Light source device

Abstract

A light source device according to one embodiment of the present disclosure includes: a first light source unit that emits first light having a wavelength in a visible light region; a second light source unit disposed in a preceding stage of the first light source unit and emitting second light having a wavelength in a near-infrared region; and a light guide portion to which the first light and the second light are incident. The first light and the second light are incident to the light guide portion through a coaxial light path.

Description

Technical Field

[0001] The present disclosure relates to a light source device including, for example, an IR light source as a light source. Background Art

[0002] For example, Patent Document 1 discloses a lighting device including: a pair of lenses that even out the illuminance distribution of light output from a plurality of light-emitting units; and a diffuser that increases the emission angle of light output from the pair of lenses between a light source having a plurality of light-emitting units and a light guide portion.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-153697 Summary of the invention

[0006] By the way, for example, in a light source device using an IR light source that outputs near-infrared light, it is necessary to achieve top-hat high-angle distribution and illuminance distribution.

[0007] It is desirable to provide a light source arrangement that enables top hat high angle distribution and top hat illumination distribution.

[0008] A light source device according to an embodiment of the present disclosure includes: a first light source unit that outputs a first light having a wavelength in a visible light region; a second light source unit that is arranged before the first light source unit and outputs a second light having a wavelength in a near infrared region; and a light guide portion on which the first light and the second light are incident. The first light and the second light are incident on the light guide portion in a coaxial optical path.

[0009] In a light source device according to an embodiment of the present disclosure, a first light source unit and a second light source unit that respectively output a first light with a wavelength in a visible light region and a second light with a wavelength in a near infrared region to be incident on a light guide portion are arranged before the first light source unit so that the optical path length of the second light is longer than that of the first light, and the first light and the second light are coaxially incident on the light guide portion. This increases the divergence angle of the second light. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0011] Figure 2 It is shown Figure 1 Schematic plan view of an embodiment of the configuration of the wavelength conversion element shown in .

[0012] Figure 3 It shows Figure 1 An exploded perspective view of an embodiment of the structure of a light source is shown in FIG.

[0013] Figure 4A It is the angular distribution diagram of IR light at the LD light-emitting point.

[0014] Figure 4B is the angular distribution of IR light at the convergence point of the converging lens arranged before the rod integrator.

[0015] Figure 5 It is shown in Figure 1 A schematic diagram of an embodiment of a method for cooling a heat source in a light source device is shown in FIG.

[0016] Figure 6 : is a schematic diagram showing a configuration example of a light source device according to a modification example of the present disclosure. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following description is a specific example of the present disclosure, but the present disclosure is not limited to the following embodiments.

[0018] Furthermore, the present disclosure is not limited to the arrangement, size, size ratio, etc. of the respective components shown in the drawings. It should be noted that the description is given in the following order.

[0019] 1. Implementation (an embodiment in which an IR light source is disposed before a visible light source, and visible light and IR light are coaxially incident on a light guide portion)

[0020] 2. Modification (Other embodiments of the configuration of the light source device)

[0021] <1. Implementation Method>

[0022] Figure 1 A configuration example of a light source device (light source device 1) according to an embodiment of the present disclosure is shown. The light source device 1 is used, for example, as a light source for medical equipment such as a gastric camera and an endoscopic camera. The light source device 1 of the present embodiment includes: a light source unit 11 that outputs light with a wavelength in the visible light region (for example, blue light Lb) as a light source; a light source unit 12 that outputs light with a wavelength in the near-infrared region (IR light Lir); and a light guide 30. The light source unit 12 is arranged before the light source unit 11, and is configured so that the blue light Lb and the IR light Lir enter the light guide in a coaxial optical path.

[0023] [Configuration of light source device]

[0024] The light source device 1 has, for example, light source units 11, 12 and a light guide 30. The light source device 1 also includes light source units 13 and 14, beam shaping elements 15 and 23, reflectors 16, 21A and 25, quarter-wave plates 17 and 26, a dichroic mirror 18, polarization beam splitter (PBS) mirrors 19 and 21, a half-wave plate 20, a reduction lens 22, a polarization plate 24, a converging lens 27, a rod integrator 28 and a diffusion plate 29.

[0025] Each component constituting the light source device 1 is arranged as follows. The light source units 11 and 12 are arranged in parallel in the Y-axis direction in the order of the light source unit 12 and the light source unit 11, for example, in the direction in which the plurality of lights (blue light Lb and IR light Lir) outputted therefrom are respectively reflected by the reflector 16 and the dichroic mirror 18 (for example, the Y-axis direction). The beam shaping element 15, the reflectors 16 and 25, the dichroic mirrors 18, the PBS mirrors 19 and 21B, the converging lens 27, the quarter-wave plate 26, and the rod integrator 28 are arranged between the light source unit 12 and the light guide portion 30 (on the optical path of the IR light Lir outputted from the light source unit 12) in the order of the reflector 16, the dichroic mirror 18, the PBS mirror 19, the polarizing plate 24, the reflector 25, the quarter-wave plate 26, the converging lens 27, and the rod integrator 28. The quarter-wave plate 17 is arranged between the light source unit 11 and the dichroic mirror 18. The light source unit 13 outputs yellow light Ly through wavelength conversion, and is arranged after the light source unit 11 so as to be opposed to the PBS mirror 19 in the X-axis direction.

