JP2011044545A - Light emission device, temperature control method for the same, display device, and light irradiation device - Google Patents

Abstract

The present invention makes it possible to shorten the temperature stabilization time in stable light emission in which wavelength fluctuation is suppressed when the output to be controlled is changed.
A light source having a semiconductor light emitting element that emits light, a temperature measuring unit for measuring a temperature of the light source, and a temperature of the light source based on a temperature measured by the temperature measuring unit. A temperature control unit 12 for instructing a temperature control element 23 to control to a control target temperature is provided. When the temperature control unit 12 causes at least binary output fluctuations in the light source 11, temperature fluctuations accompanying the output fluctuations The temperature control element 23 is instructed to suppress the temperature.
[Selection] Figure 1

Description

  The present invention relates to a light emitting device, a temperature control method for the light emitting device, a display device including the light emitting device, and a light irradiation device including the light emitting device.

  There is a projector that uses a combination of a light modulation panel that uses a lamp as a light source and modulates light from the light source in accordance with a given image signal. In such a projector, when a low-brightness image is displayed, a structure that improves the contrast is obtained by changing the aperture diameter of the aperture mechanism between the light modulation panel and the projection lens according to the video signal. In many cases (for example, refer to Patent Document 1).

As an example, a block diagram showing a general configuration of a projector apparatus using a lamp light source is shown in FIG.
As shown in FIG. 28, the image signal input from the image signal input unit is processed into an image signal of each color by the image signal processing unit, and the light source unit from the light source control unit via the system control unit based on the image signal of each color The intensity of light emitted from the light source unit is instructed. The light emitted from the light source unit is incident on the lens unit from the liquid crystal panel unit through the iris diaphragm unit set to the iris diaphragm value instructed by the system control unit to the iris control unit. (Not shown).

  When the light source is changed from a lamp to a light source (laser, LED, etc.) whose light quantity can be changed at high speed, only a specific light source can be modulated, and the brightness of the image can be changed at high speed. (For example, refer to Patent Document 2). With this configuration, there is a problem that the temperature control speed cannot follow the output modulation speed, the wavelength shifts from the set wavelength, the white balance of the image is lost, and the life is deteriorated.

As an example, FIG. 29 shows a block diagram showing a general configuration of a projector apparatus using a laser light source.
As shown in FIG. 29, the image signal input from the image signal input unit is processed into an image signal of each color by the system control unit, and a current adjustment signal is instructed to the current control circuit based on the image signal of each color. Then, the currents of the respective colors determined based on the current adjustment signal are supplied from the current control circuit to the red light source, the green light source, and the blue source unit. The emitted light (CW) emitted from each light source is modulated by a liquid crystal panel driven by a drive signal instructed from the system control unit via a liquid crystal panel drive circuit, and then an image of each color is synthesized, The light enters the projection lens, and is projected from the projection lens onto, for example, a screen (not shown).
In this way, unlike the lamp light source described above, the three color light sources are driven by current from the respective current control circuits, modulated by the light modulation panel (liquid crystal panel), and then the images of the respective colors are synthesized and emitted from the projection lens. To do.
The emission power from the light source is modulated according to the video signal to be displayed. When an image with low luminance is output, the contrast can be improved by reducing the power emitted from each light source.
Compared with a projector apparatus using a lamp light source, the amount of light can be modulated at a high speed, so that the brightness of the image can be changed at a high speed. However, a unique problem that is not conspicuous with the lamp light source also occurs.
In other words, the semiconductor laser element generates a large amount of heat when it emits light, and the scale of the heat dissipator becomes large in order to naturally dissipate heat.
In addition, since the temperature dependence of the wavelength is remarkable as a characteristic of the semiconductor laser element, using the semiconductor laser element as it is without providing a heat radiator increases the wavelength fluctuation, which is a fatal problem for video equipment such as a projector. It becomes.

  The wavelength temperature dependence of the semiconductor laser device was examined. For example, as shown in FIG. 30, when the emission intensity and relative luminous sensitivity of the semiconductor laser element are taken on the vertical axis and the emission wavelength of the semiconductor laser element is taken on the horizontal axis, the emission wavelength is increased when the temperature of the semiconductor laser element rises. It turns out that it becomes long and the specific visibility is in the direction of decreasing.

Here, the structure of a high-output light source using a general semiconductor laser element as a light source capable of high-speed modulation and the control method in the light source driving device will be described with reference to the block diagram of FIG.
As shown in FIG. 31, the current required for the semiconductor laser element to emit light is supplied from the current supply unit of the light source driving device.
The temperature of the semiconductor laser element is acquired by a light source driving device by a temperature measuring element (thermistor, platinum, etc.), and the light source driving device uses a temperature control element (Peltier element, etc.) to keep the temperature of the semiconductor laser element constant. Supply power. As a control method, PID servo control or the like is used in order to reduce the temperature stabilization time.

  In a high-power semiconductor laser element, the efficiency of the temperature control element deteriorates unless heat is diffused widely. Therefore, it is necessary to increase the thickness and thickness of the heat dissipating body as a heat diffusion body. By increasing the thickness and thickness of the radiator, the temperature time constant increases, and even if the servo control multiplier or method is changed, the temperature settling time and the temperature error from the set value until settling are reduced. There is a limit to it.

  Thus, when a semiconductor laser element is used as the light source, there are many control methods as temperature control methods (see, for example, Patent Document 3). However, when the output to be controlled is changed, a method for shortening the temperature stabilization time is not considered.

JP 2008-46572 A JP 2008-262167 A JP-A-10-178228

  The problem to be solved is that the temperature stabilization time is shortened when the output to be controlled is changed.

  The present invention makes it possible to shorten the settling time of temperature in stable light emission in which wavelength fluctuation is suppressed when the output to be controlled is changed.

The light emitting device of the present invention includes a light source having a semiconductor light emitting element that emits light, a temperature measuring unit that measures the temperature of the light source, and a temperature control target for controlling the temperature of the light source based on the temperature measured by the temperature measuring unit. A temperature control unit for instructing a temperature control element to control the temperature, and when the temperature control unit causes at least binary output fluctuations in the light source, the instruction to suppress the temperature fluctuations associated with the output fluctuations is provided. A temperature control element is used.
Alternatively, when the temperature of the temperature control element is changed, the temperature control unit instructs the temperature control element to control the temperature stabilization time and the fluctuation range to a minimum.
Alternatively, the temperature control unit may cause at least a binary output fluctuation at the light source, and at the same time, when changing the temperature of the temperature control element, minimize the settling time of the fluctuating temperature due to the output fluctuation. The temperature control element is instructed to suppress the temperature.

  In the light emitting device of the present invention, the temperature stabilization time can be shortened in stable light emission with suppressed wavelength fluctuation.

The display device of the present invention includes a light emitting unit using a light emitting device having a semiconductor light emitting element that emits light, a light modulating element that modulates light emitted from the light emitting unit, and light modulated by the light modulating element. A light source having a semiconductor light emitting element that emits light, a temperature measuring unit that measures the temperature of the light source, and a temperature measured by the temperature measuring unit. A temperature control unit for instructing a temperature control element that controls the temperature of the light source to a control target temperature, and the temperature control unit accompanies the output fluctuation when the light source causes at least binary output fluctuation. The temperature control element is instructed to suppress temperature fluctuation.
Alternatively, when the temperature of the temperature control element is changed, the temperature control unit instructs the temperature control element to control the temperature stabilization time and the fluctuation range to a minimum.
Alternatively, the temperature control unit may cause at least a binary output fluctuation at the light source, and at the same time, when changing the temperature of the temperature control element, minimize the settling time of the fluctuating temperature due to the output fluctuation. The temperature control element is instructed to suppress the temperature.

The display device of the present invention has a light modulation panel for displaying an image and a backlight for illuminating the light modulation panel, and the backlight uses a light source of a light emitting device having a semiconductor light emitting element for emitting light, The light emitting device includes: a light source having a semiconductor light emitting element that emits light; a temperature measuring unit that measures the temperature of the light source; and a temperature measured by the temperature measuring unit to set the temperature of the light source to a control target temperature. A temperature control unit for instructing a temperature control element to be controlled, and when the temperature control unit causes at least binary output fluctuations in the light source, the temperature control unit issues an instruction to suppress temperature fluctuations associated with the output fluctuations. Make an element.
Alternatively, when the temperature of the temperature control element is changed, the temperature control unit instructs the temperature control element to control the temperature stabilization time and the fluctuation range to a minimum.
Alternatively, the temperature control unit may cause at least a binary output fluctuation at the light source, and at the same time, when changing the temperature of the temperature control element, minimize the settling time of the fluctuating temperature due to the output fluctuation. The temperature control element is instructed to suppress the temperature.

  In addition, each display device of the present invention uses a light source having the light emitting device of the present invention, so that stable light emission with suppressed wavelength variation can be obtained.

