Lighting device

Abstract

The application provides a lighting device, which comprises a first light source, a second light source and a phosphor layer; the first light source is installed on a plate and emits first light with a first wavelength spectrum; the second light source is installed on the plate and emits second light with a second wavelength spectrum; the phosphor layer converts at least part of at least one of the first light and the second light into first converted light and second converted light; wherein the phosphor layer emits the remaining part of the first light, the remaining part of the second light, the first converted light and the second converted light; the phosphor layer contacts the first light source and the second light source and is continuous on a path of the first light source, the second light source and the plate, the path connects the first light source and the second light source; the phosphor layer and the plate surround the first light source and the second light source.

Description

Technical Field

[0001] This invention relates to an illumination device for illuminating objects with different spectra. In particular, the invention relates to an illumination device that can be used in the distal portion of an endoscope, and more particularly to an endoscope including a wide field-of-view objective lens. Background Technology

[0002] White light (WL) and vascular pattern enhanced illumination (so-called narrow-band illumination, which has an illumination spectrum synchronized with the hemoglobin absorption spectrum) are becoming increasingly common in endoscopic imaging. Regarding energy efficiency and to produce a wider angle of light distribution, a light source located at the distal end of the endoscope without involving optical fibers is preferable. However, there are no readily available LEDs that provide a good spectrum for vascular pattern enhanced illumination in micro-sized packages (e.g., 500µm x 500µm).

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

[0004] Figure 1 illustrates an illumination system for an endoscope according to the prior art, which allows both WLI (light-in-the-box imaging) and spectral imaging. The illumination system includes a white LED (shown herein as a blue LED, with a yellow phosphor covering the blue LED), separated from the white LED, blue-violet LED, and green LED. In spectral imaging, only the blue-violet and green LEDs emit light. Therefore, the emitted light has a gradient from blue-violet on the left, through green-violet, to green on the right. In WLI, only the white LED emits light.

[0005] This type of lighting system has several drawbacks: the relative intensity of blue-violet and green light varies with the object's position. Furthermore, white light illumination is positioned at different locations on the object compared to illumination via blue-violet and green LEDs. Therefore, physicians using existing endoscopes cannot easily observe the same location under different lighting conditions. Additionally, a considerable amount of space is required to accommodate three LEDs in the distal end of the endoscope. Summary of the Invention

[0006] The objective of this invention is to improve upon existing technologies. Specifically, according to one aspect of the invention, a lighting device as described in the independent claim is provided. Other aspects of the invention provide a rigid endpiece of an endoscope including the lighting device, an endoscope including the lighting device, and a method for manufacturing the lighting device. Further details are explained in the corresponding dependent claims.

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

[0008] • The space required for the lighting equipment is reduced, and the equipment allows for both WLI and spectral lighting;

[0009] This configuration is easy to implement;

[0010] • The color distribution is more uniform compared to existing technologies;

[0011] • Doctors can easily observe a location under different lighting conditions.

[0012] Other advantages will become apparent from the specific description below.

[0013] It should be understood that any of the above modifications and the examples described below may be applied individually or in combination to the respective aspects they refer to, unless they are explicitly stated to exclude alternative forms. Attached Figure Description

[0014] Other details, features, objectives, and advantages will become apparent from the following detailed description of preferred embodiments of the invention, which is considered in conjunction with the accompanying drawings, wherein:

[0015] Figure 1 illustrates a lighting system according to the prior art;

[0016] Figure 2 A cross-section of a cell of a lighting device for spectral illumination is shown according to some embodiments of the present invention;

[0017] Figure 3 It shows in Figure 2 The emission spectrum of the lighting equipment used for spectral illumination;

[0018] Figure 4 The basis for WLI is shown. Figure 2 The unit of the lighting equipment;

[0019] Figure 5 It shows in Figure 4 The lighting equipment is used in the case of WLI to emit light in the spectrum;

[0020] Figure 6According to some embodiments of the present invention, a cell of another lighting device is shown, the lighting device being used for spectral illumination;

[0021] Figure 7 It shows the use of spectral illumination Figure 6 The emission spectrum of lighting equipment;

[0022] Figure 8 The following is shown for use in WLI Figure 6 Lighting equipment;

[0023] Figure 9 The following is shown for use in WLI Figure 8 The emission spectrum of lighting equipment;

