JP6044611B2 - Light guide component and light source device - Google Patents

Description

  The present invention relates to a light guide technique for guiding light from a light source to a photoreceptor.

Endoscopes widely used as industrial equipment usually include a light guide that guides illumination light to an observation location, and a light source device that makes illumination light incident on the light guide is known (for example, (See Patent Document 1 and Patent Document 2).
In recent years, LEDs having a small light emitting point and a large amount of light per unit area have been put into practical use.

JP 2012-105715 A JP 2011-200380 A

  However, the light source device generally includes a condensing optical system that condenses the light of the light source on the incident surface of the light guide. However, in the conventional condensing optical system, the light emission efficiency of the LED in the light guide is low. It is difficult to efficiently use the light emission of the LED as illumination light for the endoscope. In particular, this problem becomes conspicuous because the light condensing performance at the condensing point decreases as the light emitting point increases.

  This invention is made | formed in view of the situation mentioned above, and it aims at providing the light guide component and light source device which can suppress a condensing fall, even when the light emission point of a light source is large.

In order to achieve the above object, the present invention is a cylindrical shape that extends from a light source including a plurality of light emitting points to at least the vicinity of the light receiving point, and has a line centering on a line connecting the light source and the light receiving point. A light guide comprising: a reflecting surface that collects light and guides it to an end surface of a light guide disposed at the light receiving point; and a light control element provided at an end of the reflecting surface on the light receiving point side The reflective surface is a surface formed by superimposing an elliptical reflective surface having the light emitting point as the first focal point and the light receiving point as the second focal point for each light emitting point of the light source, or on a circle. The light of the light source is reflected on the light emitting point side of the elliptical reflecting surface with the center of the circle of the light emitting points arranged densely as the first focal point and the light receiving point as the second focal point. The light is incident on the reflecting surface on the point side, and is incident on the reflecting surface on the light receiving point side. The light reflected by the light guide falls within the incident end face of the light guide and is equal to or smaller than the maximum incident angle θmax of the light guide (however, θmax = Arcsin (NA) when the numerical aperture of the light guide is NA). a surface provided with one sheet hyperbolic reflecting surface made, the light control element, by refracting light directed to the reflective surface of the end on the side of the receiving point, the exit angle of the emitted light, the light guide The maximum incident angle is not more than θmax.

According to the present invention, in the light guide component, the light control element refracts and condenses light directed to a reflection surface at an end on the light receiving point side, and the first lens body. And a second lens body that makes an emission angle of light incident from the light guide equal to or less than a maximum incident angle θmax of the light guide .

According to the present invention, in the light guide component, the second lens body having a refractive index larger than that of the first lens body is housed and integrated on an emission side of the first lens. .

Moreover, this invention is provided with the light guide component in any one of said, and the said light source, and the said light guide component combines two said reflective surfaces, and the optical path of each said reflective surface, and the optical path synthetic | combination optics. And the other reflecting surface is connected to one of the reflecting surfaces, and the optical paths of the reflecting surfaces are combined by the optical path combining optical element and condensed on the common light receiving point. Provided is a light source device including light sources having different wavelength bands on each of two reflection surfaces.

  According to the present invention, by including a plurality of light emitting points, even if the apparent light emitting point is large, the light control element controls the emitted light, so that a decrease in light collecting property at the light receiving point is suppressed. A reduction in the light source utilization efficiency in the light guide is suppressed.

It is a perspective view which shows the structure of the front side of the light source device which concerns on embodiment of this invention. It is a figure which shows the internal structure of a light source device. It is explanatory drawing of the assembly structure of a light source device. It is a disassembled perspective view of a built-in component unit. It is a figure which shows typically the structure of the reflective surface with which a condensing light guide is provided. It is explanatory drawing of an elliptical reflective surface. It is a schematic diagram which shows the structure of the light emission surface of an LED package. It is sectional drawing of a surface perpendicular | vertical to the central axis of a superimposition ellipsoid. It is sectional drawing of the surface containing the central axis of a rotary body (1st reflective surface). It is a figure which shows the illumination intensity distribution in the 2nd focus of a reflective surface. It is a figure which shows the light distribution characteristic of a reflective surface. It is sectional drawing of a condensing type light guide. It is an exploded view of a light control element. It is a figure which shows the light distribution characteristic of the reflective surface in which the light control element was installed. It is sectional drawing of the condensing type light guide which concerns on the modification of this invention. It is an exploded view of the light control element concerning the modification. It is explanatory drawing of the 1st reflective surface which concerns on the modification of this invention. It is a schematic diagram of the reflective surface which concerns on the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing the configuration of the front side of the light source device 1 according to this embodiment, and FIG. 2 is a diagram showing the internal structure of the light source device 1. In FIG. 2, the upper surface of the light source device 1 is not shown in order to show the internal structure of the light source device 1.
The light source device 1 makes light incident on a light guide 2 (FIG. 2) provided in an endoscope for observing the inside of a human body. The light incident on the light guide 2 is endoscopic by the light guide 2. The light is guided to the observation location and irradiated as illumination light.

  As shown in FIG. 1, the light source device 1 has a substantially rectangular parallelepiped shape, and the front surface 1 </ b> A of the light source device 1 is provided with a ventilation hole 4 and a mounting hole 5. A guide 2 is mounted. On the bottom surface 1B of the light source device 1, legs 6 are provided at the four corners. As shown in FIG. 2, the back surface 1 </ b> C of the light source device 1 is provided with an intake hole 11 through which cooling air is sucked and introduced, and a connector 38 to which wiring such as a power supply line and a control line is connected. ing.

The light source device 1 includes a case body 3, which includes two light source units 7A and 7B, a condensing light guide 8, a holder unit 9, and a heat dissipation fan, as shown in FIG. 10 is stored.
Specifically, a mounting stage 12 is provided in the case body 3 on the side of the front surface 3 </ b> A, and the holder unit 9 is mounted on the mounting stage 12. The case body 3 is provided with a frame plate 13 extending from the mounting stage 12 toward the back surface 3C. The light source units 7A and 7B and the concentrating light guide 8 are provided on the frame plate 13. And the heat radiating fan 10 are assembled.

