lighting equipment

Abstract

The present invention provides a lighting device, which includes an exit layer, the exit layer including a phosphor; a plurality of first light sources and a plurality of second light sources; wherein the first light sources and the second light sources are arranged in a plurality of cells; the plurality of first light sources are controllable independently of the plurality of second light sources; the first light source and the second light source are arranged to be separated from the exit layer; the phosphor converts at least a portion of the first light into a first converted light; if the first light source and the second light source respectively emit the first light and the second light projected onto the exit layer on a line, and the line connects the corresponding positions of two adjacent cells of the plurality of cells, then the change in the total intensity of the corresponding light is less than 20%.

Description

Technical Field

[0001] The present invention relates to an illumination device for illuminating an object with different spectra. In particular, the present invention relates to an illumination device that can be used in the distal end portion of an endoscope, in particular an endoscope comprising a wide-field objective. Background Art

[0002] Imaging with different colors of light is known in the art. For example, there is white light imaging (WLI) and "spectral imaging." In WLI, an object (such as the colon) is illuminated by white light. In contrast, in spectral imaging, the object is illuminated by light with a spectral distribution that differs from that of white light. For example, spectral imaging with a spectrum that generally only includes violet and green light is known.

[0003] FIG1 shows an illumination system for an endoscope according to the prior art that allows both WLI and spectral imaging. The illumination system includes a white LED (shown here as a blue LED with a yellow phosphor covering the blue LED) and is separated from the white LED, violet LED, and green LED. In spectral imaging, only the violet LED and the green LED emit light. Thus, the emitted light has a gradient from violet on the left, through green-violet, to green on the right. In WLI, only the white LED emits light.

[0004] This type of illumination system has several drawbacks: the relative intensities of the violet and green lights vary depending on the location on the object. Furthermore, illumination from white light is located at a different location on the object than illumination from violet and green LEDs. Consequently, a doctor using a conventional endoscope cannot easily observe the same location under different illumination conditions. Furthermore, considerable space is required to accommodate the three LEDs in the distal end of the endoscope.

[0005] In another prior art illumination system, as shown in FIG2 , multiple LEDs (such as white LEDs) are arranged around an objective lens. In this configuration, the space immediately in front of the objective lens becomes a blind spot due to the objective lens's shadow. Furthermore, if the objective lens has a field of view of approximately 180° or even greater, the illumination system does not illuminate the outer portion of this field of view. Consequently, an additional blind spot exists on the outer side of the illumination system. Summary of the Invention

[0006] The present invention aims to improve the prior art. Specifically, according to one aspect of the invention, an illumination system is provided according to the independent claims. Other aspects of the invention provide a rigid endoscope tip and an endoscope including an illumination system. Further details are explained in the respective 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 lighting equipment that allows both WLI and spectrum lighting is reduced;

[0009] Blind spots are reduced or even avoided completely;

[0010] The configuration is easy to implement;

[0011] Depending on the requirements, the light source can be an LED and / or the emitting end of an optical fiber;

[0012] The color distribution is more uniform compared to the existing technology;

[0013] Doctors can easily observe a location under different lighting conditions.

[0014] Other advantages will be apparent from the following detailed description.

[0015] It should be understood that the modifications mentioned above and the examples described below may be applied individually or in combination to the corresponding aspects to which they refer, unless they are explicitly stated to exclude alternative forms. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other details, features, objects and advantages will be apparent from the following detailed description of preferred embodiments of the present invention, which description is considered in conjunction with the accompanying drawings, in which:

[0017] FIG1 shows a lighting system according to the prior art;

[0018] FIG2 shows a lighting system according to the prior art;

[0019] Figure 3 A cross section of a cell of a lighting device for spectral lighting is shown according to some embodiments of the present invention;

[0020] Figure 4 Shown in Figure 3 The emission spectrum of the lighting device when used for spectral lighting;

[0021] Figure 5 shows the WLI according to Figure 3 cells of lighting equipment;

