JP2007066566A - Light source lighting control method, light source lighting control device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source lighting control method capable of suppressing wear of an electrode in lighting a light source, to provide a light source lighting control device a projector. <P>SOLUTION: This light source lighting control method comprises glow discharge generation processes S1-S4 for generating glow discharge of a light source lamp, after starting the lighting of the light source lamp comprising a high-pressure discharge lamp; rise period control processes S5-S14 for controlling the current supplied to the light source lamp after the glow discharge generation processes to raise the lamp voltage applied to the light source lamp to a rated voltage; and a constant power control process S15 for executing constant power control of the light source lamp, when the lamp voltage is raised to the rated voltage. The rise period control processes has a period S6 for supplying a current that is smaller than the current supplied to the light source lamp in the glow discharge generation processes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source lighting control method, a light source lighting control device, and a projector.

2. Description of the Related Art Conventionally, projectors that modulate and project a luminous flux emitted from a light source lamp according to image information have been used. In recent years, projectors have been used for various purposes such as presentations in business / education fields and watching movies at home.
As a light source lamp used in a projector, a high-pressure mercury lamp in which a halogen gas is sealed in a discharge tube, a metal halide lamp, or the like is employed in order to cause high luminance and stable light emission.

  The light source lamp is turned on by a discharge generated between two electrodes provided facing each other in the discharge tube. Specifically, in order to light the light source lamp stably, a high voltage is applied between the electrodes to break down the gas in the discharge tube, and then the current and voltage between the electrodes are set to values suitable for stable discharge ( It must be controlled until it reaches the rated value.

However, there is a problem that the electrode is damaged by an excessive current and voltage during the period after the dielectric breakdown until stable discharge is reached, because the fluctuations in current and voltage are large. For example, immediately after dielectric breakdown, the voltage between the electrodes temporarily decreases, so that a current much larger than the rated value flows. This current wears the electrode.
On the other hand, a control method for a high-pressure discharge lamp has been proposed in which the current flowing between the electrodes is controlled to be constant at the rated value until the voltage between the electrodes reaches the rated value after dielectric breakdown (for example, Patent Document 1). reference).

JP 2000-306687 A

However, the high pressure discharge lamp control method described in Patent Document 1 has the following problems.
That is, as shown in Patent Document 1, when a constant rated current is continuously passed between the electrodes, the voltage between the electrodes rises. However, the voltage continues to rise after reaching the rated value, and a voltage higher than the rated value is applied between the electrodes for a certain period. In the control method of the high-pressure discharge lamp described in the cited document 1, there is a problem in that electrode wear occurs due to such voltage overshoot.

  An object of the present invention is to provide a light source lighting control method, a light source lighting control device, and a projector that can suppress wear of electrodes when the light source is turned on.

  In order to achieve the above object, the light source lighting control method of the present invention includes a glow discharge generation process for generating a glow discharge of the light source after starting the lighting of the light source comprising a high pressure discharge lamp, and after the glow discharge generation process, A rising period control process for controlling a current applied to the light source and increasing a voltage applied to the light source to a rated voltage, and a constant power of the light source when the voltage applied to the light source is increased to the rated voltage. A constant power control process for performing control, wherein the rising period control process has a period in which a current smaller than a current supplied to the light source in the glow discharge generation process is applied.

  Here, various light sources can be used as the light source as long as they are discharge type light emitters, and for example, a metal halide lamp, a high-pressure mercury lamp, a halogen lamp, or the like can be used.

  According to the present invention, in the rising period control process, a current smaller than the current during the glow discharge generation process is given to the light source. Then, the rise in the voltage applied to the light source becomes more gradual than when the current during the glow discharge generation process or the rated current of the light source is input. When the voltage reaches the rated voltage, the current is controlled so that the power applied to the light source is kept constant in the constant power control process. At this time, since the voltage rise until reaching the rated voltage was moderate, the jump (overshoot) of the voltage after reaching the rated voltage can be suppressed. Therefore, according to the light source lighting control method of the present invention, wear of the electrode of the light source due to voltage overshoot can be suppressed.

In the present invention, the rising period control process includes a clocking step for measuring an elapsed time from the end of the glow discharge generation process, and increases the current supplied to the light source when the elapsed time reaches a preset time. A current increasing step is preferred.
According to the present invention, since the current applied to the light source is increased based on the elapsed time from the end of the glow discharge generation process, the voltage applied to the light source is increased to some extent on time. Therefore, according to the light source lighting control method of the present invention, the light source can be turned on efficiently without waiting for a long time until the light source reaches a stable discharge.

  In the present invention, the rising period control process is a time measuring step for measuring an elapsed time from the end of the glow discharge generation process, and when the elapsed time reaches a preset time, it is applied to the light source at that time. A light source voltage measurement step for measuring a voltage that is present, a voltage comparison step for determining whether the voltage measured in the light source voltage measurement step is less than the rated voltage, and the light source voltage measurement in the voltage comparison step When it is determined that the voltage measured in the step is lower than the rated voltage, it is preferable to include a current increasing step for increasing the current supplied to the light source.