FIG. 3 is an explanatory diagram for explaining an assembly structure of the light source device 1.
A unit insertion port 15 is provided on the back surface of the case body 3, and a built-in component unit 16 is inserted from the unit insertion port 15 and incorporated therein. The built-in component unit 16 is a unit body in which the light source units 7 </ b> A and 7 </ b> B, the condensing light guide 8, and the heat radiating fan 10 are assembled to the frame plate 13 in advance. A back panel 17 is assembled to the built-in component unit 16, and the back panel 17 closes the unit insertion port 15 of the case body 3 to constitute the back surface 1 </ b> C of the light source device 1.

FIG. 4 is an exploded perspective view of the built-in component unit 16.
Guide pieces 18, 18 are provided on both edges of the frame plate 13, and as shown in FIG. 3, guide grooves 19 for guiding the guide pieces 18, 18 are provided inside the case body 3. When the built-in component unit 16 is inserted, the guide pieces 18 and 18 are guided along the guide groove 19 to be accurately positioned inside the case body 3.
Further, when the built-in component unit 16 is assembled to the case body 3, the positional deviation between the holder unit 9 fixed in advance in the case body 3 and the concentrating light guide 8 of the built-in component unit 16 is shifted. In order to prevent this, two positioning pins 20 are provided on the front end portion 13B of the frame plate 13, that is, the contact surface with the mounting stage 12 that fixes the holder unit 9. When the built-in component unit 16 is inserted into the case body 3, these positioning pins 20 engage with positioning holes (not shown) of the mounting stage 12, and the condensing light guide 8 is accurately positioned with respect to the holder unit 9. Positioned.

Next, each part of the built-in component unit 16 will be described in detail.
Each of the light source unit 7A and the light source unit 7B is a unit constituting a light source of the light source device 1, and has different emission wavelengths. That is, as shown in FIG. 4, the light source unit 7A includes an LED unit 21A that emits light of the first wavelength band Δλ1, and the light source unit 7B is an LED that emits light of the second wavelength band Δλ2 different from the first wavelength band Δλ1. A unit 21B is provided. The first wavelength band Δλ1 and the second wavelength band Δλ2 will be described later.

  The LED unit 21A includes an LED package 24A that emits light in the first wavelength band Δλ1, and an LED substrate 23 on which the LED package 24A is mounted. Similarly to the LED unit 21A, the LED unit 21B is configured by mounting an LED package 24B that emits light in the second wavelength band Δλ2 on the LED substrate 23.

  The LED packages 24 </ b> A and 24 </ b> B include a plurality of LED chips 26 (FIG. 7) as an example of a light emitting element, and a resin bullet-type lens body 39 that covers these LED chips 26. Each LED chip 26 forms a square of about 1 mm square in plan view, and each upper surface serves as a light emitting surface (FIG. 7) and emits light. In the LED packages 24A and 24B, the light emitting surfaces 27 of these LED chips 26 gather to form an apparent light emitting surface 29 (FIG. 7) of the LED packages 24A and 24B.

Further, as shown in FIG. 4, the light source units 7A and 7B include a heat radiating unit 22 that radiates heat generated by the LED units 21A and 21B.
The heat radiating unit 22 is a unit body formed of a high thermal conductivity material on which the LED substrates 23 of the LED units 21A and 21B are placed, and includes a large number of heat radiating fins 25 integrally.

These light source units 7A and 7B have their upper surfaces 13A so that the optical axes K of the respective LED packages 24A and 24B are substantially parallel to the upper surface 13A of the frame plate 13 and the optical axes K intersect each other at 90 degrees. It is mounted almost vertically.
In the light source device 1, the light source unit 7 </ b> A is disposed so as to face the back panel 17, and the back heat radiation fan 10 is provided on the back panel 17. The heat radiating fan 10 sucks outside air from the air intake holes 11, and the outside air is blown to the heat radiating units 22 of the light source units 7 </ b> A and 7 </ b> B to be air-cooled and discharged outside through the air holes 4 on the front surface 1 </ b> A of the light source device 1.

  The light source units 7A and 7B are controlled to be lit by an LED drive circuit (not shown) disposed on the back side of the frame plate 13, for example. In the light source device 1, the two light source units 7A and 7B are lit simultaneously. Or only one of them can be lit.

The condensing light guide 8 is a light guide component that combines the light of the light source units 7A and 7B and guides the light to the holder unit 9 while condensing it. As shown in FIG. It has a shape and is fixed to the frame plate 13 by screwing four corners.
As shown in FIG. 4, the concentrating light guide 8 has a pair of plate members 30 and 31 that are joined up and down, and a reflection metal film is formed on the surface of the joining surface of each plate member 30 and 31. A deposited recess is formed. These plate members 30 and 31 are formed by using, for example, a mold made of a resin material, and the shape of the recesses is accurately formed. These recesses constitute a reflecting surface 40 having a light guiding function and a light collecting function by combining them. A light control element 60 is provided in the reflecting surface 40. Details of the reflecting surface 40 and the light control element 60 will be described later.

The concentrating light guide 8 is provided with light source side openings 32 and 33 for taking light into the reflecting surface 40 corresponding to the arrangement positions of the light source units 7A and 7B, and light reception as an emission opening on the front surface. A side opening 34 is provided, and the holder unit 9 is connected to the light receiving side opening 34.
The lens bodies 39 of the LED packages 24A and 24B are inserted into the light source side openings 32 and 33, and light leakage from the light source side openings 32 and 33 is suppressed.

  The holder unit 9 is for positioning and holding the incident end of the light guide 2 with respect to the emission end (second focal point f2 described later) of the condensing light guide 8, and as shown in FIG. The case body 3 is fixed and assembled to the mounting stage 12 in advance.

