material for forming the illumination window 52 as a base material and mixing a filler 52a in the base material. The illumination window 52 and the phosphor 50 are in close contact with each other. About other than that, it implements similarly to 1st Embodiment. Here, the close contact means that the phosphor 50 and the illumination window 52 are in contact with each other without a gap. In addition, also in the 1st and 2nd light projection units 100 and 101 of 2nd Embodiment, the outer diameter D3 of the substantially cylindrical-shaped illumination window 52 is larger than the outer diameter D1 of the fluorescent substance 50 from viewpoints, such as a thermal radiation effect. It is preferable to enlarge it.

  Even when the filler 52a is mixed in the illumination window 52 as in the first and second light projecting units 100 and 101, the first blue laser light and the fluorescence from the phosphor 50 are scattered by the filler 52a. The spread angle of light can be expanded reliably. Also in the first and second light projecting units 100 and 101, as in the first embodiment, the filler 51 a is not mixed into the phosphor 50, but an illumination window 52 separate from the phosphor 50. By mixing in, the excitation light diffusion function and the fluorescence emission function can be separated. In this case, as compared with the case where the excitation light diffusion function and the fluorescence emission function are integrated, the same effects as those in the first embodiment such as the uneven color prevention effect, the light emission efficiency reduction suppression effect, and the heat generation suppression effect are surely obtained. Can be obtained.

Further, since the illumination window 52 is in direct contact with the metal sleeve 60, even if heat is generated by scattering of the first blue laser light and fluorescence by the filler 52a, the heat can be released to the sleeve 60. it can.

  Moreover, in the 1st and 2nd light projection unit 100,101 of 2nd Embodiment, since the fluorescent substance 50 and the illumination window 52 are closely_contact | adhered, there is almost no air layer between them. Therefore, it is possible to prevent the first blue laser light and the fluorescence from being reflected from the emission surface of the phosphor 50 and from being reflected from the incident surface of the illumination window 52. Therefore, almost all of the first blue laser light and fluorescence are irradiated to the subject without being attenuated by the phosphor 50 or the illumination window 52.

  The first and second light projecting units 100 and 101 of the second embodiment are manufactured by a method different from that of the first embodiment in order to bring the phosphor 50 and the illumination window 52 into close contact with each other. First, as shown in FIG. 9, the illumination window 52 mixed with the filler 52 a is attached to the illumination window installation part 60 a of the sleeve 60. Next, the ferrule 55 in which the phosphor is fixed to the tip storage portion 55 b is inserted into the ferrule insertion hole 60 b of the sleeve 60. In that case, it inserts until the fluorescent substance 50 and the illumination window 52 contact completely. Here, the contact means that the phosphor 50 and the illumination window 52 are in contact with each other without a gap, that is, in close contact. Next, the sleeve 60 is put into the annealing device 110 and an annealing process is performed. By completing this annealing process, the first and second light projecting units 100 and 101 in which the phosphor 50 and the illumination window 52 are in close contact with each other are completed. The annealing treatment is preferably performed under predetermined conditions within the range of 70 to 90 ° C. and 10 to 30 H, for example, 80 ° C. and 20 H.

  In the first and second embodiments, the phosphor is excited only by the first blue laser beam having the center wavelength of 445 nm. In addition to the first blue laser beam, the second blue laser beam having the center wavelength of 405 nm is used. The phosphor may be excited. At that time, the second blue laser light is incident on the phosphor 50 together with the first blue laser light.

  Even when the phosphor is excited by the two wavelengths of the first and second blue laser beams in this way, as shown in FIG. 10, at the time of incidence of the phosphor 50, the first and second blue laser beams are emitted. The divergence angle and the divergence angle of the fluorescence excited from the phosphor 50 by the light are also narrowed. However, after the emission of the phosphor 50, the divergence angle of the light is expanded by the divergence angle expansion unit 51, so that the color unevenness Will not occur. In addition, the addition of one type of light that excites the phosphor 50 increases the amount of light scattered by the divergence angle widening portion 51 and increases the amount of heat generation, but the heat generation is sufficiently released to the metal sleeve 60. Therefore, the heat dissipation effect does not fall.

  Also in the case of FIG. 10, as in the first embodiment, the filler 51 a is not mixed into the phosphor 50, but is mixed into the divergence angle expanding portion 51, which is separate from the phosphor 50. The excitation light diffusion function and the fluorescence emission function can be separated. Therefore, as compared with the case where the excitation light diffusion function and the fluorescence emission function are integrated, it is possible to reliably obtain the same effects as those in the first embodiment, such as an uneven color prevention effect, a light emission efficiency reduction suppression effect, and a heat generation suppression effect. Can do.

38, 39 1st and 2nd light projection unit 50 Phosphor 51 Spreading angle expansion part 51a, 52a Filler 52 Illumination window 55 Ferrule 60 Sleeve

Claims (8)

In the endoscope projecting unit that is provided at the distal end of the endoscope and irradiates illumination light toward the subject,
A wavelength conversion member that absorbs a part of light of a predetermined wavelength and generates fluorescence by converting the wavelength, and transmits the remaining light, thereby emitting illumination light including the light of the predetermined wavelength and the fluorescence,
A divergence angle widening part that scatters the illumination light emitted from the wavelength conversion member with a scattering member mixed in a transparent base material to widen the spread angle of the illumination light; and
An illumination window for irradiating the scattered illumination light toward the subject,
The wavelength conversion member and the divergence angle widening portion, and the divergence angle widening portion and the illumination window are configured to be in close contact with each other, and the refractive index of the base material of the divergence angle widening portion is the wavelength conversion member. value der between the refractive index of the illumination window and the refractive index of the is,
The endoscope light projecting unit, wherein the wavelength conversion member and the divergence angle widening portion have a substantially cylindrical shape, and a diameter of the divergence angle widening portion is larger than a diameter of the wavelength conversion member . The refractive index of the wavelength conversion member is in the range of 1.46 to 2.0, the refractive index of the illumination window is in the range of 1.40 to 1.9, and the refractive index of the substrate is The endoscope according to claim 1 , wherein the endoscope is selected from a range of 1.40 to 2.0 according to a combination of refractive index values of the wavelength conversion member and the illumination window. Floodlight unit. Refractive index of the substrate, endoscope light projecting unit according to claim 1, wherein the a root mean square of the refractive index of the refractive index and the illumination window of the wavelength conversion member. The endoscope projection unit according to any one of claims 1 to 3, wherein the scattering member is not mixed in the wavelength conversion member. The substrate according to claim 1 to 4 endoscope light projection unit according to any one of the preceding, wherein the organic material. The endoscope projector unit according to claim 5 , wherein the base material is epoxy. The substrate according to claim 1 to 4 endoscope light projection unit according to any one of the preceding, wherein the inorganic material. Ferrule and, claims 1 to 7 endoscope light projection unit according to any one, characterized in that it comprises a metal sleeve for holding the said spread angle larger unit that holds the wavelength converting member.

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