Light source device

Abstract

A light source device according to one embodiment of the present disclosure comprises: a light source unit that divides excitation light into a plurality of light beams and outputs the plurality of light beams; a light guide member includes a hollow light guide path on an inner side thereof, the hollow light guide path having a first opening and a second opening on an opposite side to the first opening, the light guide member having a plurality of wavelength converters disposed on at least a portion of a side surface of the light guide path, the plurality of wavelength converters are configured to emit light beams with different wave bands; and a light condensing device that guides each of the plurality of light beams output from the light source unit to a corresponding one of the plurality of wavelength converters.

Description

Technical Field

[0001] This disclosure relates, for example, to a light source device that includes an IR light source as the light source. Background Technology

[0002] For example, Patent Document 1 discloses a light source device in which a condenser lens, a dichroic mirror, and a light tube are arranged in the stated order along the optical path of light output from multiple solid-state light sources. The light tube includes a pair of openings (a first opening and a second opening), and a phosphor is arranged near the second opening on the side opposite to the dichroic mirror. The luminous flux (excitation beam) output from the multiple solid-state light sources is focused by the condenser lens to a predetermined position so as to be reflected by the dichroic mirror and incident on the light tube through the first opening. The luminous flux incident on the light tube passes through the interior of the light tube and illuminates the phosphor arranged near the second opening. The phosphor generates light (illumination light) with a predetermined wavelength. The illumination light generated by the phosphor travels in the opposite direction to the excitation light and exits from the first opening to pass through the dichroic mirror, thereby being extracted in a direction different from the luminous flux output from the multiple solid-state light sources.

[0003] Citation List

[0004] Patent documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-010181 Summary of the Invention

[0006] Incidentally, for example, high color rendering is required in light source devices used in medical equipment.

[0007] Therefore, it is desirable to provide a light source device with high color rendering.

[0008] A light source device according to an embodiment of the present disclosure includes: a light source unit that splits excitation light into a plurality of beams and outputs the plurality of beams; a light guide member that includes a hollow light guide path on its inner side, the hollow light guide path having a first opening and a second opening on a side opposite to the first opening, the light guide member having a plurality of wavelength converters disposed on at least a portion of the side of the light guide path, the plurality of wavelength converters being configured to emit beams having different wavelengths from each other; and a focusing device that guides each of the plurality of beams output from the light source unit to a corresponding wavelength converter among the plurality of wavelength converters.

[0009] In a light source device according to an embodiment of the present disclosure, by using a light source unit that outputs a plurality of segmented light beams, and a light guide member having a hollow light guide path having a first opening and a second opening on the side opposite to the first opening, and having a plurality of wavelength converters disposed on at least a portion of the side of the light guide path that emit light beams having different wavelengths from each other, each of the plurality of segmented light beams output from the light source unit as excitation light is applied via a focusing device to a corresponding wavelength converter among the plurality of wavelength converters disposed inside the light guide member. This allows for the extraction of light with a desired wavelength distribution. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating an example of the configuration of a light source device according to an embodiment of the present disclosure.

[0011] Figure 2 It is a diagrammatic explanation. Figure 1 The diagram shows an example of the structure of a light source unit.

[0012] Figure 3 It is a diagrammatic explanation. Figure 1 An illustrative exploded perspective view illustrating an example of the configuration of a light source unit.

[0013] Figure 4 It is a diagrammatic explanation. Figure 1 An illustrative perspective view illustrating an example of the structure of a light tube.

[0014] Figure 5 This is an illustration showing the relationship between the size of the aperture of the light tube and the size of the excitation light spot incident on the light tube.

[0015] Figure 6 This is an illustration showing the position of the phosphor layer arranged within the light guide path of the light tube.

[0016] Figure 7A It is incident on Figure 1 The diagram shows the angular distribution of the excitation light from the optical tube.

[0017] Figure 7B It is incident on Figure 1 The diagram shows the illuminance distribution of the illumination light from the light guide.

[0018] Figure 8 From Figure 1 The diagram shows the angular distribution of the illumination light output from the tube's outlet.

[0019] Figure 9 It is through the diffuser plate from Figure 1 The diagram shows the angular distribution of the illumination light output from the tube's outlet.

[0020] Figure 10 It is a wavelength distribution diagram of illumination light extracted from a general light source device.

[0021] Figure 11 From Figure 1 The diagram shows the wavelength distribution of the illumination light extracted by the light source device.

[0022] Figure 12 This is a schematic diagram illustrating an example of the configuration of a light source device according to a variation of Example 1 of this disclosure.

[0023] Figure 13 This is a schematic diagram illustrating an example of the configuration of a light source device according to a variation 2 of this disclosure.

[0024] Figure 14 This is a schematic diagram illustrating an example of the configuration of a light source device according to Modification 3 of this disclosure.

[0025] Figure 15A This is an explanatory diagram illustrating an example of the structure of a phosphor layer arranged in the light guide path of a light tube according to a modified example 4 of this disclosure.

[0026] Figure 15B This is an explanatory diagram illustrating an example of the structure of a phosphor layer arranged in the light guide path of a light tube according to a modified example 4 of this disclosure.

[0027] Figure 16 This is an explanatory diagram illustrating an example of the structure of a phosphor layer arranged in the light guide path of a light tube according to a modified example 4 of this disclosure. Detailed Implementation

[0028] In the following, embodiments for practicing this disclosure will be described in detail with reference to the accompanying drawings. The following description are specific examples of this disclosure, and this disclosure is not limited to the following embodiments. Furthermore, this disclosure does not limit the arrangement, dimensions, aspect ratios, etc., of the corresponding components illustrated in the drawings. It should be noted that the description is given in the following order.

