JP2016198127A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control light volume from a light emitter with a high degree of precision.SOLUTION: An optical switch 110 executes control on whether or not to emit light from a light emitter 100 to the outside of a light source device 10. A light volume measurement unit 120 measures an amount of light emitted by the light emitter 100 between the light emitter 100 and the optical switch 110. A control unit 130 controls the light emitter 100 and the optical switch 110. In more detail, by controlling the optical switch 110, the control unit 130 starts to supply a fixed drive current to the optical switch 110 after the light from the light emitter 100 is made into a state of not emitted to the outside of the light source device 10. The control unit 130 controls the optical switch 110 after a value of the measurement by the light volume measurement unit 120 satisfies a criterion so that the light from the light emitter 100 is emitted to the outside of the light source device 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light source device, and more particularly, to a light source device capable of obtaining a stable light amount.

  One of the uses of a light source device using a light emitting element such as a semiconductor laser as a light source is a medical device. For example, Patent Document 1 describes that in a device for irradiating a treatment site with laser, a plurality of semiconductor lasers are electrically arranged in series, and in each of these semiconductor lasers, an anode and a cathode are connected by an electronic switch. Yes. Further, Patent Document 1 describes that a shutter is disposed between the semiconductor laser and the optical output fiber. This shutter is provided to shut off the laser when an abnormal laser output is detected.

JP 2003-290367 A

  Depending on the application of the light source device, it is desired to control the light amount from the light emitting element with high accuracy. As a method for controlling the amount of light, it is conceivable to control the current value supplied to the light emitting element and the current supply time. However, the output of the light emitting element is not stable for a certain period after activation. Therefore, with this method, it is difficult to sufficiently increase the accuracy of the amount of light.

  The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to control the amount of light from a light emitting element with high accuracy.

  In the present invention, the light source device includes a light emitting element, an optical switch, a light amount measuring unit, and a control unit. The optical switch controls whether or not the light from the light emitting element is emitted to the outside of the light source device. The light quantity measuring unit measures the amount of light emitted by the light emitting element between the light emitting element and the optical switch. The control unit controls the optical switch so that the light from the light emitting element is not emitted to the outside of the light source device, and then starts to supply a constant drive current to the optical switch. Then, the control unit causes the light from the light emitting element to be emitted to the outside of the light source device by controlling the optical switch after the measurement value by the light amount measurement unit satisfies the reference.

  According to the present invention, the amount of light from the light emitting element can be controlled with high accuracy.

It is a figure which shows the structure of the light source device which concerns on 1st Embodiment. It is a timing chart which shows an example of control of the light emitting element and optical switch by a control part. It is a figure which shows the structure of the light source device which concerns on 2nd Embodiment. It is a figure which shows the structure of the light source device which concerns on 3rd Embodiment. It is a figure which shows the structure of the light source device which concerns on 4th Embodiment. It is a figure which shows the structure of the light source device which concerns on 5th Embodiment. It is a timing chart which shows an example of control which a control part performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of a light source device 10 according to the first embodiment. The light source device 10 according to the present embodiment is used as a light source of a medical device such as a fundus examination device. In such an application, the light source device 10 is required to have a short irradiation time (for example, several milliseconds to several hundred milliseconds) and a stable light amount. However, the light source device 10 may be used for other purposes.

  The light source device 10 includes a light emitting element 100, an optical switch 110, a light amount measuring unit 120, and a control unit 130. The light emitting element 100 is a light emitting element such as a semiconductor laser. The optical switch 110 controls whether or not the light from the light emitting element 100 is emitted to the outside of the light source device 10. The light quantity measurement unit 120 measures the amount of light emitted by the light emitting element 100 between the light emitting element 100 and the optical switch 110.

  The control unit 130 controls the light emitting element 100 and the optical switch 110. Specifically, the control unit 130 controls the optical switch 110 so that the light from the light emitting element 100 is not emitted to the outside of the light source device 10, and then starts to supply a constant drive current to the optical switch 110. . Then, the control unit 130 causes the light from the light emitting element 100 to be emitted to the outside of the light source device 10 by controlling the optical switch 110 after the measurement value by the light amount measurement unit 120 satisfies the standard. Details will be described below.