The light irradiation apparatus of the present invention includes a light emitting unit having a light emitting device that irradiates light to a workpiece to process or expose the workpiece, and the light emitting device includes a semiconductor light emitting element that emits light. A light source, a temperature measurement unit that measures the temperature of the light source, and a temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit, The temperature control unit, when causing at least binary output fluctuations in the light source, instructs the temperature control element to suppress temperature fluctuations associated with the output fluctuations.
Alternatively, when the temperature of the temperature control element is changed, the temperature control unit instructs the temperature control element to control the temperature stabilization time and the fluctuation range to a minimum.
Alternatively, the temperature control unit may cause at least a binary output fluctuation at the light source, and at the same time, when changing the temperature of the temperature control element, minimize the settling time of the fluctuating temperature due to the output fluctuation. The temperature control element is instructed to suppress the temperature.

  In the light irradiation device of the present invention, since the light source having the light emitting device of the present invention is used, the temperature stabilization time is shortened in stable light emission in which the wavelength fluctuation is suppressed.

According to the temperature control method of the light emitting device of the present invention, the temperature of the light source having the semiconductor light emitting element that emits light is measured by the temperature measuring unit, and the temperature of the light source is controlled based on the temperature measured by the temperature measuring unit. When the temperature control unit causes at least binary output fluctuations with the light source, temperature fluctuations associated with the output fluctuations are suppressed.
Alternatively, when the temperature of the light source having a semiconductor light emitting element that emits light is measured by a temperature measurement unit and the temperature of the light source is controlled by the temperature control unit based on the temperature measured by the temperature measurement unit, the temperature control is performed. When the temperature of the temperature control element temperature control target is changed by the unit, the temperature stabilization time and the fluctuation range are controlled to the minimum.
Alternatively, the temperature of the light source having a semiconductor light emitting element that emits light is measured by the temperature measurement unit,
When the temperature control unit controls the temperature of the light source based on the temperature measured by the temperature measurement unit, the temperature control unit causes the light source to generate at least a binary or more output fluctuation, and at the same time, the temperature control When changing the temperature of the element temperature control target, the settling time of the fluctuating temperature accompanying the output fluctuation is minimized.

  In the temperature control method for a light emitting device of the present invention, the temperature stabilization time is shortened in stable light emission in which wavelength fluctuation is suppressed.

  In the light emitting device of the present invention, even when the emission power is modulated at a high frequency, since the temperature and output fluctuations of the light source are suppressed, a stable wavelength can be obtained.

  Since the display device of the present invention has a stable oscillation wavelength, a high-quality image can be obtained.

  In the light irradiation apparatus of the present invention, since the oscillation wavelength is stable, it is possible to stably perform without causing processing variations, and in the exposure, since exposure variation is reduced, highly accurate exposure can be performed.

  According to the temperature control method of the light emitting device of the present invention, even when the emission power is modulated at a high frequency, the temperature and output fluctuations of the light source are suppressed, so that a stable wavelength can be obtained.

It is the block diagram which showed an example of the light emission apparatus of this invention. It is the figure which showed an example of the relationship between the drive current of the light emission apparatus of this invention, temperature, and an oscillation wavelength. It is the figure which showed an example of the relationship between the drive current of the light emission apparatus of this invention, temperature, and an oscillation wavelength. It is the figure which showed an example of the relationship between the drive current of the light emission apparatus of a comparative example, temperature, and an oscillation wavelength. It is the figure which showed an example of the relationship between the drive current and temperature of the light emission apparatus of this invention. It is the block diagram which showed an example of the light emission apparatus of this invention. It is a flowchart of each parameter acquisition before operation. It is a flowchart of the determination method of the parameter before operation in the method of suppressing the temperature fluctuation of the semiconductor light emitting element at the time of drive current modulation. It is the flowchart which showed an example of the determination method of the modulation width and delay time of control target temperature. It is the flowchart which showed the operation | movement at the time of operation. It is the flowchart which showed the operation | movement at the time of operation. It is the figure which showed an example of the relationship between the drive current and temperature of the light emission apparatus of this invention. It is the figure which showed an example of the relationship between the drive current and temperature of the light emission apparatus of this invention. It is a flowchart of each parameter acquisition before operation. It is the flowchart which showed the determination method of the parameter before an operation | movement in the method of suppressing the temperature fluctuation of the semiconductor light-emitting device at the time of modulation | alteration of setting temperature. It is the flowchart which showed an example of the determination method of the relationship between preset temperature and injection power. It is the flowchart which showed an example of the determination method of preset temperature and injection | pouring power. It is the flowchart which showed the operation | movement at the time of operation. It is the figure which showed the temperature behavior of the semiconductor light-emitting device. It is the flowchart which showed the operation | movement at the time of operation | movement of the temperature control method when changing control current and temperature simultaneously. It is the block diagram which showed an example of the control object apparatus of this invention. It is the block diagram which showed an example of the control object apparatus of this invention. It is a flowchart of each parameter acquisition before operation. It is the flowchart which showed an example of the determination method of the modulation width and delay time of control target temperature among the determination methods of the parameter before an operation | movement. It is the flowchart which showed an example of the determination method of the modulation width and delay time of control target temperature among the determination methods of the parameter before an operation | movement. It is the flowchart which showed the operation | movement at the time of operation. It is a block diagram of a controlled object device which has a light source using a wavelength conversion element. It is the block diagram which showed the general structure of the projector apparatus using a lamp light source. It is the block diagram which showed the general structure of the projector apparatus using a laser light source. It is the figure which showed the wavelength temperature dependence of a semiconductor laser element. It is the block diagram which showed the structure of the high output light source using a general semiconductor laser element, and the control system in a light source drive device.

  Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described.

<Embodiment>
[First example of light emitting device]
An example of the light emission apparatus according to the embodiment of the present invention will be described with reference to the block diagram of FIG.

As shown in FIG. 1, the light source 11 includes a semiconductor light emitting element 21 that emits light. Examples of the semiconductor light emitting element 21 include a semiconductor laser element and a light emitting diode.
Further, the light source 11 is provided with a temperature measuring unit 22 that measures the temperature of the light source 11. Further, a temperature control element 23 is provided for controlling the temperature of the light source 11 (substantially the temperature of the semiconductor light emitting element 21) to a control target temperature based on the temperature information measured by the temperature measuring unit 22. And the temperature control part 12 which instruct | indicates a control target temperature to the said temperature control element 23 is provided.
The semiconductor light emitting element 21 is provided with a drive circuit 13 for driving it.

  Further, a control unit 14 is provided for instructing a set temperature to the temperature measuring unit 22 and instructing a driving current to the driving circuit 13. For example, the control unit 14 instructs the drive circuit 13 to specify a drive current value so that the emission power emitted from the semiconductor light emitting element 21 becomes a desired value, and sets the light source 11 to a predetermined temperature. The set temperature or the like is instructed to the temperature control unit 12.

A memory unit 15 is connected to the control unit 14. The memory unit 15 stores measured values of the driving voltage value and the emission power of the semiconductor light emitting element 21.
The method for obtaining the measured value utilizes, for example, that the driving voltage value of the semiconductor light emitting element 21 and the emission power of the semiconductor light emitting element 21 that are measured in advance depend on the driving current.
First, the semiconductor light emitting element 21 is caused to emit light by changing the drive current value stepwise. Then, after the temperature of the semiconductor light emitting element 21 is sufficiently settled, each of the driving voltage value and the emission power of the semiconductor light emitting element 21 is measured and obtained.

Next, a case where light is emitted from the light source 11 will be described.
In order to cause the semiconductor light emitting element 21 of the light source 11 to emit light, a driving current is supplied to the semiconductor light emitting element 21. At this time, by modulating the control target temperature simultaneously with the modulation of the current value of the supplied drive current, the temperature stabilization time and the temperature fluctuation range are eliminated or reduced.
As an example of the control temperature modulation, the value of the control target temperature is modulated in the direction opposite to the direction of temperature change, and returned to the original constant temperature in a time corresponding to the time constant.
That is, when the temperature control unit 12 causes at least binary output fluctuations in the light source 11, the temperature control element 23 gives an instruction to suppress temperature fluctuations associated with the output fluctuations.

  When the drive current is lowered in FIG. 2, when the drive current is raised in FIG. 3, the temperature of the semiconductor light emitting element, the set temperature of the semiconductor light emitting element, the oscillation wavelength of the semiconductor light emitting element when the drive current is changed Shows the behavior.

