lighting equipment

Abstract

[Solution] An illumination device is provided, comprising: a first light source mounted on a substrate that emits first light having a first wavelength spectrum; a second light source mounted on the substrate that emits second light having a second wavelength spectrum; and a phosphor layer that converts at least a portion of at least the first light and the second light into first converted light and second converted light, respectively; the phosphor layer is configured to emit a remaining portion of the first light, a remaining portion of the second light, the first converted light, and the second converted light; the phosphor layer is in contact with the first and second light sources and is continuous over the first and second light sources and on a path on the substrate connecting the first and second light sources; and the phosphor layer and the substrate surround the first light source and the second light source.

Description

[Technical Field]

[0001] The present invention relates to an illumination device for illuminating an object with different spectra, and more particularly to an illumination device useful at the distal end of an endoscope, especially an endoscope with a wide field objective lens. [Background technology]

[0002] White light (WL) and vascular pattern-enhancing illumination (so-called narrowband illumination with an illumination spectrum synchronized with the hemoglobin absorption spectrum) are becoming increasingly common in endoscopic imaging. For energy efficiency and to create a wider light distribution angle, it is more preferable to have a light source at the distal end of the endoscope without incorporating optical fibers. However, there are no off-the-shelf LEDs with a good spectrum for vascular pattern-enhancing illumination in a micro-sized package (e.g., 500 μm × 500 μm).

[0003] Generally, imaging with different colored light is known in the art. For example, there is white light imaging (WLI) and "spectral imaging." In WLI, an object (such as a colon) is illuminated with white light. In contrast, in spectral imaging, an object is illuminated with light having a spectral distribution different from that of white light. For example, spectral imaging using a spectrum that substantially includes only violet and green light is known to be used for vascular pattern enhancement illumination.

[0004] Figure 1 shows a prior art endoscopic illumination system that enables both WLI and spectral imaging. The illumination system includes a white LED (shown here as a blue LED covered with yellow phosphor) and separate violet and green LEDs. In spectral imaging, only the violet and green LEDs emit light. Thus, the emitted light has a gradient from violet on the left to green-violet on the right. In WLI, only the white LED emits light.

[0005] Such illumination systems have several drawbacks, including the relative intensities of the purple and green lights varying with location on the object. Furthermore, the white light illumination is located at a different location on the object than the purple and green LED illumination. Therefore, a physician using a prior art endoscope cannot easily observe the same location under different illumination. Furthermore, a significant amount of space is required at the tip of the endoscope to accommodate the three LEDs. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to improve upon the prior art. Thus, according to one aspect of the present invention, there is provided an illumination device as set forth in the independent claims. Further aspects of the present invention provide a rigid tip for an endoscope comprising an illumination device, an endoscope comprising an illumination device, and a method for manufacturing an illumination device. Further details are set forth in the respective dependent claims. [Means for solving the problem]

[0007] According to some embodiments of the present invention, at least one of the following advantages can be achieved:

[0008] ·Reduced space required for lighting devices that allow both WLI and spectral illumination; · Easy to implement; The color distribution is more homogeneous than that of the prior art; · Allows the physician to easily observe one position under different lighting conditions. Further advantages will become apparent from the detailed description below. [Effects of the Invention]