[0024] Figure 10 Another example of a usable phosphor layer is shown according to some embodiments of the present invention;

[0025] Figure 11 Another example of a usable phosphor layer is shown according to some embodiments of the present invention;

[0026] Figure 12 Lighting devices are shown according to some embodiments of the present invention;

[0027] Figure 13 A plan view of the rigid end of an endoscope including an illumination device is shown according to some embodiments of the present invention;

[0028] Figure 14 A manufacturing method is illustrated according to some embodiments of the present invention;

[0029] Figure 15 A manufacturing method is illustrated according to some embodiments of the present invention;

[0030] Figure 16 A manufacturing method is illustrated according to some embodiments of the present invention;

[0031] Figure 17 A manufacturing method is illustrated according to some embodiments of the present invention;

[0032] Figure 18 The determination of the preferred minimum thickness of the phosphor layer is shown; and

[0033] Figure 19 An example of the radiation distribution of an LED is shown. Detailed Implementation

[0034] In the following description, certain embodiments of the invention are given in detail with reference to the accompanying drawings, wherein features of the embodiments may be freely combined with each other unless otherwise described. However, it should be clearly understood that the description of certain embodiments is given by way of example only and is in no way intended to limit the invention to the details disclosed.

[0035] In the diagram, the same numbers represent corresponding components, which are distinguished by different letters. The diagram is for illustrative purposes only. In particular, dimensions are not to scale. For example, the light source (the emitting end of an LED or optical fiber) may be approximately a point.

[0036] According to some embodiments of the invention, at least two types of light sources with different peak wavelengths are arranged on a printed circuit board (PCB). For the remainder of the specification, it is assumed that two types of LEDs are used, but the number of types may be greater than two. Instead of LEDs, the emitting end of an optical fiber can be used as a light source, wherein a light emitting device (such as a laser or LED) is configured to emit corresponding light into the optical fiber. In this case, the light emitting device may be arranged at the proximal end of an endoscope. Light sources can be mixed: for example, the first type of light source may be an LED, and the second type of light source may be the emitting end of an optical fiber. Hereinafter, LEDs are described as examples of light sources, but the invention is not limited to LEDs as light sources.

[0037] Furthermore, a phosphor layer comprising one or more phosphors is disposed on the PCB and the LED. More specifically, the phosphor layer at least contacts the paths on the LED and the PCB such that the phosphor layer and the PCB surround the LED. The phosphor layer is continuous over the LED and the paths. In this document, the term "surround" preferably means that the PCB and the phosphor layer surround the LED from all sides without any gaps. However, the term "surround" also includes cases where one or more small gaps are provided within the PCB, and / or within 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 arranged such that at least 95% of each type of light emitted by the LED enters the phosphor layer or is absorbed by the PCB.

[0038] Figure 2According to some embodiments of the present invention, a cell of a lighting device is shown. The lighting device includes one or more cells. Each cell includes a first LED 2a of a first type (e.g., an LED emitting UV light) and a second LED 3a (which emits a different spectrum, such as a white LED). The LEDs are mounted on one surface of a PCB 4a. The LEDs 2a and 3a of the cell illuminate a phosphor layer 1a including a phosphor. The phosphor converts at least a portion of the light from the first LED (first light) into first converted light. Furthermore, the phosphor can convert at least a portion of the light from the second LED (second light) into second converted light. The first converted light has a spectrum different from the first light. The second converted light (if any) has a spectrum different from the second light.

[0039] For example, such as Figure 3 As shown, under spectral illumination, only UV LED2a illuminates the phosphor layer, while white LED3a is off. In this case, the emission spectrum includes blue-violet or deep blue light (sometimes referred to as UV light) from LED2a with a wavelength (peak wavelength) of approximately λ3 (e.g., 400 nm to 430 nm), and green light converted by the phosphor in the exit layer 1a (e.g., wavelength of approximately λ2: 520 nm to 580 nm).

[0040] In white light illumination, only the second LED 3a illuminates the exit layer 1a, while the first LED 2a remains dark. In this case, the white LED 3a is a phosphor-coated blue LED that has the following properties: Figure 5 The emission spectrum is shown by the dashed line. Specifically, it has a high peak in the blue region (λ1 is approximately 440 nm to 460 nm) and a broad maximum value in the green region at approximately λ2. Due to the conversion of phosphors in phosphor layer 1a, the intensity of blue light at approximately λ1 decreases, and the broad maximum value at approximately λ2 is enhanced and broadened. Therefore, white light illumination is performed.