[0022] Figure 6 Shown in Figure 5 The spectrum of the emitted light of the lighting equipment used in the case of WLI;

[0023] Figure 7 According to some embodiments of the present invention, a unit cell of another lighting device is shown, the lighting device being used for spectral lighting;

[0024] Figure 8 Shown for spectral lighting Figure 7 The emission spectrum of the lighting equipment;

[0025] Figure 9 Shown for WLI Figure 7 lighting equipment;

[0026] Figure 10 Shown for WLI Figure 9 The emission spectrum of the lighting equipment;

[0027] Figure 11 A cross section through a lighting device is shown according to some embodiments of the present invention;

[0028] Figure 12 A cross section of a lighting device is shown according to some embodiments of the present invention;

[0029] Figure 13 Shown Figure 12 A plan view of the lighting equipment;

[0030] Figure 14 A cross section of a lighting device is shown according to some embodiments of the present invention;

[0031] Figure 15 A cross section through a lighting device is shown according to some embodiments of the present invention;

[0032] Figure 16 A cross section through a lighting device is shown according to some embodiments of the present invention;

[0033] Figure 17 Shown according to Figure 16 A plan view of the lighting equipment;

[0034] Figure 18 shows a cross section through a lighting device according to some embodiments of the present invention; and

[0035] Figure 19 A cross section through a lighting device is shown according to some embodiments of the present invention;

[0036] Figure 20 shows how the minimum distance between a light source and an exit layer can be calculated;

[0037] Figure 21 Some embodiments according to the present invention show how to reduce blind spots;

[0038] Figure 22 A timing diagram illustrating operating a lighting device according to some embodiments of the present invention;

[0039] Figure 23Another timing diagram for operating a lighting device is shown according to some embodiments of the present invention;

[0040] Figure 24 A timing diagram illustrating operating a lighting device according to some embodiments of the present invention;

[0041] Figure 25 Another timing diagram for operating a lighting device is shown according to some embodiments of the present invention;

[0042] Figure 26 Another timing diagram for operating a lighting device is shown according to some embodiments of the present invention;

[0043] Figure 27 Another timing diagram for operating a lighting device is shown according to some embodiments of the present invention;

[0044] Figure 28 According to some embodiments of the present invention, an emission spectrum of a lighting device is shown, the lighting device being used for WLI;

[0045] Figure 29 An emission spectrum of a lighting device for near-infrared lighting is shown according to some embodiments of the present invention.

[0046] Figure 30 shows a plan view of a lighting device according to some embodiments of the present invention; and

[0047] Figure 31 Shown through the Figure 30 Cross section of a lighting fixture. DETAILED DESCRIPTION

[0048] In the following, certain embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein the features of the embodiments can be freely combined with each other unless otherwise described. However, it should be expressly 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 disclosed details.

[0049] In the figures, like numbers represent corresponding parts, and these parts are distinguished by different letters. The drawings are for schematic purposes only. In particular, the dimensions are not to scale. For example, the light source (LED or the emitting end of an optical fiber) can be roughly a point.

[0050] Figure 3According to some embodiments of the present invention, a cell of a lighting device is shown. The 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). Each of these LEDs is an example of a light source. The LEDs of the cell illuminate an exit layer 1a. A phosphor is arranged in the exit layer. The phosphor converts at least a portion of the light from the first LED (first light) into a first converted light. In addition, 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 the first light. The second converted light has a spectrum different from the second light.

[0051] For example, Figure 4 As shown, in the case of spectral illumination, only UV LED 2a illuminates the exit layer with light, while the white LED is turned off. In this case, the emission spectrum includes violet or deep blue light (sometimes also referred to as UV light) from LED 2a with a wavelength (peak wavelength) of approximately λ3 (e.g., 400nm to 430nm), and green light (e.g., wavelength of approximately λ2: 520nm to 580nm) converted by the phosphor in exit layer 1a.