[0026] The light source unit 14 outputs the blue light Lb output from the light source unit 11 and the excitation light EL to be wavelength-converted by the light source unit 13. The light source unit 14 is arranged outside the optical path of the blue light Lb output from the light source unit 11 and the IR light Lir output from the light source unit 12, so that a part of the output light (blue light Lb) is reflected by the reflective mirror 21A and the dichroic mirror 18 and enters the light source unit 11, and so that a part of the output light (excitation light EL) is reflected by the PBS mirrors 21B and 19 and enters the light source unit 13. The reflective mirror 21A, the PBS mirror 21B, the reduction lens 22, and the beam shaping element 23 are arranged in this order between the light source unit 14 and the PBS mirror 19 (on the optical path of the excitation light EL output from the light source unit 14).

[0027] The light source unit 11 corresponds to a specific embodiment of the “first light source unit” of the present disclosure. For example, the light source unit 11 includes: a diffuse reflection plate 111 that reflects part of the light output from the light source unit 14 as blue light Lb, a lens 112 that is disposed opposite to the diffuse reflection plate 111, and a quarter-wave plate 17. The diffuse reflection plate 111 diffuses the blue light Lb reflected by the dichroic mirror 18 and incident through the quarter-wave plate 17 and the lens 112, and reflects the diffused light toward the lens 112. The lens 112 is, for example, a collimating lens, and adjusts the blue light Lb reflected from the diffuse reflection plate 111 into collimated light and outputs the collimated light toward the quarter-wave plate 17. The quarter-wave plate 17 corrects the polarization state of the passing light and generates a phase difference of a quarter wavelength relative to the passing light. Therefore, blue light Lb polarized in the P polarized light output from light source unit 14 and reflected toward diffuse reflection plate 111 by dichroic mirror 18 is reflected by diffuse reflection plate 111 , polarized in the S polarized light when passing through quarter wavelength plate 17 , and reflected toward PBS mirror 19 by dichroic mirror 18 .

[0028] The light source unit 12 corresponds to a specific embodiment of the “second light source unit” of the present disclosure. The light source unit 12 includes a light emitting element 121 and a lens 122 arranged opposite to the light emitting element 121. As described above, for example, the light emitting element 121 is a solid-state light source that outputs light with a wavelength in the near-infrared region (Lir). For example, a semiconductor laser (laser diode: LD) that outputs light polarized as S-polarized light or P-polarized light (here, S-polarized light) can be used. In addition, a light emitting diode (light emitting diode: LED) can be used. The lens 122 is, for example, a collimating lens, and adjusts the IR light Lir reflected from the light emitting element 121 into collimated light and outputs the collimated light to the reflector 16.

[0029] Light source unit 13 corresponds to a specific embodiment of the "third light source unit" of the present disclosure. Light source unit 13 includes a wavelength conversion element 131 and one or more lenses 132. Yellow light Ly suitable for combining blue light Lb output from light source unit 12 and synthesizing white light is output from light source unit 13.

[0030] The wavelength conversion element 131 absorbs the light (excitation light EL) output from the light source unit 14, converts the light into light of a different wavelength band (e.g., yellow light Ly), and outputs the light. The wavelength conversion element 131 is a so-called reflective wavelength conversion element, and is configured to reflect and output the yellow light Ly generated by the incidence of the excitation light EL.

[0031] Figure 2 An embodiment of a planar configuration of the wavelength conversion element 131 is schematically shown. For example, the wavelength conversion element 131 includes a wheel substrate 1311 rotatable around a rotation axis and a phosphor layer 1312 disposed on the wheel substrate 1311 .

[0032] The wheel substrate 1311 is suitable for supporting the phosphor layer 1312, and has, for example, a circular plate shape. The wheel substrate 1311 preferably also has a function as a heat dissipation member. Therefore, the wheel substrate 1311 preferably includes a metal material having high thermal conductivity. In addition, it is preferred to use a metal material or a ceramic material that allows mirror polishing. Therefore, the temperature increase of the phosphor layer 1312 can be suppressed and the extraction efficiency of the fluorescence can be improved.

[0033] Examples of metallic materials include elemental metals such as aluminum (Al), copper (Cu), molybdenum (Mo), tungsten (W), cobalt (Co), chromium (Cr), platinum (Pt), tantalum (Ta), lithium (Li), zirconium (Zr), ruthenium (Ru), rhodium (Rh) and palladium (Pd), or alloys containing one or more of these metals. Examples of ceramic materials include materials containing silicon carbide (SiC), aluminum nitride (AlN), beryllium oxide (BeO), a composite material of Si and SiC, or a composite material of SiC and Al (having a SiC content of more than 50%).