  As shown in FIG. 2, for example, when the drive current is reduced in response to the luminance fluctuation of the video signal, the control target temperature (indicated by a dotted line in the figure) of the semiconductor light emitting element 21 is simultaneously modulated to increase. The temperature of the semiconductor light emitting element 21 is made constant. Thus, since the temperature of the semiconductor light emitting element 21 is constant, the oscillation wavelength of the semiconductor light emitting element 21 does not vary. Accordingly, there is no fluctuation time during which the semiconductor light emitting element 21 fluctuates in output due to the decrease in the drive current. In the figure, the temperature distribution and the oscillation wavelength distribution indicated by the two-dot chain line show the fluctuation state of the temperature distribution and the oscillation wavelength distribution of the semiconductor light emitting element 21 when the control target temperature is not modulated in the increasing direction. is there.

  Further, as shown in FIG. 3, for example, when the drive current is increased in response to the luminance fluctuation of the video signal, the control target temperature (indicated by the dotted line in the figure) of the semiconductor light emitting element 21 is lowered at the same time. So that the temperature of the semiconductor light emitting element 21 becomes constant. Thus, since the temperature of the semiconductor light emitting element 21 is constant, the oscillation wavelength of the semiconductor light emitting element 21 does not vary. Therefore, there is no fluctuation time during which the semiconductor light emitting element 21 is fluctuating in output due to the increased drive current. In the figure, the temperature distribution and the oscillation wavelength distribution indicated by the two-dot chain line show the fluctuation state of the temperature distribution and oscillation wavelength distribution of the semiconductor light emitting element 21 when the control target temperature is not modulated in the lowering direction. is there.

Here, as a comparative example, from a state where a constant drive current is supplied to the light source 11 (semiconductor light emitting element 21) and the temperature is controlled, the drive current is changed in accordance with the luminance fluctuation of the video signal, and the semiconductor The case where the emission power of the light emitting element 21 is changed will be described with reference to FIG. FIG. 4 shows the temperature and wavelength behavior of the semiconductor light emitting device 21 when the drive current of the semiconductor light emitting device 21 is lowered.
As shown in FIG. 4, since the time constant of the temperature conversion of the semiconductor light emitting element 21 is large with respect to the modulation speed of the driving current, the temperature of the semiconductor light emitting element 21 deviates from the set temperature immediately after the driving current is changed. To do. Due to such temperature divergence, the oscillation period continues for a certain period in a state where the wavelength of the light oscillated from the semiconductor light emitting element 21 deviates from the target wavelength, and then the wavelength converges as the temperature converges.

  Next, the modulation width ΔT-set of the control target temperature and the delay time Δt-set until returning to the original control target temperature can be improved by selecting values optimized by the modulation width of the drive current. What can be done will be described with reference to FIG.

As shown in FIG. 5A, when the modulation width ΔIop of the drive current is small, the modulation width ΔT-set and the delay time Δt-set of the control target temperature are small.
On the other hand, as shown in FIG. 5B, when the modulation width ΔIop of the drive current is large, the modulation width ΔT-set and the delay time Δt-set of the control target temperature are large.
In the figure, the temperature distribution indicated by a two-dot chain line indicates a fluctuation state of the temperature distribution of the semiconductor light emitting element 21 when the control target temperature is not modulated.

  Alternatively, the modulation width ΔT-set of the control target temperature and the delay time Δt-set until returning to the original control target temperature are proportional to the surplus power P at the time of fluctuation of the drive current obtained by the following equation (1). You may ask.

P = [Generated power after changing current value]-[Generated power before changing current value]
= (Vop2 * Iop2-Pout2)-(Vop1 * Iop1-Pout1) (1)

  Here, Vop1 is the drive voltage before change, Iop1 is the drive current before change, Pout1 is the injection power before change, Vop2 is the drive voltage after change, Iop2 is the drive current after change, and Pout2 is the injection power after change. Represents.

  The drive voltage and emission power of the semiconductor light emitting element 21 depend on the drive current. Therefore, before operation, while changing the drive current value for each stage, each measured after the temperature is sufficiently settled, put in the memory, calculate the surplus power P with reference to the actual operation, ΔT-set and Δt-set can be obtained.

  FIG. 6 shows a configuration diagram of the light emitting apparatus to which this processing is added. In addition, one configuration of the light emitting device during actual operation is as shown in FIG.

As shown in FIG. 6, the light source 11 includes a semiconductor light emitting element 21 that emits light. Examples of the semiconductor light emitting element 21 include a semiconductor laser element and a light emitting diode.
Further, the light source 11 is provided with a temperature measuring unit 22 that measures the temperature of the light source 11. Further, a temperature control element 23 is provided for controlling the temperature of the light source 11 (substantially the temperature of the semiconductor light emitting element 21) to a control target temperature based on the temperature information measured by the temperature measuring unit 22. And the temperature control part 12 which instruct | indicates a control target temperature to the said temperature control element 23 is provided.
The semiconductor light emitting element 21 is provided with a drive circuit 13 for driving it.

  Further, a control unit 14 is provided for instructing a set temperature to the temperature measuring unit 22 and instructing a driving current to the driving circuit 13. For example, the control unit 14 instructs the drive circuit 13 to specify a drive current value so that the emission power emitted from the semiconductor light emitting element 21 becomes a desired value, and sets the light source 11 to a predetermined temperature. The set temperature or the like is instructed to the temperature control unit 12.

A memory unit 15 is connected to the control unit 14. The memory unit 15 stores measured values of the driving voltage value and the emission power of the semiconductor light emitting element 21.
The method for obtaining the measured value utilizes, for example, that the driving voltage value of the semiconductor light emitting element 21 and the emission power of the semiconductor light emitting element 21 that are measured in advance depend on the driving current.
First, the semiconductor light emitting element 21 is caused to emit light by changing the drive current value stepwise. Then, after the temperature of the semiconductor light emitting element 21 is sufficiently settled, each of the driving voltage value and the emission power of the semiconductor light emitting element 21 is measured and obtained.

Next, a case where light is emitted from the light source 11 will be described.
In order to cause the semiconductor light emitting element 21 of the light source 11 to emit light, a driving current is supplied to the semiconductor light emitting element 21. At this time, by modulating the control target temperature simultaneously with the modulation of the current value of the supplied drive current, the temperature stabilization time and the temperature fluctuation range are eliminated or reduced.
As an example of the control temperature modulation, the value of the control target temperature is modulated in the direction opposite to the direction of temperature change, and returned to the original constant temperature in a time corresponding to the time constant.
That is, when the temperature control unit 12 causes at least binary output fluctuations in the light source 11, the temperature control element 23 gives an instruction to suppress temperature fluctuations associated with the output fluctuations.

  Further, the light emission power of the light emitted from the semiconductor light emitting element 21 is measured by the light receiving unit 41, the drive voltage is measured by the drive voltage measurement unit 31, and the measured value is obtained in the memory 15 by changing the drive current stepwise. Stored and used for calculation with reference to this stored value during operation. The drive voltage measurement unit 31 measures the drive power (drive voltage) supplied from the drive circuit 13. The drive voltage value measured by the drive voltage measuring unit 31 is transmitted to the control unit 14 and stored in the memory unit 15 from the control unit 14. Further, the control unit 14 extracts the drive voltage of the temperature control element 23 corresponding to the change of the drive voltage value, and instructs the temperature control unit 12 to extract it. Then, temperature control element driving power is supplied from the temperature control unit 12 to the temperature control element 23.

  Next, a method for determining each parameter before operation will be described with reference to the flowcharts of FIGS. 7 to 9, and operations during operation will be described with reference to the flowchart of FIG.

FIG. 7 shows a method for suppressing temperature fluctuations of the semiconductor light emitting device when the drive current is modulated, and is a flowchart of parameter acquisition before operation.
As shown in FIG. 7, first, in “measurement of each parameter” S7-1, the emission power of the semiconductor light emitting element, the driving voltage for driving the semiconductor light emitting element, etc. when the drive current is changed stepwise are shown. taking measurement.
Next, in “obtain relationship between set current value and emission power” S7-2, the relationship between the set current value for driving the semiconductor light emitting element 21 and the emission power output from the semiconductor light emitting element is obtained.

Next, in “Determine the modulation width ΔT-set of the control target temperature” S7-3, the modulation width ΔT-set of the control target temperature is determined.
Subsequently, in “determining the delay time Δt-set of the control target temperature” S7-4, the delay time Δt-set of the control target temperature is determined.
Then, in “END” S7-5, the above flow is ended.
By the above procedure, the modulation width ΔT-set of the control target temperature and the delay time Δt-set of the control target temperature are determined.

Next, a method for determining parameters before operation in the method for suppressing temperature fluctuation of the semiconductor light emitting element during drive current modulation will be described with reference to the flowchart of FIG.
First, in “obtain relationship between set current value and emission power” S8-1, the relationship between the set current value for driving the semiconductor light emitting element 21 and the emission power output from the semiconductor light emitting element 21 is acquired.

  Next, in “set current value to minimum value” S8-2, the previously acquired set current value is set to the minimum value.

  Next, in “temperature stabilization confirmation” S8-3, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. In this determination, if the temperature is not settled, after a certain time, “temperature stabilization confirmation” S8-3 is performed again.

