WO2016103305A1

WO2016103305A1 - Light source unit, light source device, and endoscope device

Info

Publication number: WO2016103305A1
Application number: PCT/JP2014/006503
Authority: WO
Inventors: 渡辺　吉彦; 宏幸亀江
Original assignee: オリンパス株式会社
Priority date: 2014-12-26
Filing date: 2014-12-26
Publication date: 2016-06-30
Also published as: JPWO2016103305A1; JP6367972B2

Abstract

A light source unit 1 is provided with: a plurality of laser light sources 10A and 10B that are selected from among a plurality of light sources of narrow bands included in a first wavelength region; an optical coupler 11, which couples light outputted from the laser light sources 10A and 10B, and outputs the light as one beam of output light; and an output unit 14 that outputs the output light outputted from the optical coupler 11. The first wavelength region includes a second wavelength region, and is broader than the second wavelength region, and the laser light sources 10A and 10B are selected such that the laser light sources include at least each of the laser light sources 10A and 10B wherein the peak wavelengths of light outputted when the value of an inputted current is set constant are positioned on the long wavelength side and the short wavelength side of the center wavelength of the second wavelength region, and that the hue of the output light outputted from the optical coupler 11 is within a hue range corresponding to the narrow band light within the second wavelength region.

Description

Light source unit, light source device, and endoscope device

The present invention relates to a light source unit, a light source device, and an endoscope device using them.

In recent years, the luminous efficiency of narrow-band light sources such as lasers has improved, and it has come to be used in various places from lighting to processing. However, taking a laser generally used in a narrow band light source as an example, even if the product type is the same, there may be a solid difference in the wavelength band. For this reason, for example, in applications where a desired color tone is required for a display or the like, there are those that can be used even with lasers of the same product type and those that cannot be used, and those that cannot be used are useless costs.

For this reason, a semiconductor light emitting element (narrow band light source) can be used even if it is a semiconductor light emitting element whose emission wavelength does not fall within the specified wavelength range, and it corresponds to the specified wavelength using a plurality of semiconductor elements. Techniques for generating tinted light have been proposed (see, for example, Patent Document 1). Specifically, the light emission amounts of the plurality of semiconductor light emitting elements are individually controlled by the wavelength change table prepared in advance based on the information on the center light emission wavelengths and the light emission amounts of the plurality of semiconductor light emitting elements having different center emission wavelengths. An endoscope apparatus that controls the center wavelength of light to be combined to a predetermined wavelength is described.

Japanese Patent No. 5364520

However, in order to control the amount of light emitted from each of the plurality of narrow-band light sources, the same number of light-quantity control mechanisms as the narrow-band light sources are required, which may increase the size and cost of the apparatus. In addition, the amount of light emitted from a plurality of narrow-band light sources is adjusted to a specified wavelength, and as the number of narrow-band light sources increases, there are more solutions for the amount of emitted light, making it difficult to manage the light source and light amount. Become. Furthermore, when replacing some of the narrowband light sources that have been selected once, it may be necessary to readjust the amount of light emitted from all narrowband light sources, including those that are not replaced. ,Take the trouble.

Therefore, the object of the present invention, which has been made by paying attention to these points, is to achieve a desired color with a simple configuration and management method while using a plurality of narrowband light sources including a narrowband light source that cannot achieve a desired color by itself. It is an object of the present invention to provide a light source unit, a light source device, and an endoscope device using them that can emit light included in a taste range.

The invention of the light source unit that achieves the above object is as follows:
A plurality of narrowband light sources selected from a number of narrowband light sources included in the first wavelength region;
An optical coupling unit that combines the light emitted from the plurality of narrow-band light sources and outputs the combined light;
An output unit for outputting the emitted light output from the optical coupling unit;
A light source unit comprising:
The first wavelength region includes a second wavelength region and is wider than the second wavelength region, and the plurality of narrow-band light sources has a peak wavelength of light emitted when an input current value is constant. Includes at least one narrow-band light source positioned on the long wavelength side and the short wavelength side of the center wavelength of the second wavelength region, respectively, and the color of the emitted light output from the optical coupling unit is It is selected so that it may be contained in the color range corresponding to the narrow-band light in 2 wavelength range.