[0034] The phosphor layer 1312 includes a plurality of phosphor particles, and is excited by the excitation light EL and emits fluorescence FL (e.g., yellow light Ly) having a wavelength band different from that of the excitation light EL. The phosphor layer 1312 is formed, for example, in a plate shape, and is configured, for example, of a so-called ceramic phosphor or an adhesive type phosphor. The phosphor layer 1312 is continuously formed on the wheel substrate 1311, for example, in the rotation circumferential direction.

[0035] Specifically, the phosphor layer 1312 includes phosphor particles excited by the excitation light EL output from the light source unit 14 and emits fluorescence FL (yellow light Ly) in a wavelength band corresponding to yellow. Such phosphor particles include, for example, YAG (yttrium aluminum garnet)-based materials. The phosphor layer 1312 may also include semiconductor nanoparticles such as quantum dots, organic dyes, and the like.

[0036] For example, a motor 1313 is attached to the center of the wheel substrate 1311. The motor 1313 is adapted to rotationally drive the wheel substrate 1311 at a predetermined rotation speed. As a result, the wheel substrate 1311 becomes rotatable, and the position of the excitation light EL applied to the phosphor layer 1312 temporarily changes (moves) at a speed corresponding to the rotation speed. This makes it possible to avoid degradation of the phosphor particles caused by irradiating the excitation light to the same position of the phosphor layer 1312 for a long time.

[0037] The lens 132 includes one or more lenses, and includes, for example, a condensing lens and a collimating lens. The lens 132 collects the excitation light EL reflected by the PBS mirror 19 toward the wavelength conversion element 131, converts the fluorescent light FL (yellow light Ly) output from the wavelength conversion element 131 into collimated light, and outputs the collimated light toward the PBS mirror 19.

[0038] The light source unit 14 includes one or more solid-state light emitting elements 142 as a light source that outputs light of a predetermined wavelength band. The one or more solid-state light emitting elements 142 are arranged in an array on the base 141, for example. The light source unit 14 corresponds to a specific embodiment of the "fourth light source unit" of the present disclosure. Figure 3 1 is an exploded perspective view showing an example of the configuration of the light source unit 14. Figure 1 In the light source unit 14 shown, for example, ten solid-state light emitting elements 142 are arranged at the base 141 in the form of, for example, five rows and two columns.

[0039] The base 141 supports the plurality of solid-state light emitting elements 142 and promotes heat dissipation of the plurality of solid-state light emitting elements 142. Therefore, the base 141 preferably includes a material having high thermal conductivity, and includes, for example, aluminum (Al), copper (Cu), iron (Fe), and the like.

[0040] For example, LD is used for the plurality of solid-state light emitting elements 142. Specifically, for example, an LD that oscillates laser light (excitation light EL: blue light Lb) in a wavelength band corresponding to blue light with a wavelength from 400 nm to 470 nm is used. The laser light output from the plurality of solid-state light emitting elements 142 is polarized into S polarized light or P polarized light, and here, for example, is polarized into P polarized light. In addition, LEDs may also be used as the plurality of solid-state light emitting elements 142.

[0041] The plurality of lenses 143 are respectively arranged above the plurality of solid-state light emitting elements 142. The plurality of lenses 143 are, for example, collimating lenses that adjust and output the laser light (excitation light EL) output from the plurality of solid-state light emitting elements 142 into collimated light. Figure 3 As shown, a plurality of lenses 143 are arranged in an array and fixed to the base 141 by an adhesive.

[0042] The beam shaping element 15 adjusts the angle distribution of the incident laser and outputs the laser. Figure 4A As shown, the laser light has an angle distribution in which the radiation angle difference between the slow axis (H direction) and the fast axis (V direction) is large and the LD emission point is greatly deviated. The beam shaping element 15 is, for example, a diffusion plate, and is disposed between the lens 122 and the reflector 16, and outputs the laser beam (IR light Lir) output from the light source unit 12 toward the reflector 16 while reducing the angle deviation.

[0043] The reflector 16 is arranged after the beam shaping element 15 and reflects the IR light Lir output from the light source unit 12 in a predetermined direction. Specifically, the reflector 16 reflects the IR light Lir in the X-axis direction output from the light source unit 12 in the Y-axis direction, and is arranged opposite to the light source unit 12 so that the reflective surface 16S1 is at an angle of about 45° relative to the output surface of the light source unit 12.

