JP2010272607A - Projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a semiconductor laser not illuminating among a plurality of series-connected semiconductor lasers, without causing a circuit to become complex, and so on. <P>SOLUTION: A light output change value measured at a point "t=0" of time is stored as a reference light output change value ΔW0. It is determined whether there is a difference between the stored reference light output change value ΔW0 and a light output change value ΔW measured, when a power source is turned on, this time. At this time, even after usage time elapses, the light output change value ΔW measured this time is equal to the reference light output change value ΔW0 as long as the first to third semiconductor lasers are all turned on. However, if any of the first to third semiconductor lasers is not turned on at "t=1" time, the light output change value ΔW becomes smaller than the reference light output change value ΔW0 so that "ΔW0≠ΔW" is satisfied. Hence, the number of semiconductor lasers among the three series-connected semiconductor lasers which are not turned on, can be calculated from the difference value "ΔW0-ΔW". <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light source device using a semiconductor laser, a light source failure detection program, a light source failure detection method, and a projection device using the light source device.

  Conventionally, in an apparatus that requires a light source, such as a projection apparatus, a semiconductor laser is used as the light source. Further, by using a plurality of semiconductor lasers, a necessary amount of light can be secured in the apparatus. ing. As described above, when a plurality of semiconductor lasers are used, a lighting control unit must be provided for each laser when connected in parallel, and a plurality of lighting control units corresponding to the number of semiconductor lasers connected in parallel are required. Accordingly, a projection apparatus using a plurality of semiconductor lasers connected in series has been proposed in order to reduce the number of lighting control units as much as possible to enable lighting control (see, for example, Patent Document 1).

JP 2008-123818 A

  As shown in the background art, when a plurality of semiconductor lasers are connected in series and there is a laser that does not turn on, the laser generates heat without emitting light. Therefore, there is a problem that not only light quantity and power loss occur but also temperature influence on other lasers occurs due to heat generation without emitting light. Therefore, in order to prevent the occurrence of these problems, it is necessary to detect the presence / absence of a laser that has become unlit in a plurality of semiconductor lasers connected in series.

  However, unlike an LED or the like, a semiconductor laser functions as a circuit even when one of a plurality of serially connected lights is turned off. Therefore, the presence or absence of a non-lighted laser is determined based on whether or not it functions as a circuit. It is not possible.

  Further, the semiconductor laser has a characteristic that the light emission amount decreases with the passage of time of use, and further has a characteristic that the input voltage does not change even if the light emission amount decreases. Therefore, it is impossible to detect the presence of a non-lighting laser in a plurality of semiconductor lasers connected in series based on a decrease in the amount of emitted light, and it is also possible to detect the presence of the non-lighting laser based on an input voltage. Can not.

  Of course, if there is a separate circuit that turns on the lasers connected in series individually to check lighting, or if an illuminance sensor is placed on each laser, the presence of unlit lasers in multiple semiconductor lasers connected in series is detected. Can do. However, providing such a separate circuit has a demerit that causes circuit complexity, and providing an illuminance sensor for each laser is not practical considering that many lasers may be used.

  For this reason, it is left without detecting the presence of a non-lighted laser in a plurality of semiconductor lasers connected in series, which causes the above-mentioned light amount and power loss, and temperature effects on other lasers. It was the actual situation.

  The present invention has been made in view of such a conventional problem, and is a light source device capable of detecting the presence of a non-lighting laser in a plurality of semiconductor lasers connected in series without causing a complicated circuit or the like. An object of the present invention is to provide a light source defect detection program, a light source defect detection method, and a projection apparatus.

  In order to solve the above-described problem, the light source device according to claim 1 is a light source device having a plurality of semiconductor lasers connected in series as a light source, and each of the light sources has different values of current. A supply means for supplying, a detection means for detecting an output difference value of the light source respectively emitted as the current of the different value is supplied by the supply means, and an initial output difference value detected by the detection means are stored. Based on the comparison result of the comparison means and the comparison means for comparing the initial output difference value stored in the storage means with the output difference value detected by the detection means. And determining means for determining the presence or absence of a non-lighted laser in the plurality of connected semiconductor lasers.

  The light source device according to the second aspect of the invention is characterized by comprising non-lighting notifying means for notifying the non-lighting laser when the determining means determines that the non-lighting laser exists.

