CN115004075A

CN115004075A - Light source device

Info

Publication number: CN115004075A
Application number: CN202080094206.9A
Authority: CN
Inventors: 三浦雄一
Original assignee: Ushio Denki KK
Current assignee: Ushio Denki KK
Priority date: 2020-01-24
Filing date: 2020-12-15
Publication date: 2022-09-02
Anticipated expiration: 2040-12-15
Also published as: JP2021118086A; JP7384050B2; CN115004075B; WO2021149408A1

Abstract

Provided is a light source device capable of generating light that exhibits a broad-band spectrum and reduces the proportion of light having high coherence. The light source device includes: a semiconductor laser that emits first light having a main emission wavelength belonging to a first wavelength band; a phosphor that, when the first light enters the phosphor, converts the first light into second light having a main emission wavelength in a second wavelength band different from the first wavelength band and emits the second light; a first dichroic mirror that substantially transmits one of the incident first light and second light and substantially reflects the other; an LED emitting third light having a main emission wavelength in a first wavelength band; and a second dichroic mirror that receives the second light transmitted or reflected by the first dichroic mirror and the third light emitted from the LED, and that substantially transmits one of the second light and the third light and substantially reflects the other.

Description

Light source device

Technical Field

The present invention relates to a light source device, and more particularly, to a light source device including a wavelength conversion member.

Background

A fluorescence microscope is a device for observing a sample by generating fluorescence by incident light to the sample to be observed and using the intensity of the fluorescence. Since the absorption characteristics of light vary depending on the sample, light having a wide wavelength band is required to cope with a plurality of types of samples. From this viewpoint, conventionally, discharge lamps such as short-arc type ultrahigh pressure mercury lamps, metal halide lamps, and xenon lamps have been used.

In contrast, in recent years, from the viewpoints of energy saving, downsizing of devices, long life of light sources, and the like, studies have been made on using a solid-state light-emitting element as a light source for a fluorescence microscope.

In order to generate light of a wide wavelength band using the solid-state light-emitting devices, in principle, a method of preparing LEDs emitting red light, green light, and blue light and combining light emitted from the solid-state light-emitting devices may be considered. However, at present, there is no LED that can emit light with a wavelength of 500nm to 560nm inclusive (green wavelength band) with high brightness. Therefore, it is practically difficult to realize a light source for a fluorescence microscope using only LEDs having different emission wavelengths.

In view of such circumstances, a light source device is proposed which: instead of an LED that emits light in the green wavelength band, for example, an excitation light source such as a semiconductor laser that emits light in the blue wavelength band and a phosphor that receives excitation light emitted from the excitation light source and emits fluorescence in a wavelength band of 450nm to 650nm (see patent document 1 below).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-40914

Disclosure of Invention

Problems to be solved by the invention

However, according to the intensive studies of the present inventors, it was confirmed that: when a part of laser light, which is excitation light emitted from a semiconductor laser, is irradiated onto an observation sample, speckle noise is generated in an observation image, and image quality is deteriorated. This is because the laser light emitted from the semiconductor laser has extremely high coherence compared to the LED light.

In view of the above problems, an object of the present invention is to provide a light source device capable of generating light that exhibits a broad-band spectrum and reduces the proportion of light having high coherence.

Means for solving the problems

The light source device of the present invention is characterized by comprising:

a semiconductor laser that emits first light having a main emission wavelength belonging to a first wavelength band;

a phosphor that, when the first light enters the phosphor, converts the first light into second light having a main emission wavelength in a second wavelength band different from the first wavelength band and emits the second light;

a first dichroic mirror that receives the first light and the second light, substantially transmits one of the first light and the second light, and substantially reflects the other of the first light and the second light;

an LED emitting third light having a main emission wavelength in the first wavelength band; and

and a second dichroic mirror that receives the second light transmitted or reflected by the first dichroic mirror and the third light emitted from the LED, and that substantially transmits one of the second light and the third light and substantially reflects the other.

In the present specification, the term "main emission wavelength" refers to a wavelength region where the intensity of the maximum peak is 1/2 or more.

In the present specification, the phrase "substantially transmitting light" such as an optical filter or a dichroic mirror means that the intensity of the transmitted light is 90% or more of the intensity of the incident light. In the present specification, the term "substantially reflect light" with respect to a filter, a dichroic mirror, or the like means that the intensity of the reflected light is 90% or more of the intensity of the incident light.