[0029] 1. Embodiment (including an example of a light source device comprising a light source unit capable of splitting a light beam and an optical tube including a wavelength converter on the side of the light guide path)

[0030] 2. Variations

[0031] 2-1. Variation Example 1 (Another example of the configuration of a light source device)

[0032] 2-2. Variation Example 2 (Another example of the configuration of a light source device)

[0033] 2-3. Variation Example 3 (Another example of the configuration of a light source device)

[0034] 2-4. Variation Example 4 (Another example of the construction of a wavelength converter)

[0035] <1. Example>

[0036] Figure 1 This is an illustration illustrating an example of the configuration of a light source device (light source device 1) according to an embodiment of the present disclosure. The light source device 1 is used, for example, as a light source for medical devices such as gastroscopy cameras or endoscope cameras. The light source device 1 of this embodiment includes: a light source unit 11 that splits excitation light into multiple beams and outputs the multiple beams; a light tube 14 having a hollow light guide path 140 inside it, the light tube 14 including multiple phosphor layers (red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and near-infrared (Ir) phosphor layer 154) disposed on a portion of the side of the light guide path 140, the multiple phosphor layers being configured to emit light beams having different wavelengths from each other; and a condenser lens 13 disposed between the light source unit 11 and the light tube 14. Each of the multiple light beams (excitation beams EL1, EL2, EL3, and EL4) output from the light source unit 11 illuminates a corresponding one of the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154 disposed on the side of the light guide path 140 via the condenser lens 13. This allows illumination light with a desired wavelength distribution to be extracted from the light tube 14.

[0037] [Composition of the light source device]

[0038] The light source device 1 includes, for example, a light source unit 11, a condenser lens 13, a light tube 14, and a wavelength converter 15. The light source device 1 also includes a beam shaping device 12, a diffuser plate 21, and a light guide 30.

[0039] Here, light source unit 11 corresponds to a specific example of a "light source unit" in the embodiments of this disclosure. Light pipe 14 corresponds to a specific example of a "light guide member" in the embodiments of this disclosure. Red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154 correspond to a specific example of a "multiple wavelength converter" in the embodiments of this disclosure. Condensing lens 13 corresponds to a specific example of a "condensing device" in the embodiments of this disclosure.

[0040] The components constituting the aforementioned light source device 1 are arranged as follows: The light source unit 11 is arranged to output multiple output beams in the Z-axis direction. In the output direction (Z-axis direction) of the light source unit 11, the beam shaping device 12, the condenser lens 13, the light tube 14, the diffuser plate 21, and the light guide 30 are arranged in the order described above. Multiple phosphor layers (red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and near-infrared (Ir) phosphor layer 154) are disposed on the inner side surface of the light tube 14.

[0041] The light source unit 11 is a light source capable of outputting multiple segmented beams. Specifically, the light source unit 11 is configured to output segmented beams corresponding to the number of phosphor layers disposed on the side of the light guide path 140, which is located inside the light tube 14 arranged in the stage following the light source unit 11.

[0042] Although details are described later, for example, the light tube 14 includes a hollow light guide path 140 on its inner side, the hollow light guide path 140 having four sides 140S1, 140S2, 140S3, and 140S4 opposite to each other in the vertical and horizontal directions, and each of the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154 is disposed on a corresponding one of the four sides 140S1, 140S2, 140S3, and 140S4. The phosphor layers 151, 152, 153, and 154 are respectively illuminated by independent excitation beams EL1, EL2, EL3, and EL4. That is, the light source unit 11 outputs four independent beams (excitation beams EL1, EL2, EL3, and EL4) that respectively illuminate the four types of phosphor layers 151, 152, 153, and 154.

[0043] For example, such as Figure 2 As shown in the diagram, the light source unit 11 includes four light source blocks (red light source block 110R, green light source block 110G, blue light source block 110B, and IR light source block 110Ir). The red light source block 110R outputs a light beam illuminating the red phosphor layer 151 (excitation light EL1). The green light source block 110G outputs a light beam illuminating the green phosphor layer 152 (excitation light EL2). The blue light source block 110B outputs a light beam illuminating the blue phosphor layer 153 (excitation light EL3). The IR light source block 110Ir outputs a light beam illuminating the IR phosphor layer 154 (excitation light EL4).

[0044] Light source blocks 110R, 110G, 110B, and 110Ir are arranged at positions corresponding to the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154, respectively, as described later. For example, as... Figure 1As shown in the diagram, when a condenser lens 13 is arranged between the light source unit 11 and the light tube 14, and the exit surface 11S1 of the light source unit 11 is opposite to the light entrance (opening 14H1) of the excitation beams EL1, EL2, EL3 and EL4 of the light tube 14, the light source blocks 110R, 110G, 110B and 110Ir are arranged in a manner in which their formation positions are reversed in the vertical and horizontal directions relative to the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153 and IR phosphor layer 154 provided on the corresponding four sides 140S1, 140S2, 140S3 and 140S4 of the light guide path 140 constituting the light tube 14. That is, in the light tube 14, viewed from the opening 14H1 side, the blue phosphor layer 153 is disposed on the upper side 140S3 of the light guide path 140, the red phosphor layer 151 is disposed on its lower side 140S1, the green phosphor layer 152 is disposed on its left side 140S2, and the IR phosphor layer 154 is disposed on its right side 140S4. Conversely, in the light source unit 11, viewed from the exit surface 11S1 side, the red light source block 110R is arranged on the upper side, the IR light source block 110Ir is arranged on the lower side, the green light source block 110G is arranged on the left side, and the blue light source block 110B is arranged on the right side. This allows the excitation light EL1 output from the red light source block 110R to selectively illuminate the red phosphor layer 151 via the condenser lens 13. The excitation light EL2 output from the green light source block 110G to selectively illuminate the green phosphor layer 152 via the condenser lens 13. Excitation light EL3, emitted from blue light source block 110B, selectively illuminates blue phosphor layer 153 via condenser lens 13. Excitation light EL4, emitted from IR light source block 110Ir, selectively illuminates IR phosphor layer 154 via condenser lens 13.