  In the light source device according to the third aspect of the present invention, when the non-lighting laser is determined to be present by the determination means, the initial output difference value and the detection means thereafter are detected. And calculating means for calculating the number of the unlit lasers based on the difference value with the output difference value.

  Further, the light source device according to the invention of claim 4 is characterized by further comprising a non-lighting number notifying unit for notifying the number of non-lighting calculated by the calculating unit.

  In the light source device according to the fifth aspect of the present invention, the supply means supplies a predetermined current value I and a current value I ′ obtained by changing the current value I by a minute current change amount ΔI. It is characterized by supplying to.

  In the light source device according to the invention of claim 6, the initial output difference value is an output difference value detected by the detecting means when all of the plurality of semiconductor lasers are turned on. It is characterized by being.

  In the light source device according to the invention of claim 7, the light source device includes a plurality of semiconductor lasers emitting blue light connected in series as light sources, and the light source device emits the light in the light emitting direction of the light sources. A phosphor wheel is disposed in which a diffusion region that diffuses and transmits blue light and a phosphor region that is coated with a phosphor that emits red and green light using the blue light as excitation light are arranged on the circumference, Blue light, red light, and green light are emitted in a time division manner by rotating the phosphor wheel at a predetermined speed.

  In the light source failure detection program according to the eighth aspect of the present invention, a computer having a light source device having a plurality of semiconductor lasers connected in series as a light source supplies currents of different values to the light source. Supply means, detection means for detecting an output difference value of the light source respectively emitted by supplying the current of the different value by the supply means, and storage for storing an initial output difference value detected by the detection means Means, a comparison means for comparing the initial output difference value stored in the storage means with an output difference value detected by the detection means, and the series connection based on the comparison result of the comparison means. Further, the present invention is characterized by functioning as a judging means for judging the presence or absence of a non-lighted laser in a plurality of semiconductor lasers.

  The light source failure detection method according to the invention of claim 9 is a light source failure detection method in a light source device having a plurality of semiconductor lasers connected in series as a light source. A supply step, a detection step for detecting an output difference value of each of the light sources that has emitted light in accordance with the supply of the current of the different value in the supply step, and an initial output difference value detected by the detection step Based on the comparison result in the comparison step, the comparison step for comparing the initial output difference value stored in the storage step, and the output difference value detected by the detection means thereafter And a determination step of determining presence / absence of a non-lighting laser in the plurality of semiconductor lasers connected in series. To.

  The projection device according to the invention of claim 10 is a projection device that projects an image by lighting a plurality of light sources having different emission colors in a time-sharing manner, wherein each of the plurality of light sources is connected in series. A plurality of semiconductor lasers configured to supply different values of current to the light source, and output difference values of the light sources respectively emitted as the different values of current are supplied by the supply unit. Detection means for detecting, storage means for storing the initial output difference value detected by the detection means, the initial output difference value stored in the storage means, and then the output difference detected by the detection means Comparing means for comparing values, and judging means for judging the presence or absence of a non-lighting laser in the plurality of semiconductor lasers connected in series based on the comparison result of the comparing means And features.

  According to the present invention, it is possible to detect the presence of a non-lighting laser in a plurality of semiconductor lasers connected in series without causing a complicated circuit or the like.

It is a block diagram which shows the circuit structure of the projection apparatus which concerns on one embodiment of this invention. It is a circuit diagram which shows the structure of each laser. It is a graph which shows the electric current-light output characteristic of each 1st-3rd semiconductor laser. It is a flowchart which shows the process sequence in one embodiment of this invention. It is a graph which shows the electric current-light output characteristic of each laser in t = 0 time point. It is a subroutine which shows the detail of step S2. It is a graph which shows the electric current-light output characteristic of each laser in t = 0, t = t1, etc. time points.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an electrical configuration of the projection apparatus 1 according to the present embodiment. The projection apparatus 1 includes a control unit 11, an input / output interface 12, an image conversion unit 13, a display encoder 14, a display drive unit 15, and the like, and image signals of various standards input from the input / output connector unit 16. (Image data) is converted through the input / output interface 12 and the system bus 17 so as to be unified into an image signal of a predetermined format suitable for display by the image conversion unit 13, and then sent to the display encoder 14.