[0044] The dichroic mirror 18 corresponds to a specific embodiment of the "first synthesis mirror" of the present disclosure. The dichroic mirror 18 has the characteristic of selectively reflecting colored light of a predetermined wavelength band and transmitting light of another wavelength band. Specifically, the dichroic mirror 18 selectively reflects the blue light Lb. The dichroic mirror 18 is arranged opposite to the light source unit 11 so that the reflection surface 18S is approximately 45° relative to the emission surface of the light source unit 11, and is arranged on the optical path of the IR light Lir reflected by the reflector 16. As a result, the IR light Lir and the blue light Lb are combined in the coaxial optical path.

[0045] The PBS mirror 19 corresponds to a specific embodiment of the “second synthesis mirror” of the present disclosure. The PBS mirror 19 has a polarization selection surface (surface 19S1), and selects (reflects) light having a predetermined polarization component (e.g., S polarization component) on the polarization selection surface. Similar to the dichroic mirror 18, the PBS mirror 19 has the characteristic of selectively reflecting colored light in a predetermined wavelength band and transmitting light of another wavelength band. The PBS mirror 19 is arranged opposite to the light source unit 13 so that the polarization selection surface (surface 19S1) is at an angle of about 45° relative to the emission surface of the light source unit 13, and is arranged on the optical path of the IR light Lir and the blue light Lb combined in the dichroic mirror 18.

[0046] Therefore, part of the light output from the light source unit 14 (e.g., the excitation light EL of the S polarized light) is reflected toward the light source unit 13, and the remaining light (e.g., the blue light Lb of the P polarized light) is transmitted through the PBS mirror 19 and reflected toward the light source unit 11 in the dichroic mirror 18. The IR light Lir and the blue light Lb combined in the dichroic mirror 18 are reflected in the X-axis direction on the surfaces 19S1 and 19S2 of the PBS mirror 19, respectively. In addition, the yellow light Ly output from the light source unit 13 is transmitted through the PBS mirror 19 and combined in an optical path coaxial with the IR light Lir and the blue light Lb reflected in the X-axis direction.

[0047] The half-wavelength plate 20 produces a phase difference of approximately 1 / 2 wavelength relative to light of polarization components orthogonal to each other, and is arranged opposite to a partial emitting surface of the light source unit 14 to convert partial light polarized into, for example, P-polarized light output from the light source unit 14 into S-polarized light and output the S-polarized light as the excitation light EL.

[0048] The reflector 21A reflects the light (blue light Lb) output from the light source unit 14 in a predetermined direction. Specifically, the reflector 21A reflects the blue light Lb in the X-axis direction output from the light source unit 14 in the Y-axis direction, and is arranged opposite to the light source unit 14 so that the reflective surface 21S1 is at an angle of about 45° relative to the emission surface of the light source unit 14.

[0049] The PBS mirror 21B reflects the excitation light EL output from the light source unit 14 and polarized into S-polarized light in a predetermined direction by the half-wavelength plate 20. Specifically, the PBS mirror 21B reflects the excitation light EL in the X-axis direction output from the light source unit 14 in the Y-axis direction, and is arranged opposite to the light source unit 14 so that the reflection surface 21S2 is at an angle of about 45° relative to the emission surface of the light source unit 14. In addition, the blue light Lb output from the light source unit 14 and reflected as P-polarized light in the Y-axis direction by the reflection mirror 21A is transmitted through the PBS mirror 21B as it is, and is output toward the reduction lens 22 together with the excitation light EL.

[0050] The reduction lens 22 is arranged between the PBS mirror 21B and the beam shaping element 23 so as to reduce the blue light Lb and the excitation light EL output from the light source unit 14 and reflected by the reflection mirror 21A and the PBS mirror 21B, and output the light to the beam shaping element 23. The reduction lens 22 has a configuration in which a plurality of lenses (here, lenses 22A and 22B) are combined.

[0051] The beam shaping element 23 is, for example, a diffusion plate, and adjusts the blue light L and the excitation light EL output from the reduction lens 22 to a top-hat illumination distribution and outputs the light toward the PBS 19 .

[0052] The polarizing plate 24 corresponds to a specific example of the “polarization optical element” of the present disclosure and includes a polarizer having a polarization axis in a predetermined direction and adjusts polarization of the IR light Lir disturbed by passing through the beam shaping element 15 , the reflector 16 , the dichroic mirror 18 , and the PBS mirror 19 .

[0053] The reflector 25 is arranged between the polarizing plate 24 and the quarter-wave plate 26, and reflects the combined IR light Lir, blue light Lb, and yellow light Ly in a predetermined direction. Specifically, the reflector 25 reflects the IR light Lir, blue light Lb, and yellow light Ly output by the PBS mirror 19 in the X-axis direction, and is arranged so that the reflective surface 21S1 is substantially parallel to the reflective surfaces 18S1 and 18S2 of the PBS mirror 19.

