阅读说明：本技术 发光装置以及使用了该发光装置的医疗系统、电子设备及检验方法 (Light emitting device, and medical system, electronic device and inspection method using same ) 是由 阿部岳志 大盐祥三 新田充 于 2020-02-19 设计创作，主要内容包括：本申请的发光装置(1)具备第一波长转换体(4)和第二波长转换体(7),上述第一波长转换体(4)包含吸收初级光(3)并转换成波长比初级光(3)长的第一波长转换光(10)的第一荧光体(5),上述第二波长转换体(7)包含吸收初级光(3)并转换成波长比初级光(3)长的第二波长转换光(11)的第二荧光体(8)。第一波长转换光(10)是在700nm～800nm的整个波长范围具有光成分并且在700nm以上的波长区域具有荧光强度显示出最大值的峰的荧光。第二波长转换光(11)是在380nm以上且小于700nm的波长范围内具有荧光强度显示出最大值的峰的荧光。发光装置(1)在时间上交替地放出包含第一波长转换光(10)的第一输出光(12)以及包含第二波长转换光(11)的第二输出光(13)。(A light-emitting device (1) is provided with a first wavelength converter (4) and a second wavelength converter (7), wherein the first wavelength converter (4) includes a first phosphor (5) that absorbs primary light (3) and converts the primary light into first wavelength converted light (10) having a longer wavelength than the primary light (3), and the second wavelength converter (7) includes a second phosphor (8) that absorbs the primary light (3) and converts the primary light into second wavelength converted light (11) having a longer wavelength than the primary light (3). The first wavelength converted light (10) is fluorescence having a light component in the entire wavelength range of 700nm to 800nm and having a peak in which the fluorescence intensity shows a maximum value in a wavelength region of 700nm or more. The second wavelength-converted light (11) is fluorescence having a peak whose fluorescence intensity exhibits a maximum value in a wavelength range of 380nm or more and less than 700 nm. The light emitting device (1) emits first output light (12) including first wavelength-converted light (10) and second output light (13) including second wavelength-converted light (11) alternately in time.)

1. A light emitting device includes a light source, a first wavelength converter, and a second wavelength converter,

the light source emits a primary light which is,

the first wavelength converter comprises a first phosphor that absorbs the primary light and converts into first wavelength converted light having a longer wavelength than the primary light,

the second wavelength converter includes a second phosphor that absorbs the primary light and converts into second wavelength-converted light having a longer wavelength than the primary light,

wherein the first wavelength-converted light is fluorescence having a light component in the entire wavelength range of 700nm to 800nm and having a peak in which a fluorescence intensity shows a maximum value in a wavelength region of 700nm or more,

the second wavelength-converted light is fluorescence having a peak at which a fluorescence intensity shows a maximum value in a wavelength range of 380nm or more and less than 700nm,

the light emitting device alternately emits temporally a first output light comprising the first wavelength-converted light and a second output light comprising the second wavelength-converted light.

2. The light emitting device of claim 1, wherein the primary light is a laser.

3. The light-emitting device according to claim 1 or 2, wherein the primary light that excites the first phosphor has a different optical axis from the primary light that excites the second phosphor.

4. The light-emitting device according to claim 1 or 2, wherein the primary light that excites the first phosphor and the primary light that excites the second phosphor are emitted by the same light source.

5. The light-emitting device according to claim 4, wherein an optical axis of the primary light that excites the first phosphor is the same as an optical axis of the primary light that excites the second phosphor.

6. The light-emitting device according to any one of claims 1 to 5, wherein the first output light and the second output light are emitted alternately in time by changing positions of the first wavelength converter and the second wavelength converter with respect to the light source.

7. The light-emitting device according to any one of claims 1 to 6, wherein the first phosphor is activated by a transition metal ion.

8. The light-emitting device according to any one of claims 1 to 7, wherein the second phosphor is Ce³⁺And Eu²⁺Is activated.

9. The light-emitting device according to any one of claims 1 to 8, wherein a correlated color temperature of mixed light of the primary light and the second wavelength converted light is 2500K or more and less than 7000K.

10. The light-emitting device according to any one of claims 1 to 9, which is a light source for a sensing system or an illumination system for a sensing system.

11. A light emitting device according to any one of claims 1 to 10 for use in any of fluorescence imaging or photodynamic therapy.

12. A medical system comprising the light-emitting device according to any one of claims 1 to 11.

13. An electronic device comprising the light-emitting device according to any one of claims 1 to 10.

14. The electronic device according to claim 13, which is any of an information identification means, a discrimination means, a detection means, or a verification means.

15. The electronic device according to claim 14, wherein the inspection apparatus is any of a medical inspection apparatus, an agricultural or animal husbandry inspection apparatus, a fishery inspection apparatus, or an industrial inspection apparatus.

16. An inspection method using the light-emitting device according to any one of claims 1 to 10.

Technical Field

The present invention relates to a light emitting device, and a medical system, an electronic apparatus, and a test method using the light emitting device.

Background

In recent years, a method of observing a lesion called a fluorescence imaging method has been attracting attention in the medical field. The fluorescence imaging method is as follows: a fluorescent drug that selectively binds to a lesion such as a tumor is administered to a subject, and then the fluorescent drug is excited by specific light, and fluorescence emitted from the fluorescent drug is detected and imaged by an image sensor, thereby observing the lesion. According to the fluorescence imaging method, a lesion which is difficult to visually observe can be observed.

As a representative fluorescence imaging method, a fluorescence imaging method using indocyanine green (ICG) as a fluorescent agent (ICG fluorescence method) is known. ICG is excited by near-infrared light (for example, a fluorescence peak wavelength of 770nm) that easily passes through a living body, and emits near-infrared light (for example, a fluorescence peak wavelength of 810nm) having a longer wavelength than that of ICG. Therefore, by detecting fluorescence emitted from ICG, a lesion in a living body can be observed. ICG fluorescence is a low-invasive medical technique that enables observation of a lesion in a living body without injuring the living body.

In order to utilize a fluorescence imaging method such as the ICG fluorescence method, a device that emits at least near-infrared light is required. As an optoelectronic element emitting near-infrared fluorescence, patent document 1 discloses an optoelectronic element including a semiconductor chip emitting a primary beam and a conversion material containing Cr³⁺Ions and/or Ni²⁺Ions.

Documents of the prior art

Patent document

Patent document 1: japanese Kohyo publication No. 2018-518046

Disclosure of Invention

As described above, in order to use a fluorescence imaging method such as ICG fluorescence, a device that emits at least near-infrared light is required. On the other hand, in order to perform normal observation of the state of the mucosal top layer visually through an image or a lens reflected by the visible light image sensor, it is preferable to emit visible light as well. Therefore, if there is a device that emits both visible light and near-infrared light, both normal observation using visible light and special observation using near-infrared light can be achieved.

However, for example, when a mixed light of visible light and near-infrared light is emitted, a light component in the near-infrared region in the visible light is easily detected by the image sensor for near-infrared light. Therefore, there are problems such as the following: light components other than near-infrared fluorescence emitted from the fluorescent drug are also detected by the image sensor for near-infrared light, which causes noise and makes it difficult to observe a lesion with high contrast.

The present invention has been made in view of the problems of the prior art. Further, the present invention aims to: provided are a light-emitting device which emits near-infrared light and visible light so as to obtain a high-contrast observation result, and a medical system, an electronic apparatus, and a test method using the light-emitting device.

In order to solve the above-described problems, a light-emitting device according to a first aspect of the present invention includes a light source that emits primary light, a first wavelength converter that includes a first phosphor that absorbs the primary light and converts the primary light into first wavelength converted light having a wavelength longer than the primary light, and a second wavelength converter that includes a second phosphor that absorbs the primary light and converts the primary light into second wavelength converted light having a wavelength longer than the primary light. The first wavelength-converted light is fluorescence having a light component in the entire wavelength range of 700nm to 800nm and having a peak in which the fluorescence intensity shows a maximum value in a wavelength region of 700nm or more. The second wavelength-converted light is fluorescence having a peak in which fluorescence intensity shows a maximum value in a wavelength range of 380nm or more and less than 700 nm. The light emitting device emits a first output light including the first wavelength-converted light and a second output light including the second wavelength-converted light alternately in time.

A medical system according to a second aspect of the present invention includes the light emitting device of the first aspect.

An electronic device according to a third aspect of the present invention includes the light-emitting device according to the first aspect.

A fourth aspect of the inspection method of the present invention uses the light-emitting device of the first aspect.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of a light-emitting device according to a first embodiment.

Fig. 2 is a cross-sectional view schematically showing an example of a light-emitting device according to a second embodiment.

Fig. 3 is a plan view schematically showing an example of the chopper.

Fig. 4 is a cross-sectional view schematically showing an example of a light-emitting device according to a third embodiment.

Fig. 5 is a cross-sectional view schematically showing an example of a light-emitting device according to a fourth embodiment.

Fig. 6 schematically shows a plan view of an example of the phosphor wheel.

Fig. 7 schematically shows a cross-sectional view of an example of a light-emitting device of a fifth embodiment.

Fig. 8 schematically shows a cross-sectional view of an example of a light-emitting device according to a sixth embodiment.

Fig. 9 is a schematic sectional view of an example of a light-emitting device according to a seventh embodiment.

Fig. 10 schematically shows a configuration of an endoscope according to the present embodiment.

Fig. 11 schematically shows a configuration of an endoscope system according to the present embodiment.

FIG. 12 is a fluorescence spectrum of fluorescence emitted by the first phosphor according to the example.

FIG. 13 is a fluorescence spectrum of fluorescence emitted by the second phosphor according to the example.