[0045] The red light source block 110R, green light source block 110G, blue light source block 110B, and IR light source block 110Ir are independently controlled by current. That is, the on / off state of each light source block 110R, 110G, 110B, and 110Ir can be switched independently, and the intensity of the excitation beams EL1, EL2, EL3, and EL4 illuminating the corresponding phosphor layers 151, 152, 153, and 154 can also be independently controlled. This allows for free adjustment of the wavelength distribution of the light (illumination light) extracted from the light tube 14. Furthermore, the light deteriorating over time can be adjusted.

[0046] Each light source block 110R, 110G, 110B, and 110Ir includes one or more solid-state light-emitting devices 112 as a light source, which output light in a predetermined wavelength band. The one or more solid-state light-emitting devices 112 are arranged, for example, in an array on the base portion 111. Figure 3 This is an exploded perspective view illustrating an example of the structure of the light source unit 11. Figure 1In the light source unit 11 shown in the diagram, for example, 10 solid-state light-emitting devices 112 are arranged in 3 rows and 3 columns on the base portion 111.

[0047] The base portion 111 supports a plurality of solid-state light-emitting devices 112 and facilitates heat dissipation from the plurality of solid-state light-emitting devices 112 that generate heat due to light emission. Therefore, it is preferable that the base portion 111 is formed using a material with high thermal conductivity, and for example, using aluminum (Al), copper (Cu), iron (Fe), etc.

[0048] Examples of multiple solid-state light-emitting devices 112 include semiconductor lasers (laser diodes: LDs). For example, as multiple solid-state light-emitting devices 112, an LD that oscillates a laser (excitation light EL: blue light Lb) in the blue wavelength band corresponding to a wavelength of 400 nm to 470 nm is used. The laser output from the multiple solid-state light-emitting devices 112 is polarized into S-polarized light or P-polarized light; here, for example, it is polarized into P-polarized light. As another example, light-emitting diodes (LEDs) can be used as multiple solid-state light-emitting devices 112.

[0049] Multiple lenses 113 are arranged above multiple solid-state light-emitting devices 112. Each of the multiple lenses 113 is, for example, a collimating lens. The multiple lenses 113 adjust the laser light (excitation light EL) output from each of the multiple solid-state light-emitting devices 112 into parallel light and output the parallel light. For example, as Figure 3 As shown in the diagram, a plurality of lenses 113 are arranged in an array and are fixed to the base portion 111, for example, by an adhesive.

[0050] The beam shaping device 12 outputs laser light with an adjusted angle distribution of the incident laser. For example, the laser light has a large radiation angle difference between the slow axis (H direction) and the fast axis (V direction) and has an angle distribution that is greatly offset at the LD emission point. The beam shaping device 12 outputs laser light (excitation beams EL1, EL2, EL3, and EL4) from the light source unit 11, whose angle distribution deviation has been reduced, to the condenser lens 13.

[0051] A condenser lens 13 is arranged between the beam shaping device 12 and the light pipe 14, and converges the excitation beams EL1, EL2, EL3, and EL4, whose angular distribution deviations have been reduced by the beam shaping device 12, toward the light pipe 14. The condenser lens 13 is preferably formed using, for example, a high refractive index material. As another example, the condenser lens 13 may have a configuration of a combination of multiple lenses. This allows for a reduction in the size of the focusing point and allows the excitation beams EL1, EL2, EL3, and EL4 incident on the light pipe 14 to effectively illuminate the corresponding phosphor layers 151, 152, 153, and 154.

[0052] The light tube 14 is a light guide member having a pair of opposing openings 14H1 and 14H2, and including a hollow light guide path 140 on its inner side. Specifically, for example, as Figure 4 As shown in the diagram, the light pipe 14 is a columnar light guide member obtained by combining four glass substrates 141, 142, 143, and 144, and includes a light guide path 140 between openings 14H1 and 14H2, each having a rectangular shape, surrounded by four sides 140S1, 140S2, 140S3, and 140S4 that are opposite to each other in the vertical and horizontal directions. On each of the four sides 140S1, 140S2, 140S3, and 140S4, for example, a metal film such as an aluminum film is formed to act as a reflective surface.

[0053] A red phosphor layer 151, a green phosphor layer 152, a blue phosphor layer 153, and an IR phosphor layer 154 are respectively disposed on the four sides 140S1, 140S2, 140S3, and 140S4 constituting the light guide path 140. The red phosphor layer 151 absorbs the excitation light EL1 output from the light source unit 11 to emit light including the red wavelength (red light Lr). The green phosphor layer 152 absorbs the excitation light EL2 output from the light source unit 11 to emit light including the green wavelength (green light Lg). The blue phosphor layer 153 absorbs the excitation light EL3 output from the light source unit 11 to emit light including the blue wavelength (blue light Lb). The IR phosphor layer 154 absorbs the excitation light EL4 output from the light source unit 11 to emit light including the IR wavelength (Ir light Lir).