[0009] It is to be understood that any of the improvements described above and examples described below may be applied to the respective embodiments to which they refer, either alone or in combination, unless expressly stated as excluding alternatives. Further details, features, objects and advantages will be apparent from the following detailed description of preferred embodiments of the invention, considered in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows a prior art lighting system; [Figure 2] 1 illustrates a cross section of a unit cell of an illumination device according to some embodiments of the present invention used for spectral illumination. [Figure 3] This shows the emission spectrum when the lighting device of Figure 2 is used for spectral lighting. [Figure 4] 3 shows a unit cell of the lighting device according to FIG. 2 used for WLI; [Figure 5] 5 shows the spectrum of light emitted when the lighting device of FIG. 4 is used for WLI. [Figure 6] 1 illustrates a unit cell of another lighting device according to some embodiments of the present invention used for spectral illumination. [Figure 7] 7 shows the emission spectrum of the lighting device of FIG. 6 used for spectral illumination. [Figure 8] 7 shows the illumination device of FIG. 6 used for WLI. [Figure 9] 9 shows the emission spectrum of the illuminator of FIG. 8 used in WLI. [Figure 10] 1 illustrates another example of a phosphor layer that can be used in accordance with some embodiments of the present invention. [Figure 11] 1 illustrates another example of a phosphor layer that can be used in accordance with some embodiments of the present invention. [Figure 12] 1 illustrates a lighting device according to some embodiments of the present invention. [Figure 13] 1 shows a plan view of a rigid tip of an endoscope with an illumination device according to some embodiments of the present invention. [Figure 14] 1 illustrates a manufacturing method according to some embodiments of the present invention. [Figure 15] 1 illustrates a manufacturing method according to some embodiments of the present invention. [Figure 16] 1 illustrates a manufacturing method according to some embodiments of the present invention. [Figure 17] 1 illustrates a manufacturing method according to some embodiments of the present invention. [Figure 18] 1 shows the determination of the preferred minimum thickness of the phosphor layer. [Figure 19] An example of the radiation distribution of an LED is shown. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, the features of which are freely combinable with one another unless otherwise specified, however, it should be expressly understood that the description of the specific embodiments is given by way of example only and is in no way intended to be construed as limiting the invention to the details disclosed.

[0012] In the figures, the same numerals indicate corresponding elements, and the elements are distinguished by different letters. The figures are only schematic. In particular, the sizes are not to scale. For example, the light source (LED or the output end of an optical fiber) may be substantially a point.

[0013] According to some embodiments of the present invention, at least two types of light sources having different peak wavelengths are arranged on a printed circuit board (PCB). Note that although it is assumed that two types of LEDs are used, the number of types may be more than two. Instead of LEDs, the light emitting end of an optical fiber having a light emitting element (e.g., a laser or LED) configured to emit respective light into the optical fiber can also be used as the light source. In this case, the light emitting element may be arranged at the proximal end of the endoscope. The light sources may be mixed; for example, the first type of light source may be an LED and the second type of light source may be the output end of the optical fiber. In the following, LEDs are described as an example of a light source, but the present invention is not limited to LEDs as the light source.

[0014] Furthermore, a phosphor layer containing one or more phosphors is disposed on the PCB and the LED. More specifically, the phosphor layer contacts at least the LED and the traces on the PCB so that the phosphor layer and the PCB surround the LED. The phosphor layer is continuous over the LED and the traces. Here, the term "surrounding" preferably means that the PCB and the phosphor layer surround the LED on all sides without any gaps. However, the term "surrounding" also includes the case where one or more small gaps are provided in the PCB and / or the phosphor layer and / or at the interface between the PCB and the phosphor layer. If such one or more gaps are present, they are positioned so that at least 95% of each light emitted by the LED enters the phosphor layer or is absorbed by the PCB.

[0015] FIG. 2 illustrates a unit cell of a lighting device according to some embodiments of the present invention. The lighting device includes one or more unit cells. Each unit cell includes a first LED 2a of a first type (e.g., an LED emitting UV light) and a second LED 3a emitting a different spectrum, such as a white LED. The LEDs are mounted on one side of a PCB 4a. The LEDs 2a and 3a of the unit cell illuminate a phosphor layer 1a containing a phosphor. The phosphor converts at least a portion of the light from the first LED (first light) into a first converted light. Furthermore, the phosphor can convert at least a portion of the light from the second LED (second light) into a second converted light. The first converted light has a spectrum different from that of the first light. The second converted light, if present, has a spectrum different from that of the second light.

[0016] For example, in the case of spectral illumination, only UV LED 2a illuminates the phosphor layer with light, while white LED 3a is turned off, as shown in Figure 3. In this case, the emission spectrum includes violet or deep blue light (sometimes called UV light) from LED 2a near wavelength (peak wavelength) λ3 (e.g., 400-430 nm) and green light (e.g., near λ2: 520-580 nm) from conversion by the phosphor in exit layer 1a.

[0017] For white light illumination, only the second LED 3a illuminates the exit layer 1a, while the first LED 2a is dark. In this case, the white LED 3a is a blue LED coated with phosphor, whose emission spectrum is shown by the dashed line in Figure 5. That is, it has a high peak in the blue region (λ1, approximately 440-460 nm) and a broad maximum in the green region near λ2. Due to conversion by the phosphor in the phosphor layer 1a, the intensity of the blue light near λ1 is reduced, and the broad maximum near λ2 is enhanced and broadened. In this way, white light illumination is achieved.