[0052] In white light illumination, only the second LED 3a shines light on the outlet layer 1a, while the first LED 2a is dark. In this case, the white LED is a blue LED covered with a phosphor, which has a Figure 6 The emission spectrum is shown by the dashed line in FIG. Specifically, it has a high peak in the blue region (λ is approximately 440 nm to 460 nm) and a broad maximum in the green region around λ2. Due to conversion by the phosphor in exit layer 1a, the intensity of the blue light around λ1 decreases, while the broad maximum around λ2 is enhanced and widened. Consequently, white light illumination is achieved.

[0053] Figure 4 and Figure 6 The spectra shown are examples only. Other combinations of different types of LEDs combined with different types of phosphors fall within the scope of the present invention. Instead of a single type of phosphor, multiple types of phosphors can be used in the outlet layer. These different types of phosphors can be mixed or arranged in different layers.

[0054] Figures 7 to 10 Another example of a unit is shown according to some embodiments of the present invention. These figures correspond to Figures 3 to 6 , the difference is Figure 3 and Figure 5The white LED 3a is replaced by a blue LED 3b that emits light in the range of 440nm to 460nm. Because in this example, the first LED 2b and the phosphor in the outlet layer 1b are Figure 3 and Figure 5 Same as in Figure 8 In the case of spectral illumination shown, the spectrum is Figure 4 Same as shown.

[0055] However, in the case of white light illumination, the blue LED 3b is Figure 3 and Figure 5 The white LED 3a excites the phosphor to a greater extent. Therefore, in the case of white light illumination, the emission spectrum has a larger and broader peak at about λ2, as shown in FIG. Figure 10 shown.

[0056] Figure 11 According to some embodiments of the present invention, a lighting device is shown. Figure 11 In the lighting device, an exit layer 1c is provided, having a bottom surface and a top surface. Light from LEDs 2c and 3c is irradiated onto the bottom surface and converted by the phosphor disposed in the exit layer. A combination of the remaining light emitted from LEDs 2c and 3c and the converted light is emitted from the top surface of the exit layer.

[0057] The lighting device includes a plurality of first type LEDs 2c (first LEDs) and a plurality of second type LEDs 3c (second LEDs). The first type and the second type LEDs have different emission spectra. The LEDs are arranged in cells 23, wherein each cell includes at least one first LED and at least one second LED. Figure 11 In the example of FIG, each cell 23 comprises a first LED 2c and a second LED 3c. The arrangement of the respective first and second LEDs is identical in all cells. For illustration purposes, the illumination cones of some LEDs are indicated at Figure 11 middle.

[0058] The lighting device includes a plurality of cells. The cells are periodically arranged in a base plane 21c. The base plane 21c is a plane obtained by connecting corresponding points of the cells. Figure 11 In the example of FIG. 2 , the base plane 2c1 comprises the emission surfaces of the LEDs 2c and 3c.

[0059] All first LEDs 2c and second LEDs 3c are spaced apart from the exit layer 1c. Thus, each of these LEDs can illuminate a substantial portion of the exit layer 1c, which includes the phosphor. Specifically, in region 33 of the bottom surface of the exit layer 1c, each location on the bottom surface is illuminated by at least two of the LEDs 3c. Correspondingly, in region 22 of the bottom layer, each location on the bottom layer is illuminated by at least two of the first LEDs 2c. Thus, in regions 22 and 33, relatively uniform illumination of the phosphor in the exit layer can be achieved with respect to illumination by the corresponding light. In the overlapping region 2233 of regions 22 and 33, illumination by both the first and second LEDs is relatively uniform.

[0060] The term "relatively uniform" means that the total intensity of the corresponding light illuminating the bottom surface of the exit layer does not vary by more than 20%. Preferably, the variation is less than 10%, or even less than 5%. Preferably, the illumination of the bottom surface of the exit layer is generally uniform across the entire surface. However, according to some embodiments, it is sufficient that the illumination intensity is generally uniform along a line on the bottom surface obtained by projecting corresponding points in two adjacent cells onto the bottom surface. In the case of a planar base layer, this projection may be perpendicular to the base plane (base layer).