Further, the plurality of narrowband light sources includes an average value obtained by weighting a peak wavelength of the plurality of narrowband light sources by an amount of light of the narrowband light source at the peak wavelength, and the center wavelength of the second wavelength region. It is preferable that the difference is selected so as to be 1/2 or less, more preferably 1/4 or less of the wavelength range of the second wavelength region.

The plurality of narrowband light sources may be configured to include the same number of narrowband light sources having a peak wavelength on the long wavelength side of the center wavelength and narrowband light sources having a peak wavelength on the short wavelength side of the center wavelength. it can.

Further, each of the plurality of narrow band light sources includes one narrow band light source having a peak wavelength on the long wavelength side of the center wavelength and one narrow band light source having a peak wavelength on the short wavelength side of the center wavelength. Can be configured.

Furthermore, the plurality of narrow-band light sources can be configured such that none of the peak wavelengths of the emitted light is included in the second wavelength region when the input current value is constant.

A temperature detecting unit for detecting temperatures of the plurality of narrow band light sources independently; a control unit for controlling the temperatures of the plurality of narrow band light sources; and temperatures of the plurality of narrow band light sources. Each of the plurality of narrow band light sources based on the temperature of each of the plurality of narrow band light sources detected by the temperature detection unit. The temperature may be controlled.

Furthermore, the invention of the light source device that achieves the above object is any one of the above light source units, wherein the first light source unit having the center wavelength of the second wavelength region as a red wavelength, and the second light source unit A second light source unit having a green wavelength as the central wavelength in the wavelength region; a third light source unit having a blue wavelength as the central wavelength in the second wavelength region; and the first to third light sources. And an optical coupling output unit that combines the light emitted from the unit into one output light, and is configured to emit white light as the output light.

Further, the invention of an endoscope apparatus that achieves the above object is to guide the white light emitted from the light source device and the light source device to irradiate the observation object, and receive the light obtained by the irradiation. An insertion unit including a light receiving unit and an image processing unit that generates an image from a signal obtained by the light receiving unit are provided.

In this application, “color” means the appearance of color. When a plurality of lights having peak light intensities in a relatively close wavelength range are combined, the color of the combined light can be obtained by arithmetically averaging the wavelengths of each light by the peak light intensity. It becomes substantially equal to the color of light of wavelength.

According to the present invention, in the plurality of narrowband light sources, the peak wavelength of the light emitted when the input current value is a predetermined constant value is shorter than the longer wavelength side of the central wavelength of the second wavelength region. Each including at least one narrow-band light source positioned on the wavelength side, and the color of the emitted light output from the optical coupling unit is selected to be included in the color range corresponding to the second wavelength region Therefore, a light source that can emit light in a desired color range with a simple configuration and management method while using a plurality of narrow band light sources including a narrow band light source that cannot achieve a desired color by itself. A unit, a light source device, and an endoscope apparatus using them can be provided.

It is a block diagram of the light source unit which concerns on 1st Embodiment. It is a figure explaining the relationship between the wavelength distribution of the emitted light intensity of a several laser light source, and the 1st and 2nd wavelength range. It is a figure which prescribes | regulates the difference and light quantity of the peak wavelength of a selected laser light source, and a desired center wavelength. It is a figure which shows an example of the combination of a desired center wavelength and the wavelength of the selected laser light source. It is a chromaticity diagram prescribed | regulated by CIE (International Lighting Commission). It is a figure which shows the chromaticity of the laser which combined the emitted light from two narrow-band light sources on a chromaticity diagram. It is a block diagram of the light source unit which concerns on 2nd Embodiment. It is a block diagram of the light source device which concerns on 3rd Embodiment. It is a block diagram of an endoscope apparatus concerning a 4th embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram of a light source unit according to the first embodiment. The light source unit 1 includes two

laser light sources

10A and 10B that are narrow-band light sources, an optical coupler 11 (optical coupling unit), and an output unit 14. The

laser light sources

10A and 10B are connected to the optical coupler 11 via fibers 12A and 12B, respectively. The optical coupler 11 and the output unit 14 are connected via an optical fiber 13.