Detailed Description

The following describes a light-emitting device according to the present embodiment, and a medical system, an electronic device, and a test method using the light-emitting device, with reference to the drawings. For convenience of explanation, the dimensional ratios in the drawings are exaggerated and may be different from the actual ratios.

[ light-emitting device ]

The light-emitting device of the present embodiment will be described below with reference to fig. 1 to 9.

[ first embodiment ]

As shown in fig. 1, the light emitting device 1 of the present embodiment includes a light source 2, a first wavelength converter 4, and a second wavelength converter 7. The light source 2 emits primary light 3. The first wavelength converter 4 includes a first phosphor 5. The first phosphor 5 absorbs the primary light 3 and converts it into first wavelength converted light 10 having a longer wavelength than the primary light 3. The second wavelength conversion body 7 contains a second phosphor 8. The second phosphor 8 absorbs the primary light 3 and converts it into second wavelength converted light 11 having a longer wavelength than the primary light 3.

The first wavelength converted light 10 is fluorescence having a light component in the entire wavelength range of 700nm to 800nm and having a peak in which the fluorescence intensity shows a maximum value in a wavelength region of 700nm or more. The second wavelength converted light 11 is fluorescence having a peak whose fluorescence intensity shows a maximum value in a wavelength range of 380nm or more and less than 700 nm. The light emitting device 1 emits temporally alternately a first output light 12 comprising the first wavelength converted light 10 and a second output light 13 comprising the second wavelength converted light 11.

That is, when the primary light 3 emitted from the light source 2 enters the first wavelength converter 4, the first wavelength converter 4 emits the first wavelength converted light 10 mainly containing the near-infrared fluorescent component. On the other hand, when the primary light 3 emitted from the light source 2 enters the second wavelength converter 7, the second wavelength converter 7 emits second wavelength converted light 11 mainly composed of a visible light component.

The near-infrared fluorescent component has excellent biological permeability and a wide fluorescence spectrum, and for example, a fluorescent agent used in a fluorescence imaging method is excited and emits near-infrared fluorescence having a longer wavelength than the excited near-infrared. The near-infrared fluorescence emitted by the fluorescent agent can be detected and imaged by a near-infrared image sensor, thereby enabling special observation. On the other hand, the visible fluorescent component emitted by the light-emitting device 1 is excellent in visibility, and is useful for normal observation of an affected part of a living body by visual observation.

The light emitting device 1 emits temporally alternately a first output light 12 comprising the first wavelength converted light 10 and a second output light 13 comprising the second wavelength converted light 11. Therefore, in the image sensor for near-infrared fluorescence, while the intensity of the noise component is relatively small, the near-infrared fluorescence component having a relatively high intensity ratio can be detected. Therefore, according to the light emitting device 1 of the present embodiment, near-infrared light and visible light can be emitted using the time difference so that a high-contrast observation result can be obtained.

The light source 2 may be one light source, or may include at least two light sources as shown in fig. 1. The at least two light sources 2 may be set to be the same light sources in terms of the color tone and output characteristics of the primary light 3, or may be set to be different light sources depending on the excitation characteristics of the phosphor and the like. Similarly, the primary lights 3 emitted by the light sources 2 may be lights having the same light component or lights having different light components.

In the present embodiment, as shown in fig. 1, the light source 2 includes a first light source 2A and a second light source 2B. The first light source 2A emits primary light 3A and the second light source 2B emits primary light 3B. The optical axis of the primary light 3A is oriented in a vertical direction with respect to the front surface 4A of the first wavelength conversion body 4, and the optical axis of the primary light 3B is oriented in a vertical direction with respect to the front surface 7A of the second wavelength conversion body 7. That is, in the present embodiment, the directions of the optical axes of the primary light 3A and the primary light 3B are the same. The primary light 3A is emitted by the first wavelength converter 4, and excites the first phosphor 5 included in the first wavelength converter 4. The primary light 3B is emitted by the second wavelength converter 7, and excites the second phosphor 8 included in the second wavelength converter 7.

As shown in fig. 1, the optical axes of the primary light 3A exciting the first phosphor 5 and the primary light 3B exciting the second phosphor 8 may be different. In this way, the primary light 3A and the primary light 3B can be controlled by the first light source 2A and the second light source 2B, respectively, and therefore ON-OFF (ON-OFF) control of the first wavelength-converted light 10 and the second wavelength-converted light 11 is facilitated.

In the present embodiment, the primary light 3A and the primary light 3B are emitted alternately in time. That is, the second light source 2B is turned off during the lighting of the first light source 2A, and the second light source 2B is turned on during the lighting of the first light source 2A. Therefore, the light emitting device 1 can alternately discharge the first output light 12 and the second output light 13 in terms of time.

The primary light 3 is preferably a laser. Since the laser light is a highly directional point light source with high output, not only can the optical system be downsized and the diameter of the light guide portion be reduced, but also the coupling efficiency of the laser light to the optical fiber and the like can be improved. Therefore, the light-emitting device 1 with high output can be easily obtained. From the viewpoint of downsizing of the light-emitting device 1, the laser light is preferably emitted from the semiconductor light-emitting element.

The spectrum of the light emitted from the light source 2 preferably has a peak whose intensity exhibits a maximum value at 400nm or more and less than 500 nm. It is also preferable that the spectrum of the light emitted from the light source 2 has a peak whose intensity exhibits a maximum value in a wavelength region of 420nm or more and less than 480nm and the light emitted from the light source 2 is blue light. The spectrum of the light emitted from the light source 2 preferably has a peak whose intensity exhibits a maximum in a wavelength region of 430nm or more and less than 480nm, and more preferably 440nm or more and less than 470 nm. As a result, the first phosphor 5 and the second phosphor 8 are efficiently excited, and thus the light-emitting device 1 can emit high-output near-infrared light.

The light source 2 may include a red laser element or a blue laser element. The red laser element is preferably included in the first light source 2A that excites the first phosphor 5. The red laser element has a small energy difference from the near-infrared light component, and the energy loss associated with wavelength conversion is small, and therefore, it is preferable to achieve high efficiency of the light-emitting device 1. The red laser element preferably has a peak having a maximum fluorescence intensity in a wavelength range of 600nm or more and less than 660nm, particularly 610nm or more and less than 660 nm. On the other hand, since a blue laser element is easy to obtain a high-efficiency and high-output laser element, it is preferable to increase the output of the light-emitting device 1. The light source 2 preferably includes a blue laser element as an excitation source and emits blue laser light. As a result, the first phosphor 5 and the second phosphor 8 are excited with high efficiency and high output, and thus the light emitting device 1 can emit high-output near-infrared light.

Preferably, the light source 2 includes a solid-state light emitting element and the blue light is emitted by the solid-state light emitting element. Thus, a highly reliable small-sized light emitting element is used as the light source for emitting blue light, and thus a highly reliable small-sized light emitting device 1 can be obtained.

The solid-state light-emitting element is a light-emitting element that emits primary light 3. As the solid-state light-emitting element, any light-emitting element can be used as long as it can emit the primary light 3 having a high energy density. The solid-state light-emitting element is preferably at least one of a laser element and a light-emitting diode (LED), and more preferably a laser element. The light source 2 may be, for example, a surface-emitting laser diode.

The rated light output of the solid-state light-emitting element is preferably 1W or more, and more preferably 3W or more. Thus, the light source 2 can emit the high-output primary light 3, and thus the light-emitting device 1 can be obtained which can easily achieve high output.

The upper limit of the rated light output is not particularly limited, and the light source 2 may include a plurality of solid-state light-emitting elements to increase the rated light output. However, if availability is considered, the rated light output is preferably less than 10kW, more preferably less than 3 kW.

The optical density of the primary light 3 preferably exceeds 0.5W/mm²More preferably more than 3W/mm²More preferably more than 10W/mm². The optical density may exceed 30W/mm². In this way, the first phosphor 5 and the second phosphor 8 are excited by light at high density, and thus the light emitting device 1 can emit a fluorescent component with high output.

The correlated color temperature of the mixed light of the primary light 3 and the second wavelength converted light 11 is preferably above 2500K and below 7000K. The correlated color temperature is more preferably 2700K or more and less than 5500K, and still more preferably 2800K or more and less than 3200K or 4500K or more and less than 5500K. The output light having a correlated color temperature within the above range is white, and the affected part that can be visually confirmed by an image display device or an optical instrument appears to be close to the affected part observed under natural light. Therefore, the light-emitting device 1 can be obtained which is preferable as a medical device in which a doctor can easily use his or her medical experience.

The second wavelength-converted light 11 preferably has a light component over the entire wavelength range of 500nm or more and less than 580 nm. By providing the light component to the second wavelength converted light 11, the light emitting device 1 can efficiently emit a fluorescent component favorable for visual observation. The second wavelength-converted light 11 may have a light component in the entire wavelength range of 500nm or more and less than 600 nm.

The first wavelength-converted light 10 has a light component in the entire wavelength range of 700nm to 800 nm. The first wavelength-converted light 10 more preferably has a light component in the entire wavelength range of 750nm to 800 nm. In this way, even if a chemical whose light absorption characteristics of near infrared rays are likely to vary is used, the light-emitting device 1 can emit near infrared excitation light that can excite the chemical with good efficiency. Therefore, the light emitting device 1 can increase the amount of near-infrared light emitted from the fluorescent chemical, the heat ray emitted from the photosensitive chemical, or active oxygen generated by excitation of the photosensitive chemical.

The first phosphor 5 is preferably activated by transition metal ions, more preferably by Cr³⁺And (4) activating. Thereby, as the first wavelength converted light10, it is easy to obtain fluorescence having a wide fluorescence spectrum width and having a light component over the entire wavelength range of 700 to 800 nm.