According to the above configuration, the second light emitted from the phosphor having the main emission wavelength belonging to the second wavelength band and the third light emitted from the LED having the main emission wavelength belonging to the first wavelength band are emitted from the light source device while being overlapped with each other. Since the second light is fluorescence emitted from the phosphor, the wavelength band is wider than the wavelength band of the first light emitted from the semiconductor laser. Then, the second light is superimposed on the third light from the LED belonging to the first wavelength band, whereby the emitted light is in an extremely wide wavelength band.

The first light from the semiconductor laser is guided to the fluorescent body via the first dichroic mirror. Of the second light having a main emission wavelength belonging to the second wavelength band generated by the phosphor and the first light having a main emission wavelength belonging to the first wavelength band emitted from the semiconductor laser, the traveling direction after the light enters the first dichroic mirror changes. That is, the first dichroic mirror is configured to substantially reflect the first light and substantially transmit the second light, or to substantially transmit the first light and substantially reflect the second light.

Here, the first light from the semiconductor laser, which is incident to generate the second light, is highly coherent light as described above in the section "problem to be solved by the invention". The first dichroic mirror is interposed, so that the first light is substantially not introduced into the optical system of the subsequent stage, which is a region where the third light is incident. However, it is practically difficult for the first dichroic mirror to prevent the first light from being introduced into the subsequent stage by 100%. In other words, the first light of about several percent travels in the same direction as the second light even after passing through the first dichroic mirror.

However, according to the above configuration, the second dichroic mirror is disposed at the subsequent stage in the traveling direction of the second light. The second dichroic mirror is configured to substantially reflect third light having a main emission wavelength belonging to the first wavelength band, which is the same as the first light, and substantially transmit the second light, or to substantially transmit the third light and substantially reflect the second light. Therefore, when the first light superimposed on the very small portion of the second light travels in the same direction as the second light and enters the second dichroic mirror, the very small portion of the first light travels almost in a direction different from the second light.

For example, if the first dichroic mirror and the second dichroic mirror are both configured to reflect 95% of light whose main emission wavelength belongs to the first wavelength band, the first light passing through the dichroic mirror is not more than about 0.03% at most. As a result, the ratio of the first light having high coherence to the observation sample is greatly reduced as compared with the case where the second dichroic mirror is not present. Further, since the third light having the main emission wavelength belonging to the first wavelength band is emitted from the LED, even if the third light is superimposed on the second light, the third light has sufficiently low coherence, and the speckle noise can be reduced.

The light source device may further include an optical component that is disposed between the first dichroic mirror and the second dichroic mirror and selectively transmits the second light of the first light and the second light,

the second dichroic mirror is to be incident with the second light transmitted in the optical component after being transmitted or reflected in the first dichroic mirror.

According to this configuration, the amount of the first light introduced into the second dichroic mirror can be further reduced by the optical member. This further improves the effect of reducing speckle noise.

The optical member may be configured by an optical filter that can substantially transmit the second light of the first light and the second light.

In addition, the optical component may be a third dichroic mirror that substantially transmits the second light of the first light and the second light and substantially reflects the first light.

In this case, the light source device may include a light shielding portion on which the first light reflected by the third dichroic mirror is incident.

With this configuration, it is possible to suppress a very small amount of the first light reflected by the third dichroic mirror from being reflected by the housing or the like of the light source device and guided to the optical system at the subsequent stage. The light shielding portion may be, for example, a light absorber in which a part of a wall surface of the housing is black. In addition, as another example of the light shielding portion, the following configuration may be adopted: a surface on which the first light reflected by the third dichroic mirror is incident is set as a diffusion surface, and the case is subjected to embossing so that the diffusely reflected light is incident on the inner wall of the case.

In addition, similarly, the light source device may include a light shielding portion on which the first light reflected by the second dichroic mirror is incident.

The first wavelength range may be 430nm to 480 nm. In this case, the second wavelength band may be 500nm or more and 550nm or less.

The light source device may include: a condensing optical system that condenses light in which the second light and the third light are superimposed; and an optical fiber through which the light condensed by the condensing optical system is incident.

According to this configuration, light in a state in which the second light and the third light are superimposed and substantially no light is derived from the first light having high coherence enters the optical fiber through the condensing optical system. By irradiating the observation sample with the light through the optical fiber, an observation image with greatly reduced speckle noise can be obtained.

Effects of the invention

According to the light source device of the present invention, it is possible to generate light that exhibits a spectrum in a wide band and reduces the proportion of light having high coherence.

Drawings

Fig. 1 is a diagram schematically showing a configuration of an embodiment of a light source device.

Fig. 2 is a diagram schematically showing the configuration of an optical system module of the first embodiment.

Fig. 3 is a diagram showing an example of a spectrum of light obtained by overlapping first light emitted from a semiconductor laser and second light generated by a phosphor.