  On the other hand, in the case where the temperature is stabilized, in “Measure injection power” S8-4, the emission power at the time of temperature stabilization of the semiconductor light emitting element is measured.

  Next, in “Measure drive voltage” S8-5, the drive voltage when the temperature of the semiconductor light emitting element is stabilized is measured.

  Next, in “Record injection power and drive voltage in memory” S8-6, the previously measured injection power and drive voltage are recorded in the memory unit.

  In step S8-7, it is determined whether the injection power recorded in the memory unit and the previously set drive current are upper limit values. If both are upper limits, the flow is terminated by “end” S8-9.

  On the other hand, if the upper limit is not reached, the drive current value is increased in “Increase current value” S8-8, and the above flow is repeated from “Confirm temperature stabilization” S8-3.

  Next, an example of a method for determining the modulation width and delay time of the control target temperature among the methods for determining the parameters before operation in the method for suppressing temperature fluctuations of the semiconductor light emitting element during drive current modulation is shown in the flowchart of FIG. explain.

  As shown in FIG. 9, first, the modulation width ΔT-set of the control target temperature is determined in “determining the modulation width ΔT-set of the control target temperature” S9-1.

  Next, in “Determine the width of power to be varied” S9-2, the width for varying the emission power of the semiconductor light emitting element is determined.

  Next, in “determining the delay time Δt-set of the control target temperature” S9-3, the delay time Δt-set of the control target temperature is determined.

  Next, in “determining the modulation width ΔT-set of the control target temperature” S9-4, the modulation width ΔT-set of the control target temperature is determined.

  Next, in “operation of light source with control target temperature and reference drive current” S9-5, the semiconductor light emitting element of the light source is operated with control target temperature and reference drive current.

  Next, in “temperature stabilization confirmation” S9-6, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. If it is determined that the temperature is not settled, after a predetermined time, “temperature stabilization confirmation” S9-6 is performed again.

  On the other hand, if the temperature is statically set, “modulate the drive current and simultaneously operate the light source with the target set temperature as the modulation amount (ΔT-set) and the delay time (Δt-set)” in S9-7. The drive current is modulated, and at the same time, the control target temperature is set to the modulation amount (ΔT-set) and the delay time (Δt-set) to operate the semiconductor light emitting element of the light source.

  Next, in “Measure temperature and time until settling” S9-8, the temperature and time until the temperature of the semiconductor light emitting element is settled are measured.

  Next, “is the range of ΔT-set sufficient?” In S9-9, it is determined whether the range of ΔT-set is sufficient.

  If it is determined that the range of ΔT-set is not sufficient, “change ΔT-set” S9-10 is performed, and “operate the light source at the control target temperature and reference drive current” S9-5 and the following are performed again. .

  In the above judgment, if the range of ΔT-set is sufficient, “the modulation amount with the smallest temperature variation of the light source is set as the optimum value at the time of the power variation and stored in the memory unit” S9-11, the light source (semiconductor The modulation component with the smallest temperature variation of the light emitting element is stored in the memory unit as the optimum value when the emission power of the semiconductor light emitting element varies.

  Next, it is determined whether or not the range of the emission power fluctuation range of the semiconductor light emitting element is sufficient in “Is the fluctuation power width sufficient?” S9-12.

  If the “variable power width is sufficient” S9-12, the flow is terminated by “end” S9-14.

  If the width of the fluctuation power is not enough in S9-12, the fluctuation power width is changed in S9-13, and the control target is set again. “Determine temperature delay time Δt-set”.

  Next, an example of a method for determining the modulation width and delay time of the control target temperature among the methods for determining the parameters before operation in the method for suppressing temperature fluctuations of the semiconductor light emitting element during drive current modulation is shown in the flowchart of FIG. explain.

  As shown in FIG. 10, first, “determination of control target temperature delay time Δt-set” is determined in S10-1 to determine the control target temperature delay time Δt-set.

  Next, in “Determine the width of power to be varied” S10-2, the width for varying the emission power of the semiconductor light emitting element is determined.

  Next, in “determining the modulation width ΔT-set of the control target temperature” S10-3, the modulation width ΔT-set of the control target temperature is determined.

  Next, in “determining the delay time Δt-set of the control target temperature” S10-4, the delay time Δt-set of the control target temperature is determined.

  Next, in “operating light source with control target temperature and reference drive current” S10-5, the semiconductor light emitting element of the light source is operated with control target temperature and reference drive current.

  Next, in “temperature stabilization confirmation” S10-6, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. In this determination, when the temperature is not settled, after a predetermined time, the “temperature stabilization confirmation” S10-6 is performed again.

  On the other hand, if the temperature is statically set, “modulate the drive current and simultaneously operate the light source with the target set temperature as the modulation amount (ΔT-set) and the delay time (Δt-set)” in S10-7, The drive current is modulated, and at the same time, the control target temperature is set to the modulation amount (ΔT-set) and the delay time (Δt-set) to operate the semiconductor light emitting element of the light source.

  Next, in “Measure temperature and time until settling” S10-8, the temperature and time until the temperature of the semiconductor light emitting element settles are measured.

  Next, “is the range of Δt-set sufficient?” In S10-9, it is determined whether the range of Δt-set is sufficient.

  In this determination, if the range of Δt-set is not sufficient, “change Δt-set” S10-10 is performed, and “operate the light source at the control target temperature and the reference drive current” S10-5 and the following are performed again. .

  In the above judgment, if the range of Δt-set is sufficient, “store the delay time with the shortest settling time of the light source as the optimum value at the time of power fluctuation and store it in the memory” S10-11, the light source ( The modulation amount with the shortest settling time of the semiconductor light emitting element) is stored in the memory unit as the optimum value when the emission power of the semiconductor light emitting element varies.

  Next, it is determined whether or not the range of the emission power fluctuation range of the semiconductor light emitting element is sufficient in “Is the fluctuation power width sufficient?” S10-12.

  If the “variable power width is sufficient” S10-12, the flow is terminated by “end” S10-14.

  If the width of the fluctuation power is not sufficient in the above “variable power width is enough” S10-12, the fluctuation power width is changed in “change the fluctuation power width” S10-13, and again “control target”. The temperature modulation width ΔT-set is determined.

  Next, operation during operation will be described with reference to FIG.

  As shown in FIG. 11, in “in operation” S11-1, “the light source is driven at the specified power and reference temperature” in S11-2, the semiconductor light emitting element of the light source is driven at the specified emission power and the reference temperature. ing.

  Next, in “power fluctuation value instruction” S11-3, a power fluctuation value is instructed by an external input.

  In this state, “refer to the drive current (Iop1) and drive voltage (Vop1) at the current injection power (Pout1) from the memory unit”, and drive at the injection power (Pout1) after the change from the memory unit in S11-4. Reference is made to the current (Iop1) and the drive voltage (Vop1).

  Next, “refer to the drive current (Iop2) and drive voltage (Vop2) at the changed injection power (Pout2) from the memory unit”, and drive at the changed injection power (Pout2) from the memory unit at S11-5. Reference is made to the current (Iop2) and the drive voltage (Vop2).

  Next, surplus power is calculated in “calculation of surplus power” S11-6. For example, it is calculated by the following equation (2).

P = [Generated power after changing current value]-[Generated power before changing current value]
= (Vop2 * Iop2-Pout2)-(Vop1 * Iop1-Pout1) (2)

  Here, Vop1 is the drive voltage before change, Iop1 is the drive current before change, Pout1 is the injection power before change, Vop2 is the drive voltage after change, Iop2 is the drive current after change, and Pout2 is the injection power after change. Represents.

  Next, in “refer to the modulation temperature width ΔT-set and delay time Δt-set according to the surplus power P from the memory unit” S11-7, the modulation width ΔT− of the control target temperature according to the surplus power P from the memory unit. Refer to set, delay time Δt-set.

  Next, “change the drive current and modulate the target temperature by the delay time and by the modulation temperature width” in S11-8, change the drive current and set the control target temperature by the delay time Δt-set and the control target temperature. Is modulated by the modulation width ΔT-set.

  Then, S11-2 to S11-8 are repeated so that the temperature of the semiconductor light emitting element is stabilized.

Next, a method for suppressing excessive temperature and wavelength fluctuation during temperature modulation will be described.
This method can also be applied when changing the temperature of the controlled object.

First, temperature control of the semiconductor laser element will be described.
In a control system with a large temperature time constant, even if the control target temperature is changed, there is a limit to the temperature tracking, the settling time is long, and the fluctuation is large. However, by changing the value considering the changed temperature to the control target temperature, both the settling time and the temperature fluctuation can be reduced.

  For example, the normal temperature behavior of a semiconductor light emitting device is shown in FIG. Further, FIG. 13 shows the temperature behavior of the semiconductor light emitting element when the above treatment is performed.