[0061] In the outlet layer 1c, the amount of phosphor in the direction perpendicular to the base plane may not depend on the position on the bottom surface, at least at the position of the overlapping area 2233. Alternatively, the amount of phosphor in the direction perpendicular to the base plane may vary depending on the period in which the unit cells are arranged.

[0062] Some embodiments of the present invention include a controller to control the LEDs. The first LED 2c and the second LED 3c can be controlled individually. That is, for example, for spectrum illumination, only the first LED 2c of all cells illuminates the bottom surface of the exit layer 1c; while in white light illumination, only the second LED 3c illuminates the bottom surface of the exit layer. In an optional third mode, both the first LED 2c and the third LED 3c can illuminate the bottom surface of the exit layer. Control includes turning on and off, but may also include other operations, such as changing the light intensity. In addition, in some examples, specific first LEDs 2c and / or specific second LEDs 3c can be controlled individually.

[0063] Figures 12 to 18 Shown Figure 11 If not otherwise described, then relative to Figure 11 The properties explained by the basic concepts apply to Figures 12 to 18 In general, the following only explains Figure 11 The difference in concepts.

[0064] Figure 12 Some embodiments according to the present invention show a cross section through a lighting device, and Figure 13 The corresponding plan view is shown. Figure 13 As can be seen from the cross-sectional view, LEDs 2d and 3d forming one unit cell are arranged in a circle. Figure 13 , the left and right ends of the unit cell 23c are joined together. Correspondingly, the outlet layer 1d has a ring shape having the same center as the virtual circle on which the LEDs 2d and 3d are placed.

[0065] exist Figure 14 In a variant of the invention, the outlet layer 1e has an annular shape, as in Figure 12 and Figure 13 , but in cross section, at least one of the bottom surface and the top surface is curved. Figure 14 In the example of , both the top and bottom surfaces are curved. Thus, the exit layer can act like a lens to direct light from the LEDs 2e and 3e and the corresponding converted light to a desired direction. Figure 14 The plan view of the lighting device corresponds to Figure 13 view.

[0066] The objective lens of the endoscope is arranged so that it Figure 14 In the case where the objective lens is surrounded by an illumination device, forming the exit layer in a lens shape has specific advantages. Preferably, the optical axis of the objective lens coincides with the center line of the illumination device. If the objective lens has a wide field of view (such as approximately 180° or even larger, such as 225° or larger), the lens shape of the exit layer allows illumination of a wide solid angle. In addition, the phosphor in the exit layer acts as a scattering center. Therefore, the exit layer can act as a light diffuser, so that even a field of view exceeding 180° can be fully illuminated by the illumination device surrounding the objective lens. That is, the blind spot outside the end of the endoscope shown in Figure 2 can be reduced or even eliminated. By light diffusion with the same effect, the blind spot in front of the objective lens shown in Figure 2 can also be reduced. This is shown in Figure 21 middle, Figure 21 On the left the prior art arrangement of FIG. 2 is repeated, and on the right an illumination device according to some embodiments of the present invention is shown, which is arranged around the objective lens.

[0067] Figure 15 Shown Figure 11 、 Figure 12 and Figure 14 Another variation of the lighting device. Figure 15 In the lighting device of , the first LED 2f and the second LED 3f are arranged at different levels relative to the base plane. Figure 15In the example of FIG. 5 , the base plane is defined by the light emitting face of the first LED 2 f and the light emitting face of the second LED 3 f is spaced apart from this plane by a distance d>0. Figure 15 The plan view of the lighting device corresponds to Figure 13 view.

[0068] Figure 16 Shown according to Figure 11 、 Figure 12 、 Figure 14 and Figure 15 Yet another modification of the lighting device. Figure 16 In the embodiment, the first LED 2g and the second LED 3g of each unit cell are arranged on circles having different radii. The first LED 2g is arranged on a circle having a radius r1 around the center line, and the second LED 3g is arranged on a circle having a radius r2 around the center line, where r1 and r2 are different from each other. The outlet layer 1g is arranged in a ring-shaped form having the same center line as the circle, and the first and second LEDs are arranged on the circle. Figure 16 A plan view of the lighting equipment is shown in Figure 17 middle.