  The display encoder 14 develops and stores the transmitted image signal in the video RAM 18, generates a video signal from the stored contents of the video RAM 18, and outputs the video signal to the display driving unit 15.

  A display drive unit 15 to which a video signal is input from the display encoder 14 drives a DMD 19 (digital micromirror device) as a display element at an appropriate frame rate corresponding to the transmitted video signal. The light beam emitted from the light source device 20 is incident on the DMD 19 via the light source side optical system, thereby forming an optical image with the reflected light of the DMD 19 and via the movable lens group 21 serving as the projection side optical system. The image is projected and displayed on a screen (not shown). The movable lens group 21 of the projection side optical system is driven by a lens motor 22 for zoom adjustment and focus adjustment.

  The image compression / decompression unit 23 performs recording processing for compressing the luminance signal and the color difference signal in the image signal by processing such as ADTC and Huffman coding, and writing the data onto a memory card 24 that is a detachable recording medium. The image data recorded in the memory card 24 is read out, and individual image data constituting a series of moving images is decompressed in units of one frame and sent to the display encoder 14 via the image conversion unit 13 to be stored in the image data stored in the memory card 24. Based on this, it is possible to display a moving image or the like.

  The control unit 11 controls the operation of each circuit in the projection apparatus 1 and includes a CPU and its peripheral circuits, a ROM 111, a RAM 112, and the like. The ROM 111 stores programs such as various settings, programs and data shown by flowcharts described later, and the RAM 112 is used as a work memory or the like.

  The key / indicator unit 25 includes a main key and an indicator provided in the main body case and the like, and an operation signal thereof is sent to the control unit 11. The key operation signal from the remote controller is received by the Ir receiver 26, demodulated by the Ir processor 27, and the code signal is sent to the controller 11.

  An audio processing unit 30 is connected to the control unit 11 via a system bus 17, and the audio processing unit 30 includes a sound source circuit such as a PCM sound source. In the projection mode and the reproduction mode, the audio data is converted into analog data and the speaker 31 can be driven to emit loud sounds.

  The light source device 20 includes a red laser 20R that emits an R (red) color, a green laser 20G that emits a G (green) color, and a blue laser 20B that emits a B (blue) color. The control unit 11 controls the light source control circuit 32 to control each of the lasers 20R, 20G, and 20B in a time-sharing manner according to the image signal.

  In addition, corresponding illuminance sensors 33R, 33G, and 33B are provided in the vicinity of the red laser 20R, the green laser 20G, and the blue laser 20B. These illuminance sensors 33R, 33G, and 33B detect the illuminance of the corresponding lasers 20R, 20G, and 20B, and supply the light to the control unit 11 as light output (W) through a circuit (not shown). Further, as shown in FIG. 2, each of the lasers 20R, 20G, and 20B is configured by connecting a first semiconductor laser 201, a second semiconductor laser 202, and a third semiconductor laser 203 in series.

  As described above, the semiconductor laser has a characteristic that the amount of light emission decreases with the passage of time of use (aging deterioration), and the characteristic that the amount of light emission decreases varies from one semiconductor laser to another. Therefore, for example, as shown in FIG. 3, even if the first to third semiconductor lasers 201 to 203 have the characteristics shown in the figure when the use time t = 0, the light emission amount (light output) when the use time t = t1. ) And the amount of light emitted by the third semiconductor laser 203 can be significantly reduced as compared with the first and second semiconductor lasers 201 and 202. Further, as in the illustrated third semiconductor laser 203, when the current value at which the light emission operation can be started with a decrease in the light emission amount falls below a predetermined operating current value I0, the semiconductor laser (the third semiconductor laser 203). ) Is not lit. However, the current-light output characteristics (change rate), that is, the slopes of the characteristic lines in FIG. 3 are the same.

  In the present embodiment having the above configuration, the control unit 11 of the projection apparatus 1 is turned on by operating a main key provided in the key / indicator unit 25 based on a program stored in the ROM 111. Each time, the processing is executed according to the flowchart shown in FIG. That is, in the present embodiment, the red laser 20R, the green laser 20G, and the blue laser 20B are used. First, the red laser 20R is selected in order to execute processing for the red laser 20R (step S1).