[0054] Each phosphor layer 151, 152, 153, and 154 includes, for example, a so-called ceramic phosphor or a paste-like binder phosphor formed in a plate-like shape. Phosphor layers 151, 152, 153, and 154 are each formed to include phosphor particles, which are excited by excitation beams EL1, EL2, EL3, and EL4 output from corresponding light source blocks 110R, 110G, 110B, and 110Ir of the light source unit 11 to emit fluorescent beams having wavelengths corresponding to red, green, blue, and IR bands. Examples of phosphor particles used for the red phosphor layer 151 include CaAlSiN3:Eu. Examples of phosphor particles used for the green phosphor layer 152 include Lu3Al5O. 12 Examples of phosphor particles used for blue phosphor layer 153 include (Sr, Ba). 10 (PO4)6Cl2:Eu. Examples of phosphor particles used in IR phosphor layer 154 include LiInSi2O6:Cr. 3+ Each phosphor layer 151, 152, 153, and 154 may also include semiconductor nanoparticles such as quantum dots, organic dyes, etc.

[0055] Phosphor layers 151, 152, 153, and 154 are disposed one after another on the four sides 140S1, 140S2, 140S3, and 140S4 of the light tube 14 constituting the light guide path 140, which are opposite to each other in the vertical and horizontal directions. For example, as described above, when a condenser lens 13 is arranged between the light source unit 11 and the light tube 14, the light source blocks 110R, 110G, 110B, and 110Ir, as well as the phosphor layers 151, 152, 153, and 154, are arranged opposite to each other in the vertical and horizontal directions. That is, in this embodiment, the red phosphor layer 151 is disposed on the lower side 14S1. The green phosphor layer 152 is disposed on the left side 14S2. The blue phosphor layer 153 is disposed on the upper side 14S3. The IR phosphor layer 154 is disposed on the right side 14S4.

[0056] It should be noted that when using excitation beams EL1, EL2, EL3, and EL4, for example, light with a blue wavelength, the blue phosphor layer 153 can be omitted. In this case, the excitation light EL3 applied to the side 143S constituting the light guide path 150 can be used as blue light Lb.

[0057] In the light source device 1 of this embodiment, excitation beams EL1, EL2, EL3 and EL4, which are output from the corresponding light source blocks 110R, 110G, 110B and 110Ir of the light source unit 11 and focused by the condenser lens 13, respectively illuminate the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153 and IR phosphor layer 154 on the corresponding sides 140S1, 140S2, 140S3 and 140S4 of the light guide path 140 disposed inside the light tube 14.

[0058] Figure 5 This is an explanatory diagram illustrating the relationship between the size of the opening 14H1 of the light tube 14 and the spot size of the excitation light EL incident on the light tube 14. In order to ensure that the excitation beams EL1, EL2, EL3, and EL4 output from the corresponding light source blocks 110R, 110G, 110B, and 110Ir of the light source unit 11 effectively irradiate the corresponding phosphor layers 151, 152, 153, and 154, as shown in the following expression (1), it is preferable that the spot size (H1) of the excitation light EL incident on the light tube 14 is... LD The size of the light spot (H) incident on the light tube 14 is equal to or less than the opening size (W1) of the opening 14H1 of the light tube 14. As shown in the expression (2) below, the size of the light spot (H) of the excitation light EL incident on the light tube 14 can be obtained from the size (W2) of the light emission point of the solid-state light-emitting device 112, the focal length (F1) of the lens 113, and the focal length (F2) of the condenser lens 13. LD ).

[0059] (Mathematical Formula 1)

[0060] W1≥H LD ·····(1)

[0061] =W2×F2 / F1 ·····(2)

[0062] As the spot size of the excitation light EL incident on the light tube 14 decreases, the excitation beams EL1, EL2, EL3 and EL4 can selectively irradiate the corresponding phosphor layers 151, 152, 153 and 154. That is, it is desirable that the excitation beams EL1, EL2, EL3 and EL4 are focused into the opening 14H1 of the light tube 14.

[0063] Figure 6 For example, taking red phosphor layer 151 as an example, the diagram illustrates the positions of each phosphor layer 151, 152, 153, and 154 arranged in the light guide path 140 of the light pipe 14. When the excitation beams EL1, EL2, EL3, and EL4 output from the corresponding light source blocks 110R, 110G, 110B, and 110Ir of the light source unit 11 converge to the opening 14H1 of the light pipe 14, as shown in expression (3) below, the position D of the red phosphor layer 151 in the light guide path 140 (the distance D from the opening 14H1 to the center portion of the red phosphor layer 151) can be obtained from the opening size (W1) of the opening 14H1 of the light pipe 14 and the incident angle θ of the excitation light EL1 to the opening 14H1 of the light pipe 14. As shown in expression (4) below, the position D of the red phosphor layer 151 in the light guide path 140 can be obtained from the optical axis position (H... LD-Axis The incident angle θ of the excitation light EL1 is obtained by using the focal length (F2) of the condenser lens 13 and the focal length (F2).

[0064] (Mathematical Formula 2)

[0065] D = W1 / 2 ÷ tanθ ·····(3)

[0066] θ=arctan(H LD-Axis ÷F2) ·····(4)

[0067] In the light source device 1 of this embodiment, the light beams (red light Lr, green light Lg, blue light Lb and Ir light Lir) emitted from the corresponding phosphor layers 151, 152, 153 and 154 are combined in the light guide path 140 by irradiating the phosphor layers 151, 152, 153 and 154 with the corresponding excitation beams EL1, EL2, EL3 and EL4, thereby being extracted from the opening 14H2 as illumination light.