  Here, the preset time is a general time required from the end of glow discharge until the lighting of the light source is stabilized in the conventional light source lighting control. That is, the said time is preset based on the data of the conventional light source lighting control, and can be suitably changed according to the kind, specification, and use environment of a light source.

Originally, in the rising period control process, a current smaller than that in the glow discharge process is given for a certain period, and the process waits until the voltage applied to the light source reaches the rated voltage. However, since there is a period during which the current is reduced, there may be a case where it takes time for the voltage applied to the light source to reach the rated voltage.
On the other hand, in the present invention, when a preset time has elapsed from the end of the glow discharge process, it is determined in the voltage comparison step whether or not the voltage currently applied to the light source is less than the rated voltage. And if it determines with it being less than a rated voltage, the electric current given to a light source will be increased in an electric current increase step. Then, the increase rate of the voltage applied to the light source is increased by increasing the current, and the voltage applied to the light source can be quickly reached to the rated voltage.
As described above, according to the light source lighting control method of the present invention, when it takes time for the light source to reach stable discharge, the voltage can be rapidly increased. Therefore, lighting control can be performed so that it does not take a long time to stabilize lighting of the light source.

In the current increasing step, it is preferable that the current input to the light source is increased with a time constant.
In the present invention, when the current is increased, it increases with a time constant. As a result, the power applied to the light source gradually increases, and the brightness of the light source also gradually increases. Therefore, according to the light source lighting control method of the present invention, it is possible to prevent the brightness of the light source from changing suddenly.

The present invention can be configured not only as the light source lighting control method described above but also as a light source lighting control device and a projector.
That is, the light source lighting control device of the present invention controls a glow discharge generating means for generating a glow discharge of the light source after starting the lighting of the light source comprising a high pressure discharge lamp, and a current supplied to the light source after the glow discharge is generated. And a rising period control means for increasing the voltage applied to the light source to a rated voltage, and a constant power control means for performing constant power control of the light source when the voltage applied to the light source is increased to the rated voltage. The rising period control means provides a current smaller than the current given to the light source by the glow discharge generation means at least in a certain period.
Furthermore, a projector according to the present invention includes the light source lighting control device.
ADVANTAGE OF THE INVENTION According to this invention, the lighting control apparatus and projector which can enjoy the effect | action and effect similar to the effect | action and effect which were mentioned above can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In this embodiment, the lighting control of the light source lamp 211 (FIG. 2) mounted on the projector 1 will be taken up.
[1. Internal configuration of projector 1]
The projector 1 is an optical device that modulates a light beam emitted from the light source lamp 211 in accordance with image information, and enlarges and projects it on a projection surface such as a screen.
FIG. 1 is a block diagram showing the internal configuration of the projector 1.
As shown in FIG. 1, the projector 1 includes an optical engine 2, a control board 3, and a power supply block 4.

[1-1. Configuration of optical engine 2]
FIG. 2 is a schematic plan view showing the configuration of the optical system of the optical engine 2 built in the projector 1.
As shown in FIG. 2, the optical engine 2 modulates the light beam emitted from the light source lamp 211 to form an optical image corresponding to image information input from the control board 3 described later, and the formed optical image. Is enlarged and projected by the projection lens 26.
Such an optical engine 2 includes a light source device 21, an integrator illumination optical system 22, a color separation optical system 23, a relay optical system 24, an optical device 25, a projection lens 26, and an optical that accommodates these. A component casing (not shown) and a head body (not shown) for holding and fixing the projection lens 26 are provided.

  The light source device 21 includes a light source lamp 211 as a light source composed of a high-pressure discharge lamp, a reflector 212, and an explosion-proof glass 213. Then, the light source device 21 reflects the radial light beam emitted from the light source lamp 211 by the reflector 212 into a parallel light beam, and emits the parallel light beam to the outside through the explosion-proof glass 213.

Among these, the light source lamp 211 includes a discharge tube made of glass, and an anode electrode and a cathode electrode disposed facing each other in the discharge tube. Mercury and rare gas are sealed in the discharge tube. Both electrodes are made of a refractory metal rod, and are connected to a tungsten rod, a lead wire and the like for obtaining conduction.
In this embodiment, a high-pressure mercury lamp is used, but a metal halide lamp, a halogen lamp, or the like can also be used.
Moreover, although the parabolic mirror is employ | adopted as the reflector 212, what combined the parallelizing concave lens and the ellipsoidal mirror instead of the parabolic mirror may be employ | adopted.

  The explosion-proof glass 213 is a translucent glass member that closes the opening of the reflector 212, and is configured so that when the light source lamp 211 is ruptured, the fragments of the light source lamp 211 are not scattered outside.