[0069] Figure 12 、 Figure 14 、 Figure 15 and Figure 16 The variations shown can be combined arbitrarily. An example of such a combination is shown in Figure 18 middle, Figure 18 FIG2 shows a cross section of a lighting device according to some embodiments of the present invention. In this embodiment, the outlet layer 1h has a ring shape around the center line, and in the cross section, the top surface and / or the bottom surface of the outlet layer 1h is curved, similar to FIG2 . Figure 14 Furthermore, the first LED 2h and the second LED 3h are arranged on a circle having different radii r1 and r2 around the center line. Figure 18 In the example of FIG, the unit cell includes more than two LEDs. In addition to the first LED 2h and the second LED 3h, it includes a third LED 3h'. The third LED 3h' can be of the second type (the same type as the second LED 3h), or it can be of another type that emits a spectrum that is different from the spectrum of both the first and second types.

[0070] The third LED 3h' is arranged on a third circle around the center line, the third circle having a radius R2'. In addition, the third LED 3h' is arranged at an elevated level compared to the baseline 21h. In this example, the baseline 21h is defined by the emission surfaces of the first LED 2h and the second LED 3h.

[0071] Figure 18Shown Figures 12 to 17 The illustrated combination of different variations is only one example. Other combinations of such variations are also within the scope of the present invention.

[0072] Figure 19 Another embodiment of the present invention is shown. Figure 11 Another variation of the embodiment of . Figures 11 to 18 In , the cells are arranged along the base plane. The base plane is an example of a base region. Generally speaking, the base region can be curved. Figure 19 In the example shown, the base region is curved because the cells 23i are arranged on the curved support layer 4i. The base region 21i is defined so that it connects corresponding locations at the top ends of each cell 23i. However, it can be defined by connecting other corresponding points. Therefore, the support layer 4i can also be considered the base region. Each cell 23i includes at least one first LED and at least one second LED.

[0073] Preferably, if the base layer is curved, the outlet layer is correspondingly curved to the base layer, such as Figure 19 As shown (curved outlet layer 1i).

[0074] Figure 30 and Figure 31 An embodiment of the invention is shown in which the base layer 21k is planar and the outlet layer 1k is curved in cross-section. Figure 30 A plan view of the base layer 21k is shown, and Figure 31 A cross section through the base layer 21 k and the outlet layer 1 k is shown.

[0075] Specifically, regardless of the type of LED, the first LED 2k and the second LED 3k are symmetrically arranged on either side of the center line. On each side of the center line, the first LED 2k and the second LED 3k alternate. Each first LED 2k is opposite a corresponding second LED 3k across the center line. Thus, two first LEDs 2k and two second LEDs 3k form a unit cell 23k.

[0076] The shape of the outlet layer 1k, which includes the phosphor, is set to an arc shape (e.g., a circular arc) above the base layer 21k. The vertex of the arc of the outlet layer 1k is arranged so that it coincides with the center line in a plan view. The outlet layer 1k extends in the direction of the center line. The outlet layer 1k is symmetrical about a symmetry plane that includes the center line and the vertex of the outlet layer 1k.

[0077] If the distance between the center line of the bottom surface of the outlet layer 1k (which intersects the symmetry plane) and the base layer is sufficiently large, the first LED 2k and the second LED 3k can illuminate the center line of the bottom surface of the outlet layer 1k substantially uniformly. For example, the total intensity of the first light of the first LED 2k can vary by less than 20%, and the total intensity of the second light of the second LED 3k can vary by less than 20%.

[0078] Figure 30 and Figure 31 A lighting unit is shown in which the cells 23k are arranged linearly along a center line, and the outlet layer extends linearly in the same direction. Instead of such a linear arrangement, in some embodiments of the present invention, the cells 23k are arranged in a curve (e.g., a circle), and the outlet layer extends on a corresponding curve (e.g., a circle).