Fig. 4 is a diagram showing a spectrum of light obtained after light including the second light passes through the first dichroic mirror.

Fig. 5 is a diagram illustrating a state in which the first light having passed through the first dichroic mirror travels, added to the diagram illustrated in fig. 2.

Fig. 6 is a diagram showing an example of the spectral transmittances of the first dichroic mirror and the second dichroic mirror designed under the same conditions.

Fig. 7 is a diagram showing a spectrum of light passing through the second dichroic mirror in a state where the LED is turned off in the optical system module shown in fig. 2 and 5.

Fig. 8 is a diagram showing a spectrum of light passing through the second dichroic mirror in a state where the LED is turned on in the optical system module shown in fig. 2 and 5.

Fig. 9 is another drawing schematically showing the configuration of the optical system module of the first embodiment.

Fig. 10A is a perspective view schematically showing an example of the light shielding portion.

Fig. 10B is a perspective view schematically showing an example of the light shielding portion.

Fig. 11 is a diagram schematically showing the configuration of an optical system module according to a second embodiment.

Fig. 12 is a diagram schematically showing the structure of an optical system module according to a third embodiment.

Fig. 13 is a diagram schematically showing the structure of an optical system module according to another embodiment.

Fig. 14 is a diagram schematically showing the structure of an optical system module according to another embodiment.

Fig. 15 is a diagram showing an example of the spectral transmittance of the dichroic mirror provided in the optical system module shown in fig. 14.

Fig. 16 is a diagram showing a spectrum of light passing through the dichroic mirror 41a in a state where the LEDs (16, 41) are turned on in the optical system module shown in fig. 15.

Fig. 17 is a diagram schematically showing the structure of an optical system module according to another embodiment.

Fig. 18 is a diagram schematically showing the structure of an optical system module according to another embodiment.

Fig. 19 is a diagram schematically showing the structure of an optical system module according to another embodiment.

Detailed Description

Hereinafter, embodiments of the light source device according to the present invention will be described with reference to the drawings. Note that the drawings described below are schematic drawings, and the dimensional ratio in the drawings does not necessarily match the actual dimensional ratio. In addition, the dimensional ratio is not necessarily uniform between the drawings.

[ first embodiment ]

Fig. 1 is a diagram schematically showing a configuration of a light source device for a fluorescence microscope according to an embodiment of the present invention. The light source device 1 includes an optical system module 3 and an optical fiber 4 disposed in a housing 2. The light L0 having a wide wavelength band generated by the optical system module 3 is converged and incident on the optical fiber 4 via the condensing optical system 5. The light L0 is propagated through the optical fiber 4 and then enters a subsequent optical system not shown. The light is irradiated as excitation light to a sample to be observed, and a fluorescence image is generated.

As described later, the optical system module 3 generates the light L0 having a broad band and low coherence.

Fig. 2 is a diagram schematically showing the configuration of the optical system module 3. The optical system module 3 includes a semiconductor laser 11, a fluorescent material 15, an LED16, a first dichroic mirror 21, and a second dichroic mirror 22.

In the present embodiment, the semiconductor laser 11 is an element that emits blue light (hereinafter referred to as "first light L1") having a main emission wavelength in a range of 430nm to 480nm (corresponding to the "first wavelength band"), for example. As such a semiconductor laser 11, a laser having an active layer made of a nitride semiconductor such as GaN or InGaN can be used.

In the present embodiment, the phosphor 15 is composed of: when the first light L1 emitted from the semiconductor laser 11 is incident, it is excited, and emits fluorescence (hereinafter, referred to as "second light L2") having a main emission wavelength of, for example, 450nm to 650nm (corresponding to "second wavelength band").

Fig. 3 is a diagram showing an example of a spectrum of light in which the first light L1 enters the fluorescent body 15 from the semiconductor laser 11 and the second light L2 and the first light L1 emitted from the fluorescent body 15 overlap each other. Actually, a part of the first light L1 emitted from the semiconductor laser 11 is reflected by the fluorescent material 15. Therefore, light is emitted from the fluorescent material 15, which is obtained by overlapping the second light L2 generated by the fluorescent material 15 and the first light L1 as reflected light. Fig. 3 illustrates an example of the spectrum of light obtained by overlapping the first light L1 and the second light L2 in this way.

The structure of the phosphor 15 is not limited. For example, the phosphor 15 may be made of a phosphor crystal, or may be made by binding powder of a phosphor crystal with a binder. As the fluorescent crystal, Ce-doped: LuAG of rare earth elements such as LuAG (Lu3Al5O12), Ce-doped: YAG (Y3Al5O12) or the like. In these fluorescent crystals, the doping amount of the rare earth element is, for example, about 0.5 mol%.