[0068] Figure 7A This is an angular distribution diagram of the excitation beams EL1, EL2, EL3 and EL4 incident on the opening 14H1 of the light tube 14. Figure 7B This is an illuminance distribution diagram of the illumination light output from the opening 14H2 of the light pipe 14 and incident on the light guide 30. Excitation beams EL1, EL2, EL3, and EL4 incident on the light pipe 14 illuminate phosphor layers 151, 152, 153, and 154, respectively. Phosphor layers 151, 152, 153, and 154 emit red light Lr, green light Lg, blue light Lb, and Ir light Lir, respectively. The red light Lr, green light Lg, blue light Lb, and Ir light Lir emitted from phosphor layers 151, 152, 153, and 154 are repeatedly reflected towards the opening 14H2 on the four sides 140S1, 140S2, 140S3, and 140S4 constituting the light guide path 140. This repeated reflection allows the light with illumination characteristics such as... Figure 7B The diagram shows the illumination light distribution of a flat-topped roof.

[0069] The diffuser plate 21 causes the illumination light output from the light tube 14 to be incident on the light guide 30 with the radiation angle of the illumination light being increased.

[0070] Figure 8 This is an angular distribution diagram of the illumination light output from the opening 14H2 of the light tube 14. Figure 9 This is an angular distribution diagram of the illumination light output from the opening 14H2 of the light tube 14 via the diffuser 21. In the illumination light output from the opening 14H2, the sign of the output angle is reversed depending on whether the illumination light is reflected during output. Therefore, as... Figure 8 As shown in the diagram, the illuminance distribution of the illumination light output from the opening 14H2 tends to be discrete. When a diffuser plate 21 is arranged in the opening 14H2 of the light pipe 14, it has the following characteristics: Figure 9 The illumination light with a smooth angular distribution, as shown in the diagram, is incident on the light guide 30.

[0071] The light guide 30 allows incident light from the light source device 1 to be effectively propagated to the other side, and an optical fiber can be used, for example.

[0072] [Functions and Effects]

[0073] In the light source device 1 of this embodiment, by using a light source unit 11 that splits the excitation light into multiple beams and outputs the multiple beams, and a light tube 14 that includes a hollow light guide path 140 inside and includes a red phosphor layer 151, a green phosphor layer 152, a blue phosphor sheet 153, and an IR phosphor layer 154 respectively disposed on the sides 140S1, 140S2, 140S3, and 140S4 of the light guide path 140, the multiple beams (excitation beams EL1, EL2, EL3, and EL4) output from the light source unit 11 are respectively illuminated by a condenser lens 13 to the red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154 disposed on the sides of the light guide path 140, and the beams are combined in the light guide path 140. This operation will be described below.

[0074] In recent years, since cancer cells can be visualized by indocyanine green (ICG) and IR light irradiation, IR light, along with visible light, is also necessary as a light source for medical devices from the perspective of increasing feature density.

[0075] Incidentally, light sources for medical devices require excellent color rendering. However, illumination light obtained from conventional light source devices suffers from low color rendering. Conventional light source devices extract color beams corresponding to red (R), green (G), blue (B), and near-infrared (IR) from separate wavelength conversion devices, and then combine these color beams through multiple optical configurations. One reason for this is believed to be the insertion of wavelength selection devices, such as dichroic mirrors, during the combination of the color beams extracted from the respective wavelength conversion devices. Figure 10 As shown in the diagram, the wavelength distribution has troughs within the visible light wavelength range.

[0076] Conversely, in this embodiment, illumination light is obtained by using a light source unit 11 that splits the excitation light into multiple beams and outputs multiple beams, a light tube 14 that includes a hollow light guide path 140 inside and includes a red phosphor layer 151, a green phosphor layer 152, a blue phosphor layer 153 and an IR phosphor layer 154 disposed on corresponding side surfaces 140S1, 140S2, 140S3 and 140S4 of the light guide path 140, and a condenser lens 13 disposed between the light source unit 11 and the light tube 14 and configured to converge the excitation light EL output from the light source unit 11 toward the light guide path 140 toward the light tube 14.

[0077] In the light source device 1, the light beams (excitation beams EL1, EL2, EL3, and EL4) split and output from the light source unit 11 are converged by the condenser lens 13 toward the opening 14H1 of the light tube 14. The excitation beams EL1, EL2, EL3, and EL4 converged to the opening 14H1 of the light tube 14 respectively illuminate the corresponding phosphor layers (red phosphor layer 151, green phosphor layer 152, blue phosphor layer 153, and IR phosphor layer 154) respectively disposed on the four sides 140S1, 140S2, 140S3, and 140S4 of the light guide path 140 formed inside the light tube 14. The light beams (red light Lr, green light Lg, blue light Lb, and IR light Lir) emitted from the corresponding phosphor layers 151, 152, 153, and 154 are combined in the light guide path 140 without passing through wavelength selection elements, etc., and extracted as illumination light from the opening 14H2. This allows, for example, Figure 11 As shown in the diagram, illumination light with a wavelength distribution that has no troughs in the visible light wavelength range can be obtained.

[0078] As described above, the light source device 1 of this embodiment can improve color rendering.