[0079] To ensure relatively uniform illumination, each location of a particular line (such as the center line) on the bottom surface of the outlet layer should be illuminated by all LEDs in at least one cell. The definition of a cell can depend on the location of the particular line on the bottom surface of the outlet layer. Furthermore, each location of the particular line on the bottom surface should be illuminated by corresponding LEDs in at least two cells.

[0080] Figure 20 shows the minimum distance from the light emitting surface of the LED that the outlet layer should have if the light emitting surface of the LED is arranged on a line below a specific line of the outlet layer. Figure 20 Corresponding to Figure 11 Two adjacent cells 23j, each including a different type of LED 2j and LED 3j, are shown in FIG. Figure 20 middle.

[0081] exist Figure 20 To ensure that every position on a particular line of the bottom surface of the outlet layer 1j is illuminated by at least one LED 2j at half its maximum radiant power, the minimum distance t1 is

[0082]

[0083] Where r1 represents the distance between the corresponding LEDs of each cell 23j1, and θ1 represents the angle of half maximum radiated power characteristic of the radiation pattern of each LED 2j. Box 23j2 represents another possible definition of a cell that is identical to that of cell 23j1. An example radiation pattern is shown in Figure 20 on the bottom.

[0084] However, because LEDs 2j and 3j are arranged in cell 23j and the arrangement of the LEDs is the same in each of cell 23j, the same considerations apply to LED 3j. Figure 15 and Figure 18 ), then the minimum distance for each LED type can be derived accordingly, and the maximum value of these minimum distances should apply.

[0085] Preferably, each location on the bottom surface of the outlet layer is illuminated by the LEDs of at least one unit cell at their respective half maximum radiant power.Furthermore, each location on the bottom surface of the outlet layer is preferably illuminated by corresponding LEDs of at least two units cells.

[0086] In a typical arrangement, the distance between the LEDs and the bottom surface of the outlet layer may be between 1 mm and 10 mm, preferably between 3 mm and 8 mm.

[0087] One type of LED (first LED, second LED) has the same spectrum. If they have different maximum radiant powers, then the half maximum radiant power discussed above can be replaced by a fixed value lower than the maximum radiant power of the LED with the smallest maximum radiant power.

[0088] Figures 22 to 27 An example is shown of how a lighting device according to some embodiments of the present invention may operate with an image sensor for capturing an image of a scene illuminated by the lighting device.

[0089] according to Figure 22 , the first light source and the second light source (eg, LEDs with different emission wavelengths) are turned on alternately, substantially synchronized with the exposure time of the image sensor. Figure 23 , only one of the light sources is turned on substantially synchronously with the exposure time of the image sensor, while the other light source remains off. After a certain time, the first light source and the second light source may switch their roles. Figure 24 , one of the light sources is permanently on (ie even during the readout time of the image sensor). The other light source is permanently off. Figure 23 In the embodiment, after a period of time, the first light source and the second light source may switch their roles. Figure 25 Corresponding to Figure 24 , but here both light sources are permanently on. Therefore, the scene can be different from the Figures 22 to 24 The spectra obtained are then illuminated.

[0090] exist Figure 26 and Figure 27In the example of , the image sensor is exposed by a rolling shutter, where only a portion of the image sensor is exposed at a time and this portion is shifted (rolled) across the sensor area. Figure 26 For each sweep of the rolling shutter, one of the two light sources illuminates the exit layer while the other light source is dark. The light sources are alternately turned on and off. Figure 27 , images can be acquired at a higher speed, where dark scans (where neither light source is on) are inserted between two illuminations by different light sources. Figure 27 The lighting scheme corresponds to Figure 22 Rolling shutter can also be used for Figures 23 to 25 lighting sequence.