[0054] The quarter-wave plate 26 corresponds to a specific embodiment of the "polarization optical element" of the present disclosure. The quarter-wave plate 26 corrects the polarization state of the IR light Lir, the blue light Lb, and the yellow light Ly reflected by the reflector 25, and generates a phase difference of about 1 / 4 wavelength with respect to the light of the polarization components orthogonal to each other. This reduces the deviation of the polarization of the IR light Lir, the blue light Lb, and the yellow light Ly.

[0055] The converging lens 27 corresponds to a specific embodiment of "one or more converging lenses" of the present disclosure. The converging lens 27 is arranged before the light guide portion 30, specifically, between the quarter-wave plate 26 and the rod integrator 28, and converges the IR light Lir, the blue light Lb, and the yellow light Ly toward the incident surface of the rod integrator, wherein the deviation of polarization is reduced by the quarter-wave plate 26. The converging lens 27 preferably includes, for example, a high refractive index material. Alternatively, the converging lens 27 is preferably configured by a combination of a plurality of lenses. As a result, the convergence point is reduced, and the amount of light of the IR light Lir, the blue light Lb, and the yellow light Ly entering the rod integrator 28 is increased.

[0056] The rod integrator 28 corresponds to a specific embodiment of the “integrator optical system” of the present disclosure. The rod integrator 28 uniformizes the non-uniform energy distribution of the incident light. Specifically, the rod integrator 28 enhances the uniformity of the non-uniform illumination distribution of the IR light Lir, the blue light Lb, and the yellow light Ly converged by the converging lens 27. Thus, a top-hat illumination distribution of the light applied from the light guide 30 is achieved.

[0057] The diffusion plate 29 increases the emission angle of the IR light Lir, the blue light Lb, and the yellow light Ly output from the rod integrator 28 , and causes the light to enter the light guide portion 30 .

[0058] The light guide 30 is suitable for efficiently transmitting light incident from the light source device 1 to the other side. For example, an optical fiber can be used as the light guide 30.

[0059] In the light source device 1, for example, the sensors 31 and 32 for detecting the light amount and the chromaticity may be arranged on the surfaces 16S2 and 25S2 of the respective reflectors 16 and 25 located on the opposite sides of the reflective surfaces 16S1 and 25S1. Therefore, the detection accuracy of the light amount and the chromaticity is improved compared to the case where the sensor is arranged outside the light source device 1 to detect the reflected light. In addition, the size of the sensing mechanism can be reduced.

[0060] Furthermore, the light source units 11, 12, 13, and 14 used as heat sources inside the light source device 1 are preferably as follows. Figure 1 For example, Figure 5As shown, the heat sink 33 can be arranged on the rear surface of each light source unit 11. As a result, the cooling wind blown out from the fan 34 becomes a straight line, so the cooling efficiency is improved. In addition, compared with the case where the light source units 11, 12, 13 and 14 are randomly arranged, the number of installed fans can be reduced. In addition, in the present embodiment, the light source unit 12 as an IR light source is arranged before the light source unit 11 as a blue light source, so that the light source unit 12 with high temperature sensitivity of the output can be arranged above the air of the cooling air blown from the fan 34.

[0061] [Work and Effect]

[0062] In the light source device 1 of the present embodiment, the light source unit 12 that outputs light with a wavelength in the near-infrared region (IR light Lir) is arranged before the light source unit 11 that outputs light with a wavelength in the visible light region (for example, blue light Lb), and the IR light Lir and the blue light Lb are incident on the light guide portion 30 in a coaxial optical path. This will be described below.

[0063] In recent years, due to the visualization of cancer cells caused by indocyanine green (ICG) drugs and IR light irradiation, IR light has also become indispensable as a light source for medical equipment from the viewpoint of increasing features.

[0064] In a light source for medical equipment, a top-hat high-angle distribution, a top-hat illuminance distribution, a high wattage, and a low light collection rate are required to converge the light to the light guide relative to the visible light and the IR light. From the viewpoint of usability in the medical field, the diameter of the light guide tends to decrease, and compatibility between low light collection rate and high wattage is required. Although the end-emitting LD is considered as its light source, the LD has a small beam divergence angle and is asymmetric in the H / V direction. Therefore, it is difficult to obtain converged light with a top-hat high-angle distribution. Therefore, there is a problem in that the optical configuration for dealing with the expansion of the beam divergence angle of the IR light source and the reduction of the H / V imbalance of the angle distribution becomes complicated.

[0065] In contrast, in the present embodiment, the light source unit 11 and the light source unit 12, which respectively output light (e.g., blue light Lb) having a wavelength in the visible light region and a wavelength in the near infrared region (IR light Lir) incident on the light guide portion 30, are arranged such that the light source unit 12 is arranged before the light source unit 11, so that the optical path length of the IR light Lir is longer than that of the blue light Lb and the IR light Lir and the blue light Lb are incident on the light guide portion 30 in a coaxial optical path. Therefore, the divergence angle of the IR light Lir increases, the deviation of the angle distribution decreases, and the illuminance distribution becomes uniform.