  The light emitting element 100 is a semiconductor laser as described above. However, the light emitting element 100 may be another light emitting element such as a light emitting diode.

  As described above, the optical switch 110 controls whether or not the light from the light emitting element 100 is emitted to the outside of the light source device 10. For example, the optical switch 110 switches the traveling direction (route) of the light emitted from the light emitting element 100. In this case, the optical switch 110 has a route that emits light outside the light source device 10 (in other words, opens the optical switch 110) and a route that does not emit light outside the light source device 10 (in other words, the optical switch 110). Close one). This selection is performed according to a control signal transmitted from the control unit 130. As the optical switch 110, for example, a switch manufactured using MEMS (Micro Electro Mechanical Systems) technology can be used. Such an optical switch 110 has a fast response speed of opening and closing, and opens and closes in, for example, several ms.

  As described above, the light quantity measuring unit 120 measures the amount of light emitted by the light emitting element 100 between the light emitting element 100 and the optical switch 110. For example, for example, an optical coupler is provided between the light emitting element 100 and the optical switch 110, and a part of the light from the light emitting element 100 enters the light amount measuring unit 120. The light quantity measurement unit 120 includes a photoelectric conversion element, and generates a signal indicating the intensity of light from the light emitting element 100.

  FIG. 2 is a timing chart illustrating an example of control of the light emitting element 100 and the optical switch 110 by the control unit 130. As described above, the control unit 130 controls the optical switch 110 so that the light from the light emitting element 100 is not emitted to the outside of the light source device 10 (the optical switch 110 is closed). Start supplying a constant drive current. Then, the control unit 130 causes the light from the light emitting element 100 to be emitted to the outside of the light source device 10 by controlling the optical switch 110 after the measurement value by the light amount measurement unit 120 satisfies the standard. In the example shown in the figure, the control unit 130 controls the optical switch 110 (the optical switch 110 is opened) when the fluctuation of the measurement value of the light amount measurement unit 120 becomes a predetermined value or less, and the light from the light emitting element 100 is controlled. Light is emitted to the outside of the light source device 10.

  Then, after a predetermined time has elapsed, the control unit 130 controls the optical switch 110 (closes the optical switch 110), so that light from the light emitting element 100 is not emitted to the outside of the light source device 10. Like that. Thereafter, the controller 130 stops the current supply to the light emitting element 100.

  In general, the operation immediately after the light emitting element 100 starts up is not stable. For this reason, the amount of light immediately after the light emitting element 100 rises is unstable. In addition, this instability has individual differences among the light emitting elements 100. On the other hand, in the present embodiment, the control unit 130 controls the optical switch 110 after the measurement value by the light amount measurement unit 120 satisfies the standard, thereby causing the light from the light emitting element 100 to be outside the light source device 10. Let it emit. Therefore, light from the light emitting element 100 can be emitted to the outside of the light source device 10 after the amount of light output from the light emitting element 100 is stabilized. Therefore, even if there is an individual difference in the operation immediately after the light emitting element 100 is started up, the light amount from the light source device 10 can be stabilized.

  Further, when the optical switch 110 is formed by the MEMS technology, the response speed of the optical switch 110 is increased. Therefore, the output time of the light source device 10 can be controlled with high accuracy. In this case, the amount of light output from the light source device 10 is further stabilized. This effect is particularly remarkable when the output time of the light source device 10 is short.

  In the present embodiment, as shown in FIG. 1, the control unit 130 displays information indicating the timing when the optical switch 110 is opened, in other words, information indicating the timing when light is emitted from the light source device 10. 10 to the outside. This output is used, for example, to control the imaging timing of the imaging apparatus. Specifically, when the light source device 10 is used as a light source of an imaging device (for example, a device that images the fundus) in a medical device, the imaging device controls imaging timing according to information output from the control unit 130. Thereby, the quality of the image obtained by the imaging device is improved.

(Second Embodiment)
FIG. 3 is a diagram illustrating a configuration of the light source device 10 according to the second embodiment. The light source device 10 according to the present embodiment has the same configuration as the light source device 10 according to the first embodiment except for the following points.