[0091] Figure 28 and Figure 29 Example illumination spectra are shown where the phosphor in the exit layer is a mixed phosphor (e.g., nitride and / or CaAlSiN3 (CASN), and / or (Sr,Ca)AlSiN3 (SCASN)). Figure 28 , an illumination spectrum for white light illumination is shown, which has peaks at λ1 and λ2 (the emission wavelengths of white LEDs) and an additional broad maximum at a larger wavelength λ4 (e.g., 675 nm). For example, for near-infrared imaging and / or near-infrared photoimmunotherapy, a light source (LED) emitting at a peak wavelength λ4 may be selected. Thus, the spectrum consists almost exclusively of one broad peak around λ4 (and another smaller peak at a higher wavelength λ3 due to some of the spectrum of the light source).

[0092] Some embodiments of the present invention also address another problem of spectral imaging. In conventional endoscopes, the distal end portion may include an infrared LED and a white LED, wherein the white LED includes a violet (UV) LED and a phosphor that is excited by the light of the violet LED. The phosphor covers the violet LED. In such conventional distal end portions, the phosphor of the white LED can be excited by a violet light component that is emitted by the infrared LED and reflected by components of the endoscope. This spectral portion of the phosphor of the white LED can be received as noise in spectral imaging. This problem is particularly relevant when a phosphor with high efficiency for violet light, such as a CASN or SCASN, is used for the white LED.

[0093] Compared to conventional endoscopes, in some embodiments of the present invention, the exit layer is positioned between the white LEDs and the object to be illuminated. If the phosphor in the exit layer generates violet light, only a small portion of the light from the phosphor will strike the white LEDs, and an even smaller portion will be transmitted to or through the exit layer. Consequently, noise is reduced. Alternatively, in some embodiments of the present invention, the phosphor used to generate white light may not cover the violet LEDs but may be present only in the exit layer. If the phosphor is provided on the side of the exit layer facing the LEDs, its contribution to illumination of the object can also be reduced.

[0094] Of course, this effect is not limited to the above combination of infrared LEDs and white LEDs, and it is also possible for other combinations; the phosphor of one LED can be excited by the light of the other LED reflected from a component of the endoscope.

[0095] The present invention is described with LED as the light source. However, instead of LED, the emitting end of an optical fiber can be used. In this case, the input end of the optical fiber is connected to an emitting light source that emits the corresponding light. In more detail, in the case where the optical fiber changes the spectrum of the light passing through the optical fiber, the emitting light source must compensate for this change in the spectrum. Optical fibers of the same type of light source can be connected to a single emitting light source, or some of them can be connected to independent emitting light sources. Examples of emitting light sources are LEDs and lasers. In the case of an optical fiber, a controller that controls the emission of the first light and the second light can control the emission of the emitting light source, or can control a shutter that allows or prohibits the propagation of light from the emitting light source to the emitting end of the optical fiber.

[0096] exist Figures 11 to 19 In the embodiment of the present invention, the cells are arranged one-dimensionally, for example, in a line or a circle. However, in some example embodiments of the present invention, the cells may be arranged two-dimensionally, for example, in a rectangular grid, a square grid, or a hexagonal grid.

[0097] The shape of the outlet layer may preferably correspond to the arrangement of the cells, but it may differ from this arrangement.

[0098] As explained above, the lighting device is preferably arranged in the rigid end of the endoscope, which is used to be inserted into the lumen of the human body. Such a rigid end may include an objective lens, and the lighting device may be arranged around the objective lens. In addition, the rigid end may include an image sensor, a working channel, etc. The rigid end may be connected to a flexible tube, so that embodiments of the present invention also encompass endoscopes. In some embodiments, the rigid end can be used independently (i.e., without being connected to the flexible tube of the endoscope). Therefore, the lighting device can be used in so-called "capsule endoscopes."