FIG. 5 is a diagram schematically illustrating the configuration of the reflecting surface 40 included in the concentrating light guide 8.
The reflecting surface 40 is a condensing optical system that condenses the light emitted from the LED packages 24A and 24B of the light source units 7A and 7B onto the incident end surface 35 of the light guide 2, and the light guide 2 is incident from the LED packages 24A and 24B. It has a shape that surrounds everything up to the vicinity of the end face 35 (front side).
Specifically, the reflecting surface 40 includes an elongated cylindrical first reflecting surface 50 extending to the vicinity of the incident end surface 35 and a cylindrical second reflecting surface connected perpendicularly to the side surface of the first reflecting surface 50. 51, the LED package 24 </ b> A is disposed at the end of the first reflecting surface 50, and the LED package 24 </ b> B is disposed at the end of the second reflecting surface 51.

The first reflecting surface 50 is a cylindrical condensing reflecting surface having a central axis L1, and in this example, the length along the central axis L1 is approximately 150 mm, and the maximum width in the direction perpendicular to the central axis L1 is It has a curved surface shape similar to a cigar shape or ellipsoid of about 33.8 mm.
The first reflecting surface 50 is open at both ends on the central axis L1 and is formed as the light source side opening 32 and the light receiving side opening 34, respectively. The LED package 24A is arranged in the light source side opening 32 with the optical axis K aligned with the central axis L1, and the light of the LED package 24A is incident on the first reflecting surface 50 from the light source side opening 32. An incident end face 35 of the light guide 2 is disposed at a position separated by a distance W in the light receiving side opening 34, and the light of the LED package 24 </ b> A guided while being condensed by the first reflecting surface 50 on the incident end face 35. Is incident.

  The second reflecting surface 51 is a condensing reflecting surface having a central axis L <b> 2, and an end portion on the side not connected to the first reflecting surface 50 is opened and formed as a light source side opening 33. In the light source side opening 33, the LED package 24 </ b> B is disposed with the optical axis K aligned with the central axis L <b> 2, and light is incident on the second reflecting surface 51. The second reflective surface 51 is connected to the side surface of the first reflective surface 50 so that the central axis L2 of the second reflective surface 51 intersects the central axis L1 of the first reflective surface 50 perpendicularly. .

On the central axis L1 of the first reflecting surface 50, a dichroic mirror 55 is disposed at an intersection M with the central axis L2. The dichroic mirror 55 is an optical path combining optical element that is provided at an incident angle of 45 degrees with respect to each of the central axes L 1 and L 2 and combines the optical path of the second reflecting surface 51 with the optical path of the first reflecting surface 50. As shown in FIG. 4, the first reflecting surface 50 is provided with a mirror insertion groove 43, and the edge of the dichroic mirror 55 is inserted into the mirror insertion groove 43.
Instead of the dichroic mirror 55, other optical path combining optical elements such as a prism and a half mirror can be used.

  In the reflective surface 40, the dichroic mirror 55 is disposed at the intersection point M, so that the second reflective surface 51 can be regarded as geometrically optically equivalent to the first reflective surface 50 as viewed from the intersection point M (that is, the same structure). Configured as follows. Therefore, the light incident from the light source side opening 33 of the second reflecting surface 51 is guided while being condensed toward the light receiving side opening 34 of the second reflecting surface 51, similarly to the first reflecting surface 50, and the light guide. 2 is incident on the second incident end face 35.

  As described above, the light of the LED package 24A that radiates the first wavelength band Δλ1 and the light of the LED package 24B that radiates the second wavelength band Δλ2 are incident on the reflecting surface 40, so that both of them blink. Accordingly, the light in the first wavelength band Δλ1, the light in the second wavelength band Δλ2, and the light in the wavelength band obtained by combining the first and second wavelength bands Δλ1 and Δλ2 are incident on the light receiving side opening 34. .

Here, since the second reflection surface 51 is geometrically optically equivalent to the first reflection surface 50, the light guide function, the light collection function, and the optical path of the reflection surface 40 of the light condensing type light guide 8 are as follows. This is explained by the first reflecting surface 50 in FIG.
The first reflecting surface 50 is a condensing reflecting surface that condenses the light emitted from the light source side opening 32 to the light receiving side opening 34. The reflection surface is known, and before describing the first reflection surface 50, this elliptical reflection surface will be outlined.

FIG. 6 is an explanatory diagram of the elliptical reflecting surface 70.
The elliptical reflecting surface 70 is a reflecting surface that has two focal points, a first focal point f1 and a second focal point f2, and condenses light emitted from the first focal point f1 on the second focal point f2. Therefore, if the LED package 24A is arranged at the first focal point f1 of the elliptical reflecting surface 70 and the incident end face 35 of the light guide 2 is arranged at the second focal point f2, ideally all the light of the LED package 24A is incident. The light is condensed on the end face 35.

  However, as shown in FIG. 5, the light emitting surface 29 of the LED package 24 </ b> A is not small enough to be regarded as a point in the optical design of the first reflecting surface 50, and has a certain size D <b> 1. Therefore, as shown in FIG. 6, the reflected light traveling from the light emitting surface 29 of the first focal point f1 toward the second focal point f2 spreads at an angle γ corresponding to the size D1 of the light emitting surface 29, and from the second focal point f2. The component which comes off arises. As a result, a component that does not enter the range of the opening diameter D2 (FIG. 5) of the incident end face 35 of the light guide 2 is generated and a loss occurs, so that the light use efficiency is lowered.

  The light use efficiency decreases as the numerical aperture NA of the light guide 2 decreases, the aperture diameter D2 of the incident end face 35 of the light guide 2 decreases, and the size D1 of the light emitting surface 29 of the LED package 24A increases. Become prominent.