  First, the light source device 10 includes a plurality of light emitting elements 100. The peak wavelengths of the light emitted from the plurality of light emitting elements 100 are different from each other. The optical switch 110 selects one of the light from the plurality of light emitting elements 100 and outputs the selected light to the outside of the light source device 10. Here, the optical switch 110 may be configured to simultaneously select light from two or more light emitting elements 100.

  An optical coupler is disposed between each of the plurality of light emitting elements 100 and the optical switch 110. In any of the plurality of light emitting elements 100, a part of the emitted light enters the light amount measuring unit 120. The light quantity measurement unit 120 individually measures the light quantity from the plurality of light emitting elements 100.

  Then, the control unit 130 selects the light emitting element 100 that generates light to be emitted, and performs the control illustrated in FIG. 2 on the selected light emitting element 100.

  According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the light source device 10 includes the plurality of light emitting elements 100, it is possible to emit light having a wavelength desired by the user of the light source device 10.

(Third embodiment)
FIG. 4 is a diagram illustrating a configuration of the light source device 10 according to the third embodiment. The light source device 10 according to the present embodiment is the same as the light source device 10 according to the first embodiment or the second embodiment, except that the wavelength measuring unit 140 is provided. This figure shows a case similar to that of the first embodiment.

  The wavelength measuring unit 140 measures a deviation between a peak wavelength of light emitted from the light emitting element 100 and a desired wavelength between the light emitting element 100 and the optical switch 110. The wavelength measurement unit 140 includes, for example, an etalon. The light transmittance in the etalon decreases as it deviates from a predetermined wavelength. For this reason, the wavelength measuring unit 140 can measure the shift of the peak wavelength of the light emitted from the light emitting element 100 by measuring the intensity of the light transmitted through the etalon using, for example, a photodiode.

  The measurement value of the wavelength measurement unit 140 is output to the control unit 130. And the control part 130 controls the electric power (for example, electric current value) input into the light emitting element 100 based on the output value of the wavelength measurement part 140. FIG. Specifically, the control unit 130 controls the power input to the light emitting element 100 so that the peak wavelength of the light emitted from the light emitting element 100 is constant.

  In addition, when the light source device 10 includes a plurality of light emitting elements 100 as illustrated in the second embodiment, the wavelength measuring unit 140 is provided for each of the plurality of light emitting elements 100.

  According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, the control unit 130 controls the power input to the light emitting element 100 based on the output value of the wavelength measuring unit 140. For this reason, the peak wavelength of the light output from the light source device 10 is unlikely to fluctuate.

(Fourth embodiment)
FIG. 5 is a diagram illustrating a configuration of the light source device 10 according to the fourth embodiment. The light source device 10 according to the present embodiment has the same configuration as the light source device 10 according to the third embodiment except for the following points.

  First, the light source device 10 includes a temperature adjustment unit 102. The temperature adjustment unit 102 includes, for example, a Peltier element and a temperature detection unit (for example, a thermistor), and controls the temperature of the light emitting element 100. Then, the control unit 130 controls the operation (for example, set temperature) of the temperature adjustment unit 102 based on the output value of the wavelength measurement unit 140. Specifically, the control unit 130 controls the set temperature of the temperature adjustment unit 102 so that the wavelength of light emitted from the light emitting element 100 is constant.

  According to the present embodiment, the wavelength of light emitted from the light emitting element 100 is controlled by controlling the temperature of the light emitting element 100. Therefore, the peak wavelength of the light output from the light source device 10 is less likely to vary, and the intensity of the light emitted from the light source device 10 can be controlled to a desired value.

(Fifth embodiment)
FIG. 6 is a diagram illustrating a configuration of the light source device 10 according to the fifth embodiment. The light source device 10 according to the present embodiment has the same configuration as the light source device 10 according to the fourth embodiment except for the following points.

  First, the light source device 10 includes a plurality of sets of light emitting elements 100 and temperature adjustment units 102. In addition, the control unit 130 has a power monitor 132. The power monitor 132 measures the power (for example, current value) supplied to each of the plurality of temperature adjustment units 102. The control unit 130 uses the measured value of the power monitor 132 to control the temperature adjustment unit 102 in the control unit 130.