[0041] Figure 3 and Figure 5 The spectra shown are merely examples. Other combinations of different types of LEDs with different types of phosphors fall within the scope of this invention. Instead of a single type of phosphor, multiple types of phosphors can be used in the phosphor layer. These different types of phosphors can be mixed or arranged in different layers.

[0042] Figures 6 to 9 Another example of the unit is shown according to some embodiments of the present invention, and these figures correspond to Figures 2 to 5 The difference is Figure 2 and Figure 4The white LED 3a is replaced by a blue LED 3b, which emits light in the range of 440 nm to 460 nm. This is because, in this example, the first LED 2b and the phosphor in phosphor layer 1b are... Figure 2 and Figure 4 The same in, so in Figure 7 Under the spectral illumination shown, the spectrum and Figure 3 Same as shown.

[0043] However, under white light illumination, the blue LED3b is superior to... Figure 2 and Figure 4 The white LED3a excites more phosphors. Therefore, under white light illumination, the emission spectrum has a large and broad peak of approximately λ2, such as... Figure 9 As shown.

[0044] Figure 10 and Figure 11 Other examples of usable phosphor layers 1c and 1d are shown according to some embodiments of the present invention. For example... Figure 10 As shown, the LED emits blue light (peak wavelength approximately 450 nm) and blue-violet light (peak wavelength approximately 420 nm). The phosphor in the phosphor layer converts some of these two types of light into yellow light (peak wavelength approximately 550 nm). Figure 11 As shown, phosphor layer 1d includes various types of phosphors. Besides... Figure 10 The phosphor in phosphor layer 1c is a second-type phosphor that converts a portion of the blue light from the corresponding LED into red light (peak wavelength approximately 630 nm). Therefore, with only the blue LED turned on, the output light of phosphor layer 1d is substantially white (including a sufficient amount of RGB). The conversion efficiency of the second phosphor for blue-violet to red light is extremely low. Therefore, with only the blue-violet LED turned on, the output light is essentially the same as... Figure 10 The fluorophore layer 1d is the same.

[0045] exist Figure 2 , Figure 4 , Figure 6 and Figure 8 In this configuration, phosphor layer 1 has a flat emitting surface. The emitting surface faces the surface of the PCB. However, this is not mandatory. For example, phosphor layer 1e can have a constant thickness, such as... Figure 12 As shown. In this case, the emitting surface is non-flat due to the thickness of the LED. In some embodiments, the emitting surface of phosphor layer 1 is non-flat, and phosphor layer 1 does not have a constant thickness. For example, in such embodiments, the surface non-uniformity of PCB4 can be partially flattened, and LED2 and LED3 are mounted on PCB4.

[0046] In some embodiments, a plurality of cells are arranged on PCB4 and covered by a common phosphor layer 1. Each of these cells includes at least a corresponding first LED 2 of a first type and a corresponding second LED 3 of a second type (having different peak wavelengths). In each cell, the first and second LEDs are arranged in the same manner. The cells may be arranged, for example, in lines (straight or curved).

[0047] In some embodiments, the cells are arranged in a circular or circular segment. In some of these embodiments, an illumination device comprising multiple cells of two types of LEDs and a common phosphor layer is arranged around the objective lens, the two types of LEDs being arranged on a PCB, the common phosphor layer comprising one or more phosphors, the objective lens being configured to image an object space. The illumination device is arranged to illuminate at least a portion of the object space.

[0048] Such an arrangement is shown in Figure 13 middle. Figure 13 The rigid end of the endoscope is shown in a plan view (viewed from the object space; optional transparent caps covering the illumination device have been removed). LEDs 2f and 3f surround the central objective lens 5. The working channel 51 is shown in the lower portion of the plan view.

[0049] The PCB may include an adhesive to attach the phosphor layer to the PCB. The adhesive may or may not include a phosphor. If the adhesive does not include a phosphor, it should be relatively thin. For example, the maximum thickness of the adhesive is no greater than 10% of the maximum thickness of the light source (LED) between the first and second light sources, which has a minimum maximum thickness between the first and second light sources. Preferably, the ratio is no greater than 5%. Preferably, the adhesive (if present) is arranged such that at least 95% of the light emitted by the LED enters the phosphor layer. More preferably, at least 98% or even 100% of the emitted light enters the phosphor layer.