  Generally, in an endoscope, as the numerical aperture NA of the light guide 2 is smaller, the directivity of illumination light is improved, so that a light amount can be collected and irradiated in a narrow range. In the light source device 1, a light guide 2 having a numerical aperture NA of 0.2 to 0.35 (maximum incident angle θmax = Arcsin (NA) = 11.5 ° to 20 °) and an aperture diameter D2 of about 4 mm is used. The numerical aperture NA and the aperture diameter D2 are both smaller than those of a general light guide. Further, in the light source device 1, the size D1 of the light emitting surface 29 of the LED package 24A is approximately 2 to 3 mm, and if no measures are taken, the light use efficiency is significantly reduced.

  Therefore, in this concentrating light guide 8, the first reflecting surface 50 and the second reflecting surface 51 are not the elliptical reflecting surface 70, but the light emitting surface 29 has the size D1 as follows. Even in such a case, a decrease in light condensing performance is suppressed.

FIG. 7 is a schematic diagram showing the configuration of the light emitting surface 29 of the LED package 24A.
As described above, the LED package 24A includes the LED chips 26 as an example of a plurality of (four in the illustrated example) light emitting elements. Each LED chip 26 has a 1 mm square light emitting surface 27 that is substantially rectangular in plan view. By arranging these light emitting surfaces 27 adjacent to each other in a lattice shape, an apparent light emission of the LED package 24A covering 2 to 3 mm square. A surface 29 is formed. The configuration of the LED package 24B is the same as that of the LED package 24A except that the emission wavelength band of the LED chip 26 is different.

Here, the light emitting surface 27 of the LED chip 26 is used so that its size D3 can be regarded as one point in the optical design, or small enough that the light use efficiency falls within a reasonable range, The light emitting surface 27 of the LED chip 26 can be regarded as a light emitting point P.
Therefore, when it is assumed that the LED package 24A includes only one LED chip 26, the light of the LED package 24A can be written only by using the elliptical reflection surface 70 shown in FIG. The light can be efficiently incident on the incident end face 35 of the guide 2.
However, since the LED package 24 </ b> A includes a plurality of LED chips 26, when the elliptical reflecting surface 70 is set for one LED chip 26, a sufficient light collecting action cannot be obtained for the other LED chips 26. .

Therefore, as shown in FIG. 8, a superimposed elliptical surface 80, which is a curved surface in which all of the elliptical reflective surfaces 70 defined for each LED chip 26 (that is, the light emitting point P) are superimposed, is formed. According to the superimposed elliptical surface 80, since the light condensing action to the second focal point f2 is obtained for all the LED chips 26, even if the LED package 24A includes a plurality of LED chips 26, Light is collected at the two focal points f2, and a decrease in the light utilization efficiency is suppressed.
In particular, as shown in FIG. 7, in the LED package 24 </ b> A, the light emitting surface 27 of each LED chip 26 is arranged on a circle centered on the center O, so that the second focal point is equally distributed to all the LED chips 26. The light condensing action to f2 is obtained.

  Here, as shown in FIG. 8, the overlapping ellipsoidal surface 80 is formed by connecting the outlines of the figures obtained by combining the ellipsoidal reflecting surfaces 70, so that the boundary line 81 connecting the ellipsoidal reflecting surfaces 70 is in the plane. It has a complicated shape. In addition, the overlapping ellipsoidal surface 80 has anisotropy around the central axis L <b> 1 by the respective ellipsoidal reflecting surfaces 70. For this reason, unless each LED chip 26 of the LED package 24A is arranged in alignment with the first focal point f1 of each elliptical reflecting surface 70 of the overlapping ellipsoidal surface 80, the light condensing property will be lowered. The alignment of the ellipsoid 80 and the LED package 24A becomes complicated.

Therefore, in the first reflecting surface 50, anisotropy around the central axis L1 is eliminated while suppressing a decrease in light collecting property as follows.
That is, as shown in FIG. 9, an elliptic curve 83 is defined in which the light emitting surface 27 (light emitting point P) of any LED chip 26 is the first focal point f1, and the incident end surface 35 of the light guide 2 is the second focal point. The rotating body 85 rotated about a straight line connecting the center O of the light emitting surface 29 of the LED package 24A and the second focal point f2 (the central axis L1 of the first reflecting surface 50) is used as the first reflecting surface 50.

  In the LED package 24A, as described above, the light emitting surface 27 (center P) of each LED chip 26 is arranged on a circle centered on the center O. Therefore, the rotating body 85 in which the elliptic curve 83 is rotated. In this case, the locus Q (FIG. 7) of the first focal point f1 accompanying the rotation passes through the light emitting points P of the light emitting surfaces 27 of all the LED chips 26. That is, the rotating body 85 is superimposed so as to include all the components of the elliptical reflecting surface 70 defined for each light emitting surface 27 (light emitting point P) of the LED chip 26, similarly to the superimposed elliptical surface 80. I can say that.

  Therefore, by reducing the shape of the rotating body 85 to the shape of the first reflecting surface 50, even if the LED package 24 </ b> A has a plurality of LED chips 26, a decrease in light collecting performance is suppressed. In addition, the rotator 85 has a rotator shape around the central axis L1, so there is no anisotropy around the central axis L1, and the central axis L1 of each LED chip 26 and the first reflecting surface 50 of the LED package 24A. Positioning around is unnecessary.

  In addition, the reflective surface 40 of this condensing type light guide 8 has the 2nd reflective surface 51 in addition to the 1st reflective surface 50 as above-mentioned, and this 2nd reflective surface 51 is also the 1st reflective surface 50. Similarly to the above, the rotating body 85 is used.

FIG. 10 is a diagram showing an illuminance distribution at the second focal point f2 of the reflecting surface 40. As shown in FIG.
When the first reflecting surface 50 and the second reflecting surface 51 are simple elliptical reflecting surfaces 70, as described above, the collection at the second focal point f2 is caused by the size D1 of the light emitting surface 29 of the LED package 24A. The light property deteriorates, and the distribution is as shown by a broken line in FIG.
On the other hand, according to this condensing type light guide 8, since the 1st reflective surface 50 and the 2nd reflective surface 51 are comprised by the said rotary body 85, as shown in FIG. At the two focal points f2, an illuminance distribution having a sharp peak on the central axis L1 is obtained, and a good light collecting property is obtained.