  The integrator illumination optical system 22 is an optical system for substantially uniformly illuminating image forming areas of four liquid crystal panels 251 (to be described later) constituting the optical device 25. The integrator illumination optical system 22 includes a first lens array 221, a second lens array 222, a polarization conversion element 223, and a superimposing lens 224.

The first lens array 221 has a configuration in which small lenses having a substantially rectangular outline when viewed from the optical axis direction are arranged in a matrix, and each small lens receives a plurality of light beams emitted from the light source device 21. It is divided into partial luminous fluxes.
The second lens array 222 has substantially the same configuration as the first lens array 221 and has a configuration in which small lenses are arranged in a matrix. The second lens array 222 has a function of forming, together with the superimposing lens 224, an image of each small lens of the first lens array 221 on a liquid crystal panel 251 described later.

  The polarization conversion element 223 is disposed between the second lens array 222 and the superimposing lens 224. Such a polarization conversion element 223 converts the light from the second lens array 222 into substantially one type of linearly polarized light, thereby improving the light use efficiency in the optical device 25.

  Specifically, each partial light converted into substantially one type of linearly polarized light by the polarization conversion element 223 is finally substantially superimposed on a liquid crystal panel 251 (to be described later) of the optical device 25 by the superimposing lens 224. Since only one type of linearly polarized light can be used in the projector 1 using the liquid crystal panel 251 of the type that modulates polarized light, almost half of the light from the light source lamp 211 that emits other types of randomly polarized light is not used. Therefore, by using the polarization conversion element 223, the light beam emitted from the light source lamp 211 is converted into substantially one type of linearly polarized light, and the light use efficiency in the optical device 25 is enhanced.

  The color separation optical system 23 includes two dichroic mirrors 231 and 232 and a reflection mirror 233. The dichroic mirrors 231 and 232 cause a plurality of partial light beams emitted from the integrator illumination optical system 22 to be red (R), It has a function of separating into three color lights of green (G) and blue (B).

  The relay optical system 24 includes an incident-side lens 241, a relay lens 243, and reflection mirrors 242 and 244, and red light that is color light separated by the color separation optical system 23 is used for red light described later of the optical device 25. The liquid crystal panel 251R has a function of leading to the liquid crystal panel 251R.

  At this time, the dichroic mirror 231 of the color separation optical system 23 transmits the red light component and the green light component of the light beam emitted from the integrator illumination optical system 22 and reflects the blue light component. The blue light reflected by the dichroic mirror 231 is reflected by the reflection mirror 233, passes through the field lens 255, and reaches a later-described blue light liquid crystal panel 251B of the optical device 25. The field lens 255 converts each partial light beam emitted from the second lens array 222 into a light beam parallel to the central axis (principal light beam). The same applies to the field lens 255 provided on the light beam incident side of the other light modulators for green light and red light.

  Of the red light and green light transmitted through the dichroic mirror 231, the green light is reflected by the dichroic mirror 232, passes through the field lens 255, and reaches the liquid crystal panel 251G for green light. On the other hand, the red light passes through the dichroic mirror 232, passes through the relay optical system 24, further passes through the field lens 255, and reaches the liquid crystal panel 251R for red light.

The relay optical system 24 is used for red light because the optical path length of the red light is longer than the optical path lengths of the other color lights, thereby preventing a decrease in light utilization efficiency due to light divergence or the like. It is to do. That is, this is to transmit the partial light beam incident on the incident side lens 241 to the field lens 255 as it is. The relay optical system 24 is configured to pass red light among the three color lights, but is not limited thereto, and may be configured to pass blue light and green light, for example.

  The optical device 25 modulates an incident light beam according to image information to form a color image. The optical device 25 includes three incident-side polarizing plates 252 on which the respective color lights separated by the color separation optical system 23 are incident, and three liquid crystal panels 251 (red light that are arranged downstream of the incident-side polarizing plates 252). A liquid crystal panel for liquid crystal 251R, a liquid crystal panel for green light 251G, and a liquid crystal panel for blue light 251B), three exit-side polarizing plates 253 arranged in the latter stage of the optical path of each liquid crystal panel 251 and a cross And a dichroic prism 254.

  The incident side polarizing plate 252, the liquid crystal panel 251, the emission side polarizing plate 253, and the cross dichroic prism 254 are integrated into a device. Note that the incident-side polarizing plate 252, the liquid crystal panel 251, and the exit-side polarizing plate 253 are arranged at predetermined intervals, although not specifically illustrated.

  The incident-side polarizing plate 252 receives light of each color whose polarization direction is aligned in approximately one direction by the polarization conversion element 223, and is substantially the same as the polarization axis of the light beam aligned by the polarization conversion element 223 among the incident light beams. Only polarized light in the direction is transmitted, and other light beams are absorbed. The incident-side polarizing plate 252 has a configuration in which a polarizing film is pasted on a translucent substrate such as sapphire glass or quartz.