[0079] Furthermore, the light source device 1 of this embodiment uses a light source unit 11 that splits the excitation light into multiple beams (excitation beams EL1, EL2, EL3, and EL4) and outputs the multiple beams. Specifically, for example, multiple solid-state light-emitting devices 112 arranged in an array are divided into four light source blocks (red light source block 110R, green light source block 110G, blue light source block 110B, and IR light source block 110Ir), and the beams output from the respective light source blocks 110R, 110G, 110B, and 110Ir are used as excitation beams EL1, EL2, EL3, and EL4. Furthermore, the light source blocks 110R, 110G, 110B, and 110Ir are allowed to be independently controlled by current. This allows the intensity of the respective excitation beams EL1, EL2, EL3, and EL4 to be reflected in the corresponding phosphor layers 151, 152, 153, and 154. That is, the wavelength distribution of the light (illumination light) to be extracted from the light tube 14 can be freely adjusted. In addition, it can adjust the light that has deteriorated over time.

[0080] Furthermore, in the light source device 1 of this embodiment, a red phosphor layer 151, a green phosphor layer 152, a blue phosphor layer 153, and an IR phosphor layer 154 are respectively disposed on the inner sides 140S1, 140S2, 140S3, and 140S4 of the light tube 14 constituting the light guide path 140, and the light beams (red light Lr, green light Lg, blue light Lb, and IR light Lir) emitted from the corresponding phosphor layers 151, 152, 153, and 154 are combined in the light guide path 140. This allows for a reduction in device size compared to a general light source device described above, in which color beams corresponding to red (R), green (G), blue (B), and near-infrared (IR) are extracted from corresponding independent wavelength conversion devices and the color beams are combined via multiple optical components. Furthermore, compared to the general light source device described above, the number of components can be reduced, thus cost reduction is also possible.

[0081] Furthermore, in the light source device 1 of this embodiment, the light tube 14 is arranged in the stage before the light guide 30. In the light guide path 140 of the light tube 14, the light beams (red light Lr, green light Lg, blue light Lb, and Ir light Lir) emitted from the corresponding phosphor layers 151, 152, 153, and 154 are combined while being repeatedly reflected towards the opening 14H2 on the sides 140S1, 140S2, 140S3, and 140S4, so as to be incident on the light guide 30 via, for example, the diffuser plate 21. This allows the illuminance distribution of the light applied from the light guide 30 to become more uniform. Therefore, a light source device 1 with a low optical spread and a flat-top illuminance distribution can be provided.

[0082] Next, variations 1 to 4 of this disclosure will be described. In the following, components similar to those in the above embodiments will be indicated by the same reference numerals, and their descriptions will be omitted as appropriate.

[0083] <2. Variations>

[0084] (2-1. Variation Example 1)

[0085] Figure 12 This is a schematic diagram illustrating an example of the configuration of a light source device (light source device 2) according to a variation of this disclosure, purportedly 1. Similar to the embodiments described above, the light source device 2 is used as a light source for medical devices such as gastroscopy cameras or endoscope cameras.

[0086] In the above embodiments, an example of arranging a diffuser plate 21 in the opening 14H2 of the light pipe 14 is described, but this disclosure is not limited thereto. In the light source device 2 of this modified example, a spherical lens 22 is arranged in the opening 14H2 of the light pipe 14.

[0087] Spherical lens 22 is a small-diameter spherical single lens with a short focal length and a large numerical aperture (NA). Spherical lens 22 can be mechanically mounted onto the opening 14H2 of the light pipe 14. This allows for automatic adjustment of the optical axes of the light pipe 14 and spherical lens 22, thus eliminating the need for triaxial adjustment.

[0088] As described above, in the light source device 2 of this modified example, a spherical lens 22 is arranged in the opening 14H2 of the light tube 14. This allows the light source device 2 of this modified example to easily adjust the angular distribution of the illumination light output from the opening 14H2 of the light tube 14, in addition to the effects of the above-described embodiments. Furthermore, it may contribute to a low optical spread.

[0089] (2-2. Variation Example 2)

[0090] Figure 13 This is a schematic diagram illustrating an example of the configuration of a light source device (light source device 3) according to a variation 2 of this disclosure. Similar to the embodiments described above, the light source device 3 is used as a light source for medical devices such as gastroscopy cameras or endoscope cameras.

[0091] In the light source device 3 of this modified example, a heat sink 40 is provided on the outer side of the light tube 14.

[0092] As described above, in the light source device 3 of this modified example, a heat sink 40 is provided on the outer side of the light tube 14. This allows the light source device 3 of this modified example to improve the heat resistance of the light tube 14, in addition to the effects of the above embodiment. Furthermore, it can reduce the degradation of phosphor layers 151, 152, 153, and 154 due to heat generation.

[0093] (2-3. Variation Example 3)

[0094] Figure 14 This is a schematic diagram illustrating an example of the configuration of a light source device (light source device 4) according to a variation 3 of this disclosure. Similar to the embodiments described above, the light source device 4 is used as a light source for medical devices such as gastroscopy cameras or endoscope cameras.

[0095] In the light source device 4 of this modified example, dichroic mirrors 23 and 24 are arranged in the openings 14H1 and 14H2 of the light tube 14, respectively.

[0096] Dichroic mirrors 23 and 24 both selectively reflect colored light of a predetermined wavelength and transmit light of other wavelengths. Specifically, dichroic mirror 23, arranged in the opening 14H1 of the light tube 14, selectively transmits the excitation beams EL (EL1, EL2, EL3, and EL4) split and output from the light source unit 11, and selectively reflects the fluorescence beams FL emitted from the corresponding phosphor layers 151, 152, 153, and 154. Dichroic mirror 24, arranged in the opening 14H2 of the light tube 14, selectively reflects the excitation beams EL (EL1, EL2, EL3, and EL4) split and output from the light source unit 11, and selectively transmits the fluorescence beams FL emitted from the corresponding phosphor layers 151, 152, 153, and 154.