  Next, the light source control circuit 32 is operated to change the current value of the red laser 20R (first to third semiconductor lasers 201 to 203 connected in series) by a predetermined width ΔI as shown in FIG. 33R is operated, and the light output change value ΔW at this time is measured by the illuminance sensor 33R (step S2). More specifically, as shown in the subroutine of FIG. 6, first, the optical output W1 of the red laser 20R at the current value I1 of FIG. 5 is measured (step S201). Next, the optical output W2 is measured at the current value I2 where I2 = I1 + ΔI (step S202), and then the optical output change value ΔW is calculated from the difference between the optical outputs W1 and W2 (W1−W2) (step S202). S203). The current value I2 is equal to the operating current value I0, and I2 = I0.

  In step S3 in the flowchart of FIG. 4, it is determined whether or not the reference light output change value ΔW0 is stored in the RAM 112. This reference light output change value ΔW0 is the light output change at the beginning of use of the projection apparatus 1 or at the start of use after repairing and resetting a laser generated by a non-lighted semiconductor laser as will be described later. This is an actual measurement value ΔW. Therefore, when the projector 1 is turned on for the first time or reset after repair, the reference light output change value ΔW0 is not stored. In this case, the determination in step S3 is NO, the process proceeds to step S4, and the light output change value ΔW calculated in step S2 is stored as the reference light output change value ΔW0 (step S4).

  Therefore, as shown in FIG. 7, if the first power-on of the projection apparatus 1 or the first power-on after reset is performed at the time “t = 0”, the measurement is performed at the time “t = 0”. The changed light output change value is stored as the reference light output change value ΔW0.

  If the reference light output change value ΔW0 is already stored in the projection apparatus 1, the difference between the stored reference light output change value ΔW0 and the light output change value ΔW measured at the time of power-on this time is different. It is determined whether or not there is (step S5). At this time, as described with reference to FIG. 3, the light emission amount of the semiconductor laser decreases due to aging, and the current value I required for the light output value W to rise increases, but the current-light output characteristic (rate of change). That is, the inclination of each characteristic line in FIG. 3 is the same. Therefore, as long as all of the first to third semiconductor lasers 201 to 203 are lit even after the usage time has elapsed, as indicated by a one-dot chain line L in FIG. It is the same as the time point of “t = 0”, and the alternate long and short dash line L is parallel to the characteristic line L0 at the time point of “t = 0”. Therefore, as long as all the first to third semiconductor lasers 201 to 203 are lit even when the usage time has elapsed, the measured light output change value ΔW of this time is equal to the reference light output change value ΔW0. “ΔW0 = ΔW”, and the determination in step S5 is NO.

  However, in any one of the first to third semiconductor lasers 201 to 203, for example, as shown in FIG. 3, the third semiconductor laser 203 is not lit, and as shown in FIG. 7, “t = t1 Is measured at the time of the light output change value ΔW of the red laser 20R in which the non-lighted third semiconductor laser 203 exists. Then, since one of the three semiconductor lasers is not lit, the current-light output characteristic (rate of change) has a slope more than the characteristic line L0 at the time of “t = 0” as shown in FIG. There are few characteristic lines Lt1. Accordingly, the output change value ΔW measured in step S2 at the time of “t = t1” becomes smaller than the reference light output change value ΔW0 as shown in FIG. 7, and “ΔW0 ≠ ΔW”, so that step S5. The determination is YES.

  That is, when the determination in step S5 is YES, it is possible to detect the presence of non-lighted lasers in the plurality of semiconductor lasers 201 to 203 connected in series without incurring circuit complexity.

If the presence of the non-lighting laser in the semiconductor lasers 201 to 203 is detected in this way, the process proceeds from step S5 to step S6, and from the difference value of “ΔW0−ΔW”, the three semiconductor lasers connected in series are detected. The number of non-lighting is calculated (step S6).
That means
If ΔW0−ΔW = 1 / 3ΔW0, the number of non-lighting = 1
If ΔW0−ΔW = 2 / 3ΔW0, the number of non-lighting = 2
If ΔW0−ΔW = 3 / 3ΔW0 = ΔW0, the number of non-lighting = 3
It is.