The

laser light sources

10A and 10B are laser light sources selected from a number of laser light sources that can be procured for a desired wavelength to be output by the light source unit 1. For the desired wavelength, the actual wavelength of the lasers that can be procured varies within a specific wavelength range. Hereinafter, the wavelength range of the peak wavelength of the laser light source that can be procured is referred to as a first wavelength region. The first wavelength region is defined in, for example, a product specification value of a manufacturer that supplies the

laser light sources

10A and 10B. The narrow band light source is a light source such as a laser or LED having a narrower band than that of a light source normally used for observation. When a semiconductor laser is used, its spectral width is about 1 to several nm. In addition, when an LED is used, the spectrum width is about several nm to several tens of nm.

The light emitted from the

laser light sources

10A and 10B is output to the optical fibers 12A and 12B, respectively. The optical coupler 11 is an optical coupler that can multiplex laser beams from the

laser light sources

10A and 10B input via the optical fibers 12A and 12B with little optical loss. As the optical coupler 11, an optical fiber type multiplexer or the like can be used. The output light obtained by combining the laser light output from the laser light sources 10 </ b> A and 10 </ b> B by the optical coupler 11 is configured to be output as output light from the output unit 14 via the optical fiber 13. The output unit 14 is appropriately configured according to a method of emitting output light to the outside of the light source unit 1. For example, when the emitted light is connected to an external optical fiber, it can be connected to the optical fiber. A multimode fiber can be used as the optical fibers 12A and 12B and the optical fiber 13.

Next, a method for selecting the

laser light sources

10A and 10B will be described. FIG. 2 is a diagram for explaining the relationship between the wavelength distribution of the emission intensity of a plurality of laser light sources and the first and second wavelength regions. Of the many laser light sources that can be procured, the wavelength distribution of the emission intensity when a constant current is input to the _four lasers L ₁ to L ₄ is illustrated. In FIG. 2, the first wavelength region is the wavelength region of the peak wavelength of the laser light source that can be procured as described above. Further, λ _C is a desired wavelength of the light source unit 1. Furthermore, the second wavelength region is a wavelength region of a desired peak wavelength that is determined by an application such as illumination. The second wavelength region has a spread on the long wavelength side and the short wavelength side with the desired wavelength λ _C as the center wavelength. The second wavelength region indicates a peak wavelength range that is allowed as the color of the output light of the light source unit 1. The second wavelength region is narrower than the first wavelength region, and the peak wavelength does not belong to the second wavelength region among procurable laser light sources that emit laser light in the first wavelength region. This includes laser light sources that cannot be used alone.

Therefore, when the input current value is constant, the peak wavelength of the light emitted straddles the center wavelength λ _C of the second wavelength region, and the short wavelength side laser L ₁ and the long wavelength side laser L ₄ Are selected as the

laser light sources

10A and 10B, respectively. Thereby, the color of the emitted light output by combining the laser beams from the

laser light sources

10A and 10B is included in the range of the color corresponding to the narrow band light in the second wavelength region. be able to. When at least one peak wavelength of the lasers L ₁ and L ₄ is not included in the second wavelength region, a laser that cannot be used alone for the light source unit 1 is combined with another laser as a light source. The unit 1 can be used.