[0097] As described above, in the light source device 4 of this modified example, dichroic mirrors 23 and 24 are respectively arranged at the openings 14H1 and 14H2 of the light tube 14. This allows the excitation light EL that has reached the opening 14H2 without undergoing wavelength conversion in each phosphor layer 151, 152, 153, and 154 to return to the light guide path 140 through the dichroic mirror 24, and allows the fluorescence FL emitted from each phosphor layer 151, 152, 153, and 154 toward the opening 14H1 to return to the light guide path 140 through the dichroic mirror 23. Therefore, in addition to the effects of the above embodiment, the light source device 4 can also achieve improved optical efficiency.

[0098] (2-4. Variation Example 4)

[0099] In the above embodiments, an example is given in which phosphor layers 151, 152, 153 and 154 are arranged at the same position from the opening 14H1 on the corresponding four sides 140S1, 140S2, 140S3 and 140S4 constituting the light guide path 140, but the present disclosure is not limited thereto.

[0100] like Figure 15A and Figure 15B As shown in the diagram, based on the incident angle θ of the excitation light EL and the optical axis position (H) of the solid-state light-emitting device 112... LD-Axis In the longitudinal direction of the light guide path 140 (e.g., from...), Figure 15A 151X fluorophore Figure 15B On the phosphor layer 151Y), the positions of the corresponding phosphor layers 151, 152, 153 and 154 can be changed based on the above expressions (3) and (4).

[0101] Furthermore, the concentration of phosphor particles included in phosphor layers 151, 152, 153, and 154 can be varied in the longitudinal direction (Z-axis direction) of the light guide path 140. As another example, such as Figure 16As shown in the diagram, multiple phosphor layers 151a and 151b, which differ in the concentration of phosphor particles, can be arranged in the longitudinal direction (Z-axis direction). Furthermore, when multiple phosphor layers are arranged in the longitudinal direction along the light guide path 140, phosphor particles with different emission wavelengths can be used in phosphor layers 151a and 151b.

[0102] As described above, by changing the positions of the corresponding phosphor layers 151, 152, 153, and 154 in the light guide path 140, a concentration gradient of phosphor particles is formed in the corresponding phosphor layers 151, 152, 153, and 154 or in the multiple phosphor layers 151a and 151b arranged in the longitudinal direction. Alternatively, multiple phosphor layers (e.g., phosphor layers 151a and 151b) arranged in the longitudinal direction can be formed by using phosphor particles with different emission wavelengths. This allows for fine-tuning of the chromaticity of the illumination light.

[0103] The present technology has been described above through embodiments and variations 1 to 4. However, the present technology is not limited to the above embodiments and other embodiments, and various modifications can be made thereto. For example, the arrangement and number of components of the optical system illustrated in the above embodiments and other embodiments are merely examples. It is not required that all components be included, and other components may also be included.

[0104] Furthermore, the light source devices 1 to 4 of this technology can be used in electronic devices other than medical devices. For example, the light source devices 1 to 4 can be used for lighting purposes and are suitable for, for example, vehicle headlights or lighting sources.

[0105] It should be noted that the effects are not always limited to those described herein, but may be any effect recorded in this disclosure.

[0106] It should be noted that this technology can be configured as follows. According to this technology having the following configuration, by using a light source unit configured to output multiple segmented beams, and a light guide member having a hollow light guide path having a first opening and a second opening on the side opposite to the first opening, and having multiple wavelength converters disposed on at least a portion of the side of the light guide path that emit beams having different wavelengths from each other, each of the multiple segmented beams output from the light source unit as excitation light is applied via a focusing device to a corresponding wavelength converter among the multiple wavelength converters disposed inside the light guide member. This allows light with a desired wavelength distribution to be extracted, and high color rendering can be achieved.

[0107] (1) A light source device, comprising:

[0108] A light source unit that splits the excitation light into multiple beams and outputs the multiple beams;

[0109] A light guide member, the light guide member including a hollow light guide path on its inner side, the hollow light guide path having a first opening and a second opening on a side opposite to the first opening, the light guide member having a plurality of wavelength converters disposed on at least a portion of the side of the light guide path, the plurality of wavelength converters being configured to emit light beams having different wavelengths from each other; and

[0110] A focusing device that guides each of the plurality of light beams output from the light source unit to the corresponding wavelength converter among the plurality of wavelength converters.

[0111] (2) The light source device according to (1), wherein the light source unit divides the excitation light into the same number of beams as the plurality of wavelength converters and outputs the plurality of beams.

[0112] (3) The light source device according to (1) or (2), wherein

[0113] The plurality of wavelength converters includes a first wavelength converter that converts the excitation light wavelength to red-band light, a second wavelength converter that converts the excitation light wavelength to green-band light, a third wavelength converter that converts the excitation light wavelength to blue-band light, and a fourth wavelength converter that converts the excitation light wavelength to near-infrared light.

[0114] The light source unit includes a first light source block that illuminates a first wavelength converter, a second light source block that illuminates a second wavelength converter, a third light source block that illuminates a third wavelength converter, and a fourth light source block that illuminates a fourth wavelength converter.

[0115] (4) The light source device according to (3), wherein the first light source block, the second light source block, the third light source block and the fourth light source block are independently controlled by current.