[0018] The spectra shown in Figures 3 and 5 are merely examples. Other combinations of different types of LEDs with different types of phosphors are within the scope of the present invention. The phosphor layer may use multiple types of phosphors rather than a single type of phosphor. These different types of phosphors may be mixed or located in different layers.

[0019] Figures 6-9 show another example of a unit according to some embodiments of the present invention, which corresponds to Figures 2-5 except that the white LED 3a of Figures 2 and 4 is replaced with a blue LED 3b emitting light in the range of 440-460 nm. In this example, the first LED 2b and the phosphor in the phosphor layer 1b are the same as in Figures 2 and 4, so the spectrum for the spectral illumination shown in Figure 7 is the same as the spectrum shown in Figure 3.

[0020] However, for white light illumination, the blue LED 3b excites the phosphor more than the white LED 3a of Figures 2 and 4. Therefore, the emission spectrum for white light illumination has a larger and broader peak near λ2, as shown in Figure 9.

[0021] 10 and 11 show further examples of phosphor layers 1c and 1d that can be used in accordance with some embodiments of the present invention. As shown in FIG. 10, the LEDs emit blue light (peak wavelength: approximately 450 nm) and violet light (peak wavelength: approximately 420 nm). The phosphors in the phosphor layer convert a portion of both of these lights to yellow light (peak wavelength: approximately 550 nm). As shown in FIG. 11, phosphor layer 1d includes multiple types of phosphors. In addition to the phosphors in phosphor layer 1c of FIG. 10, a second type of phosphor converts a portion of the blue light from each LED to red light (peak wavelength: approximately 630 nm). In this way, the output light from phosphor layer 1d is substantially white (containing a sufficient amount of RGB) when only the blue LED is on. The conversion efficiency of the second phosphor for violet light to red light is very small. Therefore, when only the violet LED is on, the output light is essentially the same as that of phosphor layer 1d of FIG. 10.

[0022] In Figures 2, 4, 6, and 8, phosphor layer 1 has a flat light-emitting surface. The light-emitting surface is opposite the surface facing the PCB. However, this is not required. For example, as shown in Figure 12, phosphor layer 1e may have a constant thickness. In this case, the light-emitting surface is not flat due to the thickness of the LED. In some embodiments, the light-emitting surface of phosphor layer 1 is not flat, and the thickness of phosphor layer 1 is not constant. For example, in such embodiments, the unevenness of the surface of PCB 4 on which LEDs 2 and 3 are mounted may be partially flattened.

[0023] In some embodiments, a plurality of unit cells, each including at least a first LED 2 of a first type and a second LED 3 of a second type different from the first type (having a different peak wavelength), are arranged on a PCB 4 and covered by a common phosphor layer 1. In each unit cell, the first and second LEDs are arranged in the same manner. The unit cells may be arranged, for example, in a line (straight or curved).

[0024] In some embodiments, the unit cells are arranged in a circle or a portion of a circle. In some of these embodiments, an illumination device including a plurality of unit cells of two types of LEDs arranged on a PCB and a common phosphor layer including one or more phosphors is arranged around an objective lens configured to image an object space. The illumination device is positioned to illuminate at least a portion of the object space.

[0025] Such an arrangement is shown in Figure 13, which shows the rigid tip of the endoscope in plan view (viewed from the object space; the phosphor layer and optional transparent cap covering the illumination device have been omitted). LEDs 2f, 3f surround a central objective lens 5. At the bottom of this plan view, a working channel 51 is shown.

[0026] The PCB may include an adhesive to attach the phosphor layer to the PCB. The adhesive may or may not include phosphor. If the adhesive does not include phosphor, it must be fairly thin. For example, the maximum thickness of the adhesive is 10% or less of the maximum thickness of the light source (LED) with the smallest maximum thickness among the first and second light sources. Preferably, this ratio is 5% or less. Preferably, the adhesive, if present, is positioned so that at least 95% of the light emitted by the LED penetrates the phosphor layer. More preferably, at least 98%, or even 100%, of the emitted light penetrates the phosphor layer.