The first wavelength converted light 10 is fluorescence having a peak whose fluorescence intensity exhibits a maximum value in a wavelength region of 700nm or more. The first wavelength converted light 10 preferably has a peak in which the fluorescence intensity shows a maximum value in a wavelength region of 710nm or more. Thus, the light emitting device 1 can emit a large amount of fluorescence including a near infrared light component having high biological permeability.

The first wavelength converted light 10 preferably comprises Cr-based³⁺Fluorescence of electron energy transitions. The fluorescence spectrum of the first wavelength converted light 10 preferably has a peak in which the fluorescence intensity shows a maximum value in a wavelength region having a wavelength of more than 720 nm. Thus, the first phosphor 5 can emit fluorescence in which a spectral component having a short afterglow and a broad afterglow is dominant over a linear spectral component having a long afterglow. As a result, the light emitting device 1 can emit a large amount of light containing a near-infrared component. Furthermore, the linear spectral components are based on Cr³⁺Is/are as follows²E→⁴A₂(t₂ ³) Has a fluorescence component of electron energy transition (spin forbidden transition) and has a peak in which fluorescence intensity shows a maximum value in a wavelength region of 680 to 720 nm. The broad spectral content is based on Cr³⁺Is/are as follows⁴T₂(t₂ ²e)→⁴A₂(t₂ ³) Has a fluorescence component of electron energy transition (spin-allowed transition) and has a peak in which fluorescence intensity shows a maximum value in a wavelength region exceeding 720 nm.

The fluorescence spectrum of the first wavelength converted light 10 may have a peak whose fluorescence intensity exhibits a maximum value in a wavelength region exceeding 720nm and not more than 900 nm. The fluorescence spectrum of the first wavelength converted light 10 preferably has a peak whose fluorescence intensity exhibits a maximum value in a wavelength region exceeding 730nm, and more preferably has a peak whose fluorescence intensity exhibits a maximum value in a wavelength region exceeding 750 nm.

The 1/10 afterglow time of the first wavelength converted light 10 is preferably less than 1ms, more preferably less than 300 mus, even more preferably less than 100 mus. Thereby, even when excitedWhen the optical density of the excitation light of the first phosphor 5 is high, the output of the first wavelength converted light 10 is also less likely to be saturated. Therefore, the light-emitting device 1 capable of emitting high-output near-infrared light can be obtained. The 1/10 afterglow time is the time τ required from the time when the maximum emission intensity is exhibited to the time when the intensity of 1/10 that is the maximum emission intensity is reached_1/10。

The 1/10 afterglow time of the first wavelength converted light 10 is preferably longer than the 1/10 afterglow time of the second wavelength converted light 11. Specifically, the 1/10 afterglow time of the first wavelength converted light 10 is preferably 10 μ s or more. In addition, is coated with Cr³⁺1/10 persistence time ratio of the activated first wavelength converted light 10 is based on Ce³⁺、Eu²⁺Etc. the cosmetical terms allow short persistence (less than 10. mu.s) of transition and long persistence of 1/10. This is because: which is based on Cr with a longer afterglow time of the first wavelength converted light 10³⁺Fluorescence of spin-allowed electron energy transition.

In the fluorescence spectrum of the first wavelength-converted light 10, the spectral width at an intensity of 80% of the maximum value of the fluorescence intensity is preferably 20nm or more and less than 80 nm. Thus, the main component of the first wavelength-converted light 10 becomes a broad spectral component. Therefore, in the medical field using the fluorescence imaging method or the photodynamic therapy (PDT method), even if there is a variation in the wavelength dependence of the sensitivity of the fluorescent drug or the photosensitive drug, the light-emitting device 1 can emit high-output near-infrared light that can sufficiently function with these drugs.

In the fluorescence spectrum of the first wavelength-converted light 10, the ratio of the fluorescence intensity with a wavelength of 780nm to the maximum value of the fluorescence intensity is preferably more than 30%. The ratio of the fluorescence intensity at a wavelength of 780nm to the maximum value of the fluorescence intensity is more preferably more than 60%, still more preferably more than 80%. Thus, the first phosphor 5 can emit a large amount of fluorescence including a fluorescence component in a near-infrared wavelength region (650 to 1000nm) in which light called "biological window" easily passes through a living body. Therefore, according to the light emitting device 1, the intensity of near-infrared light transmitted through a living body can be increased.

The fluorescence spectrum of the first wavelength-converted light 10 is preferably notThe residue is derived from Cr³⁺Is the linear spectral component of the electron energy transition. That is, the first wavelength converted light 10 preferably has only a broad spectral component (short afterglow) including a peak having a maximum fluorescence intensity in a wavelength region exceeding 720 nm. Thus, the first phosphor 5 does not contain Cr³⁺The fluorescent substance (2) contains only a short-afterglow fluorescent substance due to a spin-forbidden transition. Thus, even when the optical density of the excitation light that excites the first phosphor 5 is high, the output of the first wavelength converted light 10 becomes less likely to be saturated. Therefore, the light-emitting device 1 can be obtained as a point light source capable of emitting near-infrared light of higher output.

The first phosphor 5 preferably does not contain other than Cr³⁺An activator other than the above. In this way, the light absorbed by the first phosphor 5 is converted to Cr only³⁺The light emitting device 1 can be easily designed to output light with the output ratio of the near-infrared fluorescent component increased to the maximum.

The first phosphor 5 also preferably contains two or more kinds of Cr³⁺The phosphor is activated. Accordingly, since the output light component in at least the near-infrared wavelength region can be controlled, the light-emitting device 1 can be obtained in which the spectral distribution can be easily adjusted according to the application using the near-infrared fluorescent component.

The first phosphor 5 is preferably an oxide-based phosphor, and more preferably an oxide phosphor. The oxide-based phosphor is a phosphor containing oxygen but not containing nitrogen or sulfur. The oxide-based phosphor may contain at least one selected from the group consisting of an oxide, a complex oxide, and a compound containing oxygen and a halogen as an anion.

Since the oxide is a substance stable in the atmosphere, even when the oxide phosphor generates heat due to high-density light excitation by a laser beam, the deterioration of the phosphor crystal due to oxidation by the atmosphere, such as that caused by a nitride phosphor, is less likely to occur. Therefore, when all the phosphors included in the first wavelength converter 4 are oxide phosphors, the light-emitting device 1 with high reliability can be obtained.

The first phosphor 5 preferably has a crystal structure of garnet. The first phosphor 5 is also preferably an oxide phosphor having a crystal structure of garnet. The garnet phosphor is easily compositionally deformed and can provide a large amount of phosphor compounds, and thus Cr is easily performed³⁺The peripheral crystal field adjustment of Cr-based crystal is easily performed³⁺The hue of the fluorescence of the electron energy transition.

In addition, the phosphor having a garnet structure, particularly the oxide, has a particle shape of a polyhedron close to a sphere, and the dispersibility of the phosphor particle group is excellent. Therefore, when the phosphor included in the first wavelength converter 4 has a garnet structure, the first wavelength converter 4 having excellent light transmittance can be relatively easily produced, and high output of the light-emitting device 1 can be achieved. Further, since a phosphor having a garnet crystal structure has practical utility as a phosphor for LED, by providing the first phosphor 5 with a garnet crystal structure, the light-emitting device 1 having high reliability can be obtained.

The first phosphor 5 may include, for example, Lu₂CaMg₂(SiO₄)₃:Cr³⁺、Y₃Ga₂(AlO₄)₃:Cr³⁺、Y₃Ga₂(GaO₄)₃:Cr³⁺、Gd₃Ga₂(AlO₄)₃:Cr³⁺、Gd₃Ga₂(GaO₄)₃:Cr³⁺、(Y,La)₃Ga₂(GaO₄)₃:Cr³⁺、(Gd,La)₃Ga₂(GaO₄)₃:Cr³⁺、Ca₂LuZr₂(AlO₄)₃:Cr³⁺、Ca₂GdZr₂(AlO₄)₃:Cr³⁺、Lu₃Sc₂(GaO₄)₃:Cr³⁺、Y₃Sc₂(AlO₄)₃:Cr³⁺、Y₃Sc₂(GaO₄)₃:Cr³⁺、Gd₃Sc₂(GaO₄)₃:Cr³⁺、La₃Sc₂(GaO₄)₃:Cr³⁺、Ca₃Sc₂(SiO₄)₃:Cr^{3 +}、Ca₃Sc₂(GeO₄)₃:Cr³⁺、BeAl₂O₄:Cr³⁺、LiAl₅O₈:Cr³⁺、LiGa₅O₈:Cr³⁺、Mg₂SiO₄:Cr³⁺,Li⁺、La₃Ga₅GeO₁₄:Cr³⁺And La₃Ga_5.5Nb_0.5O₁₄:Cr³⁺And the like.

As described above, the first wavelength-converted light 10 has a fluorescent component in the near infrared. Thus, according to the light-emitting device 1, a fluorescent drug such as ICG, for example, a photosensitive drug (also a fluorescent drug) such as phthalocyanine, for example, can be efficiently excited.

The second phosphor 8 is preferably Ce-doped³⁺And Eu²⁺Is activated. This makes it easy to obtain the second wavelength converted light 11 having a peak whose fluorescence intensity exhibits a maximum value in a wavelength range of 380nm or more and less than 700 nm. In addition, the second phosphor 8 is preferably Ce-coated³⁺An activated phosphor.

The second phosphor 8 may be at least one of an oxide-based phosphor such as an oxide and a halogen oxide, and a nitride-based phosphor such as a nitride and an oxynitride.