[0066] As described above, according to the present embodiment, it is possible to provide the light source device 1 having the top hat height angle distribution and the top hat illuminance distribution.

[0067] In addition, in the light source device 1 of the present embodiment, as described above, the light source unit 11 that outputs the blue light Lb is arranged between the light source unit 12 that outputs the IR light Lir and the condensing lens 27, for example, so that the optical path length of the IR light Lir can be easily extended. Therefore, the light source device 1 can be miniaturized.

[0068] Furthermore, in the light source device 1 of the present embodiment, the beam shaping element 15 is arranged between the light source unit 12 that outputs the IR light Lir and the condensing lens 27, specifically, at a stage after the lens 122 that constitutes the light source unit 12 and is close to the light source unit 12. Therefore, for example, Figure 4A The angular distribution of the greatly deviated IR light Lir output immediately after the light source unit 12 is corrected as shown in FIG. Figure 4B The angle distribution with reduced deviation is shown at the convergence point of the converging lens 27 arranged before the rod integrator 28. Therefore, a light source device 1 having a higher top hat height angle distribution and a higher top hat illuminance distribution can be provided.

[0069] Furthermore, in the light source device 1 of the present embodiment, as described above, the divergence angle of the IR light Lir when reaching the condensing lens 27 is expanded by extending the optical path length of the IR light Lir output from the light source unit 12. Therefore, since the IR light Lir is quickly condensed by the condensing lens 27, the angular distribution of the light applied from the light guide portion 30 increases. Therefore, it is possible to provide a light source device 1 having a top-hat type high angular distribution.

[0070] In the light source device 1 of the present embodiment, since the condensing lens 27 is made of a high refractive index material or is configured by a combination of a plurality of lenses, the convergence point of the IR light Lir is reduced. Therefore, since the amount of IR light Lir entering the rod integrator 28 increases, the light utilization efficiency is improved.

[0071] In the light source device 1 of the present embodiment, since the rod integrator 28 is disposed between the condenser lens 27 and the light guide 30, the illuminance distribution of the light irradiated from the light guide 30 is more uniform. Therefore, the light source device 1 having a higher top hat illuminance distribution can be provided.

[0072] In addition, for example, when the polarization reflection characteristics of the object to be illuminated at the end of the light guide portion 30 are biased (for example, S polarized light has a high reflectivity, while P polarized light has a low reflectivity), the object to be illuminated will appear bright or dark depending on the angle at which the object to be illuminated is observed. In addition, when the degree of polarization varies depending on the color of the illumination light, the white balance of white can be changed. In contrast, in the light source device 1 of the present embodiment, for example, because the polarizing plate 24 and the quarter-wave plate 26 are arranged before the converging lens 27, the polarization of the IR light Lir disturbed by passing through the beam shaping element 15, the reflector 16, the dichroic mirror 18, and the PBS mirror 19 is adjusted and the deviation of the polarization is reduced, so that the brightness can be reduced at any observation angle. In addition, the change in white balance can be reduced.

[0073] Incidentally, by using the reflection mirror 25 as a PBS mirror, the polarization plate 24 can be removed. Furthermore, the quarter-wavelength plate 26 can be reduced by using a polarization scrambler.

[0074] Next, a modification of the present disclosure will be described. Hereinafter, components similar to those of the above-described embodiment are denoted by the same reference numerals, and description thereof is appropriately omitted.

[0075] [2. Modifications]

[0076] Figure 6 The configuration example of the light source device (light source device 2) according to the modification of the present disclosure is schematically shown. The light source device 2 is used as a light source of medical equipment such as a gastric camera or an endoscope camera, for example, similarly to the above-mentioned embodiment.

[0077] In the above-described embodiment, an example is described in which the light source unit 12 that outputs blue light Lb is used as the light source unit that outputs light with a wavelength in the visible light region, the light source unit 13 that outputs yellow light Ly, and the light source unit 14 that outputs, for example, excitation light EL. However, the configuration of the light source unit that outputs light with a wavelength in the visible light region is not limited thereto.

[0078] like Figure 6 As shown, the light source device 2 of this variant example uses a light source unit 41, wherein a plurality of solid-state light-emitting elements that respectively output red light Lr, green light Lg, and blue light Lb are arranged in an array, so that red light Lr, green light Lg, and blue light Lb are output from a light source unit 11 corresponding to the "first light source unit" of the present disclosure.

[0079] For example, the light source device 2 includes light source units 11 and 12 and a light guide portion 30, and further includes beam shaping elements 15 and 46, reflectors 16 and 43, dichroic mirrors 18, 44 and 45, a reduction lens 22, a converging lens 27, a rod integrator 28, a diffuser plate 29, a light guide portion 30, a light source unit 41, a half-wavelength plate 42, a PBS prism 47 and a quarter-wavelength plate 48.