[0050] According to some embodiments, if the phosphor layer is partially parallel to the PCB surface facing the phosphor layer, then the amount of phosphor in the direction perpendicular to the PCB surface is substantially constant. That is, its variation around the average value is no more than 20%, preferably no more than 10%, and still more preferably no more than 5%. If the lighting device comprises multiple cells, then in some embodiments, the amount of phosphor in the direction perpendicular to the PCB surface facing the phosphor layer can vary corresponding to the arrangement of the cells. For example, if the cells are arranged periodically, then the amount of phosphor in the vertical direction can vary at the same period. The PCB surface facing the phosphor layer is the surface on which the LED is mounted.

[0051] The concentration of phosphors can be substantially constant along the thickness direction of the phosphor layer. However, according to some embodiments, the concentration of phosphors may have a peak. If the phosphor layer comprises multiple phosphors, they can be uniformly distributed within the phosphor layer, or they can be arranged at different levels along the thickness direction.

[0052] Preferably, the surface of the PCB facing the phosphor layer can be generally flat. The flatness, due to variations in wiring and / or adhesives, may not exceed 10% of the maximum thickness of the light source (LED) between the first and second light sources, which has a minimum maximum thickness between the first and second light sources. Preferably, the ratio is no greater than 5%. However, the invention is not limited to a generally flat surface of the PCB. Some embodiments of the invention may include a curved surface of the PCB facing the phosphor layer.

[0053] If the light source is an LED, then the PCB may include circuitry for controlling the LEDs. For this purpose, the LEDs are electrically connected to terminals arranged on the PCB. In some embodiments, each LED may be controlled individually. In some embodiments, at least a first type of LED may be controlled independently of a second type of LED. "Control" at least means turning on and off. It may additionally mean setting the intensity and / or color of the light emitted by the respective LED. "Control" also applies to other light sources that locally generate light (on the PCB), for example, in the case of a laser diode.

[0054] LEDs can be mounted on a PCB in any known manner (such as surface mount devices (SMD)) or via flip-chip bonding.

[0055] As explained above, the illumination device is preferably disposed in the rigid end of an endoscope for insertion into a lumen of the human body. Such a rigid end may include an objective lens, and the illumination device may be disposed around the objective lens. Furthermore, the rigid end may include an image sensor, a working channel, etc. The rigid end may be directly or indirectly (via an angled section) connected to a flexible or rigid shaft for insertion into a lumen of the human body, such that embodiments of the invention also cover endoscopes. In some embodiments, the rigid end may be used independently (i.e., without connection to the shaft of the endoscope). Therefore, the illumination device can be used in so-called "capsule endoscopes".

[0056] However, the present invention is not limited to the illumination device in the rigid end-effector portion of an endoscope intended for insertion into a lumen of the human body. The illumination device can also be applied to other endoscopes (those not suitable for insertion into a lumen of the human body, such as endoscopes for tubing). The illumination device can even be applied to the outside of the endoscope, for example, to illuminate the object space of a camera, such as a CCTV camera.

[0057] According to some embodiments of the invention, several options exist for manufacturing such lighting devices. These are explained using LEDs as an example of a light source, but they are not limited to LEDs.

[0058] The first manufacturing method is shown in Figure 14 In the process, the phosphor is dissolved in a fluid or gel, and the fluid or gel is dispensed onto a PCB on which the light source is mounted via a dispenser 100. Specifically, the fluid or gel is dispensed at least onto the LED and the path connecting the LED, such that the PCB and the fluid or gel surround the LED. The fluid is then dried or the gel is cured, resulting in a phosphor layer including the phosphor.

[0059] The fluid or gel must have sufficient viscosity to remain substantially within the area in which it is dispensed before drying or curing is complete. If the light source locally generates light (e.g., an LED, laser diode, etc.), then these light sources are electrically connected to terminals arranged on the PCB prior to dispensing. If an adhesive is required to adhere the phosphor (or a medium including the phosphor) to the PCB, then the adhesive can be applied as a thin layer to the PCB and LED prior to dispensing.

[0060] Examples of solvents used to form fluids or gels including phosphors are siloxanes. Examples of adhesives are polymers.