The second phosphor 8 is preferably selected from garnet type, calcium ferrite type and lanthanum silicon nitride (La)₃Si₆N₁₁) Ce comprising a compound containing at least one of the compounds having a crystal structure of the type (III) as a main component as a matrix³⁺The phosphor is activated. Alternatively, the second phosphor 8 is preferably selected from the group consisting of garnet type, calcium ferrite type, and lanthanum silicon nitride (La)₃Si₆N₁₁) Ce comprising at least one compound of the group of compounds having a crystalline structure of type³⁺The phosphor is activated.By using such a second phosphor 8, a large amount of output light having green to yellow light components can be obtained.

Specifically, the second phosphor 8 is preferably to be selected from M₃RE₂(SiO₄)₃、RE₃Al₂(AlO₄)₃、MRE₂O₄And RE₃Si₆N₁₁Ce comprising a compound containing at least one of the main components as a matrix³⁺The phosphor is activated. Alternatively, the second phosphor 8 is preferably selected from M₃RE₂(SiO₄)₃、RE₃Al₂(AlO₄)₃、MRE₂O₄And RE₃Si₆N₁₁Ce comprising at least one of the above elements as a matrix³⁺The phosphor is activated. Alternatively, the second phosphor 8 is preferably Ce containing a solid solution containing the compound as an end component as a matrix³⁺The phosphor is activated. Further, M is an alkaline earth metal, and RE is a rare earth element.

Such a second phosphor 8 absorbs light in a wavelength range of 430nm to 480nm well, and efficiently converts the light into green to yellow light having a peak whose fluorescence intensity exhibits a maximum value in a wavelength range of 540nm or more and less than 590 nm. Therefore, by using such a phosphor as the second phosphor 8 in addition to the light source 2 which emits cold color light in the wavelength range of 430nm to 480nm as the primary light 3, the visible light component can be easily obtained.

At least the second wavelength converter 7 may further comprise a third phosphor that absorbs the primary light 3 and emits a third wavelength-converted light. The third wavelength-converted light is preferably included in the second output light 13 and the second output light 13 is white. For example, when the primary light 3 is blue light, such white light and the blue light are emitted by the light emitting device 1 by additive color mixing.

The first wavelength converting body 4 is preferably formed of an inorganic material. The inorganic material herein refers to a material other than an organic material, and is a concept including ceramics and metals. By forming the first wavelength converter 4 of an inorganic material, the thermal conductivity is higher than that of a wavelength converter including an organic material such as a sealing resin, and thus high heat dissipation design is facilitated. Therefore, even when the phosphor is excited at a high density by the primary light 3 emitted from the light source 2, the temperature rise of the first wavelength converter 4 can be effectively suppressed. As a result, temperature quenching of the phosphor in the first wavelength converter 4 is suppressed, and high output of light emission can be achieved. This improves the heat dissipation of the first phosphor 5, and therefore, the decrease in the output of the phosphor due to temperature quenching is suppressed, and high-output near-infrared light can be emitted. Furthermore, the second wavelength converting body 7 is also preferably formed of an inorganic material for the same reason as the first wavelength converting body 4.

Preferably, at least either one of the first wavelength conversion body 4 and the second wavelength conversion body 7 is entirely formed of an inorganic material. This improves the heat dissipation properties of the first phosphor 5 and/or the second phosphor 8, and therefore, the decrease in the output of the phosphors due to temperature quenching is suppressed, and the light-emitting device 1 that emits high-output near-infrared fluorescence and/or visible light can be obtained. Further, it is preferable that both the first wavelength conversion body 4 and the second wavelength conversion body 7 are formed of an inorganic material.

At least one of the first phosphor 5 and the second phosphor 8 may be ceramic. This increases the thermal conductivity of at least one of the first wavelength conversion body 4 and the second wavelength conversion body 7, and thus a high-power light-emitting device 1 that generates less heat can be provided. Here, the ceramic refers to a sintered body in which particles are bonded to each other.

As shown in fig. 1, the first wavelength converter 4 preferably further includes a first sealing material 6 for dispersing the first phosphor 5 in addition to the first phosphor 5. Further, in the first wavelength converter 4, the first phosphor 5 is preferably dispersed in the first sealing material 6. By dispersing the first phosphor 5 in the first sealing member 6, the light emitted to the first wavelength converter 4 can be efficiently absorbed and wavelength-converted into near-infrared light. In addition, the first wavelength conversion body 4 can be easily molded into a sheet or film shape. For the same reason as that of the first wavelength converter 4, it is preferable to further include a second sealing material 9 for dispersing the second phosphor 8 in addition to the second phosphor 8.

The first sealing material 6 is preferably at least one of an organic material and an inorganic material, and particularly at least one of a transparent (light-transmitting) organic material and a transparent (light-transmitting) inorganic material. Examples of the sealing material of an organic material include transparent organic materials such as silicone resin. As the sealing material of an inorganic material, for example, a transparent inorganic material such as low melting point glass can be cited. The second sealing member 9 is also preferably the same as the first sealing member 6.

As described above, the first wavelength converter 4 is preferably formed of an inorganic material, and therefore the first sealing material 6 is preferably formed of an inorganic material. As the inorganic material, zinc oxide (ZnO) is preferably used. This further improves the heat dissipation properties of the phosphor, and therefore, the reduction in the output of the phosphor due to temperature quenching is suppressed, and a light-emitting device 1 that emits high-output near-infrared light can be obtained. The second sealing member 9 is also preferably the same as the first sealing member 6.

The first sealing material 6 may not be used for the first wavelength converter 4, and the second sealing material 9 may not be used for the second wavelength converter 7. In this case, the phosphors may be fixed to each other with an organic or inorganic binder. Further, the phosphors may be fixed to each other by a heating reaction of the phosphors. As the binder, a commonly used resin-based binder, ceramic fine particles, low-melting glass, or the like can be used. The first wavelength converter 4 not using the first sealing material 6 or the second wavelength converter 7 not using the second sealing material 9 can be reduced in thickness, and thus can be suitably used for the light-emitting device 1.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 1, in the light emitting device 1 of the present embodiment, first, the primary light 3A emitted from the first light source 2A and the primary light 3B emitted from the second light source 2B are irradiated to the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time. The primary light 3A is irradiated to the front surface 4A of the first wavelength converter 4, and the irradiated primary light 3A is transmitted through the first wavelength converter 4. The primary light 3B is irradiated to the front surface 7A of the second wavelength converter 7, and the irradiated primary light 3B is transmitted through the second wavelength converter 7. When the primary light 3A passes through the first wavelength converter 4, the first phosphor 5 included in the first wavelength converter 4 absorbs a part of the primary light 3A and emits the first wavelength-converted light 10. Similarly, when the primary light 3B passes through the second wavelength converter 7, the second phosphor 8 included in the second wavelength converter 7 absorbs a part of the primary light 3B and emits the second wavelength-converted light 11. Thus, the first output light 12 including the primary light 3A and the first wavelength-converted light 10 is emitted from the back surface 4B of the first wavelength converter 4. Similarly, second output light 13 comprising the primary light 3B and the second wavelength-converted light 11 is emitted from the back surface 7B of the second wavelength converting body 7.

Thus, the first light source 2A and the second light source 2B repeat lighting and lighting-off temporally differently from each other, and therefore the light emitting device 1 can emit the first output light 12 and the second output light 13 temporally alternately.

[ second embodiment ]

Next, a light-emitting device 1 according to a second embodiment will be described with reference to fig. 2. Note that the same constituent elements as those of the above-described embodiment are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 2, the present embodiment is different from the first embodiment in that the first output light 12 and the second output light 13 are emitted alternately in time by the chopper 14 without flickering of the light source 2.

In the present embodiment, the light source 2 includes a first light source 2A and a second light source 2B, as in the first embodiment. The first light source 2A emits primary light 3A and the second light source 2B emits primary light 3B. Further, the optical axis of the primary light 3A exciting the first phosphor 5 is different from the optical axis of the primary light 3B exciting the second phosphor 8. In the present embodiment, the primary light 3A and the primary light 3B are continuously and continuously emitted. That is, the primary light 3A is emitted simultaneously with the primary light 3B, and the second light source 2B is also turned on during the period in which the first light source 2A is turned on.

The light emitting device 1 of the present embodiment includes a chopper 14. The chopper 14 is disposed on the back surface 4B side of the first wavelength converting body 4 and on the back surface 7B side of the second wavelength converting body 7. That is, the first wavelength converter 4 is disposed between the chopper 14 and the first light source 2A, and the second wavelength converter 7 is disposed between the chopper 14 and the second light source 2B. As shown in fig. 3, the chopper 14 is a circular plate having a center point, and is provided so as to rotate about a rotation axis C1 passing through the center point.