FIG. 11 is a diagram showing the light distribution characteristics of the reflecting surface 40.
When the first reflection surface 50 and the second reflection surface 51 (that is, the reflection surface 40) are simple elliptical reflection surfaces 70, the inventor has found that the half-value angle (2α) of the light distribution characteristic is about 46 through experiments and simulations. It has been found that the value is more than °.
On the other hand, this reflective surface 40 has a half-value angle (2α) of about 26 degrees, and it can be seen that the light condensing property is improved as compared with the elliptical reflective surface 70.
The angle used for the half-value angle is an angle α (hereinafter referred to as “exit angle”) formed by the optical axis K and the light beam. In the description of the present embodiment, the emission angle α is the same as the incident angle θ to the light guide 2.

  Thus, in the condensing light guide 8, even when the LED packages 24A and 24B including the plurality of LED chips 26 are used as the light source, the light condensing property at the second focal point f2 is good. Thus, light is efficiently incident on the light guide 2 disposed at the second focal point f2.

As described above, the light distribution characteristic of the reflecting surface 40 has a good half-value angle (2α). Therefore, as shown in FIG. 11, the peak range Wp of the emission angle α is within a range of about 20 °. However, in this reflection surface 40, the light intensity of the range Wa on both sides of the peak range Wp (hereinafter referred to as “side lobe range”) is relatively large, and the light component having an emission angle α exceeding 20 ° is also large in the output light. It is understood that it is included.
As described above, the light source device 1 is used for the light source of the light guide 2 having a numerical aperture NA of 0.2 to 0.35 (maximum incident angle θmax = Arcsin (NA) = 11.5 ° to 20 °). It is. Therefore, even if the illuminance distribution at the second focal point f2 has a sharp peak at the central axis L1, if the light included in the peak contains a light component with an emission angle α exceeding 20 °, the light Even if the component enters the light guide 2, it is lost without being guided.

  Therefore, in the light source device 1, the light condensing light guide 8 includes the light control element 60 provided in the reflection surface 40, so that the light intensity in the side lobe range Wa is reduced. ing.

FIG. 12 is a cross-sectional view of the concentrating light guide 8. In this figure, a cross section of the concentrating light guide 8 cut so as to include the optical axis K of the reflecting surface 40 is shown together with the LED packages 24A and 24B.
The light control element 60 is a transmissive optical element that transmits light directed to the light receiving side opening 34 in the reflecting surface 40, and is an end of the reflecting surface 40 on the side of the second focal point f2 that is a light receiving point (hereinafter, “ 48 ”(referred to as“ light receiving point side end ”).
The light control element 60 controls the light component H1 directed to the reflection surface 40 of the light receiving point side end portion 48, and the emission angle α of the light component H1 is a predetermined angle (in the light source device 1, the maximum incident angle θmax). ) It has a function of controlling to be directed to the second focal point f2 at an angle as follows.
More specifically, in the general elliptical reflecting surface 70, the incident angle θ at which the reflected light is incident on the second focal point f2 is reflected at a location away from the first focal point f1, that is, a location closer to the second focal point f2. The larger the reflection, the larger it becomes.

Since this reflection surface 40 is also based on the elliptical reflection surface 70, the incident angle θ of the reflected light becomes larger as it is reflected at a location closer to the second focus f2, and a predetermined end portion on the second focus f2 side is determined. The light reflected in the range Y will exceed the maximum incident angle θmax.
Therefore, the light control element 60 controls the directivity direction of the light component H1 directed to the reflection surface 40 in the predetermined range Y so as to be incident on the second focal point f2 at a maximum incident angle θmax or less. Thereby, in the light distribution characteristic, the light intensity in the peak range Pw is increased and the light intensity in the side lobe range Wa is reduced, so that the loss in the light guide 2 is suppressed and the efficiency is increased.

FIG. 13 is an exploded view of the light control element 60.
The light control element 60 includes a first lens body 61 and a second lens body 62 as shown in FIG. The first lens body 61 refracts the light component H1 in a direction that prevents the light receiving point side end portion 48 from being incident on the reflecting surface 40, and the second lens body 62 projects the first lens body 61 from the first lens body 61. The emission angle α of the incident light is controlled to be equal to or less than the maximum incident angle θmax.

  More specifically, the first lens body 61 is a transmissive optical element having a function of condensing incident light, and has a substantially cylindrical body portion 61C. One end surface is a convex incident surface 61A. The other end surface that is formed and has a reduced diameter is formed as an exit surface 61B. As shown in FIG. 13, the incident surface 61A is arranged in accordance with the entrance position Ya where the light enters the predetermined range Y, and the exit surface 61B is in front of the second focus f2 (more precisely, the light receiving side opening 34). To the second lens body 62 so as to secure a space for arranging the second lens body 62). The body portion 61 </ b> C is formed in a shape that engages with the reflecting surface 40, and the first lens body 61 is fitted and fixed to the reflecting surface 40.

The incident surface 61A is incident on the reflecting surface 40 in a predetermined range Y with respect to the optical axis K, that is, the optical axis K with respect to a light component (corresponding to the light component H1) at an angle incident on the peripheral surface of the body 61C. It is formed in a curved surface that gives refraction at a refraction angle such that the light is condensed.
Further, the curved surface of the incident surface 61A has a refraction given to the light component H1 with respect to a light component having an angle not incident on the peripheral surface of the body portion 61C, that is, a light component H2 (FIG. 12) directed to the second focal point F1. It is also a curved surface that gives refraction smaller than an angle.
The exit surface 61B is a surface connecting the first lens body 61 and the second lens body 62, and the entrance surface 62A of the second lens body 62 is fitted with no gap.

The second lens body 62 is a transmissive optical element having a function of condensing the light incident from the first lens body 61 on the second focal point f2, and a drum lens is used for the second lens body 62. .
The second lens body 62 has an entrance surface 62A and an exit surface 62B formed as convex surfaces, and has a refractive index n2 larger than the refractive index n1 of the first lens body 61.
The second lens body 62 has a curvature and a refractive index of the convex surfaces of the incident surface 62A and the output surface 62B so that the output angle α of the output light does not exceed the maximum incident angle θmax and is focused on the second focal point f2. n2 is set.