[0027] According to some embodiments, when the phosphor layer is locally parallel to the surface of the PCB facing the phosphor layer, the amount of phosphor in the direction perpendicular to the surface of the PCB is substantially constant, i.e., does not vary by more than 20% around a mean value, preferably does not vary by more than 10%, and even more preferably does not vary by more than 5%. When the lighting device includes multiple unit cells, in some embodiments, the amount of phosphor in the direction perpendicular to the surface of the PCB facing the phosphor layer may be varied according to the arrangement of the unit cells. For example, when the unit cells are arranged periodically, the amount of phosphor in the perpendicular direction can be varied with the same period. The surface of the PCB facing the phosphor layer is the surface on which the LEDs are mounted.

[0028] The concentration of phosphors may be substantially constant across the thickness of the phosphor layer. However, according to some embodiments, the concentration of phosphors may have peaks. When the phosphor layer includes multiple phosphors, they may be uniformly distributed within the phosphor layer or may be arranged at different levels across the thickness.

[0029] Preferably, the surface of the PCB facing the phosphor layer may be substantially flat. For example, variations in planarity due to wiring and / or adhesive may be 10% or less of the maximum thickness of the light source (LED) having the smallest maximum thickness among the first and second light sources. Preferably, this ratio is 5% or less. However, the present invention is not limited to a substantially flat surface of the PCB. Some embodiments of the present invention may include a curved surface of the PCB facing the phosphor layer.

[0030] If the light sources are LEDs, the PCB can include circuitry for controlling the LEDs. For this purpose, the LEDs are electrically connected to terminals disposed on the PCB. In some embodiments, each LED can be controlled separately. In some embodiments, at least a first type of LED can be controlled separately from a second type of LED. "Control" means at least switching on and off. It can further mean setting the intensity and / or color of the light emitted by each LED. The same applies to other light sources that generate light locally (on the PCB), such as when the light source is a laser diode.

[0031] The LEDs may be mounted on the PCB in any known manner, such as by surface mounted device (SMD) or flip chip bonding.

[0032] As described above in this specification, the illumination device is preferably disposed in the rigid tip of an endoscope for insertion into a body lumen. Such a rigid tip can include an objective lens, and the illumination device can be disposed around the objective lens. Furthermore, the rigid tip can include an imaging element, a working channel, etc. The rigid tip can be directly or indirectly (via an angle segment) connected to a flexible or rigid shaft for insertion into a body lumen, such that embodiments of the present invention also encompass endoscopes. In some embodiments, the rigid tip can be used alone (i.e., without being connected to the shaft of an endoscope). That is, the illumination device can be used in so-called "capsule endoscopy."

[0033] However, the present invention is not limited to illumination devices in the rigid tip portion of endoscopes intended for insertion into human body lumens. It can also be applied to other endoscopes (such as endoscopes for pipelines that are not suitable for insertion into human body lumens). It can also be applied to non-endoscopes, for example, to illuminate the target space of a camera, such as a CCTV camera.

[0034] According to some embodiments of the present invention, there are several options for manufacturing such lighting devices, which are described using LEDs as an example of the light source, but are not limited to LEDs.

[0035] A first manufacturing method is shown in Figure 14. The phosphor is dissolved in a fluid or gel, and the fluid or gel is dispensed by a dispenser 100 onto a PCB on which a light source is mounted. Specifically, the fluid or gel is dispensed at least onto the LEDs and the paths connecting the LEDs so that the LEDs are surrounded by the PCB and the fluid or gel. The fluid is then dried or the gel is hardened to obtain a phosphor layer containing the phosphor.

[0036] The fluid or gel must have sufficient viscosity so that it remains substantially in the area where it is dispensed until it has dried or cured. If the light source generates light locally (e.g., the light source is an LED, laser diode, etc.), the light source is electrically connected to terminals located on the PCB prior to dispensing. If an adhesive is required to adhere the phosphor (or medium containing the phosphor) to the PCB, the adhesive can be applied as a thin layer to the PCB and LED prior to dispensing.

[0037] An example of a solvent for forming a fluid or gel containing the phosphor is silicone. An example of an adhesive is a polymer.