The chopper 14 includes a center portion 14A, an outer frame portion 14B, a blocking portion 14C, and a non-blocking portion 14D, the center portion 14A is provided at the center of the disk, the outer frame portion 14B is provided at the outer periphery of the disk, and the blocking portion 14C and the non-blocking portion 14D are provided between the center portion 14A and the outer frame portion 14B. The first wavelength converters 4 and the second wavelength converters 7 are alternately arranged in the circumferential direction. The chopper 14 has a blocking portion 14C on one side with respect to the rotation axis C1 and a non-blocking portion 14D on the opposite side in a cross section passing through the rotation axis C1. The blocking portion 14C is formed of a plate-shaped member and is formed to block the first output light 12 and the second output light 13. The non-blocking section 14D is a space surrounded by the central section 14A, the outer frame section 14B, and the blocking section 14C, and is formed so that the first output light 12 and the second output light 13 can pass therethrough. The chopper 14 rotates about the rotation axis C1, and the first output light 12 and the second output light 13 are cut off by the cut-off portion 14C or pass through the non-cut-off portion 14D. The chopper 14 is formed in the following manner: the second output light 13 passes through the non-blocking section 14D while the first output light 12 is blocked by the blocking section 14C, and the first output light 12 passes through the non-blocking section 14D while the second output light 13 is blocked by the blocking section 14C. The central portion 14A, the outer frame portion 14B, and the cut portion 14C may be integrally formed of the same material.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 2, in the light emitting device 1 of the present embodiment, first, the primary light 3A emitted from the first light source 2A and the primary light 3B emitted from the second light source 2B are simultaneously irradiated onto the first wavelength converter 4 and the second wavelength converter 7, respectively. The primary light 3A is irradiated to the front surface 4A of the first wavelength converter 4, and the irradiated primary light 3A is transmitted through the first wavelength converter 4. The primary light 3B is irradiated to the front surface 7A of the second wavelength converter 7, and the irradiated primary light 3B is transmitted through the second wavelength converter 7. When the primary light 3A passes through the first wavelength converter 4, the first phosphor 5 included in the first wavelength converter 4 absorbs a part of the primary light 3A and emits the first wavelength-converted light 10. Similarly, when the primary light 3B passes through the second wavelength converter 7, the second phosphor 8 included in the second wavelength converter 7 absorbs a part of the primary light 3B and emits the second wavelength-converted light 11. Thus, the first output light 12 including the primary light 3A and the first wavelength-converted light 10 is emitted from the rear surface 4B of the first wavelength converter 4. Similarly, second output light 13 comprising the primary light 3B and the second wavelength-converted light 11 is emitted by the back surface 7B of the second wavelength converting body 7.

Then, by rotating the chopper 14, the first output light 12 emitted from the first wavelength converter 4 repeats the cutoff by the cutoff unit 14C and the passage through the non-cutoff unit 14D alternately in time. Similarly, the second output light 13 emitted from the second wavelength conversion body 7 temporally alternately repeats the cutoff by the cutoff section 14C and the passage through the non-cutoff section 14D. The second output light 13 passes through the non-blocking section 14D while the first output light 12 is blocked by the blocking section 14C, and the first output light 12 passes through the non-blocking section 14D while the second output light 13 is blocked by the blocking section 14C. Thus, the first output light 12 and the second output light 13 are alternately output in time by the chopper 14, and therefore the light emitting device 1 can alternately emit the first output light 12 and the second output light 13 in time.

[ third embodiment ]

Next, a light-emitting device 1 according to a third embodiment will be described with reference to fig. 4. The same components as those in the above embodiments are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 4, the present embodiment is different from the first embodiment in that the directions of the optical axes of the primary light 3A and the primary light 3B are different from each other.

The first light source 2A is disposed at a position closer to the second wavelength conversion body 7 than the cross-sectional center of the first wavelength conversion body 4. The second light source 2B is disposed at a position closer to the first wavelength conversion body 4 than the cross-sectional center of the second wavelength conversion body 7. That is, the relative positions of the first light source 2A and the second light source 2B are arranged closer to the relative positions of the cross-sectional center portions of the first wavelength converter 4 and the second wavelength converter 7. Therefore, in the light emitting device 1 of the present embodiment, the relative positions of the first light source 2A and the second light source 2B are close, and therefore the size of the light sources can be reduced.

Therefore, the light emitting device 1 of the present embodiment can emit the first output light 12 and the second output light 13 alternately in time, as in the first embodiment.

[ fourth embodiment ]

Next, a light-emitting device 1 according to a fourth embodiment will be described with reference to fig. 5. The same components as those in the above embodiments are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 5, the present embodiment is different from the first embodiment in that the first output light 12 and the second output light 13 are emitted alternately in time by changing the positions of the first wavelength conversion body 4 and the second wavelength conversion body 7 with respect to the light source 2.

As in the present embodiment, the primary light 3 that excites the first phosphor 5 and the primary light 3 that excites the second phosphor 8 can be emitted from the same light source 2. That is, the light emitting device 1 of the present embodiment includes a single light source 2. Therefore, the number of light sources 2 can be set to a minimum necessary, which is advantageous in terms of downsizing and cost reduction of the light-emitting device 1.

As in the present embodiment, the optical axes of the primary light 3 exciting the first phosphor 5 and the primary light 3 exciting the second phosphor 8 may be the same. Therefore, the type and number of optical components can be set to the minimum necessary, which is advantageous for downsizing and cost reduction of the light-emitting device 1.

As in the present embodiment, by changing the positions of the first wavelength conversion body 4 and the second wavelength conversion body 7 with respect to the light source 2, the first output light 12 and the second output light 13 can be emitted alternately in time. This makes it possible to make the optical axis of the primary light 3 that excites the first phosphor 5 the same as the optical axis of the primary light 3 that excites the second phosphor 8. However, as described later, when the optical axes are different, the first output light 12 and the second output light 13 may be alternately emitted in time by changing the positions of the first wavelength converter 4 and the second wavelength converter 7 with respect to the light source 2.

In the present embodiment, the light emitting device 1 includes the fluorescent substance wheel 15 provided with the first wavelength conversion member 4 and the second wavelength conversion member 7. The phosphor wheel 15 is a circular plate having a center point, and is provided so as to rotate about a rotation axis C2 passing through the center point. As shown in fig. 6, the phosphor wheel 15 includes a center portion 15A provided at the center of the disk and an outer frame portion 15B provided at the outer periphery of the disk. The first wavelength converters 4 and the second wavelength converters 7 are alternately arranged in the circumferential direction between the center portion 15A and the outer frame portion 15B. The phosphor wheel 15 is provided with the first wavelength converter 4 on one side with respect to the rotation axis C2 and the second wavelength converter 7 on the opposite side in the cross section through which the rotation axis C2 passes.

The light source 2 is disposed radially outward of the rotation axis C2 and is provided to irradiate either the first wavelength converter 4 or the second wavelength converter 7. The optical axis of the primary light 3 is oriented in a vertical direction with respect to the front surface 4A of the first wavelength converting body 4 or the front surface 7A of the second wavelength converting body 7. The phosphor wheel 15 is provided so that the primary light 3 is irradiated onto the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time by rotating about the rotation axis C2. That is, the phosphor wheel 15 is formed in the following manner: the second wavelength converter 7 does not irradiate the primary light 3 during irradiation of the primary light 3 to the first wavelength converter 4, and the primary light 3 does not irradiate the first wavelength converter 4 during irradiation of the primary light 3 to the second wavelength converter 7. Further, a heat dissipating substrate through which the primary light 3 is transmitted may be provided on the light source 2 side of the phosphor wheel 15. This can suppress a temperature increase of the phosphor wheel 15 due to heat generation of the first phosphor 5 having a large stokes loss, and thus can suppress a decrease in light emission efficiency due to temperature quenching of the phosphor, and can obtain the light emitting device 1 that emits light with high output. Examples of a material for forming the heat dissipating substrate include sapphire.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 5, in the light emitting device 1 of the present embodiment, first, the primary light 3 emitted from the light source 2 is irradiated to the front surface 4A of the first wavelength converter 4. The primary light 3 irradiated to the front surface 4A is transmitted through the first wavelength converter 4. When the primary light 3 passes through the first wavelength converter 4, the first phosphor 5 included in the first wavelength converter 4 absorbs a part of the primary light 3 and emits the first wavelength-converted light 10.

The positions of the first wavelength conversion body 4 and the second wavelength conversion body 7 with respect to the light source 2 are changed by rotating the fluorescent substance wheel 15 about the rotation axis C2. Therefore, after the primary light 3 is irradiated to the first wavelength converter 4, the primary light 3 is irradiated to the front surface 7A of the second wavelength converter 7, and the irradiated primary light 3 is transmitted through the second wavelength converter 7. When the primary light 3 passes through the second wavelength converter 7, the second phosphor 8 included in the second wavelength converter 7 absorbs a part of the primary light 3 and emits the second wavelength-converted light 11. Thus, the first output light 12 including the primary light 3 and the first wavelength-converted light 10 is emitted from the rear surface 4B of the first wavelength converter 4. Then, second output light 13 comprising the primary light 3 and the second wavelength-converted light 11 is emitted by the back surface 7B of the second wavelength converting body 7. By rotating the phosphor wheel 15, the primary light 3 is irradiated to the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time, and therefore the light emitting device 1 can emit the first output light 12 and the second output light 13 alternately in time.

[ fifth embodiment ]

Next, a light-emitting device 1 according to a fifth embodiment will be described with reference to fig. 7. The same components as those in the above embodiments are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 7, in the light-emitting device 1 of the present embodiment, the primary light 3A is irradiated to the front surface 4A of the first wavelength converter 4, and the first wavelength-converted light 10 is emitted from the front surface 4A of the first wavelength converter 4. The primary light 3B is irradiated to the front surface 7A of the second wavelength converter 7, and the second wavelength-converted light 11 is emitted from the front surface 7A of the second wavelength converter 7. In these respects, the light-emitting device 1 of the present embodiment is different from the light-emitting device 1 of the first embodiment.