The liquid crystal panel 251 has a configuration in which liquid crystal, which is an electro-optical material, is hermetically sealed between a pair of transparent glass substrates, and the liquid crystal in the image forming area according to a control signal output from the control substrate 3 described later. The polarization state of the polarized light beam emitted from the incident side polarizing plate 252 is modulated.
The exit-side polarizing plate 253 has substantially the same configuration as the incident-side polarizing plate 252, and out of the light beams emitted from the image forming area of the liquid crystal panel 251, the polarization axis orthogonal to the light transmission axis of the incident-side polarizing plate 252. Only the light beam having a light is transmitted and other light beams are absorbed.

  The cross dichroic prism 254 is an optical element that synthesizes an optical image modulated for each color light emitted from the emission side polarizing plate 253 to form a color image. The cross dichroic prism 254 has a square shape in plan view in which four right angle prisms are bonded together, and four dielectric multilayer films are formed at the interface where the right angle prisms are bonded together. These dielectric multilayer films reflect each color light emitted from the liquid crystal panels 251R and 251B via the emission side polarizing plate 253, and transmit green light emitted from the liquid crystal panel 251G via the emission side polarizing plate 253. In this way, the color lights modulated by the liquid crystal panels 251R, 251G, and 251B are combined to form a color image.

  The projection lens 26 has a configuration in which a plurality of lenses and a mirror that deflects an incident light beam are housed in a lens barrel, and enlarges and projects a color image emitted from the optical device 25. The projection lens 26 is disposed on the light beam exit side of the optical device 25 and is fixed to a head body described later.

A predetermined illumination optical axis D is set inside the optical component casing, and the above-described optical components 24 to 25 are arranged at predetermined positions with respect to the illumination optical axis D.
The head body is made of a metal material such as an aluminum alloy or a magnesium alloy, and integrates the optical device 25 and the projection lens 26, and attaches the integrated device to the optical component casing.

[1-2. Configuration of control board 3]
Returning to FIG. 1, the control board 3 includes a control unit 31, a liquid crystal panel driving IC 32, and an interface 33. A connector group is mounted on the interface 33, and image information input from the connector group Is output to the control unit via this interface.
The control unit 31 performs arithmetic processing in accordance with the detected various signals, and outputs a control command based on the arithmetic processing result to the constituent members 2 and 4. For example, when image information is input via the interface 33, the control unit 31 performs an image information calculation process and outputs a control command based on the calculation process result to the liquid crystal panel drive IC 32.
The liquid crystal panel drive IC 32 generates and outputs a drive signal based on this control command, and drives each liquid crystal panel 251 (251R, 251G, 251B). Thereby, the light modulation according to the image information is performed in each liquid crystal panel 251 to form an optical image.

[1-3. Configuration of power supply block 4]
As shown in FIG. 1, the power supply block 4 includes a power supply unit 41 and a lamp driving unit 42.
Among these, the power supply part 41 supplies the electric power supplied from the outside through a power cable to the lamp drive part 42, the control board 3, etc. FIG.
An exhaust fan (not shown) is provided in the vicinity of the power supply block 4, and air that has cooled each component in the projector 1 is collected by the exhaust fan and discharged to the outside.

[1-3-1. Configuration of lamp driving unit 42]
The lamp driving unit 42 is a conversion circuit for supplying power to the light source device 21 described above with a stable voltage. The commercial AC current is rectified by the power supply unit 41, further converted by the lamp driving unit 42, and supplied to the light source device 21 as a DC current or an AC rectangular wave current. The lamp driver 42 corresponds to the light source lighting control device of the present invention.
FIG. 3 is a schematic diagram for explaining the configuration of the lamp driving unit 42.
As shown in FIG. 3, the lamp driving unit 42 includes a down chopper 51, an inverter bridge 52, an igniter 53, a controller 54, and a memory 55.

  The down chopper 51 is a circuit that drops a DC voltage input at approximately 300 to 400 V to approximately 50 to 150 V suitable for lighting the light source lamp 211. The down chopper 51 includes a coil 511 and a diode 512 connected in series, and these elements. A transistor 513 and a capacitor 514 that are branched and connected are provided.

The coil 511, the diode 512, and the capacitor 514 function as elements that remove high-frequency components of the input DC current, rectify, and make the input DC voltage constant power.
The transistor 513 is connected to the ground on the side opposite to the side connected to the coil 511 and the diode 512. By using the transistor 513 as a switching element, a part of the input direct current flows to the ground. The voltage drops. Specifically, by controlling the switching speed and time constant of the transistor 513, the input DC voltage can be lowered to a desired voltage.