[0080] Each member constituting the light source device 2 is arranged as follows. In the light source units 11 and 12, for example, the light source unit 12 and the light source unit 11 are arranged in parallel in this order in the X-axis direction (for example, the direction in which the plurality of lights (blue light Lb and IR light Lir) respectively output from the light source units 11 and 12 are respectively reflected by the reflector 16 and the dichroic mirror 18 (for example, the Y-axis direction)). As in the above-described embodiment, the beam shaping element 15, the reflector 16, and the dichroic mirror 18 are sequentially disposed on the optical path of the IR light Lir output from the light source unit 12.

[0081] In the light source device 2 of the present modification, for example, a half-wavelength plate 42 and a reflector 43 are arranged on the optical path in the X-axis direction of the red light Lr output from the light source section 41. The red light Lr is reflected in the Y-axis direction by the reflector 43, enters the PBS prism 47 via the dichroic mirrors 44 and 45 and the reduction lens 22 and the beam shaping element 46 arranged on its optical path, and is reflected toward the light source unit 11 at the polarization selection surface of the PBS prism 47. The green light Lg output from the light source unit 41 in the X-axis direction is reflected in the Y-axis direction by the dichroic mirror 44, enters the PBS prism 47 via the dichroic mirror 45 and the reduction lens 22 and the beam shaping element 46 arranged on its optical path, and is reflected toward the light source unit 11 at the polarization selection surface of the PBS prism 47. The blue light Lb output from the light source unit 41 in the X-axis direction is reflected in the Y-axis direction by the dichroic mirror 45 , enters the PBS prism 47 via the reduction lens 22 and the beam shaping element 46 arranged on its optical path, and is reflected toward the light source unit 11 on the polarization selective surface of the PBS prism 47 .

[0082] The red light Lr, green light Lg, and blue light Lb reflected by the PBS prism 47 are diffused and reflected by the diffuse reflection plate 111 via the quarter-wave plate 48 and the lens 112. The red light Lr, green light Lg, and blue light Lb diffused and reflected by the diffuse reflection plate 111 enter the dichroic mirror 18 via the lens 112, the quarter-wave plate 48, and the PBS prism 47, are reflected on the Y axis on the reflection surface 18S, and are combined in an optical path coaxial with the IR light Lir. Thereafter, the combined IR light Lir, red light Lr, green light Lg, and blue light Lb are converged by the converging lens 27 and enter the light guide portion 30 through the rod integrator 28 and the diffuser plate 29.

[0083] As described above, regardless of the configuration of the optical system of the light source unit 11 that outputs light with a wavelength within the visible light region, the light source unit 11 that outputs light with a wavelength within the visible light region is arranged between the light source unit 12 that outputs IR light Lir and, for example, the converging lens 27, so that an effect similar to that of the above-mentioned embodiment can be obtained.

[0084] Although the present technology has been described with reference to the embodiments and the modified examples, the present technology is not limited to the above-mentioned embodiments, etc., and various modifications are possible. For example, the arrangement and number of components of the optical system illustrated in the above-mentioned embodiments, etc. are only examples, and not all components are necessarily included, and other components may also be included.

[0085] In addition, the light source device 1 or 2 of the present technology can be used for electronic devices other than medical devices. For example, the light source device 1 or 2 can be used as a lighting application and can be applied to, for example, a headlight of a car and a light source for lighting.

[0086] The effects described herein are not necessarily limited and may be any effects described in the present disclosure.

[0087] It should be noted that the present technology may have the following configuration. According to the present technology configured as follows, a first light source unit and a second light source unit that respectively output a first light having a wavelength in a visible light region and a second light having a wavelength in a near-infrared region to be incident on a light guide portion are arranged before the first light source, so that the optical path length of the second light is longer than the optical path length of the first light and the first light and the second light are coaxially incident on the light guide portion. Therefore, the divergence angle of the second light is amplified, and a light source device having a top-hat high angle distribution and a top-hat illuminance distribution can be provided. (1)

[0089] A light source device, comprising:

[0090] A first light source unit outputs a first light with a wavelength in the visible light region;

[0091] a second light source unit disposed before the first light source unit and outputting second light having a wavelength in a near infrared region; and

[0092] A light guide portion, the first light and the second light are incident on the light guide portion, wherein,

[0093] The first light and the second light are incident on the light guide portion in a coaxial optical path. (2)

[0095] The light source device according to (1), further including: a beam shaping element arranged between the second light source unit and the first light source unit, and controlling an angular distribution of the second light. (3)

[0097] The light source device according to (1) or (2), further including: one or more condensing lenses arranged between the first light source unit and the light guide portion. (4)

[0099] The light source device according to (3), further comprising: an integrator optical system arranged between the light guide portion and the one or more condensing lenses. (5)