The

laser light sources

10A and 10B have a difference between the average value obtained by weighting the peak wavelength with the light amount at the peak wavelength (hereinafter referred to as “arithmetic combined wavelength”) and the center wavelength λ _c in the second wavelength region. It is preferable to select the wavelength range (that is, a value obtained by subtracting the lower limit value from the upper limit value of the wavelength in the second wavelength region) to be 1/2 or less, more preferably 1/4 or less. For example, as shown in FIG. 3, a laser L ₁ and a laser L ₄ are selected as the

laser light sources

10A and 10B, and the absolute value of the difference between the center wavelength λ _C and each peak wavelength is Δλ ₁ , Δλ ₄ , respectively. It is assumed that the light amount values of the peak wavelengths are LI ₁ and LI ₄ . Further, it is assumed that the arithmetic combined wavelength λ _av is closer to the peak wavelength (short wavelength side) of the laser L ₁ than the center wavelength λ _c . here,
LI ₁ × (Δλ ₁ −Δλ _av ) = LI ₄ (Δλ ₄ + Δλ _av )
When the arithmetic combined wavelength λ _av is calculated, the difference Δλ _av between λ _av and λ _c is made ½ of the wavelength width of the second wavelength region, preferably ¼ or less. . By doing so, the color of the emitted light can be brought close to the color of the light having a desired wavelength. Furthermore, the smaller the value of Δλ _av, the better. By selecting Δλ ₁ × LI ₁ and Δλ ₄ × LI ₄ to be approximately equal on both sides of the center wavelength λ _C , the arithmetic combined wavelength becomes approximately equal to the center wavelength λ _c, and optical coupling The color of the emitted light combined by the vessel 11 becomes closer to the color of the desired wavelength.

As described above, according to the present embodiment, the

laser light sources

10A and 10B have the peak wavelength of the light emitted when the input current value is constant, the center wavelength λ _C of the second wavelength region. Each of which has at least one laser positioned on the long wavelength side and the short wavelength side, and the color of the emitted light output from the optical coupler 11 corresponds to the narrow band light in the second wavelength region. Since it is selected so as to be included in the range, it emits light included in the desired color range while using a plurality of narrow-band light sources including lasers L ₁ and L ₄ that cannot realize a desired color by itself. The light source unit 1 that can be provided can be provided. In the light source unit 1 of the present invention, a conversion table for obtaining a desired wavelength from the

laser light sources

10A and 10B and control of the input current are not required, and a predetermined current is applied to the

laser light sources

10A and 10B. good. Therefore, there is an advantage that the device configuration and the management method are simple.

An arithmetic combined wavelength λ _av that is an average value obtained by weighting the narrow-

band light sources

10A and 10B with the peak wavelengths of the narrow-

band light sources

10A and 10B by the light amounts of the

light sources

10A and 10B at the peak wavelength; Is selected so that the difference from the central wavelength λ _c of the wavelength region of the second wavelength region is ½ or less, particularly ¼ or less of the wavelength range of the second wavelength region. It can be close to the color of the desired wavelength. In particular, if the arithmetic combined wavelength λ _av is selected so as to be substantially equal to the center wavelength λ _c , it is possible to obtain a color substantially equivalent to the color of the desired wavelength.

Furthermore, the same number of laser light sources having a peak wavelength on the long wavelength side of the center wavelength λ _C and one laser light source having a peak wavelength on the short wavelength side, in particular one each, reduce the cost of the light source. The volume of the light source unit 1 can be reduced.

Next, the light source unit 1 of the present embodiment will be described using a more specific example. For example, when the desired chromaticity is 515 nm for green, a semiconductor laser NDG4216 (oscillation wavelength 510 nm to 520 nm manufactured by Nichia Corporation) is available as a narrow-band light source that can be procured and has a chromaticity close to the desired chromaticity. ). In this case, the chromaticity values of the laser light sources having wavelengths 510 nm and 520 nm that are most different from the desired 515 nm are 510 nm (x: 0.0189, y: 0.75) and 520 nm (x: 0.075, y), respectively. : 0.835), and a chromaticity value of 515 nm (x: 0.034, y: 0.8) has a maximum difference of 0.041 for x and 0.05 for y. Here, as an allowable value of the difference in chromaticity value, for example, when the chromaticity specification (ANSI C78.377 5700K white) of the white power LED is cited, the allowable value of the error range is 0.0169 for x, and 0.00 for y. 0373, and the difference in the case of 510 nm and 520 nm described above exceeds the allowable value. Therefore, in order to enter the allowable range, the tint of the narrower wavelength region 513 nm to 517 nm (second wavelength region) from the wavelength range of 510 nm to 520 nm (first wavelength region) which is the specification value of ND4216. It is desirable to select the light source so that it is within the range.