The inverter bridge 52 is a part that converts a direct current into an alternating current rectangular wave current, and is configured as a bridge circuit including a pair of transistors 521 and a pair of transistors 522. The light source lamp 211 is connected between the transistor 521 and the transistor 522.
When a direct current rectified through the down chopper 51 is input to this bridge circuit and a pulse signal is given to the transistors 521 and 522, a path including the pair of transistors 521 and a path including the pair of transistors 522 are obtained. An electric current flows by alternately short-circuiting, whereby an AC rectangular wave current flows through the light source lamp 211 connected therebetween.

The igniter 53 is a circuit that prompts the start of the light source lamp 211 by performing dielectric breakdown between the electrodes of the light source lamp 211. The igniter 53 is connected between the lighting device including the down chopper 51 and the inverter bridge 52 and the light source lamp 211 so as to be in parallel with the light source lamp 211.
In this example, the igniter 53 is omitted in the drawing, but includes a high voltage pulse generation circuit and a pulse transformer connected to the primary side of the high voltage pulse generation circuit. By boosting the voltage on the secondary side of the transformer and applying the boosted voltage to the light source lamp 211, the insulation between the electrodes of the light source lamp 211 is broken, electrical conduction is ensured, and the light source lamp 211 starts lighting.

The controller 54 is a part that controls the down chopper 51, the inverter bridge 52, and the igniter 53 described above. The controller 54 is configured as a 4-bit or 8-bit microcomputer chip.
As shown in FIG. 3, the controller 54 includes a chopper control unit 541, an inverter control unit 542, an igniter control unit 543, a lighting activation detection unit 544, and a lamp voltage measurement unit 545A that operate as an internally executable program. A lamp current measurement unit 545B, a current value control unit 546, and a constant power control unit 547.

  The chopper control unit 541 controls the operation of the down chopper 51 according to the control of a current value control unit 546 and a constant power control unit 547 described later. The chopper control unit 541 gives rated power to the light source lamp 211 or gives less power than this to control lighting of the light source lamp. Specifically, the chopper control unit 541 controls the transistor 513 that functions as a switching element of the down chopper 51 by outputting a pulse signal.

The inverter control unit 542 controls the operation of the inverter bridge 52. Specifically, the inverter control unit 542 outputs pulse signals having the same frequency and different phases to the transistor 521 and the transistor 522, respectively, controls switching of the transistors 521 and 522, and supplies an alternating current to the power lamp 211. Let them enter.
The igniter control unit 543 controls the operation of the igniter 53. When the activation operation signal is input to the projector 1, the igniter control unit 543 outputs a control signal to the igniter 53 described above to operate the igniter 53.
The igniter 53 and the igniter control unit 543 correspond to glow discharge generating means of the present invention.

The lighting activation detection unit 544 is a part that detects whether or not a lamp lighting command for instructing lighting of the light source lamp 211 is input. When the lighting activation detection unit 544 detects a lamp lighting command, it outputs a command to start driving the igniter 53 to the igniter control unit 543.
Note that the lamp lighting command is output from the control unit 31 on the control board 3 to the power supply block 4 in response to pressing of a power key (not shown) provided outside the housing of the projector 1 or on the remote controller. Is a control command.
The lamp voltage measurement unit 545A measures a voltage (lamp voltage) applied between the electrodes of the light source lamp 211.
The lamp current measuring unit 545B measures a current (lamp current) flowing through the light source lamp 211.

A current value control unit 546 and a constant power control unit 547 described below analyze a current value to be input to the light source based on the lamp voltage, and output a control command corresponding to the analyzed current value to the chopper control unit 541. To do.
Among these, the current value control unit 546 controls the lamp current input to the light source lamp 211 from when the high voltage is applied to the light source lamp 211 by the igniter 53 until the lamp voltage reaches the rated voltage of the light source lamp 211. I do.

First, the current value control unit 546 uses a timer (not shown) provided in the controller 54 to measure the elapsed time from the application of the high voltage, and determines that the glow discharge has been completed after a certain period of time. ing. In the present embodiment, the predetermined time is 3 seconds.
Then, when the glow discharge is finished, the current value control unit 546 decreases the current value of the lamp current input to the light source. In this embodiment, it is lowered gradually with a preset reduction range.
Thereafter, until the lamp voltage reaches the rated voltage or until a target arrival time to be described later elapses, the current value control unit 546 controls the chopper control unit 541 according to a preset change in the current value. Is output.

When a preset time (target arrival time) has elapsed since the end of glow discharge, the current value control unit 546 checks the lamp voltage and determines whether the lamp voltage is less than the rated voltage of the light source lamp 211. .
The target arrival time is a general time required until the rated voltage is secured after the glow discharge is completed in the conventional light source lighting control. That is, the target arrival time is set in advance based on conventional light source lighting control data, and can be changed as appropriate according to the type, specification, and usage environment of the light source lamp 211. In this embodiment, the target arrival time is 3 minutes.
When the current value control unit 546 determines that the lamp voltage is less than the rated voltage, the current value control unit 546 changes the value change of the current value that is initially planned, and increases the lamp current until the rated current is reached. In this embodiment, it is gradually increased with a preset time constant.
The down chopper 51, the chopper control unit 541, and the current value control unit 546 correspond to the rising period control means of the present invention.