  As shown in FIG. 12, in a control system with a large temperature time constant, if the drive current is constant and there is a limit to follow the temperature even if the control target temperature is changed, the temperature of the semiconductor light emitting element is kept constant. It takes a long time and the temperature fluctuation range becomes large. As described above, since the time during which the temperature of the semiconductor light emitting element 21 is constant is long, the fluctuation of the oscillation wavelength of the semiconductor light emitting element 21 increases.

  On the other hand, as shown in FIG. 13, in a control system having a large temperature time constant, when the drive current is constant and the control target temperature is modulated, the time during which the temperature of the semiconductor light emitting element is constant is shortened. The fluctuation range is also reduced. As described above, since the time during which the temperature of the semiconductor light emitting element 21 is constant is short and the temperature fluctuation range is small, the fluctuation of the oscillation wavelength of the semiconductor light emitting element 21 hardly occurs or is greatly reduced.

  The modulation width ΔT-set of the control target temperature and the delay time Δt-set until returning to the original control target temperature can be obtained in proportion to the power difference before and after the temperature change. The surplus power P is expressed by the following equation (3).

P = [Generated power after temperature change]-[Generated power before temperature change]
= (Vop2 * Iop2-Pout2)-(Vop1 * Iop1-Pout1) (3)

  Here, Vop1 is the drive voltage before change, Iop1 is the drive current before change, Pout1 is the injection power before change, Vop2 is the drive voltage after change, Iop2 is the drive current after change, and Pout2 is the injection power after change. Represents.

  As described above, the temperature and emission power of the semiconductor light emitting element 21 depend on the temperature. Therefore, before operation, while changing the drive current value for each stage, each measured after the temperature is sufficiently settled, put in the memory, calculate the surplus power P with reference to the actual operation, ΔT-set and Δt-set can be obtained.

Further, the configuration enabling the above processing is the same as the configuration shown in FIG. 6 described above. Before the operation, the light receiving unit 41 is used to store the injection power at each temperature in the memory unit 15 and the actual processing. Reference during operation.
FIG. 14 shows a method for determining each parameter before operation, and FIG. 15 shows an operation description during operation.

FIG. 14 shows a method for suppressing temperature fluctuations of the semiconductor light emitting element 21 when the control target temperature is modulated, and is a flowchart for acquiring each parameter before operation.
As shown in FIG. 14, first, in “measurement of each parameter” S <b> 14-1, the emission power of the semiconductor light emitting element 21, the temperature of the semiconductor light emitting element 21, etc. when the control target temperature is changed stepwise are measured. .
Next, in “obtain relationship between set temperature and emission power” S14-2, the relationship between the set temperature when driving the semiconductor light emitting element 21 and the emission power output from the semiconductor light emitting element 21 is acquired.

Next, in “determining the modulation width ΔT-set of the control target temperature” S14-3, the modulation width ΔT-set of the control target temperature is determined.
Subsequently, in “Determine delay time Δt-set of control target temperature” S14-4, the delay time Δt-set of control target temperature is determined.
Then, in “END” S14-5, the above flow is ended.
By the above procedure, the modulation width ΔT-set of the control target temperature and the delay time Δt-set of the control target temperature are determined.

Next, a method for determining parameters before operation in the method for suppressing temperature fluctuations of the semiconductor light emitting element during modulation of the set temperature will be described with reference to the flowchart of FIG.
First, in “obtain relationship between set temperature and injection power” S15-1, the relationship between the set temperature when driving the semiconductor light emitting element and the injection power output from the semiconductor light emitting element is acquired.

  Next, in “Set temperature as reference temperature” S15-2, the previously acquired set temperature is set as the reference temperature.

  Next, in “temperature stabilization confirmation” S15-3, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. In this determination, when the temperature is not settled, after a certain period of time, “temperature stabilization confirmation” S15-3 is performed again.

  On the other hand, in the case where the temperature is stabilized, in “Measure injection power” S15-4, the emission power at the time of temperature stabilization of the semiconductor light emitting element is measured.

  Next, in “Measure drive voltage” S15-5, the drive voltage when the temperature of the semiconductor light emitting element is stabilized is measured.

  Next, in “record injection power and drive voltage in memory” S15-6, the previously measured injection power and drive voltage are recorded in the memory unit.

  Next, it is determined whether or not the entire range of the set temperature has been grasped in “Successfully grasped the entire range of the set temperature” S15-7. If both of them are grasped, this flow is ended by “END” S15-9.

  On the other hand, if it is not grasped, the set temperature is changed in “change set temperature” S15-8, and the following flow is repeated again from the “confirm temperature confirmation” S15-3.

  Next, an example of a method for determining the relationship between the set temperature and the injection power among the methods for determining the parameters before operation in the method for suppressing temperature fluctuation of the semiconductor light emitting element during the control target temperature modulation will be described with reference to the flowchart of FIG. To do.

  As shown in FIG. 16, first, in “Determine target temperature modulation width ΔT-set” S16-1, the control target temperature modulation width ΔT-set is determined.

  Next, in “Determine the temperature range to be varied” S16-2, the width for varying the control target temperature is determined.

  Next, in “Assuming delay time Δt-set” S16-3, the delay time Δt-set of the control target temperature is assumed.

  Next, in “determining the target temperature overmodulation width ΔT-set” S16-4, the control target temperature overmodulation width ΔT-set is determined.

  Next, in “activate light source with target temperature and reference drive current” S16-5, the semiconductor light emitting element of the light source is operated with the control target temperature and reference drive current.

  Next, in “temperature stabilization confirmation” S16-6, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. In this determination, when the temperature is not settled, after a certain period of time, “temperature stabilization confirmation” S16-6 is performed again.

  On the other hand, in the case where the temperature is statically set, “the target temperature is modulated by adding an excess modulation amount ΔT-set and the light source is operated with a delay time (Δt-set)”. In S16-7, the control target temperature is excessively exceeded. Modulation is performed by adding a modulation amount ΔT-set, and the semiconductor light emitting element of the light source is operated with a delay time (Δt-set).

  Next, in “Measure temperature and time until settling” S16-8, the temperature and time until the temperature of the semiconductor light emitting element settles are measured.

  Next, “is the range of ΔT-set sufficient?” In S16-9, it is determined whether the range of ΔT-set is sufficient.

  If it is determined that the range of ΔT-set is not sufficient, “change ΔT-set” S16-10 is performed, and “operate the light source at the target temperature and reference current” S16-5 and the subsequent steps are performed again.

  In the above determination, if the range of ΔT-set is sufficient, “the modulation amount with the smallest temperature variation of the light source is set as the optimum value at the time of this power variation and stored in the memory” S16-11, the light source (semiconductor light emission) The modulation component with the smallest temperature variation of the element) is stored in the memory unit as the optimum value when the emission power of the semiconductor light emitting element varies.

  Next, it is determined whether or not the temperature variation range of the semiconductor light emitting element is sufficient in “Is the temperature variation range sufficient” S16-12.

  If the “temperature variation range is sufficient” S16-12 and the temperature variation range is sufficient, the flow is terminated by “end” S16-14.

  If the temperature fluctuation range is not sufficient in the above “Saturation fluctuation range is sufficient” S16-12, the temperature fluctuation range is changed in “Change temperature fluctuation range” S16-13, and again “delay time Δt− Assumes set "S16-3 and subsequent steps.

  Next, among the parameter determination methods before operation in the method for suppressing temperature fluctuation of the semiconductor light emitting element during the control target temperature modulation, an example of a method for determining the set temperature and the injection power will be described with reference to the flowchart of FIG.

  As shown in FIG. 17, first, “determination of target temperature delay time Δt-set” is determined in S17-1 to determine the control target temperature delay time Δt-set.

  Next, in “Determine the width of power to be varied” S17-2, the width for varying the emission power of the semiconductor light emitting element is determined.

  Next, in “Fix target temperature overmodulation width ΔT-set” S17-3, the control target temperature overmodulation width ΔT-set is fixed.

  Next, in “Assuming delay time Δt-set” S17-4, the delay time Δt-set of the control target temperature is assumed.

  Next, in “operating light source with control target temperature and reference drive current” S10-5, the semiconductor light emitting element of the light source is operated with control target temperature and reference drive current.

  Next, in “temperature stabilization confirmation” S17-6, the semiconductor light emitting element is caused to emit light, and it is determined whether or not the temperature is stabilized. In this determination, when the temperature is not settled, after a predetermined time, the “temperature stabilization confirmation” S17-6 is performed again.

  On the other hand, in the case where the temperature is settled, “the target temperature is modulated by adding an overmodulation component (ΔT-set), and the light source is operated with a delay time (Δt-set)”. Is modulated by adding an excess modulation component (ΔT-set) to operate the semiconductor light emitting element of the light source with a delay time (Δt-set).

  Next, in “Measure temperature and time until settling” S17-8, the temperature and time until the temperature of the semiconductor light emitting element is settled are measured.