Here, as the narrow-band light source selected as the

laser light sources

10A and 10B, as shown in FIG. 4, the center wavelength is the desired wavelength of 515 nm, and the difference between the peak wavelength and the center wavelength between the long wavelength side and the short wavelength side is as shown in FIG. The laser L ₅ (oscillation wavelength: 510 nm) and the laser L ₆ (oscillation wavelength: 520 nm) are selected to be a combination in which the multiplication value of the absolute value (5 nm) and the light amount value (10 mW) of the peak wavelength are equal. In this case, on the chromaticity diagram (CIE1931) defined by the CIE (International Commission on Illumination) in FIG. 5, the chromaticity of the light having the desired wavelength combined with the lasers L ₅ and L ₆ is shown in FIG. Shown in Here, FIG. 6 is an enlarged view of the broken line portion of FIG. The laser L ₅ and the chromaticity of the combined laser obtained by synthesizing the light emitted laser L _6, the represented on the chromaticity diagram at point P _2, is located on the straight line connecting the laser L ₅ and the laser L _6. As shown in Table 1, the chromaticity value (x: 0.044, y: 0.792) of this synthetic laser is the chromaticity value (x: 0.034) at the desired wavelength 515 nm represented by the point P _1. , Y: 0.8).

Thus, the laser L ₆ of the laser L ₅ and the peak wavelength 520nm of peak wavelength 510 nm, laser light sources 10A, used as 10B, to output the light emitted by combining with the optical coupler 11 from the output unit 14 As a result, it is possible to obtain emission light having a color almost equal to that of the narrow-band light having a wavelength of 515 nm.

Note that the number of laser light sources included in the light source unit 1 is not limited to two, and it is possible to provide three or more narrow-band light sources. Also in this case, at least one narrow-band light source in which the peak wavelength of the light emitted when the input current value is constant is located on the long wavelength side and the short wavelength side of the center wavelength λ _C in the second wavelength region, respectively. Narrow band light source by selecting more than one so that the color of the emitted light output from the optical coupler 11 is included in the color range corresponding to the narrow band light in the second wavelength region The same effect as when there are two is obtained.

Also, the long wavelength side and / or the short wavelength side of the center wavelength lambda _C, in the case of providing a plurality of narrow-band light sources, the difference of the wavelength range of the second wavelength region of the arithmetic combining wavelength and the center wavelength lambda _c By setting it to 1/2 of this, more preferably 1/4 or less, the color of the emitted light can be made closer to the color of the desired wavelength.

(Second Embodiment)
FIG. 7 is a block diagram of a light source unit according to the second embodiment. The light source unit 1A has

temperature detection units

20A and 20B that detect temperatures and temperature adjustments that adjust the temperatures of the

laser light sources

10A and 10B, respectively, with respect to the

laser light sources

10A and 10B of the light source unit 1 in the first embodiment. The

units

30A and 30B are provided, and the control unit 40 is provided. (Hereinafter, the configuration including the

temperature detection units

20A and 20B, the

temperature adjustment units

30A and 30B, and the control unit 40 is also referred to as a “temperature adjustment mechanism”.)