  FIG. 7 is a timing chart illustrating an example of control performed by the control unit 130. The drive power of the temperature adjustment unit 102 is greatest immediately after the temperature adjustment unit 102 is started up. For this reason, if the control part 130 starts up the several temperature adjustment part 102 simultaneously, the electric power required at the moment will become large.

  Therefore, in the present embodiment, the control unit 130 starts up the plurality of temperature adjustment units 102 while shifting the time. Specifically, the control unit 130 starts up one temperature adjustment unit 102. At this time, the power supplied to the temperature adjustment unit 102 is monitored by the power monitor 132. When the power supplied to the temperature adjustment unit 102 is stabilized, the next temperature adjustment unit 102 is started up. By repeating this sequentially, a plurality of temperature adjustment units 102 are started up. In this way, the peak value of power required for temperature control of the plurality of light emitting elements 100 can be reduced.

  Thereafter, the controller 130 starts supplying a constant drive current to the plurality of light emitting elements 100. Then, the control unit 130 controls the optical switch 110 (the optical switch 110 is opened) when the fluctuation of the measurement value of the light amount measurement unit 120 becomes a certain value or less in all the light emitting elements 100, and a plurality of light emission. Light from the element 100 is sequentially emitted to the outside of the light source device 10 at different timings.

  In the present embodiment, the light source device 10 may not include the power monitor 132. In this case, the control unit 130 activates the plurality of temperature adjustment units 102 while shifting the time according to a timing chart stored in advance. For example, the control unit 130 sequentially activates the plurality of temperature adjustment units 102 with a certain time interval. The certain time here is obtained, for example, by actually measuring the rise time of the temperature adjustment unit 102. Even in this case, the peak value of power required for temperature control of the plurality of light emitting elements 100 can be reduced.

  Also in this embodiment, the same effect as that of the light source device 10 according to the fourth embodiment can be obtained. In addition, the control unit 130 activates the plurality of temperature adjustment units 102 while shifting the time. Therefore, the peak value of power required for temperature control of the plurality of light emitting elements 100 can be reduced.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

DESCRIPTION OF SYMBOLS 10 Light source device 100 Light emitting element 102 Temperature adjustment part 110 Optical switch 120 Light quantity measurement part 130 Control part 132 Power monitor 140 Wavelength measurement part

Claims (6)

A light emitting element;
An optical switch for controlling whether to emit light from the light emitting element to the outside;
A light quantity measuring unit that measures the amount of light emitted by the light emitting element between the light emitting element and the optical switch;
A control unit for controlling the light emitting element and the optical switch;
With
The controller is
By controlling the optical switch, after the light from the light emitting element is not emitted to the outside, begins to supply a constant drive current to the light emitting element,
A light source device that emits light from the light emitting element to the outside by controlling the optical switch after a measurement value by the light quantity measurement unit satisfies a reference. The light source device according to claim 1,
The light emitting element is a semiconductor laser;
A temperature adjusting unit for adjusting the temperature of the light emitting element;
A wavelength measuring unit for measuring a wavelength of light emitted by the light emitting element between the light emitting element and the optical switch;
With
The said control part is a light source device which controls the said temperature adjustment part based on the measurement result of the said wavelength measurement part. The light source device according to claim 2,
The light emitting element is a semiconductor laser;
A temperature adjusting unit for adjusting the temperature of the light emitting element;
A wavelength measuring unit for measuring a wavelength of light emitted by the light emitting element between the light emitting element and the optical switch;
With
The said control part is a light source device which controls the drive current of the said light emitting element based on the measurement result of the said wavelength measurement part. The light source device according to claim 2 or 3,
Comprising a plurality of the light emitting elements,
The temperature adjustment unit is provided for each of the plurality of light emitting elements,
And a power measuring unit that measures power supplied to each of the plurality of temperature adjusting units,
The control unit is a light source device that activates the plurality of temperature adjustment units while shifting the time using the measurement result of the power measurement unit. The light source device according to claim 2 or 3,
Comprising a plurality of the light emitting elements,
The temperature adjustment unit is provided for each of the plurality of light emitting elements,
The control unit is a light source device that activates the plurality of temperature adjustment units while shifting the time in accordance with a timing chart stored in advance. In the light source device according to any one of claims 1 to 5,
The control unit is a light source device that outputs a control signal of the optical switch to the outside of the light source device.

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