According to the light control element 60, the first lens body 61 is refracted so that the light component H1 is condensed, so that the incidence on the body 61C is suppressed, and the second lens body together with the other light components H2. 62 is incident. Then, in the second lens body 62, the light components H1 and H2 are focused on the second focal point f2, and once condensed, the emission angle α does not exceed the maximum incident angle θmax (˜20 ° in this embodiment). Will be.
Further, the light control element 60 is provided in the light receiving side opening 34 of the concentrating light guide 8, and the light control element 60 collects light at the second focal point f2, so that the condensing property at the second focal point f2 is improved. It is done.

FIG. 14 is a diagram showing the light distribution characteristics of the reflecting surface 40 (that is, the condensing light guide 8) in which the light control element 60 is installed.
As is clear from the comparison between FIG. 14 and FIG. 11, the light distribution characteristic when the light control element 60 is provided in the reflecting surface 40 is the sidelobe range compared to the case where the light control element 60 is not provided. It can be seen that the light intensity of Wa is greatly suppressed, and the light intensity is collected in the peak range Wp where the emission angle α is in the range of 20 ° or less.

  And as above-mentioned, in this condensing type light guide 8, even if it is a case where LED package 24A, 24B provided with the some LED chip 26 is used for a light source, the condensing in the 2nd focus f2. Therefore, the light is collected and incident on the light guide 2 arranged at the second focal point f2, and the incident light guides the light guide 2 without loss.

In the light source device 1, as described above, each of the LED packages 24A and 24B has a different wavelength band of emitted light, the LED package 24A emits light of the first wavelength band Δλ1, and the LED package 24B has a second wavelength. The light of the band Δλ2 is emitted.
The first wavelength band Δλ1 and the second wavelength band Δλ2 are determined in accordance with the purpose of use of the light source device 1, and the light source device 1 is based on the use of an endoscope and the material of the light guide 2. The first wavelength band Δλ1 is set with a wavelength band of 700 nm or less (visible light having a near infrared wavelength or less), and the second wavelength band Δλ2 is set with a wavelength band of 700 nm or more (near infrared wavelength or more). Has been. The first wavelength band Δλ1 and the second wavelength band Δλ2 do not have to be partially overlapped, that is, completely separated from each other.

The LED package 24A that emits light in the first wavelength band Δλ1 includes an LED chip 26 that emits red light (R), an LED chip 26 that emits green light (G), an LED chip 26 that emits blue light (B), and white light. As shown in FIG. 7, a total of four LED chips 26 of LED chips 26 that emit light are arranged in a grid pattern. As described above, by combining the LED chips 26 having different emission colors, light in a desired wavelength band can be easily obtained.
On the other hand, the LED package 24B that emits light in the second wavelength band Δλ2 is configured by arranging four LED chips 26 that emit the same near-infrared light (IR) in a grid pattern as shown in FIG. . Thus, the light output can be easily increased by combining the LED chips 26 having the same emission color.

  Each of the LED packages 24A and 24B includes the plurality of LED chips 26, so that even when each of the LED packages 24A and 24B has a large light emitting surface 29, each light emitting surface 29 is obtained by using the concentrating light guide 8. Therefore, it is possible to maintain the light condensing property to the second focal point f2 well, to efficiently enter the light guide 2, and to guide the light guide 2 without loss.

As described above, according to the present embodiment, the curved reflection surface 40 based on the elliptical reflection surface 70 that condenses and guides the light at the first focal point f1 to the second focal point f2 that is the light receiving point. The light control element 60 is installed in the light receiving point side end portion 48, the light control element 60 refracts the light component H1 directed to the reflection surface 40 of the light receiving point side end portion 48, and the emission angle α is equal to or less than a predetermined angle. It was set as the structure controlled so that it might become.
As a result, the reflection of the light component H1 at the light receiving point side end portion 48 is suppressed, and the emission angle α is controlled to be equal to or smaller than the predetermined angle, so that the light intensity is concentrated in the peak range Pw in the light distribution characteristics. Thus, a characteristic in which the light intensity in the side lobe range Wa is greatly reduced can be obtained.
The predetermined angle of the emission angle α is set based on the application of the light source device 1. In the light source device 1, the predetermined angle is set based on the maximum incident angle θmax of the light guide 2.

Further, according to the present embodiment, the light control element 60 includes the first lens body 61 that refracts and collects the light component H1 directed to the reflection surface 40 of the light receiving point side end portion 48, and the first lens body 61. And a second lens body 62 that sets the exit angle α of the condensed light to a predetermined angle or less.
According to this configuration, the first lens body 61 reliably suppresses the reflection of the light component H1 directed to the reflection surface 40 of the light receiving point side end portion 48, and the second lens body 62 emits the emission angle of the emitted light. α is accurately controlled to be kept below a predetermined angle.
That is, according to the light control element 60, it is possible to accurately control the reflection of the light component H1 and control the emission angle α of the emitted light.

Further, according to the present embodiment, the reflection surface 40 (first reflection surface 50) of the condensing light guide 8 is used as the first focal point f1 and the light receiving point of the light emitting surface 27 of the LED chip 26 provided in the LED package 24A. The incident end face 35 of the light guide 2 was used as the second focal point f2, and each of the elliptical reflecting faces 70 defined for each LED chip 26 was formed so as to overlap.
Thereby, the condensing action to the second focal point f2 is obtained for all the LED chips 26, and even when the LED package 24A includes a plurality of LED chips 26, the light condensing performance is maintained well, and the light The use efficiency is reduced.

  In particular, according to the present embodiment, in the LED package 24A, each LED chip 26 is arranged on a circle centered on the center O, and an elliptical reflecting surface 70 corresponding to each LED chip 26 arranged on this circle. Therefore, it is possible to obtain the light condensing action to the second focal point f2 equally for all the LED chips 26.