[0116] (5) The light source device according to (3) or (4), wherein

[0117] The light guide member has four sides facing each other in the vertical and horizontal directions on its inner side, and

[0118] Any one of the first wavelength converter, the second wavelength converter, the third wavelength converter, and the fourth wavelength converter is disposed on one of the corresponding sides of the four sides.

[0119] (6) The light source device according to any one of (1) to (5), wherein the light guide component includes a light tube.

[0120] (7) The light source device according to any one of (1) to (6) further includes a spherical lens arranged in the second opening of the light guide member.

[0121] (8) The light source device according to any one of (1) to (7) further includes a heat sink disposed on the outer side of the light guide member.

[0122] (9) The light source device according to any one of (1) to (8) further includes a first dichroic mirror arranged in the first opening of the light guide member, the first dichroic mirror transmitting the excitation light and reflecting the light that has been wavelength converted in the plurality of wavelength converters.

[0123] (10) The light source device according to any one of (1) to (9) further includes a second dichroic mirror arranged in the second opening of the light guide member, the second dichroic mirror reflecting the excitation light and transmitting the light that has undergone wavelength conversion in the plurality of wavelength converters.

[0124] (11) The light source device according to any one of (1) to (10), wherein

[0125] Each of the plurality of wavelength converters includes a phosphor, and

[0126] Each of the plurality of wavelength converters has a phosphor concentration gradient in the longitudinal direction of the light guide member.

[0127] (12) A light source device according to any one of (1) to (11), wherein each of the plurality of wavelength converters includes a plurality of wavelength conversion blocks having different conversion wavelengths from one another within a predetermined wavelength range in the longitudinal direction of the light guide member.

[0128] (13) The light source device according to any one of (1) to (12), wherein

[0129] The light guide member has four sides facing each other in the vertical and horizontal directions on its inner side, and

[0130] One of the plurality of wavelength converters is provided on any one of the three sides of the four sides, and none of the plurality of wavelength converters is provided on one of the four sides.

[0131] (14) The light source device according to any one of (1) to (13) further includes a diffuser plate on the second opening side of the light guide member.

[0132] This application claims the benefit of Japanese priority patent application JP2023-051786, filed with the Japan Patent Office on March 28, 2023, the entire contents of which are incorporated herein by reference.

[0133] Those skilled in the art will understand that various modifications, combinations, sub-combinations and alterations may be made depending on design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents.

Claims

1. A light source device, comprising: A light source unit that splits the excitation light into multiple beams and outputs the multiple beams; A light guide member, the light guide member including a hollow light guide path on its inner side, the hollow light guide path having a first opening and a second opening on a side opposite to the first opening, the light guide member having a plurality of wavelength converters disposed on at least a portion of the side of the light guide path, the plurality of wavelength converters being configured to emit light beams having different wavelengths from each other; and A focusing device that guides each of the plurality of light beams output from the light source unit to the corresponding wavelength converter among the plurality of wavelength converters.

2. The light source device according to claim 1, wherein the light source unit divides the excitation light into the same number of beams as the plurality of wavelength converters and outputs the plurality of beams.

3. The light source device according to claim 1, wherein... The plurality of wavelength converters includes a first wavelength converter that converts the excitation light wavelength to red-band light, a second wavelength converter that converts the excitation light wavelength to green-band light, a third wavelength converter that converts the excitation light wavelength to blue-band light, and a fourth wavelength converter that converts the excitation light wavelength to near-infrared light. The light source unit includes a first light source block that illuminates a first wavelength converter, a second light source block that illuminates a second wavelength converter, a third light source block that illuminates a third wavelength converter, and a fourth light source block that illuminates a fourth wavelength converter.

4. The light source device according to claim 3, wherein the first light source block, the second light source block, the third light source block and the fourth light source block are independently controlled by current.

5. The light source device according to claim 3, wherein... The light guide member has four sides facing each other in the vertical and horizontal directions on its inner side, and Any one of the first wavelength converter, the second wavelength converter, the third wavelength converter, and the fourth wavelength converter is disposed on one of the corresponding sides of the four sides.

6. The light source device according to claim 1, wherein the light guide component comprises a light tube.

7. The light source device according to claim 1 further includes a spherical lens arranged in the second opening of the light guide member.

8. The light source device according to claim 1 further includes a heat sink disposed on the outer side of the light guide member.

9. The light source device according to claim 1 further includes a first dichroic mirror arranged in the first opening of the light guide member, the first dichroic mirror transmitting the excitation light and reflecting the light that has undergone wavelength conversion in the plurality of wavelength converters.

10. The light source device according to claim 1, further comprising a second dichroic mirror arranged in the second opening of the light guide member, the second dichroic mirror reflecting the excitation light and transmitting light that has undergone wavelength conversion in the plurality of wavelength converters.

11. The light source device according to claim 1, wherein Each of the plurality of wavelength converters includes a phosphor, and Each of the plurality of wavelength converters has a phosphor concentration gradient in the longitudinal direction of the light guide member.

12. The light source device according to claim 1, wherein each of the plurality of wavelength converters comprises a plurality of wavelength conversion blocks having different conversion wavelengths from one another within a predetermined wavelength range in the longitudinal direction of the light guide member.

13. The light source device according to claim 1, wherein... The light guide member has four sides facing each other in the vertical and horizontal directions on its inner side, and One of the plurality of wavelength converters is provided on any one of the three sides of the four sides, and none of the plurality of wavelength converters is provided on one of the four sides.

14. The light source device according to claim 1, further comprising a diffuser plate on the second opening side of the light guide member.

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