When the phosphor 15 is formed by binding the fluorescent crystal powder with a binder, the average particle diameter of the fluorescent crystal powder is, for example, 1 μm or more and 60 μm or less. The ratio of the fluorescent crystal powder in the phosphor 15 is, for example, 30 vol% or more and 70 vol% or less. As the binder, an inorganic binder such as glass or an organic binder such as silicone resin can be used.

As shown in fig. 2, the first light L1 emitted from the semiconductor laser 11 is converted into parallel light by a collimator lens 12 provided as necessary and then enters the first dichroic mirror 21. In the present embodiment, the first dichroic mirror 21 is designed to substantially reflect the first light L1 and substantially transmit the second light L2. In the example of the present embodiment, the first dichroic mirror 21 reflects 95% or more of light having a wavelength of 440nm to 470nm inclusive and transmits 95% or more of light having a wavelength of 500nm to 550nm inclusive, for example, when the light is incident at 45 °. Such a first dichroic mirror 21 is formed by alternately laminating dielectric films having a high refractive index and dielectric films having a low refractive index on the upper surface of a glass substrate, for example.

As described above, since the first dichroic mirror 21 is designed to substantially reflect the first light L1, the first light L1 emitted from the semiconductor laser 11 is reflected by the first dichroic mirror 21 and travels toward the arrangement portion of the fluorescent material 15 when entering the first dichroic mirror 21. The optical system module 3 includes a condensing optical system 13 as necessary. The light collecting optical system 13 collects the first light L1 reflected by the first dichroic mirror 21 toward the fluorescent material 15 and emits it. This causes the phosphor 15 to be incident with the first light L1 having high luminance.

As described above, when the first light L1 enters the phosphor 15, the phosphor is excited to generate the second light L2. The second light L2 enters the first dichroic mirror 21 after passing through the condensing optical system 13 again. Since the first dichroic mirror 21 is designed to substantially transmit the second light L2, the second light L2 emitted from the fluorescent material 15 is transmitted as it is in the first dichroic mirror 21 and travels toward the second dichroic mirror 22 of the subsequent stage.

Further, a part of the first light L1 incident on the phosphor 15 is reflected by the phosphor 15 and travels toward the condensing optical system 13. This reflected light is referred to as "first light L1 a". In fig. 2, for convenience of illustration, a line indicating the first light L1 traveling toward the phosphor 15 and a line indicating the first light L1a reflected by the phosphor 15 are indicated to be shifted from each other. The same applies to the following drawings.

The first light L1a passes through the condensing optical system 13 in a state of overlapping with the second light L2, and then enters the first dichroic mirror 21. However, as described above, the first dichroic mirror 21 is designed to substantially reflect the wavelength region of the first light L1, that is, the wavelength region of the first light L1 a. Therefore, most of the first light L1a reflected by the fluorescent material 15 is reflected by the first dichroic mirror 21 (first light L1b), and hardly travels toward the second dichroic mirror 22 of the subsequent stage.

However, according to the intensive studies of the present inventors, it was confirmed that: according to the structure of the first dichroic mirror 21, the first light L1a reflected by the fluorescent material 15 also has a light passing through the first dichroic mirror 21 to some extent. Fig. 4 is a diagram showing a spectrum of light obtained after light including the second light L2 shown in the spectrum of fig. 3 passes through the first dichroic mirror 21. Therefore, the following steps are carried out: although the intensity of the first light L1 was confirmed to be greatly reduced compared to fig. 3, the intensity of light derived from the first light L1 still appeared. That is, in the first light L1a that is reflected by the fluorescent material 15 and then directed toward the first dichroic mirror 21, there is a part of the light that travels through the first dichroic mirror 21 in addition to the first light L1b reflected by the first dichroic mirror 21 (first light L1 c; refer to fig. 5). Fig. 5 is a diagram illustrating a state in which the first light L1c having passed through the first dichroic mirror 21 travels in addition to the diagram illustrated in fig. 2. On the drawing, the first light L1c is illustrated with a line width thinner than that of the first light (L1, L1a, L1b), which is intended to mean that the light intensity of the first light L1c is extremely small compared to other lights.

The optical system module 3 of the present embodiment includes a second dichroic mirror 22 at a stage subsequent to the first dichroic mirror 21. In the present embodiment, light emitted from the LED16 (hereinafter referred to as "third light L3") is incident on the dichroic mirror 22.