[0038] To form the phosphor layer, the fluid or gel can be dispensed to each location once or multiple times. When the fluid or gel is dispensed multiple times, the phosphor in the fluid or gel may be the same, or different phosphors may be included in the fluid or gel in different dispense runs. Thus, the phosphor layer may have an internal layered structure consisting of different phosphors.

[0039] The second manufacturing method is shown in Figure 15. According to Figure 15, a fluid with dissolved phosphor is sprayed onto the PCB by a sprayer 101 and then dried. Otherwise, the second manufacturing method corresponds to the first manufacturing method.

[0040] 16 shows a third manufacturing method. In the third manufacturing method, a phosphor sheet is prepared, which includes phosphor dispersed in a medium (e.g., silicone) or consists of phosphor. The phosphor sheet may be much larger than the PCB on which the light source is mounted. Pieces having a shape corresponding to the shape of the phosphor layer are then cut out from the phosphor sheet. Here, the term "corresponding" means that the pieces may have the same shape as the phosphor layer, or may have a shape that takes into account level differences with the LEDs, shrinkage due to thermal expansion, etc. That is, the cut pieces may have a slightly different shape from the final phosphor layer.

[0041] One of the cut pieces is then applied to a PCB on which a light source is mounted (and, if necessary, electrically connected to a terminal on the PCB). The cut piece should preferably have some flexibility so that it can fit the surface of the PCB on which the LED (light source) is mounted. If an adhesive is required to bond the cut piece to the PCB and / or LED, the adhesive can be applied as a thin layer to the PCB and / or LED and / or to the phosphor sheet (either before or after the pieces are cut). An example of an adhesive that can be used in this manufacturing method is an adhesive transfer tape such as 3M's 467MP.

[0042] Fig. 17 shows a fourth manufacturing method, which is a variation of the third manufacturing method. According to Fig. 17, a phosphor sheet is laminated onto a number of PCBs on which light sources are mounted (and, if necessary, electrically connected to the terminals of the PCBs). An adhesive can be applied onto the phosphor sheet and / or the PCBs / LEDs. Afterwards, unnecessary parts of the laminate are removed by cutting. In this way, the phosphor layer covers the entire PCBs on which the light sources are mounted. In other respects, the fourth method corresponds to the third method.

[0043] In some embodiments (not shown), the PCBs for the multiple lighting devices may be portions of a larger PCB. In these embodiments, the PCBs for the lighting devices may be cut out from the larger PCB during the step of cutting the phosphor layer according to the fourth method. In this way, one manufacturing step may be saved because the PCB and phosphor layer for each lighting device are cut out in the same process.

[0044] Figure 18 shows the derivation of the minimum thickness that the phosphor layer should preferably have to ensure that the lighting device provides substantially uniform illumination. At the bottom of Figure 18, it is shown that each position on the emitting surface of the phosphor layer should be illuminated by at least one of the first LEDs with at least 50% of its intensity. This condition is met by the minimum thickness T 11 =D 11 / 2*tanθ 50 D 11 refers to the distance between two adjacent first LEDs, and θ 50 θ is the radiation angle at which the first LED emits 50% of its maximum light emission. 50 The value of θ can be obtained from the radiation characteristics of the first LED. A typical example is shown in Figure 19. In this example, θ 50 is about 55°.

[0045] The same considerations apply to the second LED as well. If the respective minimum thicknesses are different, the phosphor layer should preferably have a minimum thickness that is the greater of the respective minimum thicknesses of the two types of LEDs. The emission angle at which the second LED emits 50% of its maximum emission is defined as Φ 50 This indicates:

[0046] At the top of FIG. 18, the θ (for a given distance between the LEDs and a given height of the LEDs and opaque wall, if present) is plotted. 50 and Φ 50 Determine the maximum value of (θ 50 and Φ 50 Determine the minimum distance between the LEDs (for a given value of θ and a given height of the LEDs and opaque wall, if any), or (θ 50 and Φ 50 An additional consideration is shown for determining the maximum height of the LEDs and opaque walls (if present) for a given value of λ and a given distance between the LEDs. That is, the height of the emitted light beam with 50% intensity must be higher than the height of the adjacent LEDs or walls (if present). At the top of Figure 18,

[0047] T 12 denotes the height of this ray from the first LED at the position of the edge of the second LED facing the first LED, T 21 denotes the height of this ray from the second LED at the position of the edge of the first LED facing the second LED, T 13 denotes the height of this ray from the first LED at the edge of the adjacent wall facing the first LED, T 23 denotes the height of this ray from the second LED at the edge of the adjacent wall (not shown) facing the first LED, D 12 denotes the shortest distance between the first and second LEDs, D 21 denotes the shortest distance between the second LED and the first LED (D 12 =D21 ), D 13 denotes the shortest distance between the first LED and the adjacent wall, D 23 indicates the shortest distance between the second LED and the adjacent wall (not shown).