[0061] A fluid or gel can be dispensed once or multiple times at each site to form a fluorophore layer. If the fluid or gel is dispensed multiple times, the fluorophores in the fluid or gel can be the same, or different fluorophores can be included in the fluid or gel used for different dispensing operations. Therefore, the fluorophore layer can have an internal layered structure with different fluorophores.

[0062] The second manufacturing method is shown in Figure 15 According to Figure 15 The fluid in which the phosphor is dissolved is sprayed onto the PCB through sprayer 101 and then dried. Otherwise, the second manufacturing method corresponds to the first manufacturing method.

[0063] Figure 16 A third manufacturing method is illustrated. In this method, a phosphor sheet is prepared, wherein the phosphor sheet comprises phosphors dispersed in a medium (e.g., siloxane), or the phosphor sheet is composed of phosphors. The phosphor sheet can be much larger than a PCB on which a light source is mounted. Then, parts with shapes corresponding to the shape of the phosphor layer are cut from the phosphor sheet. In this document, the term "corresponding" means that these parts may have the same shape as the phosphor layer, or they may have a shape that takes into account horizontal differences with the LED, contraction due to thermal expansion, etc. That is, the cut parts may have a shape slightly different from the final phosphor layer.

[0064] The cut piece is then applied to a PCB on which the light source is mounted (and electrically connected to the terminals of the PCB, if necessary). The cut piece should preferably have some flexibility to conform to 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 the LED, it can be applied as a thin layer to the PCB and / or the LED, and / or it can be applied as a thin layer to a phosphor sheet (before the piece is cut, or applied to the cut piece). Examples of adhesives that can be used in this manufacturing method are adhesive transfer tapes, such as 3M's 467MP.

[0065] Figure 17 A fourth manufacturing method is shown, which is a variation of the third manufacturing method. According to... Figure 17 Phosphor sheets are laminated onto multiple PCBs on which the light source is mounted (and electrically connected to the terminals of the PCBs if necessary). Adhesive may be applied to the phosphor sheets and / or the PCBs / LEDs. Unwanted portions of the laminate are then removed by cutting. Thus, the phosphor layer covers the entire PCB on which the light source is mounted. Alternatively, the fourth method corresponds to the third method.

[0066] In some embodiments (not shown), the PCBs of multiple lighting devices may be corresponding portions of a larger PCB. In these embodiments, the PCBs of the lighting devices may be cut from the larger PCB in the step of cutting the phosphor layer according to the fourth method. Therefore, since the PCB and phosphor layer of each lighting device are cut in the same step, a manufacturing step can be saved.

[0067] Figure 18 The derivation of the minimum thickness that the phosphor layer should preferably have is shown to ensure that the lighting device provides substantially uniform illumination. Figure 18 As shown in the bottom portion, each location on the emitting surface of the phosphor layer should be illuminated by at least one of the first LEDs at at least 50% of its intensity. At a minimum thickness T... 11 =D 11 / 2*tanθ 50 Under these circumstances, this condition is met. 11 Let θ represent the distance between two adjacent first LEDs, and let θ represent the distance between them. 50 θ represents the radiation angle, at which the first LED emits 50% of its maximum emission. 50 The value can be obtained from the radiation characteristics of the first LED. A typical example is shown in... Figure 19 In this example, θ 50 It is approximately 55°.

[0068] The same considerations apply correspondingly to the second LED. If the corresponding minimum thicknesses are different, then the phosphor layer should preferably have a minimum thickness that is the larger of the minimum thicknesses of the two types of LEDs. The radiation angle at which the second LED emits at 50% of its maximum emission is denoted as Φ. 50 .

[0069] exist Figure 18 The top section shows additional considerations for determining θ. 50 and Φ 50 The maximum value (with a given distance between LEDs and a given height of the LEDs and the non-transparent wall, if any), or the minimum distance between LEDs (in θ) is determined. 50 and Φ 50 Given a given value for the LED and the given height of the non-transparent wall (if any), or determine the maximum height of the LED and the non-transparent wall (if any) in θ. 50 and Φ 50 (Given values ​​and given distances between LEDs). That is, the height of the emitted light at 50% intensity should be higher than the height of adjacent LEDs or walls (if any). Figure 18 In the top part:

[0070] ·T 12 This indicates the height of the light ray from the first LED at the edge position of the second LED facing the first LED;