The LED16 is an element that emits blue light having a main emission wavelength in a range of 430nm to 480nm (corresponding to the "first wavelength band"), for example, as in the case of the semiconductor laser 11. As such an LED16, an LED having an active layer made of a nitride semiconductor such as GaN or InGaN can be used. In the present embodiment, the second dichroic mirror 22 is designed to substantially transmit the second light L2 and substantially reflect the third light L3.

Note that the configuration may be such that the main emission wavelength of the first light L1 emitted from the semiconductor laser 11 and the main emission wavelength of the third light L3 emitted from the LED16 both belong to the first wavelength band. This means that the main peak wavelength of the first light L1 and the main peak wavelength of the third light L3 are not necessarily the same.

The second dichroic mirror 22 may be configured to substantially reflect light belonging to the first wavelength band and substantially transmit light belonging to the second wavelength band, as in the first dichroic mirror 21. That is, the second dichroic mirror 22 may be designed to have the same reflection/transmission condition as the first dichroic mirror 21, or may be designed to have a reflection/transmission condition different from that.

Fig. 6 is a diagram showing an example of the spectral transmittance of the first dichroic mirror 21 and the second dichroic mirror 22 designed under the same conditions. Dichroic mirrors (21, 22) exhibiting the characteristics shown in FIG. 6 substantially transmit light having a wavelength of 500nm to 550nm, while substantially reflecting light having a wavelength in the range of 430nm to 480 nm. In fig. 6, it is understood that light having a wavelength in the range of 430nm to 480nm has a transmittance of about 5% and light that has not been transmitted is substantially reflected, and thus the light in the above-described wavelength region is substantially reflected.

As shown in fig. 2 and 5, the third light L3 emitted from the LED16 is converted into parallel light by a collimator lens 17 provided as necessary, and then enters the second dichroic mirror 22. Then, the third light L3 is substantially reflected by the second dichroic mirror 22 and travels in the direction of the subsequent condensing optical system 5 and the optical fiber 4 (see fig. 1). The second light L2 that travels through the first dichroic mirror 21 substantially transmits when entering the second dichroic mirror 22, and therefore travels in the same manner as the third light L3.

On the other hand, as described above, when the first light L1c of an extremely small amount of light transmitted through the first dichroic mirror 21 enters the second dichroic mirror 22, it is substantially reflected by the second dichroic mirror 22. As a result, since the light travels in a direction different from the second light L2 and the third light L3, the light does not travel in the direction of the subsequent condensing optical system 5 and the optical fiber 4.

When the first dichroic mirror 21 and the second dichroic mirror 22 are configured to transmit about 5% of the first light L1, the ratio of the first light L1 transmitted through the second dichroic mirror 22 remains at about 0.03%, and is substantially equal to zero. If the ratio of the first light L1 included in the total light L0 (see fig. 1) including the second light L2 and the third light L3 is of this degree, the total light L0 does not contribute to the occurrence of speckle noise even when the sample to be observed is irradiated with the light L0 via the optical fiber 4.

On the other hand, the third light L3 emitted from the LED16 has low coherence unlike the first light L1 emitted from the semiconductor laser 11. Therefore, even if the third light L3 is irradiated to the sample to be observed, it does not contribute to the occurrence of speckle noise.

Therefore, according to the above configuration, the light L0 having a wide wavelength band in which the second light L2 having the main emission wavelength belonging to the second wavelength band and the third light L3 having the main emission wavelength belonging to the first wavelength band are superimposed can be generated with the components having high coherence being almost completely removed. Thus, a light source for a fluorescence microscope capable of suppressing speckle noise more than ever before can be realized.

Fig. 7 is a diagram showing the spectrum of light passing through the second dichroic mirror 22 in a state where the LED16 is off in the optical system module 3 shown in fig. 2 and 5. As compared with fig. 4, it was confirmed that the light intensity from the first light L1 was greatly reduced. Fig. 8 is a diagram showing the spectrum of light passing through the second dichroic mirror 22 in the state where the LED16 is turned on in the optical system module 3 shown in fig. 2 and 5. It can be confirmed that: by overlapping the third light L3 with the second light L2, light of a wide wavelength band is obtained in a state where light derived from the first light L1 with high coherence is suppressed.

As shown in fig. 9, the light shielding unit 30 may be provided so that a very small amount of the first light L1c reflected by the second dichroic mirror 22 does not travel toward the optical system of the subsequent stage where the optical fiber 4 and the like are arranged. The light shielding portion 30 may be, for example, a light absorber in which a part of the wall surface of the housing 2 is black. In addition, as another example of the light shielding portion 30, the following configuration may be adopted: a part of the wall surface of the case 2 is made a diffusing surface, and the case 2 is subjected to embossing so that the light reflected diffusely enters the inner wall of the case 2.