  Next, “whether the range of Δt-set is sufficient” is determined in S17-9 to determine whether the range of Δt-set is sufficient.

  If it is determined by this determination that the range of Δt-set is not sufficient, “change Δt-set” S17-10 is performed, and “operate the light source at the target temperature and reference drive current” S17-5 and subsequent steps are performed again.

  In the above judgment, if the range of Δt-set is sufficient, “the modulation amount with the smallest temperature variation of the light source is set as the optimum value at the time of this power variation and stored in the memory” S17-11, the light source (semiconductor light emission The modulation component with the smallest temperature variation of the element) is stored in the memory unit as the optimum value when the emission power of the semiconductor light emitting element varies.

  Next, it is determined whether or not the range of the emission power fluctuation range of the semiconductor light emitting device is sufficient in “Is the fluctuation power width sufficient?” S17-12.

  If the “variable power width is sufficient” S17-12, the flow is terminated by “end” S17-14.

  If the width of the fluctuation power is not enough in S17-12, the fluctuation power width is changed in "Change the fluctuation power width" S17-13, and again "Target temperature" The over-modulation width ΔT-set is fixed ”at S17-3 and thereafter.

  Next, operation during operation will be described with reference to FIG.

  As shown in FIG. 18, in “in operation” S18-1, “the light source is driven at the specified power and reference temperature” in S18-2, the semiconductor light emitting element of the light source is driven at the specified emission power and the reference temperature. ing.

  Next, in “temperature fluctuation value instruction” S18-3, a temperature fluctuation value is instructed by an external input.

  In this state, “refer to the drive current (Iop1) and drive voltage (Vop1) at the current injection power (Pout1) from the memory unit”, and drive at the injection power (Pout1) after the change from the memory unit in S18-4. Reference is made to the current (Iop1) and the drive voltage (Vop1).

  Next, “refer to the drive current (Iop2) and drive voltage (Vop2) at the changed injection power (Pout2) from the memory unit”, and drive at the changed injection power (Pout2) from the memory unit at S18-5. Reference is made to the current (Iop2) and the drive voltage (Vop2).

  Next, surplus power is calculated in “calculation of surplus power” S18-6. For example, it is calculated by the following equation (4).

P = [Generated power after changing current value]-[Generated power before changing current value]
= (Vop2 * Iop2-Pout2)-(Vop1 * Iop1-Pout1) (4)

  Here, Vop1 is the drive voltage before change, Iop1 is the drive current before change, Pout1 is the injection power before change, Vop2 is the drive voltage after change, Iop2 is the drive current after change, and Pout2 is the injection power after change. Represents.

  Next, “refer to the modulation temperature width ΔT-set and delay time Δt-set according to the surplus power P from the memory unit” in S18-7, the modulation width ΔT− of the control target temperature according to the surplus power P from the memory unit. Refer to set, delay time Δt-set.

  Next, “modulate the target temperature obtained by adding the overmodulation amount to the target temperature by the delay time of the target temperature” in S18-8, the control target temperature is added to the control target temperature obtained by adding the overmodulation amount to the control target temperature. Modulate by the delay time.

  Then, S18-2 to S18-8 are repeated so that the temperature of the semiconductor light emitting element is stabilized.

Next, a method for suppressing excessive temperature and wavelength fluctuation during temperature modulation will be described.
This method can also be applied when changing the temperature of the controlled object.

First, temperature control of the semiconductor laser element will be described.
In a control system with a large temperature time constant, even if the control target temperature is changed, there is a limit to the temperature tracking, the settling time is long, and the fluctuation is large. However, by changing the value considering the changed temperature to the control target temperature, both the settling time and the temperature fluctuation can be reduced.
For example, FIG. 19 shows the temperature behavior of the semiconductor light emitting element when the above processing is performed.

  As shown in FIG. 19, when the drive current is modulated and the control target temperature is modulated at the same time, the time during which the temperature of the semiconductor light emitting element becomes constant is shortened, and the temperature fluctuation range is also reduced. As described above, since the time during which the temperature of the semiconductor light emitting element 21 is constant is short and the temperature fluctuation range is small, the fluctuation of the oscillation wavelength of the semiconductor light emitting element 21 hardly occurs or is greatly reduced.

  Next, the operation at the time of operation of the temperature control method when the control current and the temperature are simultaneously changed will be described with reference to FIG.

  As shown in FIG. 20, in “in operation” S20-1, “light source is driven at specified power and reference temperature” in S20-2, the semiconductor light emitting element of the light source is driven at the specified emission power and reference temperature. ing.

  Next, in “injection power and temperature fluctuation value instruction” S20-3, the injection power and temperature fluctuation value are instructed by an external input.

  In this state, “refer to the drive current (Iop1) and drive voltage (Vop1) at the current injection power (Pout1) from the memory unit”, and drive at the injection power (Pout1) after the change from the memory unit in S20-4. Reference is made to the current (Iop1) and the drive voltage (Vop1).

  Next, “refer to the drive current (Iop2) and drive voltage (Vop2) at the injection power (Pout2) after the output change from the memory unit”, the injection power (Pout2) after the output change from the memory unit at S20-5. Reference is made to the drive current (Iop2) and the drive voltage (Vop2).

  Next, “See the drive current (Iop3) and the drive voltage (Vop3) at the injection power (Pout3) after temperature change from the memory unit”) In S20-6, the injection power (Pout3) after temperature change from the memory unit Reference is made to the drive current (Iop3) and the drive voltage (Vop3).

  Next, surplus power is calculated in “calculation of surplus power P1, P2” S20-7. For example, it is calculated by the following formulas (5) and (6).

P = [Generated power after output change]-[Generated power before output change]
= (Vop2 * Iop2-Pout2)-(Vop1 * Iop1-Pout1) (5)

P = [Generated power after temperature change]-[Generated power before temperature change]
= (Vop3 * Iop3-Pout3)-(Vop1 * Iop1-Pout1) (6)

  Here, Vop1 is the drive voltage before change, Iop1 is the drive current before change, Pout1 is the injection power before change, Vop2 is the drive voltage after change, Iop2 is the drive current after change, and Pout2 is the injection power after change. , Vop3 represents the changed driving voltage, Iop3 represents the changed driving current, and Pout3 represents the changed ejection power.

  Next, in “S20-8, refer to modulation temperature width ΔT-set 1 and 2 and delay time Δt-set 1 and 2 according to surplus power P1 and P2 from the memory unit”, according to surplus power P1 and P2 from the memory unit. Reference is made to the modulation width ΔT-set 1 and 2 and the delay time Δt-set 1 and 2 of the control target temperature.

  Next, “ΔT-set 1, 2, Δt-set 1, 2 is added to calculate the modulation amount” S 20-9, the control target temperature modulation width ΔT-set 1, 2 and delay time Δt-set 1, 2 are set. Add and calculate the modulation.

  Next, “modulate the drive current and modulate the target temperature to an excessive amount by the delay time” in S20-10, change the drive current and change the control target temperature to the delay time Δt-set minutes. Then, modulation is performed by the modulation width ΔT-set of the control target temperature.

  Then, the above S20-2 to S20-10 are repeated so that the temperature of the semiconductor light emitting element is stabilized.

  Next, an application when the temperature control target is different from the drive target will be described below.

  As an application of the temperature control method described above, there is a method of controlling the stabilization time of the temperature of the controlled object and the fluctuation time width to the minimum when the energy given to the temperature controlled object fluctuates.

For example, the block diagram of FIG. 21 shows a configuration in which the temperature control target is different from the drive target.
As illustrated in FIG. 21, the control target device 51 includes a control target 61 that emits light. Examples of the control target 61 include a semiconductor laser element and a light emitting diode.
Further, the control target device 51 is provided with a temperature measuring unit 62 that measures the temperature of the control target device 51. Further, a temperature control element 63 is provided for controlling the temperature of the control target device 51 (substantially the temperature of the control target 61) to the control target temperature based on the temperature information measured by the temperature measuring unit 62. A temperature control unit 52 that instructs the temperature control element 63 to control the target temperature is provided.
The control object 61 is provided with a drive object 56 that supplies energy to drive the control object 61. A power supply circuit 53 that supplies drive power is connected to the drive target 56.

  Further, a control unit 54 is provided that instructs the temperature measurement unit 52 to set a temperature and instructs the power supply circuit 53 to supply a power value. For example, the control unit 54 instructs the power supply circuit 53 to set a current value so that the energy released from the control target device 51 becomes a desired value, and sets the control target device 51 to a predetermined temperature. The set temperature or the like is instructed to the temperature control unit 52.

  Next, the configuration during actual temperature control operation of the control target apparatus described with reference to FIG. 21 will be described with reference to the block diagram of FIG.