When the lamp voltage reaches the rated voltage, the constant power control unit 547 controls the power applied to the light source lamp 211 to maintain the rated power thereafter. Specifically, the constant power control unit 547 monitors the lamp voltage and the lamp current, obtains the power applied to the light source lamp 211 based on the lamp voltage and the lamp current, and is necessary for applying the rated power to the light source lamp 211. Analyze current values.
The down chopper 51, the chopper control unit 541, and the constant power control unit 547 correspond to the constant power control means of the present invention.

  The memory 55 stores the programs of the chopper control unit 541, the inverter control unit 542, the igniter control unit 543, the lighting activation detection unit 544, the lamp voltage measurement unit 545A, the current value control unit 546, and the constant power control unit 547. This is a storage area to be stored. These programs are called and function on the controller 54 when the projector 1 is activated.

[2. Operation of controller 54]
Next, the light source lighting control process executed by the controller 54 of the lamp driving unit 42 will be described with reference to FIGS.
FIG. 4 is a flowchart for explaining the light source lighting control process.
In the controller 54, the lighting activation detection unit 544 monitors the control command output from the control unit 31, and determines whether or not the lamp lighting command is output (S1). When the lamp lighting command is not output, the lighting activation detection unit 544 continues to monitor the control command.
On the other hand, when the lamp lighting command is output, the igniter control unit 543 drives the igniter 53 and applies a high voltage between the electrodes of the light source lamp 211 (S2). Further, the current value control unit 546 starts measuring time using a timer simultaneously with the application of the high voltage in the process S2 (S3).

The current value control unit 546 monitors the elapsed time measured by the timer and determines whether or not 3 seconds have elapsed (S4). When it is determined that 3 seconds have not elapsed, the current value control unit 546 continues to monitor the elapsed time. Processes S1 to S4 correspond to the glow discharge generation process of the present invention.
On the other hand, if it is determined that 3 seconds have elapsed, the current value control unit 546 resets the time that has been counted, and starts counting again (S5). Further, the current value control unit 546 reduces the lamp current I (FIG. 5) input to the light source lamp 211 with a preset reduction width (S6).

FIG. 5A is a graph (time t-current I graph) showing the time change of the lamp current I from the end of glow discharge, and FIG. 5B is a time change of the lamp voltage V (time t-voltage V). It is a graph showing a graph.
5 as represented in A period of time t- current I in the graph of (A), by treatment S6, the lamp current I is going to gradually decreases from the current value I ₀ at the glow discharge end. In the period A, the lamp voltage V increases as the temperature in the discharge tube rises, as shown in the time t-voltage V graph of FIG.

Next, the lamp voltage measurement unit 545A measures the lamp voltage V (S7), and the current value control unit 546 determines whether or not the measured lamp voltage V has reached the rated voltage V _range of the light source lamp 211. (S8).
When the lamp voltage reaches the rated voltage V _range , the process proceeds to step S15, and the constant power control unit 547 performs constant power control of the light source lamp 211.
On the other hand, when the lamp voltage V does not reach the rated voltage V _range , the current value control unit 546 monitors the elapsed time measured by the timer and determines whether or not 3 minutes have elapsed (S9). If it is determined that three minutes have not elapsed, the lamp voltage measurement unit 545A returns to step S7 and measures the lamp voltage V.

On the other hand, when it is determined that three minutes have elapsed, the lamp voltage measurement unit 545A measures the lamp voltage V (S10), and the current value control unit 546 determines whether the measured lamp voltage V is less than the rated voltage V _range . It is determined whether or not (S11). When it is determined that the lamp voltage V is equal to or higher than the rated voltage V _range , the process proceeds to step S15, and the constant power control unit 547 performs constant power control of the light source lamp 211.
On the other hand, when it is determined that the lamp voltage V is less than the rated voltage V _range , the current value control unit 546 increases the value of the lamp current I until the rated current I _range is reached (S12).

As shown in the period B in the time t-current I graph of FIG. 5A, the lamp current I gradually increases by the process S12 and eventually reaches the rated current I _range .
Further, since the lamp current I is increased in the process S12, the lamp voltage V is increased at a rate higher than that in the A period as shown in the B period of the time t-voltage V graph of FIG. It will increase.
That is, the time t-current I graph and the time t-voltage V graph shown in FIG. 5 are determined in step S8 that the lamp voltage V has not reached the rated voltage V _range , and from the end of glow discharge. after 3 minutes has elapsed, a graph ramp voltage V in step S11 showed time change of the lamp current I and lamp voltage V when it is determined to be less than the rated voltage V _range.