Fig. 10A and 10B are perspective views schematically showing an example of the light shielding portion 30. Fig. 10A and 10B are different in the direction of observation, respectively. In the example shown in fig. 10A and 10B, a part of the wall surface of the case 2 is engraved toward the second dichroic mirror 22. Accordingly, even if the first light L1c reflected by the second dichroic mirror 22 is scattered and reflected by the wall surface 2a of the housing 2 after entering the wall surface 2a, it enters the wall surface of the housing 2 in the recess region constituting the light shielding portion 30, and therefore, it can be suppressed from traveling toward the optical system of the subsequent stage.

In the example shown in fig. 10A and 10B, a part of the case 2 is cut toward the second dichroic mirror 22, so that the distance between the end position of the second dichroic mirror 22 and the wall surface of the case 2 is close. Therefore, a part of the wall surface of the housing 2 functioning as the light shielding section 30 can also be used to hold the second dichroic mirror 22.

[ second embodiment ]

A second embodiment of the light source device of the present invention will be described mainly focusing on differences from the first embodiment. In the following embodiments, the same reference numerals are given to elements common to those of the first embodiment, and the description thereof will be omitted as appropriate.

Fig. 11 is a diagram schematically showing the structure of the optical system module 3 included in the light source device 1 of the present embodiment. In the present embodiment, the third dichroic mirror 23 is further provided, which is different from the first embodiment. The third dichroic mirror 23 corresponds to an "optical component".

The third dichroic mirror 23 is configured to substantially reflect light belonging to the first wavelength band and substantially transmit light belonging to the second wavelength band, similarly to the first dichroic mirror 21. That is, the third dichroic mirror 23 may be designed to have the same reflection/transmission condition as the first dichroic mirror 21, or may be designed to have a reflection/transmission condition different therefrom.

According to the optical system module 3 of the present embodiment, when the first light L1c of a very small amount of light transmitted through the first dichroic mirror 21 enters the third dichroic mirror 23, it is substantially reflected by the third dichroic mirror 23. As a result, since the light travels in a direction different from the second light L2, the light does not travel in the direction of the second dichroic mirror 22 at the subsequent stage.

Further, according to the configuration of the present embodiment, even if the first light L1c having an extremely small amount of light passes through the third dichroic mirror 23, it is substantially reflected by the second dichroic mirror 22 disposed at the subsequent stage, and the traveling direction changes with respect to the second light L2. As a result, according to the optical system module 3 of the present embodiment, it is possible to generate the light L0 in a wide wavelength band from which components having high coherence are removed, as compared with the configuration of the first embodiment.

The optical system module 3 shown in fig. 11 includes a light shielding unit 30 so that a very small amount of the first light L1c reflected by the third dichroic mirror 23 does not travel toward the second dichroic mirror 22. However, whether or not the optical system module 3 includes the light shielding portion 30 is arbitrary. Further, as in the first embodiment, the light shielding portion 30 may be provided so that a very small amount of the first light L1c reflected by the second dichroic mirror 22 does not travel toward the optical system of the subsequent stage where the condensing optical system 5, the optical fiber 4, and the like are arranged. The same applies to the following embodiments.

[ third embodiment ]

A third embodiment of the light source device of the present invention will be described mainly focusing on differences from the first embodiment.

Fig. 12 is a diagram schematically showing the structure of the optical system module 3 included in the light source device 1 of the present embodiment. The present embodiment is different from the first embodiment in that an optical filter 25 is further provided. The optical filter 25 corresponds to an "optical component".

The optical filter 25 is designed to substantially transmit light belonging to the second wavelength band, while not substantially transmitting light belonging to the first wavelength band. The optical filter 25 may substantially absorb or reflect the light belonging to the first wavelength band.

According to the optical system module 3 of the present embodiment, the first light L1c having an extremely small amount of light transmitted through the first dichroic mirror 21 is substantially not transmitted through the optical filter 25 when entering the optical filter 25, and therefore does not travel in the direction of the second dichroic mirror 22 at the subsequent stage. On the other hand, the second light L2 substantially transmits through the optical filter 25 and travels toward the second dichroic mirror 22.

In the configuration of the present embodiment, as in the second embodiment, even if the first light L1c having an extremely small amount of light passes through the optical filter 25, it is substantially reflected by the second dichroic mirror 22 disposed further to the rear stage, and the traveling direction changes with respect to the second light L2. As a result, according to the optical system module 3 of the present embodiment, it is possible to generate the light L0 in a wide wavelength band from which components having high coherence are removed, as compared with the configuration of the first embodiment.

Further, the light source device 1 according to the second embodiment may further include an optical filter 25 in addition to the third dichroic mirror 23.