[0101] The light source device according to (3) or (4), further comprising: a polarization optical element arranged between the first light source unit and the one or more converging lenses. (6)

[0103] The light source device according to any one of (2) to (5), further comprising:

[0104] a reflector disposed after the beam shaping element and reflecting the second light in a first direction; and

[0105] The first combining mirror is arranged on an optical path of the second light and combines the first light and the second light by transmitting the second light and selectively reflecting the first light in a first direction. (7)

[0107] The light source device according to (6), wherein the first combining mirror is a dichroic mirror. (8)

[0109] The light source device according to any one of (1) to (7), wherein the first light source unit and the second light source unit are arranged linearly. (9)

[0111] The light source device according to any one of (1) to (8), wherein:

[0112] The second light source unit includes one or more light emitting elements, and

[0113] One or more of the light emitting elements is a semiconductor laser. (10)

[0115] The light source device according to (3) to (9), wherein the one or more converging lenses include a high refractive index material. (11)

[0117] The light source device according to any one of (6) to (10), wherein at least one of the light amount sensor or the colorimetry sensor is arranged on a surface of the reflective mirror on a side opposite to the reflective surface. (12)

[0119] The light source device according to any one of (3) to (11), further including: a third light source unit arranged between the first light source unit and the one or more condensing lenses, and outputting third light having a wavelength in a visible light region. (13)

[0121] The light source device according to (12) further includes: a second combining mirror arranged on an optical path of the combined first light and second light, and combining the first light, the second light, and the third light by transmitting the third light and selectively reflecting the first light and the second light in the second direction. (14)

[0123] The light source device according to (13), wherein the second combining mirror is a polarization beam splitter. (15)

[0125] The light source device according to any one of (12) to (14), wherein the first light is blue light, and the third light is yellow light. (16)

[0127] The light source device according to any one of (12) to (15), further comprising: a fourth light source unit, outputting excitation light, wherein:

[0128] The third light source unit includes a wavelength conversion unit that outputs third light by performing wavelength conversion on the excitation light, and

[0129] The first light source unit, the second light source unit, the third light source unit, and the fourth light source unit are linearly arranged.

[0130] This application claims the benefit of Japanese Priority Patent Application JP2022-096759 filed in the Japan Patent Office on Jun. 15, 2022, the entire contents of which are incorporated herein by reference.

[0131] It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.

Claims

1. A light source device, comprising: A first light source unit outputs a first light with a wavelength in the visible light region; a second light source unit, arranged before the first light source unit, and outputting a second light having a wavelength in a near-infrared region; as well as A light guide portion on which the first light and the second light are incident, wherein the first light and the second light are incident on the light guide portion in a coaxial optical path.

2. The light source device according to claim 1, further comprising: A beam shaping element is disposed between the second light source unit and the first light source unit and controls an angular distribution of the second light.

3. The light source device according to claim 1, further comprising: One or more converging lenses are arranged between the first light source unit and the light guide portion.

4. The light source device according to claim 3, further comprising: An integrator optical system is disposed between the light guide and the one or more converging lenses.

5. The light source device according to claim 3, further comprising: A polarization optical element is arranged between the first light source unit and the one or more converging lenses.

6. The light source device according to claim 2, further comprising: a reflector arranged after the beam shaping element and reflecting the second light in a first direction; as well as A first combining mirror is disposed on an optical path of the second light and combines the first light and the second light by transmitting the second light and selectively reflecting the first light in the first direction.

7. The light source device according to claim 6, wherein: The first combining mirror includes a dichroic mirror.

8. The light source device according to claim 1, wherein: The first light source unit and the second light source unit are arranged linearly.

9. The light source device according to claim 1, wherein: The second light source unit includes one or more light emitting elements, and The one or more light emitting elements include a semiconductor laser.

10. The light source device according to claim 3, wherein: The one or more converging lenses include a high refractive index material.

11. The light source device according to claim 6, wherein: At least one of a light amount sensor and a colorimetric sensor is arranged on a surface of the reflective mirror on a side opposite to the reflective surface.

12. The light source device according to claim 3, further comprising: The third light source unit is disposed between the first light source unit and the one or more condensing lenses, and outputs third light having a wavelength in a visible light region.

13. The light source device according to claim 12, further comprising: The second combining mirror is arranged on an optical path of the combined first light and the second light, and combines the first light, the second light, and the third light by transmitting the third light and selectively reflecting the first light and the second light in a second direction.

14. The light source device according to claim 13, wherein: The second combining mirror includes a polarizing beam splitter.

15. The light source device according to claim 12, wherein: The first light includes blue light, and the third light includes yellow light.

16. The light source device according to claim 12, further comprising: The fourth light source unit outputs excitation light, wherein: The third light source unit includes a wavelength conversion unit that outputs the third light by performing wavelength conversion on the excitation light, and The first light source unit, the second light source unit, the third light source unit, and the fourth light source unit are linearly arranged.

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