In the present embodiment, as shown in fig. 7, the light source 2 includes a first light source 2A and a second light source 2B. The first light source 2A emits primary light 3A and the second light source 2B emits primary light 3B. In the present embodiment, the optical axes of the primary light 3A exciting the first phosphor 5 and the primary light 3B exciting the second phosphor 8 are different, and the primary light 3A and the primary light 3B are emitted alternately in time.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 7, in the light emitting device 1 of the present embodiment, first, the primary light 3A emitted from the first light source 2A and the primary light 3B emitted from the second light source 2B are irradiated to the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time. The primary light 3A is irradiated toward the front surface 4A of the first wavelength converting body 4, and most of the irradiated primary light 3A enters the inside from the front surface 4A of the first wavelength converting body 4, and the rest is reflected by the surface of the first wavelength converting body 4. The primary light 3B is irradiated toward the front surface 7A of the second wavelength converting body 7, and most of the irradiated primary light 3B enters the inside from the front surface 7A of the second wavelength converting body 7, and the rest is reflected at the surface of the second wavelength converting body 7. In the first wavelength converter 4, the first phosphor 5 excited by the primary light 3A emits the first wavelength-converted light 10, and the front surface 4A emits the first wavelength-converted light 10. On the other hand, in the second wavelength converter 7, the second phosphor 8 excited by the primary light 3B emits the second wavelength-converted light 11, and the second wavelength-converted light 11 is emitted from the front surface 7A. Thus, the first light source 2A and the second light source 2B repeat lighting and lighting-off temporally differently from each other, and therefore the light emitting device 1 can emit the first output light 12 and the second output light 13 temporally alternately.

[ sixth embodiment ]

Next, a light-emitting device 1 according to a sixth embodiment will be described with reference to fig. 8. The same components as those in the above embodiments are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 8, in the light-emitting device 1 of the present embodiment, the primary light 3A is irradiated to the front surface 4A of the first wavelength converter 4, and the first wavelength-converted light 10 is emitted from the front surface 4A of the first wavelength converter 4. The primary light 3B is irradiated to the front surface 7A of the second wavelength conversion body 7, and the second wavelength converted light 11 is emitted from the front surface 7A of the second wavelength conversion body 7. In these respects, the light-emitting device 1 of the present embodiment is different from the light-emitting device 1 of the fourth embodiment.

As shown in fig. 8, the primary light 3 exciting the first phosphor 5 and the primary light 3 exciting the second phosphor 8 are emitted by the same light source 2. The primary light 3 exciting the first phosphor 5 has the same optical axis as the primary light 3 exciting the second phosphor 8. By changing the positions of the first wavelength conversion body 4 and the second wavelength conversion body 7 with respect to the light source 2, the first output light 12 and the second output light 13 are emitted alternately in time. The light emitting device 1 includes a phosphor wheel 15 provided with the first wavelength conversion body 4 and the second wavelength conversion body 7.

A reflective layer for reflecting the primary light 3, the first wavelength converted light 10 and the second wavelength converted light 11 may be provided on the side of the phosphor wheel 15 opposite to the light source 2. The reflective layer is not particularly limited as long as it has a function of reflecting light, and is formed of, for example, a resin containing silver and/or titanium oxide. Thus, the first wavelength-converted light 10 and the second wavelength-converted light 11 are extracted from the correction surface side, and thus the light-emitting device 1 that emits light with high output can be obtained. The heat dissipating substrate may be provided on the back surface side of the fluorescent substance wheel 15. This can suppress a temperature increase of the phosphor wheel 15 due to heat generation of the first phosphor 5 having a large stokes loss, and thus can suppress a decrease in light emission efficiency due to temperature quenching of the phosphor, and can obtain the light-emitting device 1 that emits light with high output.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 8, in the light emitting device 1 of the present embodiment, first, the primary light 3 emitted from the light source 2 is irradiated to the front surface 4A of the first wavelength converter 4. Most of the primary light 3 irradiated toward the front surface 4A enters the inside of the first wavelength converting body 4, and the rest is reflected by the surface of the first wavelength converting body 4. In the first wavelength converter 4, the first phosphor 5 excited by the primary light 3 emits the first wavelength-converted light 10, and the front surface 4A emits the first wavelength-converted light 10.

The first wavelength conversion body 4 and the second wavelength conversion body 7 change the positions with respect to the light source 2 by rotating the fluorescent substance wheel 15 about the rotation axis C2. Therefore, after the primary light 3 is irradiated to the first wavelength converter 4, the primary light 3 emitted from the light source 2 is irradiated to the front surface 7A of the second wavelength converter 7. Most of the irradiated primary light 3 enters the inside from the front face 7A of the second wavelength converting body 7, and the rest is reflected by the surface of the second wavelength converting body 7. In the second wavelength converter 7, the second phosphor 8 excited by the primary light 3 emits the second wavelength-converted light 11, and the second wavelength-converted light 11 is emitted from the front surface 7A. In this way, the primary light 3 is irradiated to the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time by rotating the fluorescent wheel 15, and therefore the light emitting device 1 can emit the first output light 12 and the second output light 13 alternately in time.

[ seventh embodiment ]

Next, a light-emitting device 1 according to a seventh embodiment will be described with reference to fig. 9. The same components as those in the above embodiments are denoted by the same reference numerals, and redundant description thereof is omitted.

As shown in fig. 9, in the light-emitting device 1 of the present embodiment, the primary light 3A is irradiated to the front surface 4A of the first wavelength converter 4, and the first wavelength-converted light 10 is emitted from the rear surface 4B of the first wavelength converter 4. The primary light 3B is irradiated to the front surface 7A of the second wavelength conversion body 7, and the second wavelength converted light 11 is emitted from the front surface 7A of the second wavelength conversion body 7. In these respects, the light-emitting device 1 of the present embodiment is different from the light-emitting device 1 of the first embodiment.

In the present embodiment, as shown in fig. 9, the light source 2 includes a first light source 2A and a second light source 2B. The first light source 2A emits primary light 3A and the second light source 2B emits primary light 3B. In the present embodiment, the optical axes of the primary light 3A exciting the first phosphor 5 and the primary light 3B exciting the second phosphor 8 are different, and the primary light 3A and the primary light 3B are emitted alternately in time.

Next, an operation of the light emitting device 1 of the present embodiment will be described. As shown in fig. 9, in the light emitting device 1 of the present embodiment, first, the primary light 3A emitted from the first light source 2A and the primary light 3B emitted from the second light source 2B are irradiated to the first wavelength conversion body 4 and the second wavelength conversion body 7 alternately in time. The primary light 3A is irradiated toward the front surface 4A of the first wavelength converting body 4, and most of the irradiated primary light 3A enters the inside from the front surface 4A of the first wavelength converting body 4, and the rest is reflected by the surface of the first wavelength converting body 4. When the primary light 3A passes through the first wavelength converter 4, the first phosphor 5 included in the first wavelength converter 4 absorbs a part of the primary light 3A and emits the first wavelength-converted light 10. The first wavelength-converted light 10 is emitted from the back surface 4B of the first wavelength converter 4. On the other hand, the primary light 3B is irradiated toward the front surface 7A of the second wavelength converting body 7, and most of the irradiated primary light 3B enters the inside from the front surface 7A of the second wavelength converting body 7, and the rest is reflected by the surface of the second wavelength converting body 7. In the second wavelength converter 7, the second phosphor 8 excited by the primary light 3 emits the second wavelength-converted light 11, and the second wavelength-converted light 11 is emitted from the front surface 7A. Thus, the first light source 2A and the second light source 2B repeat lighting and lighting-off temporally differently from each other, and therefore the light emitting device 1 can emit the first output light 12 and the second output light 13 temporally alternately.

In the light emitting device 1 of the present embodiment, the positions of the first wavelength conversion body 4 and the second wavelength conversion body 7 may be changed. That is, the primary light 3A may be irradiated to the front surface 4A of the first wavelength converter 4, and the first wavelength-converted light 10 is emitted from the front surface 4A of the first wavelength converter 4. The primary light 3B may be irradiated to the front surface 7A of the second wavelength converter 7, and the second wavelength converted light 11 may be emitted from the rear surface 7B of the second wavelength converter 7.

In the present embodiment, the first output light 12 and the second output light 13 can be emitted alternately in time by changing the positions of the first wavelength converter 4 and the second wavelength converter 7 with respect to the light source 2.

The light-emitting device 1 of the present embodiment has been described above with reference to the light-emitting devices of the first to seventh embodiments. The light emitting device 1 as described above can also be used for medical treatment. That is, the light-emitting device 1 may be a medical light-emitting device. In other words, the light-emitting device 1 may be a medical lighting device. Such a light-emitting device 1 can perform both normal observation and special observation as described above, and is advantageous for diagnosing a disease state.

The light emitting device 1 can also be used for Optical Coherence Tomography (OCT) and the like. However, the light-emitting device 1 is preferably used for any method in fluorescence imaging or photodynamic therapy. The light-emitting device 1 used in these methods is a light-emitting device for a medical system using a drug such as a fluorescent drug or a photosensitive drug. These methods are medical techniques expected to have wide applications and are highly practical. These light emitting devices 1 can sufficiently function a fluorescent drug or a photosensitive drug after introduction into a living body by irradiating the inside of the living body with a wide near-infrared high-output light through a "biological window", and thus can expect a large therapeutic effect.

The fluorescence imaging method is a method described below: a fluorescent drug that selectively binds to a lesion such as a tumor is administered to a subject, and then the fluorescent drug is excited by specific light, and fluorescence emitted from the fluorescent drug is detected and imaged by an image sensor, thereby observing the lesion. According to the fluorescence imaging method, a lesion which is difficult to observe can be observed only with normal illumination. As the fluorescent agent, an agent that absorbs excitation light in the near infrared region and further emits fluorescence having a longer wavelength than the excitation light and in the near infrared region can be used. As the fluorescent agent, for example, at least one selected from indocyanine green (ICG), phthalocyanine-based compounds, talaporfin sodium-based compounds, and lutidine cyanine (DIPCY) -based compounds can be used.

Photodynamic therapy is a treatment as follows: after a photosensitive drug that selectively binds to a target living tissue is applied to a subject, the photosensitive drug is irradiated with near infrared rays. When the photosensitive agent is irradiated with near infrared rays, active oxygen is generated from the photosensitive agent, and thus, a lesion such as a tumor or an infection can be treated. As the photosensitive agent, at least one selected from the group consisting of phthalocyanine-based compounds, talaporfin-based compounds, and porfimer-sodium-based compounds can be used, for example.