The lamp voltage measurement unit 545A measures the lamp voltage V (S13), and the current value control unit 546 determines whether or not the measured lamp voltage V has reached the rated voltage V _range of the light source lamp 211. (S14). When the lamp voltage V has not reached the rated voltage V _range , the lamp voltage measuring unit 545A returns to step S13 and measures the lamp voltage V. Processes S5 to S14 correspond to the rising period control process of the present invention.

On the other hand, when the lamp voltage V reaches the rated voltage V _range , the constant power control unit 547 performs constant power control of the light source lamp 211 (S15).
As shown in a period C in the time t-current I graph of FIG. 5A, the constant power control unit 547 determines the power applied to the light source lamp 211 in accordance with the fluctuations in the lamp voltage V and the lamp voltage I. The lamp current I is adjusted so as to be maintained at the rated power. Further, as shown in the period C in the time t-voltage V graph of FIG. 5B, the ramp voltage V exhibits a constant voltage characteristic after reaching the rated voltage V _range . This process S15 corresponds to the constant power control process of the present invention.

FIG. 6 is a graph (voltage V-current I graph) showing the relationship between the lamp current I and the lamp voltage V after the end of glow discharge in the above-described light source lighting control process.
Among these, a broken line graph I ₁ shows a change in the value of the lamp current I when it is determined in step S8 (FIG. 4) that the lamp voltage V has reached the rated voltage V _range .
In contrast, graph I ₂ solid lines, in the process S8, the lamp voltage V is determined not to have reached the rated voltage V _range, further, step S11 (FIG. 4), the lamp voltage V is the rated voltage V _range The change in the value of the lamp current I when it is determined to be smaller than the value is shown.

As described above, according to the present embodiment, in the rising period control process, the lamp current I smaller than the current I ₀ during the glow discharge generation process is given to the light source (process S6). Then, the increase in the lamp voltage V becomes gradual as compared with the case where the lamp current I ₀ at the time of glow discharge or the rated current I _range of the light source lamp 211 is input.
When the lamp voltage V reaches the rated voltage V _range , the constant power control unit 547 controls the lamp current I so that the power applied to the light source lamp 211 is kept constant in process S15. At this time, since the rise of the lamp voltage V until reaching the rated voltage V _range was gradual, the jump (overshoot) of the lamp voltage V after reaching the rated voltage V _range can be suppressed.
Therefore, according to the light source lighting control method of the present embodiment, wear of the electrodes of the light source lamp 211 due to the overshoot of the lamp voltage V can be suppressed.

Originally, after the lamp current I input to the light source lamp 211 is reduced in step S6, the process waits until the lamp voltage V reaches the rated voltage V _range. However, since the lamp current I is reduced, the rated voltage V _{range is} reached. It may be time consuming until
In contrast, in this embodiment, when it is determined in process S9 that the target arrival time has elapsed since the end of glow discharge, in process S11, the current value control unit 546 determines that the current lamp voltage V is the rated voltage V _range. It is determined whether or not. If it is determined that the rated voltage V _range has not been reached, the lamp current I is increased in step S12. By increasing the lamp current I, the rate of increase of the voltage V increases, and the rated voltage V _range can be reached quickly.
That is, according to the light source lighting control method of the present embodiment, when it takes time for the light source lamp 211 to reach a stable discharge, the increase of the lamp voltage V can be accelerated. Therefore, it can be controlled so that it does not take a long time to stabilize the lighting of the light source lamp 211.

  In the present embodiment, when the lamp current I is increased, it is increased with a time constant. As a result, the power applied to the light source lamp 211 gradually increases, so that the brightness of the light source lamp 211 also increases gradually. Therefore, according to the light source lighting control method of the present embodiment, it is possible to prevent the brightness of the light source lamp 211 from changing suddenly.

[3. Modification of the above embodiment]
The best configuration for implementing the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, since the embodiment does not limit the present invention, description of the names of members excluding some or all of the limitations on the shape, material, etc. is included in the present invention. is there.
In the above embodiment, the lamp current I input to the light source lamp 211 is controlled by the value change shown in FIG. 6 in the rising period control process, but in the present invention, at least at the end of the glow discharge in the rising period control process. There may be a period in which the lamp current I ₀ and the lamp current I smaller than the rated current are input to the light source lamp 211. Therefore, the current value control unit 546 may control the lamp current I by a value change as shown in FIGS.

In the embodiment, the light source control method according to the present invention is used for the light source lamp 211 of the projector 1. However, the present invention is not limited to this, and in short, any device including a light source having a discharge tube and an electrode can adopt the present invention, and can enjoy the same operations and effects as described above.
In the above embodiment, various controls including the current value control unit 546 and the constant power control unit 547 are configured as programs developed in the controller 54. However, the present invention is not limited to this, and for example, a board Various circuit elements may be mounted on the top.