[0071] ·T 21 This indicates the height of the light ray from the second LED at the edge position where the first LED faces the second LED;

[0072] ·T 13 This indicates the height of the light ray from the first LED at the edge position of the adjacent wall facing the first LED;

[0073] ·T 23 This indicates the height of the ray from the second LED at the edge of the adjacent wall (not shown) facing the first LED;

[0074] ·D 12 Indicates the shortest distance between the first LED and the second LED;

[0075] ·D 21 This represents the shortest distance (D) between the second LED and the first LED. 12 =D 21 );

[0076] ·D 13 This represents the shortest distance between the first LED and its adjacent wall; and

[0077] ·D23 This represents the shortest distance between the second LED and the adjacent wall (not shown).

[0078] If the first LED, the second LED, and the wall have thicknesses t1, t2, and t3, then the relationship T is obtained. 12 >t2;T 21 >t1;T 13 >t3; and T 23 >t3. In the limiting case, θ 50 and Φ 50 The condition is 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 .

[0079] According to some embodiments of the present invention, in Figure 18 The conditions derived from the top and bottom portions are preferred, but not mandatory. For example, in some embodiments, only a subgroup of these conditions may be satisfied, or even none of these conditions may be satisfied.

[0080] Some embodiments of the present invention, having a light emitting device arranged at the distal end of an endoscope, are advantageous compared to other illumination systems in which the light emitting device is arranged in a box at the proximal end, and the light is guided to the distal end via one or more optical fibers due to higher efficiency with respect to power conversion. Even if the light source is located in the control body at the proximal end of the endoscope, space is limited.

[0081] Furthermore, considering the following factors relative to the arrangement at the proximal end, it is preferred (but not mandatory) to arrange the common phosphor system of blue-violet or blue LEDs at the distal end of the endoscope:

[0082] White LEDs (WLEDs) have a standard phosphor-covered package. However, the phosphor causes scattering, meaning it's difficult to effectively focus light into an optical fiber. For blue-violet LEDs, a standard phosphor package does not exist. It must be custom-made at considerable cost, and the phosphor will scatter light, just like in WLEDs.

[0083] In contrast, if the phosphor layer is placed on the distal end, the scattering of light by the phosphor can even help distribute the light over a wider angle, thus facilitating a wider field of view for illumination. Light emitting devices (such as LEDs) can also be arranged in the distal end (behind the phosphor layer), or they can be arranged at the proximal end, with light guided from the light emitting devices to the distal end via one or more optical fibers. In this case, the emitting end of the optical fiber acts as the light source, as described above.

Claims

1. A lighting device, comprising plate; A first light source is mounted on the plate, wherein... The first light source is configured to emit first light having a first wavelength spectrum; A second light source is mounted on the plate, wherein the second light source is configured to emit second light having a second wavelength spectrum different from the first wavelength spectrum; A phosphor layer comprising phosphors arranged to convert at least a portion of at least one of a first light and a second light into a first converted light and a second converted light, respectively, wherein a third wavelength spectrum of the first converted light differs from the first wavelength spectrum, and a fourth wavelength spectrum of the second converted light differs from the second wavelength spectrum; wherein, The phosphor layer is configured to emit the remaining portion of the first light, the remaining portion of the second light, and at least one of the first converted light and the second converted light; The phosphor layer contacts the first light source and the second light source, and is continuous along the path of the first light source, the second light source, and the plate, the path connecting the first light source and the second light source; The phosphor layer and the plate surround the first light source and the second light source. The phosphor layer has a minimum thickness T. 11 So that each location on the emitting surface of the phosphor layer is illuminated by at least one of the first light sources at at least 50% of the intensity of the first light source, wherein the minimum thickness T 11 Satisfying the formula: T 11 =D 11 / 2 tanθ 50 , where D 11 θ represents the distance between two adjacent first light sources. 50 This indicates the radiation angle at which the emission of the first light source is 50% of its maximum emission.

2. The lighting device according to claim 1, comprising: A plurality of first light sources are mounted on the plate and each is configured to emit the first light. A plurality of second light sources are mounted on the plate, each configured to emit the second light; wherein... The phosphor layer contacts each of the first light source and each of the second light source, and is continuous in each of the first light source, each of the second light source, and along the path connecting the first light source and the second light source; The phosphor layer and the plate surround the first light source and the second light source.