The light emitting device 1 of the present embodiment may be a light source for a sensing system or an illumination system for a sensing system. In the light emitting device 1, a high-sensitivity sensing system can be configured using a conventional light receiving element having light receiving sensitivity in the near-infrared wavelength region. Therefore, a light emitting device in which the size of the sensing system can be reduced and the sensing range can be expanded easily can be obtained.

[ medical System ]

Next, a medical system including the light emitting device 1 will be described. Specifically, as an example of the medical system, an endoscope 20 including the light-emitting device 1 and an endoscope system 100 using the endoscope 20 will be described with reference to fig. 10 and 11.

(endoscope)

As shown in fig. 10, the endoscope 20 of the present embodiment includes the light emitting device 1 described above. The endoscope 20 includes a scope 110, a light source connector 111, a mounting adapter 112, a relay lens 113, a camera 114, and an operation switch 115.

The mirror 110 is an elongated light guide member that guides light from the distal end to the distal end, and is inserted into the body when used. The mirror 110 has an imaging window 110z at the tip, and an optical material such as optical glass or optical plastic is used for the imaging window 110 z. The mirror 110 has an optical fiber for guiding the light introduced by the light source connector 111 to the front end and an optical fiber for transmitting the optical image incident from the imaging window 110 z.

The light source connector 111 introduces illumination light from the light emitting device 1 to be irradiated to an affected part or the like in the body. In the present embodiment, the illumination light includes visible light and near-infrared light. The light introduced into the light source connector 111 is guided to the distal end of the mirror 110 via an optical fiber, and is irradiated to a diseased part in the body through the imaging window 110 z. As shown in fig. 10, a transmission cable 111z for guiding illumination light from the light emitting device 1 to the mirror 110 is connected to the light source connector 111. The transmission cable 111z may also include optical fibers.

The mounting adapter 112 is a member for mounting the mirror 110 to the camera 114. Various mirrors 110 are detachably attached to the attachment adapter 112.

The relay lens 113 focuses an optical image transmitted through the mirror 110 on an image forming surface of the image sensor. The relay lens 113 can perform focus adjustment and magnification adjustment by moving the lens in accordance with the operation amount of the operation switch 115.

The camera 114 has a dichroic prism inside. The dichroic prism splits the light condensed by the relay lens 113 into four colors of R light (red light), G light (green light), B light (blue light), and IR light (near-infrared light). The dichroic prism is made of a light-transmitting member such as glass.

Further, the camera 114 has an image sensor as a detector therein. The image sensors are four, for example, and the four image sensors convert optical images formed on the respective imaging surfaces into electric signals. The image sensor is not particularly limited, and at least one of a CCD (Charge Coupled Device) and a CMOS (complementary metal Oxide Semiconductor) may be used. The four image sensors are dedicated sensors that receive light of an IR component (near-infrared component), an R component (red component), a G component (green component), and a B component (blue component), respectively.

The camera 114 may have a color filter inside instead of the dichroic prism. The image sensor includes a color filter on an image forming surface. The four color filters receive the light condensed by the relay lens 113 and selectively transmit R light (red light), G light (green light), B light (blue light), and IR light (near-infrared light), respectively.

The color filter that selectively transmits IR light preferably includes a barrier film that blocks a reflective component of near infrared light (IR light) included in illumination light. Thus, for example, only fluorescence including IR light emitted from a fluorescent drug such as ICG is imaged on the imaging surface of the IR light image sensor. Therefore, the affected part that emits light by the fluorescent agent can be easily and clearly observed.

As shown in fig. 10, the camera 114 is connected to a signal cable 114z for transmitting an electric signal from the image sensor to a CCU21 described later.

In the endoscope 20 configured as described above, light from the subject passes through the mirror 110, is guided to the relay lens 113, and further passes through the dichroic prism in the camera 114, and forms an image on the four image sensors.

(endoscope system)

As shown in fig. 11, the endoscope system 100 includes an endoscope 20 for imaging the inside of a subject, a CCU (Camera Control Unit)12, and a display device 22 such as a display.

The CCU21 includes at least an RGB signal processing unit, an IR signal processing unit, and an output unit. The CCU21 executes programs stored in an internal or external memory of the CCU21 to realize the functions of the RGB signal processing unit, the IR signal processing unit, and the output unit.

The RGB signal processing unit converts the electrical signals of the R component, G component, and B component from the image sensor into video signals that can be displayed on the display device 22, and outputs the video signals to the output unit. The IR signal processing unit converts the electrical signal of the IR component from the image sensor into a video signal and outputs the video signal to the output unit.

The output unit outputs at least one of the video signal of each color component of RGB and the video signal of IR component to the display device 22. For example, the output unit outputs the video signal based on any one of the synchronous output mode and the superimposed output mode.

In the case of the synchronous output mode, the output section synchronously outputs the RGB image and the IR image through different screens. By the synchronous output mode, the RGB image and the IR image are compared on different screens, and the affected part can be observed. In the superimposed output mode, the output unit outputs a composite image in which the RGB image and the IR image are superimposed. By the superimposition output mode, for example, an affected part emitted by ICG is clearly observed in an RGB image.

The display device 22 displays an image of an object such as an affected part on a screen based on a video signal from the CCU 21. In the synchronous output mode, the display device 22 divides the screen into a plurality of sections, and displays the RGB image and the IR image in parallel on each screen. In the superimposed output mode, the display device 22 displays a composite image in which the RGB image and the IR image are superimposed on the 1 screen.

Next, the functions of the endoscope 20 and the endoscope system 100 according to the present embodiment will be described. In the case of observing a subject using the endoscope system 100, indocyanine green (ICG) as a fluorescent substance is first applied to the subject. Thus, ICG accumulates in lymph, tumor, or other sites (affected parts).

Then, the visible light and the near infrared light are introduced from the light emitting device 1 into the light source connector 111 through the transmission cable 111 z. The light introduced into the light source connector 111 is guided to the distal end side of the mirror 110 and projected from the imaging window 110z, thereby irradiating the affected part and the periphery of the affected part. The light reflected by the affected part or the like and the fluorescence emitted from the ICG are guided to the rear end side of the mirror 110 through the imaging window 110z and the optical fiber, converged by the relay lens 113, and incident on the dichroic prism inside the camera 114.

In the dichroic prism, the light of the IR component decomposed by the IR decomposition prism among the incident light is imaged as an optical image of the infrared light component by the IR light image sensor. The light of the R component decomposed by the red dichroic prism is captured as an optical image of the red component by the R-light image sensor. The light of the G component split by the green dichroic prism is imaged by the G light image sensor as an optical image of the green component. The light of the B component decomposed by the blue dichroic prism is imaged by the B light image sensor as an optical image of the blue component.

The electrical signal of the IR component converted by the IR light image sensor is converted into a video signal by an IR signal processing unit inside the CCU 21. The R component, G component, and B component electrical signals converted by the RGB optical image sensor are converted into video signals by an RGB signal processing unit in the CCU 21. The IR component video signal and the R, G, and B component video signals are synchronously output to the display device 22.

In the case where the synchronous output mode is set inside the CCU21, the RGB image and the IR image are displayed on two screens in synchronization with each other with respect to the display device 22. When the superimposed output mode is set in the CCU21, a composite image in which an RGB image and an IR image are superimposed is displayed on the display device 22.

As described above, the endoscope 20 of the present embodiment includes the light emitting device 1. Therefore, by using the endoscope 20 to efficiently excite the fluorescent drug and emit light, the affected part can be clearly observed.

The endoscope 20 of the present embodiment preferably further includes a detector for detecting fluorescence emitted from the fluorescent drug that has absorbed the first wavelength converted light 10. The endoscope 20 is provided with a detector for detecting fluorescence emitted from the fluorescent drug in addition to the light emitting device 1, and thus can specify an affected part only with the endoscope. Therefore, it is not necessary to perform an abdominal opening and identify the affected part as much as in the conventional art, and therefore, examination and treatment with less burden on the patient can be performed. In addition, since the doctor using the endoscope 20 can accurately grasp the affected part, the treatment efficiency can be improved.

As mentioned above, the medical system is preferably used for any of fluorescence imaging or photodynamic therapy. The medical system used in these methods is a medical technique expected to have a wide range of applications and is highly practical. These medical systems can sufficiently function a fluorescent drug or a photosensitive drug after introduction into a living body by irradiating the inside of the living body with a wide near-infrared high-output light through a "biological window", and thus can expect a large therapeutic effect. In addition, since such a medical system uses the light emitting device 1 having a relatively simple configuration, it is advantageous to achieve miniaturization and low price.

[ electronic apparatus ]

Next, the electronic device of the present embodiment will be explained. The electronic device of the present embodiment includes a light-emitting device 1. As described above, the light-emitting device 1 can expect a large therapeutic effect, and can easily realize downsizing of a sensing system and the like. Since the electronic device of the present embodiment uses the light-emitting device 1, if it is used for medical equipment and sensing equipment, it is expected that a large therapeutic effect, miniaturization of a sensing system, and the like will be obtained.

The electronic device includes, for example, the light emitting device 1 and the light receiving element. The light receiving element is, for example, a sensor such as an infrared sensor that detects light in a near-infrared wavelength range. The electronic device may be any of an information identification apparatus, a discrimination apparatus, a detection apparatus, or a verification apparatus. These devices can also easily achieve downsizing of the sensing system and expansion of the sensing range as described above.

The information recognition device is, for example, a drive support system that detects a reflected component of the radiated infrared ray and recognizes a surrounding situation.