[ other embodiments ]

Other embodiments of the light source device of the present invention will be described below. In the following drawings, for convenience of illustration, the first light L1a reflected by the phosphor 15 and the light (L1b, L1c, and the like) derived from the first light L1a may not be illustrated. The following other embodiments can be combined with the structures of the above embodiments as appropriate.

As shown in fig. 13, the semiconductor laser 11 and the LED16 may be disposed on the same side (on the + Z side in the drawing). In this case, the reflection surface of the first dichroic mirror 21 and the reflection surface of the second dichroic mirror 22 are not parallel to each other. With this configuration, the semiconductor laser 11 serving as a heat source and the LED16 are disposed on the same side, and therefore can be cooled by the same cooling surface.

As shown in fig. 14, the optical system module 3 may further include an LED41 that emits light L4 in a wavelength region different from that of the LED 16. The optical system module 3 shown in fig. 14 further includes an LED41 and a dichroic mirror 41a, compared to the first embodiment.

The dichroic mirror 41a is designed to substantially reflect the light L4 emitted from the LED41, and substantially transmit the second light L2 and the third light L3. For practical reasons, the light L4 emitted from the LED41 is light of a shorter wavelength band than the third light L3. That is, the dichroic mirror 41a is designed to transmit light of a shorter wavelength than the first dichroic mirror 21 and the second dichroic mirror 22. Fig. 15 is a diagram illustrating an example of the spectral transmittance of the dichroic mirror 41a, which is illustrated in accordance with fig. 6. Fig. 15 is a diagram showing an example of the spectral transmittances of the first dichroic mirror 21 and the second dichroic mirror 22 shown in fig. 6, superimposed on the diagram.

With this configuration, light in which light L4 having a shorter wavelength is superimposed can be generated as compared with the light source device 1 of each of the above embodiments, and therefore, light in a wider wavelength band can be generated. Fig. 16 is a diagram showing the spectrum of light transmitted through the dichroic mirror 41a in a state where the

LEDs

16 and 41 are turned on. This light does not include light derived from the first light L1 with high coherence, which is the same as described above.

The optical system module 3 may further include LEDs of other wavelength bands.

< 3 > in each of the above embodiments, the first dichroic mirror 21 substantially reflects the first light L1 and substantially transmits the second light L2. On the contrary, the first dichroic mirror 21 may substantially transmit the first light L1 and substantially reflect the second light L2. Fig. 17 is a view schematically showing the structure of the optical system module 3 included in the light source device 1 according to the other embodiment, with reference to fig. 5.

In the optical system module 3 of this embodiment, the first light L1 emitted from the semiconductor laser 11 is transmitted through the first dichroic mirror 21 and enters the fluorescent material 15. Second light L2 generated by phosphor 15 is reflected by first dichroic mirror 21 and guided to second dichroic mirror 22. In addition, almost all of the first light L1a reflected by the fluorescent material 15 is transmitted through the first dichroic mirror 21 and travels toward the semiconductor laser 11 (first light L1 b). However, the first light L1a of about several percent is reflected by the first dichroic mirror 21 (first light L1c) and guided to the second dichroic mirror 22.

Even in the configuration of the optical system module 3 shown in fig. 17, since the traveling direction of the first light L1c can be changed with respect to the second light L2 by the second dichroic mirror 22, it is possible to introduce light of a wide wavelength band in which almost all components having high coherence are removed into the optical system of the subsequent stage, as in the first embodiment.

< 4 > in the second embodiment (see fig. 11), the third dichroic mirror 23 substantially reflects the first light L1 and substantially transmits the second light L2. On the contrary, the third dichroic mirror 23 may substantially transmit the first light L1 and substantially reflect the second light L2. Fig. 18 is a view schematically showing the structure of the optical system module 3 included in the light source device 1 according to the other embodiment, with reference to fig. 11.

In the optical system module 3 of this embodiment, the second light L2 generated by the fluorescent material 15 is reflected by the third dichroic mirror 23 and guided to the second dichroic mirror 22. Further, almost all of the first light L1a reflected by the fluorescent material 15 is reflected by the first dichroic mirror 21 and travels toward the semiconductor laser 11 (first light L1b), but the first light L1a of about several percent is transmitted through the first dichroic mirror 21 (first light L1c) and introduced into the third dichroic mirror 23.

Since the first light L1c having the extremely small amount of light is substantially transmitted by the third dichroic mirror 23, the traveling direction is changed with respect to the second light L2 by the third dichroic mirror 23. As a result, the light from the third dichroic mirror 23 toward the second dichroic mirror 22 is substantially light derived from the second light L2. Further, by overlapping the third light L3 emitted from the LED16 with the second dichroic mirror 22, it is possible to introduce a wide-band light in a state where almost all the components having high coherence are removed into the optical system of the subsequent stage.