Further, according to the present embodiment, the shape of the reflecting surface 40 (first reflecting surface 50) is set such that one of the LED chips 26 has the first focal point f1, and the incident end surface 35 of the light guide 2 as the light receiving point has the second focal point f2. Is defined as the shape of the rotating body 85 rotated around a straight line connecting the center O of each LED chip 26 and the second focal point f2 (that is, the central axis L1).
Since the rotating body 85 includes all components of the elliptical reflecting surface 70 defined for each light emitting surface 27 of the LED chip 26, the shape of the rotating body 85 is changed to the shape of the first reflecting surface 50. Even when the LED package 24 </ b> A has a plurality of LED chips 26, a decrease in light collecting property is suppressed. In addition, the rotator 85 has a rotator shape around the central axis L1, so there is no anisotropy around the central axis L1, and the central axis L1 of each LED chip 26 and the first reflecting surface 50 of the LED package 24A. It is not necessary to align the surroundings.

Further, according to the present embodiment, the reflecting surface 40 includes the first reflecting surface 50 and the second reflecting surface 51, and the dichroic mirror that combines the optical paths of the first reflecting surface 50 and the second reflecting surface 51. 55, a second reflecting surface 51 is connected to the first reflecting surface 50, and light paths of the first reflecting surface 50 and the second reflecting surface 51 are combined by a dichroic mirror 55, and a light guide serving as a common light receiving point. 2 is configured to collect light on the incident end surface 35.
Accordingly, the light sources arranged on the first reflecting surface 50 and the second reflecting surface 51 can be easily combined and efficiently incident on the light guide 2.

  In particular, in the light source device 1 of the present embodiment, since the emission wavelengths of the light sources arranged on the first reflecting surface 50 and the second reflecting surface 51 are made different, the wavelength of light incident on the light guide 2 is used. Can be selected.

  The above-described embodiments are merely examples of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

  The light control element according to the present invention gives the light component H1 refraction to prevent the light receiving point side end portion 48 from entering the reflection surface 40, and the emission angle α of the emitted light is equal to or less than a predetermined angle. The light control element 60 is not limited to the above-described light control element 60.

FIG. 15 is a cross-sectional view of the concentrating light guide 108 according to this modification. FIG. 16 is an exploded view of the light control element 160 according to this modification. In FIG. 15, a cross section of the condensing light guide 108 cut so as to include the optical axis K of the reflecting surface 40 is shown together with the LED packages 24 </ b> A and 24 </ b> B.
The light condensing light guide 108 of the present modification is different from the light control element 60 in the structure of the light control element 160, and is otherwise the same as the light concentrating light guide 8.

The light control element 160 refracts the light component H1 in a direction that prevents the light receiving point side end portion 48 from being incident on the reflection surface 40, and the emission angle of the emitted light from the first lens body 161. and a second lens body 162 for adjusting α.
The first lens body 161 is a transmissive optical element having a function of condensing incident light, and has a substantially conical body portion 161 </ b> C that is curved so as to be engaged with the reflecting surface 40. It is formed as a convex incident surface 161A. The incident surface 161A is formed as a convex surface having different curvatures in the central portion 161A1 including the optical axis K and the peripheral portion 161A2. In the first lens body 161, the central portion 161A1 has a larger curvature than the peripheral portion 161A2.
As described above, since the incident surface 161A has two curvatures, the light component H1 and the other light component H2 are controlled to give refraction to each of the pair.

The focal point of the incident surface 161A is set on the optical axis K in the trunk portion 161C in both the central portion 161A1 and the peripheral portion 161A2. The body 161C is provided with an insertion hole 161D that is recessed along the optical axis K from the end surface on the opposite side of the incident surface 161A. The second lens body 162 is inserted into the insertion hole D without a gap (without an air layer interposed), whereby the second lens body 162 is accommodated in the first lens body 161 and the light control element 160 is inserted. Are integrated.
By integrating the light control element 160 in this way, the first lens body 161 and the second lens body 162 are prevented from being displaced, and the light source device 1 and the condensing light guide 108 can be easily assembled. Become.

  The second lens body 162 is a transmissive optical element having a function of emitting light incident from the first lens body 161 from the emission surface 162B having a predetermined light beam diameter Dr. Specifically, a substantially conical lens is used for the second lens body 162, the outer peripheral surface is formed as the incident surface 162A, and the bottom surface is formed as the output surface 162B having the diameter of the light beam diameter Dr. The refractive index n2 is smaller than the refractive index n1. The light beam diameter Dr is set based on the irradiation range at the light receiving point, and is set based on the diameter of the incident end face 35 of the light guide 2 in the concentrating light guide 108.

The incident surface 162A of the second lens body 162 is a curved surface (tapered surface, free surface) that directs the light incident from the first lens body 161 toward the output surface 162B and gives refraction with an output angle α equal to or less than a predetermined angle. (Object surface or elliptical surface).
Therefore, the outgoing surface 162B of the second lens body 162 emits outgoing light having an outgoing angle α that is equal to or smaller than a predetermined angle and a predetermined luminous flux diameter Dr.
Thereby, according to this condensing type light guide 108, light gathers within the range of the incident end surface 35 of the light guide 2, and the light guided through the light guide 2 without loss can be emitted.

  For example, in the above-described embodiment, in LED packages 24A and 24B including a plurality of LED chips 26 arranged on a circle, another LED chip 26 may be arranged inside these LED chips 26.

Further, for example, instead of the LED packages 24A and 24B having a plurality of LED chips 26, as shown in FIG. 17, a COB that is a surface emitting light source in which a large number of LEDs are densely arranged to form one large light emitting surface 129. A type LED 124 (COB: Chip on Board) can also be used.
In this case, the shape of the first reflecting surface 150 is within the light emitting surface 129, and the first focal point f1 is a position off the center O of the light emitting surface 129, and the incident end surface 35 of the light guide 2 is a light receiving point. The elliptical curve having the second focal point f2 is formed into the shape of the rotating body 185 obtained by rotating the elliptical curve about the straight line connecting the center O of the light emitting surface 129 and the second focal point f2. At this time, the position of the first focal point f1 on the light emitting surface 129 is preferably an intermediate point from the center O of the light emitting surface 129 to the outer edge 129A.