The discrimination device discriminates the predetermined object to be irradiated from each other by using the difference between the infrared light components of the irradiation light and the reflected light reflected by the object to be irradiated, for example.

The detection device is, for example, a device for detecting a liquid. Examples of the liquid include water and a flammable liquid that prohibits transportation by an aircraft or the like. Specifically, the detection device may be a device that detects moisture adhering to glass and moisture absorbed by an object such as sponge or fine powder. The detection means may visualize the detected liquid. In particular, the detection means may visualize the distribution information of the detected liquid.

The inspection device may be any of a medical inspection device, an agricultural or animal husbandry inspection device, a fishery inspection device, or an industrial inspection device. These apparatuses are useful for inspecting an object to be inspected in various industries.

The medical test device is a test device for testing the health status of a human or an animal other than a human, for example. The animal other than human is, for example, livestock. The medical examination device is used for biological examination such as fundus examination and blood oxygen saturation examination, and for examination of organs such as blood vessels and organs. The medical examination device may be a device for examining the inside of a living body or an apparatus for examining the outside of a living body.

The inspection device for agriculture and animal husbandry is, for example, a device for inspecting agricultural and animal products including agricultural products and animal products. The agricultural products may be products used as food, such as vegetables, fruits, and grains, or may be fuels such as oil. Livestock products are, for example, edible meat and dairy products. The agricultural or animal husbandry inspection device may be a device that non-destructively inspects the interior or exterior of agricultural or animal products. Examples of the agricultural and animal husbandry testing device include a device for testing the sugar content of vegetables and fruits, a device for testing the sour taste of vegetables and fruits, a device for testing the freshness of vegetables and fruits by visualizing veins and the like, a device for testing the quality of vegetables and fruits by visualizing scars and internal defects, a device for testing the quality of meat, and a device for testing the quality of processed foods processed from milk, meat and the like as raw materials.

The fishery inspection device is, for example, a device for inspecting meat quality of fish such as tuna, a device for inspecting the presence or absence of shellfish meat in shellfish shells, or the like.

The industrial inspection device is, for example, a foreign matter inspection device, an internal volume inspection device, a state inspection device, an inspection device for a structure, or the like.

The foreign matter inspection device is, for example, a device for inspecting a foreign matter in a liquid in a container in which a beverage, a liquid medicine, or the like is put, a device for inspecting a foreign matter in a packaging material, a device for inspecting a foreign matter in a printed image, a device for inspecting a foreign matter in a semiconductor or an electronic component, a device for inspecting a foreign matter such as a bone residue, garbage, or machine oil in food, a device for inspecting a foreign matter in processed food in a container, and a device for inspecting a foreign matter in medical equipment such as a plaster, or in medicines and quasi-medicines.

The internal content inspection device is, for example, a device for inspecting the internal content of a liquid in a container in which a beverage, a liquid medicine, or the like is put, a device for inspecting the internal content of a processed food put in a container, a device for inspecting the content of asbestos in a building material, or the like.

The state inspecting device is, for example, a device for inspecting a packaged state of a packaging material, a device for inspecting a printed state of a packaging material, or the like.

The inspection device for a structure is, for example, an internal nondestructive inspection device and an external nondestructive inspection device for a composite member or a composite part such as a resin product. As a specific example of a resin product or the like, for example, a metal brush in which a part of a metal wire is embedded in a resin is used, and the bonding state between the resin and the metal can be inspected by an inspection device.

The electronic device may utilize color night vision technology. The color night vision technology is a technology for colorizing an image by assigning RGB signals to each wavelength of infrared rays using a correlation between the reflection intensity of visible light and infrared rays. According to the color night vision technology, a color image can be obtained only by infrared rays, and therefore, the color night vision technology is particularly suitable for crime prevention devices and the like.

As described above, the electronic device includes the light-emitting device 1. The light emitting device 10 may include the power source, the light source 2, the first wavelength converter 4, and the second wavelength converter 7, but it is not necessary to store all of them in one housing. Therefore, the electronic device of the present embodiment can provide a compact inspection method with high accuracy and excellent operability.

[ test method ]

Next, the inspection method of the present embodiment will be explained. As described above, the electronic apparatus provided with the light-emitting device 1 can be used as a checking device. That is, the inspection method of the present embodiment can use the light emitting device 1. Thus, a compact inspection method with high accuracy and excellent operability can be provided.

Examples

The light-emitting device of the present embodiment will be described in further detail below with reference to examples, but the present embodiment is not limited thereto.

[ preparation of phosphor ]

(first phosphor)

The first phosphor was synthesized using a preparation method using a solid-phase reaction. Cr used for first phosphor³⁺The activated phosphor is composed of (Gd)_0.75La_0.25)₃(Ga_0.97Cr_0.03)₂Ga₃O₁₂An oxide phosphor represented by the composition formula (1). The following compound powders were used as main raw materials for synthesizing the first phosphor.

Gadolinium oxide (Gd)₂O₃): purity of 3N, Wako pure chemical industries, Ltd

Lanthanum oxide (La)₂O₃): purity of 3N, Wako pure chemical industries, Ltd

Gallium oxide (Ga)₂O₃): purity of 4N, Wako pure chemical industries, Ltd

Chromium oxide (Cr)₂O₃): purity of 3N, high purity chemical institute of Kabushiki Kaisha

First, a compound (Gd) having a stoichiometric composition_0.75La_0.25)₃(Ga_0.97Cr_0.03)₂Ga₃O₁₂The above raw materials were weighed. Subsequently, the weighed raw materials were put into a beaker containing pure water, and stirred for 1 hour using a magnetic stirrer. This gave a slurry-like mixed raw material comprising pure water and the raw material. Thereafter, the slurry-like mixed raw material was dried in its entirety by using a dryer. Then, the dried mixed raw material was pulverized using a mortar and a pestle to obtain a fired raw material.

The above-mentioned raw material for firing was transferred to a small alumina crucible and fired in an atmosphere of 1400 to 1500 ℃ for 1 hour by a box-type electric furnace to obtain the phosphor of this example. The temperature increase/decrease rate was set to 400 ℃/hr. The color of the phosphor obtained was pale green.

(second phosphor)

A commercially available YAG phosphor (Y) was obtained₃Al₂Al₃O₁₂:Ce³⁺) And acts as a second phosphor. In addition, the chemical composition of the YAG phosphor is estimated to be (Y) in consideration of the fluorescence peak wavelength and the like_0.97Ce_0.03)₃Al₂Al₃O₁₂。

[ evaluation ]

(analysis of Crystal Structure)

The crystal structures of the first phosphor and the second phosphor were evaluated by using an X-ray diffraction apparatus (X' PertPRO; manufactured by PANALYTICAL CORPORATION, Seikagaku corporation).

Details are omitted, but the results of the evaluation are known: the first phosphor and the second phosphor are mainly composed of a compound having a garnet crystal structure. Namely, it can be seen that: the first phosphor and the second phosphor are both garnet phosphors.

(fluorescence Spectroscopy)

Next, a wavelength converter including the first phosphor and the second phosphor was prepared and the fluorescence characteristics were evaluated. Specifically, the first phosphor was fired in an atmosphere of 1450 ℃ for 1 hour from the above-mentioned firing raw material which was molded into a pellet form by a manual press, thereby obtaining a wavelength conversion body. The second phosphor is fired in a reducing atmosphere at 1600 to 1700 ℃ for 1 to 6 hours in the form of pellets molded by a manual press, thereby obtaining a wavelength converter. Next, the obtained wavelength conversion body was excited with a laser beam, and the fluorescence spectrum of the fluorescence emitted from the wavelength conversion body at this time was evaluated. In this case, the center wavelength of the laser light was set to 445 nm. The energy of the laser was set to 3.87W.

Fig. 12 shows a fluorescence spectrum of the first phosphor. The fluorescence spectrum of the first phosphor can be regarded as being formed by Cr³⁺A broad spectrum is formed due to the d-d transition of (2). The first phosphor has a fluorescence spectrum having a light component in the entire wavelength range of 700nm to 800 nm. The first phosphor has a fluorescence spectrum having a peak whose intensity exhibits a maximum value in a wavelength region of 700nm or more. Specifically, the peak wavelength of the fluorescence spectrum of the first phosphor was 768 nm.

Fig. 13 shows a fluorescence spectrum of the second phosphor. The fluorescence spectrum of the second phosphor is visualized as being composed of Ce³⁺5d of¹→4f¹Wide spectrum formation due to transition. The second phosphor has a peak whose fluorescence intensity exhibits a maximum value in a wavelength range of 380nm or more and less than 700 nm. Specifically, the peak wavelength of the fluorescence spectrum of the second phosphor was 570 nm.

For example, a phosphor wheel coated with a first phosphor and a second phosphor is prepared, and these phosphors are excited with laser light while the phosphor wheel is rotated. Thus, from the above results, it is considered that: a light-emitting device that alternately outputs near-infrared light emitted by the first phosphor and visible light emitted by the second phosphor in terms of time can be realized.

The entire contents of Japanese patent application No. 2019-082915 (application date: 2019, 4 and 24) are incorporated herein by reference.

While the present embodiment has been described with reference to the examples, it will be apparent to those skilled in the art that the present embodiment is not limited to these descriptions, and various modifications and improvements can be made.

Industrial applicability

According to the present application, a light-emitting device that emits near-infrared light and visible light so as to obtain a high-contrast observation result, and a medical system, an electronic apparatus, and a test method using the light-emitting device can be provided.

Description of the symbols

1 light emitting device

2 light source

3 primary light

4 first wavelength converter

5 first phosphor

7 second wavelength converter

8 second phosphor

10 first wavelength converted light

11 second wavelength converted light

12 first output light

13 second output light