As the

temperature detection units

20A and 20B, for example, a thermocouple temperature sensor or a semiconductor temperature sensor can be used. Further, as the

temperature adjustment units

30A and 30B, for example, Peltier elements can be used. The control unit 40 is electrically connected to the

temperature detection units

20A and 20B via connection lines 21A and 21B, respectively. The control unit 40 is electrically connected to the

temperature adjustment units

30A and 30B via connection lines 31A and 31B. Thereby, the control unit 40 controls the temperatures of the

laser light sources

10A and 10B to be within a predetermined range based on the temperatures of the

laser light sources

10A and 10B detected by the

temperature detection units

20A and 20B. Since other configurations are the same as those of the first embodiment, the same or corresponding components are denoted by the same reference numerals and description thereof is omitted.

In general, the oscillation wavelength of a laser light source varies depending on the temperature. However, according to this embodiment, the temperature adjustment mechanism maintains the temperature variation of the

laser light sources

10A and 10B within a predetermined range. A change in the oscillation wavelength due to the change can be suppressed. Therefore, the color of the emitted light can be kept constant.

(Third embodiment)
FIG. 8 is a block diagram of a light source device according to the third embodiment. The light source device 50 includes a light source unit 51R (first light source unit) having red chromaticity, a light source unit 51G (second light source unit) having green chromaticity, and a light source unit having blue chromaticity. 51B (third light source unit), an optical coupling unit 52 that combines light emitted from each of the

light source units

51R, 51G, and 51B into one output light, and an output unit that emits the output light to the outside 55. Each

light source unit

51R, 51G, 51B and the optical coupler 52 are connected by

optical fibers

53R, 53G, 53B, respectively. The optical coupler 52 and the output unit 55 are connected by an optical fiber 54. The optical coupling output unit includes an optical coupler 52 and an output unit 55.

As the

light source units

51R, 51G, and 51B, a light source unit configured similarly to the light source unit 1 according to the first embodiment is used. Since each

light source unit

51R, 51G, 51B emits the emitted light having a desired color, it is easy to make the light combined with the coupler 52 and output from the output unit 55 white light.

Note that the

light source units

51R, 51G, and 51B can be configured in the same manner as the light source unit 1A according to the second embodiment having a temperature adjustment mechanism. In that case, stable white light can be provided by constantly controlling the temperature.

(Fourth embodiment)
FIG. 9 is a block diagram of an endoscope apparatus according to the fourth embodiment. The endoscope apparatus 100 is inserted into an object to be detected, the light source device 60, an insertion unit 70 that irradiates an observation target with illumination light from the light source device 60, and detects an image signal. The image processing apparatus 80 (image processing unit) that processes the image signal to generate an image and a monitor 90 that displays the image signal output from the image processing apparatus 80 are configured.

The light source device 60 uses the light source device 50 according to the third embodiment. The insertion unit 70 guides the light emitted from the light source device 60, and the optical fiber 71, which is a multimode optical fiber that emits light from the distal end of the insertion unit 70 toward the observation target, and the distal end of the insertion unit 70. A light receiving element 72 (light receiving unit) such as a CCD that two-dimensionally receives light from the observation target, and a signal line 73 for transmitting an electric signal of the light receiving element 72 to the image processing device 80 are provided.

With such a configuration, the white light emitted from the light source device 50 passes through the optical fiber 71 in the insertion unit 70 and is irradiated to the observation target. The white light reflected and scattered by the observation target is detected by the light receiving element 72, converted into an electric signal, and transmitted to the image processing unit 80 via the signal line 73. The image processing unit 80 can generate an image from the signal of the light receiving element 72 received via the signal line 73 and display it on the screen of the monitor 90.

The endoscope apparatus 100 according to the present embodiment uses the light source device 50 according to the third embodiment as the light source device 60, so that a stable white light can be obtained while using a laser light source having a wavelength variation alone. It can be used for endoscopic observation. Further, as the light source unit of the light source device 60, a light source unit configured similarly to the light source unit 1A of the second embodiment may be used. In this case, since the temperature adjustment mechanism is provided, stable white light can be obtained regardless of the heat generation inside the light source device 60.