Claims

1. A lighting device for a distal end portion of an endoscope, comprising: an outlet layer comprising a bottom surface and a top surface, the top surface being opposite the bottom surface, wherein a phosphor is disposed in the outlet layer; a plurality of first light sources, each first light source being configured to emit first light of a first emission spectrum from a corresponding light emitting surface; a plurality of second light sources, each second light source being configured to emit a second light having a second emission spectrum different from the first emission spectrum from a corresponding light emitting surface; wherein, The first light source and the second light source are arranged in a plurality of cells; Each of the cells includes at least one of the first light sources and at least one of the second light sources; In each of the cells, corresponding at least one of the first light sources and corresponding at least one of the second light sources are arranged in the same manner; The plurality of cells are periodically arranged in the base region with a first period; The plurality of first light sources are controllable independently of the plurality of second light sources; The first light source and the second light source are arranged to be spaced apart from the exit layer so that if the first light source and the second light source emit the first light and the second light, respectively, each position of the bottom surface is illuminated by the first light of at least two of the cells and the second light of at least two of the cells; the phosphor being configured to convert at least a portion of the first light into first converted light such that if the first light source and the second light source emit the first light and the second light, combined light exits the top surface of the exit layer; if the phosphor is configured to convert at least a portion of the second light into second converted light, the combined light includes the remaining portion of the first light, the remaining portion of the second light, the first converted light, and the second converted light, wherein a spectrum of the first converted light is different from a spectrum of the second converted light; if the phosphor is not configured to convert at least a portion of the second light into second converted light, the combined light includes the remaining portion of the first light, the second light, and the first converted light; If the first light source and the second light source respectively emit the first light and the second light projected onto the bottom surface on a line connecting corresponding positions of two adjacent cells of the plurality of cells, then a change in the total intensity of the first light is less than 20%, and a change in the total intensity of the second light is less than 20%.

2. The lighting device according to claim 1, wherein in each of the cells: The light emitting surfaces of all the first light sources and the light emitting surfaces of all the second light sources of a corresponding cell are arranged in the base area; or The light emitting surface of at least one of the first light source and the second light source of the corresponding cell is arranged in an elevated area different from the base area, and the light emitting surfaces of the remaining first light sources and the light emitting surfaces of the remaining second light sources of the corresponding cell are arranged in the base area.

3. The lighting device according to any one of claims 1 to 2, wherein: The amount of the phosphor in a direction perpendicular to the base region is independent of a position on the bottom surface or is adjusted with the first period according to the position on the bottom surface.

4. The lighting device according to any one of claims 1 to 3, wherein: If the first light source and the second light source emit the first light and the second light, respectively, a total intensity of the first light on the bottom surface varies by less than 20%, and a total intensity of the second light on the bottom surface varies by less than 20%.

5. The lighting device according to any one of claims 1 to 4, wherein at least one of the following: Each of the first light sources is a corresponding LED, or each of the first light sources is an emitting end portion of a corresponding optical fiber, the optical fiber being connected at its input end to a corresponding first light emitting light source; Each of the second light sources is a corresponding LED, or each of the second light sources is an emitting end portion of a corresponding optical fiber, the optical fiber being connected at its input end to a corresponding second light emitting light source. 6 . The lighting device according to claim 1 , further comprising a controller configured to individually control emission of the first light by the first light source and emission of the second light by the second light source.

7. The lighting device according to any one of claims 1 to 6, wherein: The cells are arranged one-dimensionally in the base region with the first period, or the cells are arranged in the base region with a first dimension and the first period and with a second dimension and a second period. 8 . The lighting apparatus according to claim 7 , wherein the units are one-dimensionally arranged in a circle, and the first period is an angular period.

9. The lighting device of claim 8, wherein the exit layer acts as a light diffuser such that the combined light exits the exit layer at an angle exceeding 180° about the center of the circle.

10. A rigid tip of an endoscope or capsule endoscope for insertion into a lumen of a human body, the rigid tip comprising an objective lens and an illumination device according to any one of claims 8 to 9, the illumination device being arranged around the objective lens.

11. An endoscope comprising the rigid tip according to claim 10, and a flexible tube for insertion into the lumen of the human body, wherein the rigid tip is connected to the flexible tube.

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