  Moreover, in embodiment mentioned above, a light emitting element is not restricted to LED, Other elements may be sufficient.

  In the above-described embodiment, the light of the two LED packages 24A and 24B is synthesized by the dichroic mirror 55. However, the present invention is not limited to this. That is, for example, three or more lights may be combined by using a dichroic prism instead of the dichroic mirror 55. Further, the reflective surface 40 may be configured by only the first reflective surface 50 without providing the second reflective surface 51 on the reflective surface 40.

Further, for example, in the above-described embodiment, when the size of the light source is such that the light collecting property is not hindered, the reflection surface 40 may be the elliptical reflection surface 70.
When the reflecting surface 40 is the elliptical reflecting surface 70, the light from the light source is reflected toward the reflecting surface 40 on the light receiving point (second focal point f2) side toward the light emitting point (first focal point f1). In addition, a curved reflecting surface that obtains light directed at a predetermined incident angle at the light receiving point by reflection on the reflecting surface 40 on the light receiving point side may be provided. The technique disclosed in Japanese Patent Application No. 2012-232292 can be used for such a reflective surface.

FIG. 18 is a schematic diagram of the reflecting surface 140 according to this modification.
As shown in FIG. 18, the reflection surface 40 has a configuration of a compound elliptical mirror in which the reflection region Rc on the first focal point f1 side of the elliptical reflection surface 70 is a hyperbolic reflection surface 140A.
The hyperbolic reflection surface 140A obtains reflected light directed to the second focal point f2 by using the reflected light (primary reflected light) reflected by the elliptical reflecting surface 70 (secondary reflected light). The hyperbolic reflection surface 140A is configured so that the reflected light at the light receiving point side end portion 48 of the elliptical reflection surface 70 falls within the incident end surface 35 of the light guide 2 and is incident at a maximum incident angle θmax or less. It is designed to make light incident on Ra.
As a result, the reflected light E (primary reflected light) at the reflection region Rc is reflected by the elliptical reflecting surface 70 and is reflected at an angle equal to or smaller than the maximum incident angle θmax and within the range of the opening diameter D2 of the light guide 2. Therefore, most of the reflected light from the reflection region Rc can be made incident on the light guide 2, and the use efficiency of light emission of the LED packages 24 and 24B is improved.
Furthermore, the light control elements 60 and 160 are provided at the light receiving point side end portion 48 of the reflecting surface 14 so that light can be efficiently incident on the light guide 2 and guided without loss.

DESCRIPTION OF SYMBOLS 1 Light source device 7A, 7B Light source unit 8, 108 Condensing light guide (light guide component)
24A, 24B LED package 26 LED chip 27 Light emitting surface (light emitting point)
29 Apparent light emitting surface 129 Light emitting surface of surface emitting light source 32, 33 Light source side opening 34 Light receiving side opening 35 Incident end surface 40, 140 Reflecting surface 48 Light receiving point side end 50, 150 First reflecting surface (reflecting surface)
51 Second reflecting surface 55 Dichroic mirror (optical path combining optical element)
60, 160 Light control element 61, 161 First lens body 62, 162 Second lens body 70 Ellipsoidal reflecting surface 80 Superimposed ellipsoidal surface 81 Borderline 83 Elliptic curve 85, 185 Rotating body f1 First focal point f2 Second focal point K Optical axis L1, L2 Center axis M Intersection point O Arrangement center P Light emission point Y Predetermined range Ya entry position Wa Sidelobe range Wp Peak range θmax Maximum incident angle

Claims (4)

A cylindrical shape extending from a light source including a plurality of light emitting points to at least the vicinity of the light receiving point, centering on a line connecting the light source and the light receiving point, and condensing the light from the light source and disposed at the light receiving point A reflective surface leading to the end surface of the light guide,
A light control element provided at the end of the reflecting surface on the light receiving point side, and a light guide component comprising:
The reflective surface is
A surface formed by superimposing an elliptical reflecting surface having the light emitting point as a first focal point and the light receiving point as a second focal point for each light emitting point of the light source, or
The light of the light source is reflected on the side of the light emitting point of the elliptical reflecting surface with the center of the circle of the light emitting points densely arranged on the circle as the first focal point and the light receiving point as the second focal point. The light incident on the reflecting surface on the light receiving point side and incident on the reflecting surface on the light receiving point side and reflected by the reflecting surface falls within the incident end surface of the light guide and the light. It is a surface provided with a one- leaf hyperbolic reflecting surface that is equal to or smaller than the maximum incident angle θmax of the guide (however, when the numerical aperture of the light guide is NA, θmax = Arcsin (NA))
The light control element is:
The light guide component, wherein the light directed toward the reflection surface at the end on the light receiving point side is refracted so that the outgoing angle of outgoing light is equal to or less than the maximum incident angle θmax of the light guide. The light control element is:
A first lens body that refracts and condenses light directed to the reflecting surface at the end on the light receiving point side;
A second lens body that sets an outgoing angle of light incident from the first lens body to be equal to or smaller than a maximum incident angle θmax of the light guide;
The light guide component according to claim 1, comprising:   The light guide component according to claim 2, wherein the second lens body having a refractive index larger than that of the first lens body is housed and integrated on an emission side of the first lens. The light guide component according to any one of claims 1 to 3,
The light source,
The light guide component is:
Two said reflective surfaces;
An optical path combining optical element for combining the optical paths of the respective reflecting surfaces,
The other reflection surface is connected to one of the reflection surfaces, and the optical paths of the respective reflection surfaces are combined by the optical path combining optical element, and are collected at a common light receiving point. Each of the light source devices includes light sources having different wavelength bands.