It should be noted that the present invention is not limited to the above embodiment, and many variations or modifications are possible. For example, the wavelength of light generated by the light source unit is not limited to the R, G, and B wavelengths, and may generate light of other wavelengths. In addition, the light source device according to the fourth embodiment uses a light source unit corresponding to three wavelengths of R, G, and B. However, four or more light source units corresponding to four or more wavelengths may be provided. . Further, the light source device is not limited to an endoscope application, and can be used for various illumination applications.

DESCRIPTION OF SYMBOLS 1

Light source unit

10A, 10B Laser light source 11 Optical coupler 12A, 12B Optical fiber 13 Optical fiber 14

Output part

20A, 20B Temperature detection part 21A,

21B Connection line

30A, 30B Temperature adjustment part 31A, 31B Connection line 40 Control part 50

Light source Device

51R, 51G, 51B Light source unit 52

Optical coupler

53R, 53G, 53B Optical fiber 54 Optical fiber 55 Output unit 60 Light source device 70 Insertion unit 71 Optical fiber 72 Light receiving element 73 Signal line 80 Image processing device 90 Monitor 100 Endoscope apparatus

Claims

A plurality of narrowband light sources selected from a number of narrowband light sources included in the first wavelength region;
An optical coupling unit that combines the light emitted from the plurality of narrow-band light sources and outputs the combined light;
An output unit for outputting the emitted light output from the optical coupling unit;
A light source unit comprising:
The first wavelength region includes a second wavelength region and is wider than the second wavelength region, and the plurality of narrow-band light sources has a peak wavelength of light emitted when an input current value is constant. Includes at least one narrow-band light source positioned on the long wavelength side and the short wavelength side of the center wavelength of the second wavelength region, respectively, and the color of the emitted light output from the optical coupling unit is The light source unit is selected so as to be included in a color range corresponding to narrowband light in the wavelength region of 2.
The plurality of narrowband light sources are different from an average value obtained by weighting a peak wavelength of the plurality of narrowband light sources by a light amount of the narrowband light source at the peak wavelength, and the center wavelength of the second wavelength region. The light source unit according to claim 1, wherein the light source unit is selected to be ½ or less of a wavelength range of the second wavelength region.
The plurality of narrowband light sources includes the same number of narrowband light sources having a peak wavelength on the long wavelength side of the center wavelength and narrowband light sources having a peak wavelength on the short wavelength side of the center wavelength. Light source unit.
The plurality of narrow band light sources each include one narrow band light source having a peak wavelength on the long wavelength side of the center wavelength and one narrow band light source having a peak wavelength on the short wavelength side of the center wavelength. The light source unit described in 1.
5. The peak wavelength of emitted light is not included in the second wavelength region when the input current value is constant in the plurality of narrow-band light sources. 6. The light source unit described in 1.
A temperature detecting unit for independently detecting temperatures of the plurality of narrow-band light sources; a control unit for controlling the temperatures of the plurality of narrow-band light sources; and the control of the temperatures of the plurality of narrow-band light sources. A temperature adjustment unit that adjusts by control from a unit, wherein the control unit is configured to control each temperature of the plurality of narrowband light sources based on the temperature of each of the plurality of narrowband light sources detected by the temperature detection unit. The light source unit according to claim 1, wherein the light source unit is controlled.
The light source unit according to any one of claims 1 to 6, wherein the first light source unit has the center wavelength of the second wavelength region as a red wavelength, and the second wavelength region of the light source unit. A second light source unit having a center wavelength as a green wavelength, a third light source unit having a blue wavelength as the center wavelength in the second wavelength region, and the first to third light source units. A light source device configured to emit white light as the output light.
The light source device according to claim 7, an insertion unit including a light receiving unit that guides white light emitted from the light source device and irradiates the observation target, and receives light obtained by the irradiation, and the light receiving unit An endoscope apparatus comprising: an image processing unit that generates an image from the obtained signal.