[0048] If the first LED, the second LED, and the wall have thicknesses t1, t2, and t3, then the relationship T 12 >t2, T 21 >t1, T 13 >t3, and T 23 >t3 is obtained. In the limit case, θ 50 and Φ 50 The condition for tanθ 50 =D 12 / T 12 , tanθ 50 =D 13 / T 13 , tanΦ 50 =D 21 / T 21 , and tanΦ 50 =D 23 / T 23 is.

[0049] The conditions derived at the top and bottom of Figure 18 are preferred, but not required, according to some embodiments of the present invention. For example, in some embodiments, only a subset of these conditions may be met, or none of these conditions may be met.

[0050] Some embodiments of the present invention that include a light emitting device located at the distal end of the endoscope are advantageous because they are more efficient in terms of power conversion than other illumination systems in which the light emitting device is located in a box located at the proximal end and the light is directed to the distal end via one or more optical fibers. Even when the light source is located within the control body at the proximal end of the endoscope, space is limited.

[0051] Additionally, locating a common phosphor system for the purple and blue LEDs at the distal end of the endoscope is preferred (but not required) due to the following considerations regarding placement at the proximal end:

[0052] White LEDs (WLEDs) have standard packaging covered with phosphor. However, phosphor causes scattering, meaning that it is difficult to efficiently collect light into an optical fiber. For purple LEDs, there is no standard phosphor package. Customization is required, which involves significant cost, and this phosphor scatters light in the same way as WLEDs.

[0053] In contrast, if the phosphor layer is located at the distal end, scattering of light by the phosphor is even advantageous because it distributes the light over a wider angle to illuminate a wider field of view. The light emitting element (such as an LED) may be located at the distal end (behind the phosphor layer) or at the proximal end, with light being guided from the light emitting element through one or more optical fibers to the distal end. In this case, as described above, the output end of the optical fiber acts as the light source.

Claims

1. A substrate; a plurality of first light sources mounted on the substrate, each configured to emit first light having a first wavelength spectrum; a plurality of second light sources mounted on the substrate, each configured to emit second light having a second wavelength spectrum different from the first wavelength spectrum; a phosphor layer including a phosphor arranged to convert at least a portion of at least one of the first light and the second light into first converted light and second converted light, respectively, wherein a third wavelength spectrum of the first converted light is different from the first wavelength spectrum and a fourth wavelength spectrum of the second converted light is different from the second wavelength spectrum; and It is equipped with the phosphor layer is configured to emit the first converted light and the second converted light converted by the phosphor, a remaining portion of the first light, and a remaining portion of the second light; the phosphor layer contacts each of the first light sources and each of the second light sources and is continuous over each of the first light sources, over each of the second light sources, and on a path on the substrate connecting the first light sources and the second light sources; the phosphor layer and the substrate surround the first light source and the second light source; The phosphor layer has a thickness equal to or greater than the larger of {distance between adjacent first light sources / 2×tan (radiation angle at which the emission of the first light source is 50% of the maximum emission)} and {distance between adjacent second light sources / 2×tan (radiation angle at which the emission of the second light source is 50% of the maximum emission)}. Lighting equipment.

2. the phosphor layer covers the entire substrate; 100% of the first light enters the phosphor layer; and 100% of the second light enters the phosphor layer. The lighting device according to claim 1 , wherein the at least one of

3. the first wavelength spectrum primarily includes blue light having a peak wavelength of about 450 nm; the second wavelength spectrum primarily includes violet and / or ultraviolet light having a peak wavelength of about 420 nm; the phosphor is configured to convert a portion of the blue light into yellow light so that a first output light output based on the first light appears white; The phosphor is configured to convert a portion of the violet and / or ultraviolet light into the yellow light.