As illustrated in FIG. 22, the control target device 51 includes a control target 61 that emits light. Examples of the control target 61 include a semiconductor laser element and a light emitting diode.
Further, the control target device 51 is provided with a temperature measuring unit 62 that measures the temperature of the control target device 51. Further, a temperature control element 63 is provided for controlling the temperature of the control target device 51 (substantially the temperature of the control target 61) to the control target temperature based on the temperature information measured by the temperature measuring unit 62. A temperature control unit 52 that instructs the temperature control element 63 to control the target temperature is provided.
The control object 61 is provided with a drive object 56 that supplies energy to drive the control object 61. A power supply circuit 53 that supplies drive power is connected to the drive target 56.

  Further, a control unit 54 is provided that instructs the temperature measurement unit 52 to set a temperature and instructs the power supply circuit 53 to supply a power value. For example, the control unit 54 instructs the power supply circuit 53 to set a current value so that the energy released from the control target device 51 becomes a desired value, and sets the control target device 51 to a predetermined temperature. The set temperature or the like is instructed to the temperature control unit 52.

  Further, a memory unit 55 is connected to the control unit 54. The memory unit 55 stores a control target temperature modulation value and a delay time.

A case where the temperature is controlled to be constant in the configuration described with reference to FIGS. 21 and 22 will be described.
A certain amount of power is supplied from the power supply circuit 53 to the drive target 56, some energy from the drive target 56 is supplied to the control target 61, and the control target 61 is controlled to a constant temperature. In this state, the electric power supplied to the drive target 56 is modulated, and at the same time, the target temperature of the control target 61 is modulated, whereby the temperature settling time and the fluctuation time width can be controlled to the minimum.

FIG. 23 is a flowchart of each parameter acquisition before operation, showing a method for suppressing temperature fluctuation when changing the power supplied to the drive target when the temperature control target is different from the drive target.
As shown in FIG. 23, first, in “measurement of each parameter” S23-1, the emission energy of the controlled object, the energy for driving the controlled object, etc. when the drive current is changed stepwise are measured.

Next, in “Determine target temperature modulation width ΔT-set” S23-2, the control target temperature modulation width ΔT-set is determined.
Subsequently, in “Determine target temperature delay time Δt-set” S23-3, the control target temperature delay time Δt-set is determined.
Then, in “END” S23-4, the above flow is ended.
By the above procedure, the modulation width ΔT-set of the control target temperature and the delay time Δt-set of the control target temperature are determined.

  Next, an example of a method for determining a modulation width and a delay time of a control target temperature among methods for determining a parameter before operation in a method for suppressing temperature fluctuation at the time of changing power supplied to a drive target is shown in the flowchart of FIG. explain.

  As shown in FIG. 24, first, the modulation width ΔT-set of the control target temperature is determined in “determining the modulation width ΔT-set of the target temperature” S24-1.

  Next, in “Determine fluctuation range of power supplied to drive target” S24-2, the fluctuation width of power supplied to the drive target is determined.

  Next, in “Assuming Delay Time Δt-set” S24-3, the delay time Δt-set of the control target temperature is assumed.

  Next, in “determine target temperature modulation width ΔT-set” S24-4, the control target temperature modulation width ΔT-set is determined.

  Next, in “operate control target with target temperature and reference drive current” S24-5, the control target of the control target device is operated with the control target temperature and reference drive current.

  Next, in “temperature stabilization confirmation” S24-6, the control target is operated to determine whether or not the temperature is stabilized. In this determination, if the temperature is not settled, after a predetermined time, the “temperature stabilization confirmation” S24-6 is performed again.

  On the other hand, when the temperature is statically set, “the power supplied to the drive target is changed and the target temperature of the control target is simultaneously operated by the modulation amount (ΔT-set) and the delay time (Δt-set)” S24. In -7, the electric power supplied to the drive target is changed, and at the same time, the control target temperature of the control target is operated by the modulation amount (ΔT-set) and delay time (Δt-set) of the control target temperature.

  Next, in “Measure temperature and time until settling” S24-8, the temperature and time until the temperature of the controlled object is settling are measured.

  Next, “is the range of ΔT-set sufficient” in S24-9, it is determined whether the range of ΔT-set is sufficient.

  In this determination, if the range of ΔT-set is not sufficient, “change ΔT-set” S24-10 is performed, and “activate the control target with the control target temperature and the reference drive current” S24-5 or less is performed again. Do.

  In the above determination, if the range of ΔT-set is sufficient, “the modulation amount with the smallest temperature fluctuation of the drive target is set as the optimum value at the time of the supplied power and stored in the memory unit” S24-11. The modulation component with the smallest temperature fluctuation of the device (control target) is stored in the memory unit as the optimum value when the emission energy of the control target is changed.

  Next, in “S24-12, whether the range of change in power supplied to the drive target is sufficient” is determined in S24-12, whether the range of change in power supplied to the drive target is sufficient.

  In the above-mentioned “Will the range of change in the power supplied to the drive target is sufficient” S24-12, if sufficient, this flow is ended by “End” S24-14.

  If the range of change power is not enough in S24-12, the power supply is changed in S24-13, and the power supply is changed again. , “Determine delay time Δt-set of control target temperature” S24-3 and subsequent steps.

  Next, an example of a method for determining a modulation width and a delay time of a control target temperature among methods for determining a parameter before operation in a method for suppressing temperature fluctuation at the time of changing power supply to a drive target is shown in the flowchart of FIG. explain.

  As shown in FIG. 25, first, “determining the delay time Δt-set of the control target temperature” is determined in S25-1 to determine the delay time Δt-set of the control target temperature.

  Next, in “Determine fluctuation range of power supplied to drive target” S25-2, the fluctuation width of power supplied to the drive target is determined.

  Next, in “determining the target temperature modulation width ΔT-set” S25-3, the control target temperature modulation width ΔT-set is determined.

  Next, in “Assuming Delay Time Δt-set” S25-4, the delay time Δt-set of the control target temperature is assumed.

  Next, in “operating the control target with the target temperature and the reference drive current” S25-5, the control target of the control target device is operated with the control target temperature and the reference drive current.

  Next, in “temperature stabilization confirmation” S25-6, the control target is operated to determine whether or not the temperature is stabilized. If it is determined that the temperature is not settled, after a predetermined time, “temperature stabilization confirmation” S25-6 is performed again.

  On the other hand, when the temperature is statically set, “the power supplied to the drive target is changed and the target temperature of the control target is simultaneously operated by the modulation amount (ΔT-set) and the delay time (Δt-set)” S25. In -7, the electric power supplied to the drive target is changed, and at the same time, the control target temperature of the control target is operated by the modulation amount (ΔT-set) and delay time (Δt-set) of the control target temperature.

  Next, in “Measure temperature and time until settling” S25-8, the temperature and time until the temperature of the controlled object is settling are measured.

  Next, “is the range of Δt-set sufficient?” In S25-9, it is determined whether the range of Δt-set is sufficient.

  If it is determined that the range of Δt-set is not sufficient, “change Δt-set” S25-10 is performed, and “operate the control target at the control target temperature and the reference drive current” S25-5 or less again. Do.

  In the above determination, if the range of Δt-set is sufficient, “the delay time with the smallest temperature settling time is set as the optimum value at the time of power fluctuation and stored in the memory unit” in S25-11, the control target The delay time with the shortest settling time is set as the optimum value at the time of power fluctuation and stored in the memory unit.

  Next, it is determined whether or not the range of the change width of the power supplied to the drive target is sufficient in “Is the change width of the power supplied to the drive target sufficient” S25-12.

  In the above-mentioned “Will the range of change in the power supplied to the drive target is sufficient” S24-12, if sufficient, this flow is ended by “End” S24-14.

  If the width of change power is not enough in S24-12, the change power width is changed in S25-13. Again, “determine delay time ΔT-set of control target temperature” S25-3 and subsequent steps.

  Next, operation during operation will be described with reference to FIG.

  As shown in FIG. 26, in “in operation” S26-1, “is the drive target driven at the specified power and the reference temperature” in S26-2, the drive target is driven at the specified power and the reference temperature. ing.

  Next, in “Supply power fluctuation instruction” S26-3, a supply power fluctuation is instructed by an external input.

  In this state, the surplus power P is calculated in “calculate surplus power P” S26-4. For example, it is calculated by the following equation (7).

  P = [Supply power after change]-[Supply power before change] (7)

  Next, “refer to the modulation temperature width ΔT-set and delay time Δt-set according to the surplus power P from the memory unit” in S26-5, the modulation width ΔT− of the control target temperature according to the surplus power P from the memory unit. Refer to set, delay time Δt-set.

  Next, “change the power supplied to the drive target and modulate the target temperature of the control target by the modulation temperature width by an excessive amount of time” in S26-8, change the power supplied to the drive target, The target temperature is modulated by the excess time Δt-set and the modulation temperature width ΔT-set of the control target temperature.

  Then, the above S26-2 to S26-6 are repeated so that the drive target is temperature-settling.