In the optical system module 3 shown in fig. 18, even if an extremely small amount of the first light L1c is reflected by the third dichroic mirror 23 and travels in the same direction as the second light L2, the first light L1c is reflected by the second dichroic mirror 22 arranged further on the rear stage. As a result, the first light L1c having a very small amount of light travels in a direction different from the traveling direction of the second light L2 and the third light L3, and is therefore not introduced into the optical system of the subsequent stage. Thereby, compared to the configuration of the first embodiment, the light L0 of the wide band from which the components having high coherence are further removed can be generated.

< 5 > in each of the above embodiments, the second dichroic mirror 22 substantially transmits the second light L2, while substantially reflects the third light L3. On the contrary, the second dichroic mirror 22 may substantially transmit the third light L3 and substantially reflect the second light L2. Fig. 19 is a view schematically showing the structure of the optical system module 3 included in the light source device 1 according to the other embodiment, with reference to fig. 2.

In this case, the third light L3 emitted from the LED16 passes through the second dichroic mirror 22 and travels. Further, the second light L2 emitted from the fluorescent material 15 and entering the second dichroic mirror 22 through the first dichroic mirror 21 is reflected by the second dichroic mirror 22 and overlaps the third light L3.

On the other hand, a very small amount of the first light L1c passing through the first dichroic mirror 21 substantially transmits and travels when entering the second dichroic mirror 22. As a result, as in the above-described embodiments, since the traveling direction of the first light L1c can be changed with respect to the second light L2, it is possible to introduce a wide-band light in which most of the components having high coherence are removed into the optical system of the subsequent stage.

The optical system module 3 of (6) may include a plurality of semiconductor lasers 11. Similarly, the optical system module 3 may include a plurality of LEDs 16.

The first light L1 emitted from the semiconductor laser 11 in (7) is not limited to blue light. The first light L1 may be any light that can excite the phosphor 15 and generate the second light L2 having a wavelength region different from that of the first light L1.

The light source device 1 including the optical system block 3 in (8) is not limited to the light source for the fluorescence microscope. The light source device 1 of the present invention can be used for various applications assuming that light having a broad band and low coherence is used. Whether or not the light source device 1 includes the optical fiber 4 and the condensing optical system 5 is arbitrary.

Description of the reference numerals

1: light source device

2: shell body

2 a: wall surface

3: optical system module

4: optical fiber

5: light-condensing optical system

11: semiconductor laser device

12: collimating lens

13: light-condensing optical system

15: phosphor

16：LED

17: collimating lens

21: first dichroic mirror

22: second dichroic mirror

23: third dichroic mirror

25: optical filter

30: light shielding part

41：LED

41 a: dichroic mirror

L0: light (es)

L1(L1a, L1b, L1 c): first light

L2: the second light

L3: third light

L4: light (es)

Claims

1. A light source device is characterized by comprising:

a phosphor that converts the first light into second light having a main emission wavelength in a second wavelength band different from the first wavelength band and emits the second light, when the first light enters the phosphor;

a first dichroic mirror to which the first light and the second light are incident, the first dichroic mirror substantially transmitting one of the first light and the second light and substantially reflecting the other;

an LED emitting third light having a main emission wavelength belonging to the first wavelength band; and

and a second dichroic mirror to which the second light transmitted or reflected by the first dichroic mirror and the third light emitted from the LED are incident, the second dichroic mirror substantially transmitting one of the second light and the third light and substantially reflecting the other.

2. The light source device according to claim 1,

the light source device includes an optical component disposed between the first dichroic mirror and the second dichroic mirror, and selectively transmitting the second light of the first light and the second light,

the second dichroic mirror is made incident on the second light transmitted in the optical component after being transmitted or reflected in the first dichroic mirror.

3. The light source device according to claim 2,

the optical component is a third dichroic mirror that substantially transmits the second light and substantially reflects the first light.

4. The light source device according to claim 3,

the light source device includes a light shielding portion on which the first light reflected by the third dichroic mirror is incident.

5. The light source device according to claim 1,

the light source device includes a light shielding portion on which the first light reflected by the second dichroic mirror is incident.

6. The light source device according to claim 1,

the first wavelength range is 430nm to 480 nm.

7. The light source device according to claim 6,

the second band is 500nm to 550 nm.

8. The light source device according to claim 1, comprising:

a condensing optical system that condenses light in which the second light and the third light are superimposed; and

and an optical fiber into which the light condensed by the condensing optical system is incident.