3. The lighting device according to claim 1, wherein, At least one of the following: The phosphor layer covers the entire plate; 100% of the first light enters the phosphor layer; and 100% of the second light enters the phosphor layer.

4. The lighting device according to claim 1, wherein, The first wavelength spectrum mainly includes blue light; The second wavelength spectrum mainly includes blue-violet light and / or ultraviolet light; The phosphor is configured to convert a first portion of the blue light into yellow light, so that the first output light appears white; The phosphor is configured to convert a second portion of the blue-violet light and / or the ultraviolet light into the yellow light; The first part is larger than the second part.

5. The lighting device according to claim 1, wherein, The first wavelength spectrum mainly includes blue light; The second wavelength spectrum mainly includes blue-violet light and / or ultraviolet light; The phosphor is configured to convert a first portion of the blue light into green and red light, so that the first output light appears white; The phosphor is configured to convert a second portion of the blue-violet light and / or the ultraviolet light into green light.

6. The lighting device according to claim 1, wherein, In the phosphor layer, the phosphor is dispersed in a medium.

7. The lighting device according to claim 1, wherein, At least one of the following: 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.

8. The lighting device according to claim 7, wherein, At least one of the following: If the first light source is a light-emitting diode or a laser diode, then the board includes a first terminal and the first light source is electrically connected to the first terminal; If the second light source is a light-emitting diode or a laser diode, then the board includes a second terminal and the second light source is electrically connected to the second terminal.

9. The lighting device according to claim 8, wherein, The first light source is controllable via the first terminal; The second light source is controllable via the second terminal; and The first light source can be controlled independently of the second light source.

10. The lighting device according to claim 1, wherein, At least one of the following: The first light source is the emitting end of the first optical fiber, and the lighting device includes a first light-emitting device configured to input the first light into the first optical fiber; The second light source is the emitting end of the second optical fiber, and the lighting device includes a second light-emitting device configured to input the second light into the second optical fiber.

11. The lighting device according to claim 1, wherein, The phosphor layer includes multiple phosphors.

12. The lighting device according to claim 1, wherein, The board includes an adhesive; The adhesive adheres to the phosphor layer; The maximum thickness of the adhesive is no greater than 10% of the maximum thickness of the light source between the first light source and the second light source, and the light source has a minimum maximum thickness between the first light source and the second light source.

13. A method for manufacturing a lighting device according to claim 1, the method comprising: The plate is provided, and the first light source and the second light source are mounted on the plate; A fluid or gel including the phosphor is dispensed onto the path of the first light source, the second light source, and the plate, the path connecting the first light source and the second light source; The gel is cured and the fluid is dried to obtain the phosphor layer.

14. The method of claim 13, further comprising: Allow the fluorescent gel to flow before curing.

15. A method for manufacturing a lighting device according to claim 1, the method comprising: The plate is provided, and the first light source and the second light source are mounted on the plate; A fluid comprising the phosphor is sprayed onto the path of the first light source, the second light source, and the plate, the path connecting the first light source and the second light source; The sprayed fluid is dried to obtain the phosphor layer.

16. A method of manufacturing a lighting device according to claim 1, the method comprising: The plate is provided, and the first light source and the second light source are mounted on the plate; A sheet comprising the phosphor is prepared such that, in a plan view, the sheet has a shape corresponding to the shape of the path connecting the first light source and the second light source. The sheet is attached to the plate, the first light source, and the second light source such that the sheet covers the first light source, the second light source, and the path to obtain the phosphor layer.

17. A method for manufacturing a lighting device according to claim 1, the method comprising: The plate is provided, and the first light source and the second light source are mounted on the plate; A sheet including the phosphor is attached to the plate such that the sheet covers the path of the first light source, the second light source, and the plate, the path connecting the first light source and the second light source; The portion of the sheet extending beyond the plate is cut off to obtain the phosphor layer.

18. A rigid end portion of an endoscope or capsule endoscope for insertion into a lumen of a human body, the rigid end portion comprising an objective lens and an illumination device according to claim 1, the illumination device being arranged to illuminate at least a portion of an object space imaged by the objective lens by at least one of a first output light and a second output light.

19. An endoscope comprising a flexible or rigid shaft and a rigid end portion according to claim 18, the flexible or rigid shaft being for insertion into the lumen of the human body, wherein, The rigid end portion is directly or indirectly connected to the flexible or rigid shaft.

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