3. The lighting device according to claim 1 or 2.

4. the first wavelength spectrum primarily includes blue light having a peak wavelength of about 450 nm; the second wavelength spectrum primarily includes violet and / or ultraviolet light having a peak wavelength of about 420 nm; the phosphor is configured to convert a portion of the blue light into green light and red light so that a first output light output based on the first light appears white; 3. The lighting device of claim 1, wherein the phosphor is configured to convert a portion of the violet and / or ultraviolet light into the green light.

5. In the phosphor layer, the phosphor is dispersed in a medium. The lighting device according to any one of claims 1 to 4.

6. the first light source is a light emitting diode or a laser diode; and the second light source is a light emitting diode or a laser diode; The lighting device according to any one of claims 1 to 5, wherein the lighting device is at least one of:

7. When the first light source is a light emitting diode or a laser diode, the substrate includes a first terminal, and the first light source is electrically connected to the first terminal. When the second light source is a light emitting diode or a laser diode, the substrate includes a second terminal, and the second light source is electrically connected to the second terminal.

7. The lighting device according to claim 6, wherein the at least one of

8. the first light source is controllable via the first terminal; the second light source is controllable via the second terminal; 8. The lighting device of claim 7, wherein the first light source is controllable separately from the second light source.

9. the first light source is an output end of a first optical fiber, and the illumination device includes a first light-emitting element configured to input the first light into the first optical fiber. the second light source is an output end of a second optical fiber, and the illumination device includes a second light emitting element configured to input the second light into the second optical fiber. The lighting device according to any one of claims 1 to 5, wherein the lighting device is at least one of:

10. 10. The lighting device according to claim 1, wherein the phosphor layer comprises a plurality of phosphors.

11. the substrate comprises an adhesive; the adhesive adheres to the phosphor layer; 11. The lighting device according to claim 1, wherein a maximum thickness of the adhesive is 10% or less of a maximum thickness of a light source having a smallest maximum thickness among the first light source and the second light source.

12. A method for manufacturing a lighting device according to any one of claims 1 to 11, comprising the steps of: providing the substrate having the first light source and the second light source mounted thereon; dispensing a fluid or gel containing the phosphor onto the first light source, onto the second light source, and onto the path on the substrate connecting the first light source and the second light source; hardening the gel or drying the fluid to obtain the phosphor layer; A method comprising:

13. allowing the phosphor-containing fluid or gel to flow prior to said curing The method of claim 12 further comprising:

14. A method for manufacturing a lighting device according to any one of claims 1 to 11, comprising the steps of: providing the substrate having the first light source and the second light source mounted thereon; spraying the phosphor-containing fluid onto the first light source, onto the second light source, and onto the path on the substrate connecting the first light source and the second light source; drying the atomized fluid to obtain the phosphor layer; A method comprising:

15. A method for manufacturing a lighting device according to any one of claims 1 to 11, comprising the steps of: providing the substrate having the first light source and the second light source mounted thereon; creating a sheet including the phosphor such that in plan view the sheet has a shape corresponding to the shapes of the first light source, the second light source, and the paths on the substrate connecting the first light source and the second light source; attaching the sheet to the substrate, the first light source, and the second light source such that the sheet covers the first light source, the second light source, and the channel to obtain the phosphor layer; A method comprising:

16. A method for manufacturing a lighting device according to any one of claims 1 to 11, comprising the steps of: providing the substrate having the first light source and the second light source mounted thereon; attaching the phosphor-containing sheet to the substrate such that the sheet covers the first light source, the second light source, and the path on the substrate connecting the first light source and the second light source; cutting the portion of the sheet extending beyond the substrate to obtain the phosphor layer; A method comprising:

17. 12. A rigid tip portion of an endoscope or a capsule endoscope for insertion into a lumen of a human body, comprising: an objective lens; and the illumination device according to any one of claims 1 to 11, which is arranged to illuminate at least a portion of a target space imaged by the objective lens with at least one of first output light output based on the first light and second output light output based on the second light.

18. An endoscope comprising a rigid tip portion as described in claim 17 and a flexible or rigid shaft for insertion into the lumen of the human body, wherein the rigid tip portion is connected directly or indirectly to the flexible or rigid shaft.

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