As described above, the following effects can be obtained by using this temperature control method for a light emitting device, a device to be controlled, and the like.
Even when the emission power is modulated at a high frequency, since the temperature and output fluctuations of the light source are suppressed, a stable wavelength can be obtained.
Further, when the control temperature is changed, the temperature fluctuation range is small, and an excessive shift in wavelength is suppressed.

In addition, the following advantages can be given as the design of the light source.
By using the present invention, it is not necessary to consider the design of the time constant for tuning the temperature control system, and design constraints are reduced. That is, the restriction of the temperature control element having a time constant can be relaxed.
In addition, even when the control system of the temperature servo cannot be changed, the time constant of the control system can be adjusted by changing the setting of the target temperature.

The present invention also provides a light emitting unit using a light emitting device having a semiconductor light emitting element that emits light, a light modulating element that modulates light emitted from the light emitting unit, and light modulated by the light modulating element. The present invention can be applied to a display device having a projection optical unit for projecting.
Furthermore, the present invention includes a light modulation panel (for example, a liquid crystal display panel) that displays an image and a backlight that illuminates the light modulation panel, and the backlight includes a semiconductor light emitting element that emits light. It can be applied to a display device using the light source.
For example, in a video apparatus such as a projector or a television using a light source capable of high-speed modulation, the following effects can be obtained by using a temperature control system using this processing.
When the screen brightness is switched, there is no wavelength fluctuation of the light source or output fluctuation other than intended, so that a high-contrast image with good color reproducibility can be reproduced.
Furthermore, since it becomes an efficient light source, it becomes low power consumption.
In addition, the output variation of each light source is suppressed when the screen brightness is switched.
Furthermore, even a high frame rate image has a small output fluctuation, so that a beautiful image can be obtained.

Further, the present invention is applied to a light source control unit of an irradiation apparatus for processing, exposure or the like, which includes a light emitting unit having a light emitting device for irradiating the workpiece with light to process or expose the workpiece. By using it, stable output and wavelength can be maintained even when the intensity is changed by current modulation.
In addition, the present method can also be applied when the external energy applied to the temperature control object varies.

An example of use is a light source using a wavelength conversion element.
As shown in FIG. 27, in the light source, power is supplied to the fundamental wave light source, and light emitted from the fundamental wave light source is output as a target wavelength through the wavelength conversion element. In such a light source, in order to control to a stable wavelength, it is necessary to control the temperature of the wavelength conversion element. The temperature control of the wavelength conversion element is often controlled at a constant temperature by a temperature control mechanism (measurement element, control element, control unit).
In this light source, when the power supplied to the fundamental wave light source is changed and the output fluctuates, the wavelength of the wavelength conversion element is controlled to be constant regardless of fluctuations in the output of the fundamental wave light by this method. Output light is obtained.

  DESCRIPTION OF SYMBOLS 1 ... Light emission apparatus, 11 ... Light source, 12 ... Temperature control part, 21 ... Semiconductor light-emitting device, 22 ... Temperature measurement part, 23 ... Temperature control element

Claims (20)

A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
When the temperature control unit causes at least binary output fluctuations in the light source, the light emission device uses the temperature control element as an instruction to suppress temperature fluctuations associated with the output fluctuations. The light emitting apparatus according to claim 1, wherein the temperature control unit modulates a control target temperature of the semiconductor light emitting element simultaneously with modulation of a current value of a current supplied to the semiconductor light emitting element. The light emitting apparatus according to claim 2, wherein the temperature control unit varies the temperature of the semiconductor light emitting element in a direction to suppress wavelength fluctuation of the semiconductor light emitting element. The light emitting device according to claim 3, wherein the value of the control target temperature is modulated in a direction opposite to the temperature change of the semiconductor light emitting element, and is returned to the original constant temperature in a time corresponding to a time constant. A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The temperature control unit, when changing the temperature of the temperature control element, instructs the temperature control element to instruct the temperature control element to minimize the temperature stabilization time and the fluctuation range. A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The temperature control unit causes at least binary output fluctuations at the light source, and at the same time, when changing the temperature of the temperature control element, suppresses the stabilization time of the fluctuating temperature accompanying the output fluctuations to the minimum. A light emitting device for instructing the temperature control element to perform an instruction. A light emitting unit using a light emitting device having a semiconductor light emitting element for emitting light;
A light modulation element for modulating the light emitted from the light emitting unit;
A projection optical unit that projects light modulated by the light modulation element;
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The said temperature control part makes the said temperature control element the instruction | indication which suppresses the temperature fluctuation accompanying the output fluctuation, when producing the output fluctuation of at least binary with the said light source. A light emitting unit using a light emitting device having a semiconductor light emitting element for emitting light;
A light modulation element for modulating the light emitted from the light emitting unit;
A projection optical unit that projects light modulated by the light modulation element;
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The said temperature control part instruct | indicates the instruction | indication which controls the settling time and fluctuation range of temperature to the minimum to the said temperature control element, when changing the temperature of the said temperature control element. The display apparatus. A light emitting unit using a light emitting device having a semiconductor light emitting element for emitting light;
A light modulation element for modulating the light emitted from the light emitting unit;
A projection optical unit that projects light modulated by the light modulation element;
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The temperature control unit causes an output fluctuation of at least binary value at the light source, and at the same time, when changing the temperature of the temperature control element, suppresses the stabilization time of the fluctuating temperature due to the output fluctuation to a minimum. A display device for instructing the temperature control element. A light modulation panel for displaying an image;
A backlight for illuminating the light modulation panel;
The backlight uses a light source of a light emitting device having a semiconductor light emitting element that emits light,
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The said temperature control part makes the said temperature control element the instruction | indication which suppresses the temperature fluctuation accompanying the output fluctuation, when producing the output fluctuation of at least binary with the said light source. A light modulation panel for displaying an image;
A backlight for illuminating the light modulation panel;
The backlight uses a light source of a light emitting device having a semiconductor light emitting element that emits light,
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The temperature control unit, when changing the temperature of the temperature control element temperature control target, instructs the temperature control element to control the temperature stabilization time and the fluctuation range to a minimum. A light modulation panel for displaying an image;
A backlight for illuminating the light modulation panel;
The backlight uses a light source of a light emitting device having a semiconductor light emitting element that emits light,
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
The temperature control unit causes an output fluctuation of at least binary value at the light source, and at the same time, when changing the temperature of the temperature control element, suppresses the stabilization time of the fluctuating temperature due to the output fluctuation to a minimum. A display device for instructing the temperature control element. The display device according to any one of claims 7 to 12, wherein when the energy applied to the temperature control element from the outside fluctuates, the stabilization time and fluctuation range of the temperature of the light source are controlled to a minimum. A light emitting unit having a light emitting device for irradiating the workpiece with light to process or expose the workpiece;
The light emitting device is:
A light source having a semiconductor light emitting element that emits light;
A temperature measuring unit for measuring the temperature of the light source;
A temperature control unit that instructs a temperature control element that controls the temperature of the light source to a control target temperature based on the temperature measured by the temperature measurement unit;
When the temperature control unit causes at least binary output fluctuations with the light source, the light irradiation device uses an instruction to suppress temperature fluctuations associated with the output fluctuations as the temperature control element. The light irradiation apparatus according to claim 14, wherein when the energy applied from the outside to the temperature control element varies, the light settling time and the fluctuation range of the temperature of the light source are controlled to the minimum. Measure the temperature of the light source with a semiconductor light emitting element that emits light with a temperature measurement unit,
When controlling the temperature of the light source based on the temperature measured by the temperature measurement unit,
A temperature control method for a light emitting device that suppresses temperature fluctuations associated with output fluctuations when the temperature control unit causes at least binary output fluctuations in the light source. The temperature control method for a light emitting device according to claim 16, wherein the temperature control unit modulates a control target temperature of the semiconductor light emitting element simultaneously with modulation of a current value of a current supplied to the semiconductor light emitting element. The temperature control method for a light emitting device according to claim 17, wherein the temperature controller changes the temperature of the semiconductor light emitting element in a direction to suppress the wavelength fluctuation of the semiconductor light emitting element. Measure the temperature of the light source with a semiconductor light emitting element that emits light with a temperature measurement unit,
When controlling the temperature of the light source based on the temperature measured by the temperature measurement unit,
A temperature control method for a light emitting device, wherein when the temperature of the temperature control element is changed by the temperature control unit, the temperature stabilization time and the fluctuation range are controlled to a minimum. Measure the temperature of the light source with a semiconductor light emitting element that emits light with a temperature measurement unit,
When controlling the temperature of the light source based on the temperature measured by the temperature measurement unit,
When the temperature control unit causes the light source to generate at least a binary output fluctuation, and simultaneously changes the temperature of the temperature control element, the temperature stabilization time associated with the output fluctuation is minimized. Temperature control method for light emitting device.

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