Further, in the present invention, when it is determined in step S11 that the lamp voltage V is less than the rated voltage V _range , the increase in the lamp current I performed in step S12 is performed according to the lamp voltage V measured in step S10. You may devise a method.
For example, when the lamp voltage V is a value much smaller than the rated voltage V _range , the current value control unit 546 can rapidly increase the lamp current I by rapidly increasing the lamp current I with a small time constant. That's fine. On the other hand, when the lamp voltage V is slightly smaller than the rated voltage V _range , the current value control unit 546 gradually increases the lamp current I with a large time constant so that overshoot of the voltage V does not occur. What is necessary is just to raise the voltage V. FIG.
In contrast to this, in the present invention, if it is determined in step S9 of the above embodiment that three minutes have elapsed since the end of glow discharge, the process proceeds to step S12 without performing steps S10 and S11. Thus, the lamp current I may be increased immediately.

  In the process S5 to process S14 of the present embodiment and the rising period control process of the modification shown in FIGS. 7 to 10 described above, the lamp current I input to the light source lamp 211 is controlled according to the lamp voltage V. . On the other hand, in the present invention, the lamp current I may be controlled according to the elapsed time measured from the end of glow discharge. FIG. 11 is a time t-current I graph for explaining the present modification. Time t is the elapsed time from the end of glow discharge. As shown in FIG. 11, in the present invention, when the time t reaches 0.5 minutes, the lamp current I is reduced, and when the time t reaches 1.5 minutes, the lamp current I is increased. The lamp current I may be controlled based on the above.

  The present invention can be used for a light source lighting control method, a light source lighting control device, and a projector.

1 is a block diagram showing an internal configuration of a projector according to an embodiment of the invention. The schematic plan view which shows the optical system of the optical engine which concerns on the said embodiment. The schematic diagram for demonstrating the structure of the lamp drive part which concerns on the said embodiment. The flowchart for demonstrating the effect | action of the controller which concerns on the said embodiment. The graph showing the time change of the electric current at the time of the light source lamp lighting which concerns on the said embodiment, and the time change of a voltage. The graph showing the relationship between the electric current at the time of the light source lamp lighting concerning the said embodiment, and a voltage. The graph showing the relationship between the electric current at the time of the light source lamp lighting concerning the modification of the said embodiment, and a voltage. The graph showing the relationship between the electric current at the time of the light source lamp lighting concerning the modification of the said embodiment, and a voltage. The graph showing the relationship between the electric current at the time of the light source lamp lighting concerning the modification of the said embodiment, and a voltage. The graph showing the relationship between the electric current at the time of the light source lamp lighting concerning the modification of the said embodiment, and a voltage. The graph showing the time change of the electric current at the time of the light source lamp lighting concerning the modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Optical engine, 211 ... Light source lamp (light source), 42 ... Lamp drive part (light source lighting control apparatus), 54 ... Controller, 545A ... Lamp voltage measurement part, 546 ... Current value control part, 547 ... Constant Power control unit, I: Lamp current, I _range ... Rated current, I ₀ ... Lamp current at the end of glow discharge, V ... Lamp voltage, V _range ... Rated voltage

Claims (6)

A glow discharge generation process for generating a glow discharge of the light source after starting lighting of the light source composed of a high-pressure discharge lamp,
After the glow discharge generation process, the current applied to the light source is controlled, and the rising period control process for raising the voltage applied to the light source to a rated voltage;
A constant power control process for performing constant power control of the light source when the voltage applied to the light source is increased to the rated voltage;
The light source lighting control method characterized in that the rising period control process has a period in which a current smaller than the current applied to the light source in the glow discharge generation process is applied. In the light source lighting control method according to claim 1,
The rising period control process includes:
A time measuring step for measuring an elapsed time from the end of the glow discharge generation process;
A light source lighting control method comprising: a current increasing step for increasing a current applied to the light source when the elapsed time reaches a preset time. In the light source lighting control method according to claim 1,
The rising period control process includes:
A time measuring step for measuring an elapsed time from the end of the glow discharge generation process;
When the elapsed time reaches a preset time, a light source voltage measuring step for measuring a voltage applied to the light source at that time;
A voltage comparison step for determining whether or not the voltage measured in the light source voltage measurement step is less than the rated voltage;
A current increasing step of increasing a current applied to the light source when the voltage comparing step determines that the voltage measured in the light source voltage measuring step is less than the rated voltage. A light source lighting control method. In the light source lighting control method according to claim 2 or claim 3,
In the current increasing step, the current applied to the light source is increased with a time constant. A glow discharge generating means for generating a glow discharge of the light source after starting the lighting of the light source comprising a high-pressure discharge lamp;
A rising period control means for controlling a current applied to the light source after the occurrence of the glow discharge and increasing a voltage applied to the light source to a rated voltage;
A constant power control means for performing constant power control of the light source when the voltage applied to the light source is raised to the rated voltage;
The light source lighting control device characterized in that the rising period control means gives a current smaller than the current given to the light source by the glow discharge generation means at least in a certain period.   A projector comprising the light source lighting control device according to claim 5.

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