  If the number of non-lighting is calculated, it is determined whether or not the calculated number of non-lighting is within an allowable range (step S7). If the number of non-lighting is within an allowable range (for example, 1), the process proceeds to step S11. On the other hand, if the number of non-lighting exceeds the allowable range, the indicator of the key / indicator unit 25 is operated to notify the non-lighting warning (step S8). Therefore, the user can know the occurrence of the non-lighting laser and take an early action by this warning notification.

  In addition, in step S6, since the number of non-lighting is calculated, when notifying the non-lighting, it is possible to notify the number of non-lighting, so that the user can know the number of non-lighting of the laser, Appropriate response is possible. Subsequently, it is determined whether or not a warning confirmation operation has been performed by the user at the key / indicator unit 25 (step S9). If there is a warning confirmation operation, the warning notification is terminated (step S10).

  Thereafter, it is determined whether or not the processing of steps S1 to S10 described above has been completed for all of the red laser 20R, the green laser 20G, and the blue laser 20B (step S11). If the execution has not ended, another laser is selected (step S12), and the processing from step S1 is repeated. As a result, for all the lasers 20R, 20G and 20, it is possible to detect the non-lighting and the number of unlit light in the semiconductor lasers 201 to 203 connected in series. When the execution of the processes of steps S1 to S10 is completed for all the lasers 20R, 20G, and 20, the lasers 20R, 20G, and 20B are time-division controlled, and each unit is controlled to start projection.

  In this embodiment, the number of semiconductor lasers connected in series is calculated up to the number of non-lighted semiconductor lasers, but a non-lighted laser in a series-connected semiconductor laser is simply detected without calculating the number of non-lighted semiconductor lasers. Then, only this may be notified. Moreover, although the case where this invention was applied to the projection apparatus was shown, it can apply not only to a projection apparatus but to the various apparatuses which use a semiconductor laser as a light source.

  Further, in the present embodiment, the light source device 20 has a red laser 20R, a blue laser 20B, and a green laser 20G, and is configured to obtain red, blue, and green light by emitting each in a time-sharing manner. The configuration of the light source device is not limited to this configuration. For example, the laser has only the blue laser 20B, and a diffusion region that diffuses and transmits the emitted blue light and a phosphor that emits red and green using the blue light as excitation light are provided on the front surface of the blue laser 20B. Place a phosphor wheel with the coated phosphor area arranged on the circumference, and rotate the phosphor wheel at a predetermined speed to emit blue light, red light, green light in a time division manner, respectively It is good also as a structure to obtain.

  Further, the light source device 20 includes a blue laser 20B and a red laser 20R, a diffusion region that diffuses and transmits the emitted blue light on the front surface of the blue laser 20B, and a phosphor that emits green using the blue light as excitation light. And a phosphor wheel in which a phosphor region coated with is disposed on the circumference, and a diffusion region that diffuses and transmits the emitted red light is disposed on the front surface of the red laser 20R. It is good. In any case, it is only necessary to have at least one color light source that emits light by connecting a plurality of semiconductor lasers in series, and the specific configuration thereof is not particularly limited.

DESCRIPTION OF SYMBOLS 11 Control part 12 Input / output interface 13 Image conversion part 14 Display encoder 15 Display drive part 18 Video RAM
19 DMD
20 Light source device 20R Red laser 20B Blue laser 20G Green laser 25 Key / indicator unit 32 Light source control circuit 33R, 33G, 33B Illuminance sensor 111 ROM
112 RAM
201 First semiconductor laser 202 Second semiconductor laser 203 Third semiconductor laser

Claims (10)

A light source device having a plurality of semiconductor lasers connected in series as a light source,
Supply means for supplying different values of current to the light source;
Detecting means for detecting an output difference value of each of the light sources that has emitted light in accordance with the supply of the currents of different values by the supplying means;
Storage means for storing an initial output difference value detected by the detection means;
Comparing means for comparing the initial output difference value stored in the storage means with the output difference value detected by the detecting means;
A light source device comprising: determination means for determining the presence or absence of unlit lasers in the plurality of semiconductor lasers connected in series based on a comparison result of the comparison means.   The light source device according to claim 1, further comprising a non-lighting notifying unit that notifies the non-lighting laser when the determination unit determines that the non-lighting laser exists.   The number of the non-lighted lasers based on the difference value between the initial output differential value and the output differential value detected by the detection means thereafter when the non-lighted laser is determined to be present by the determining means The light source device according to claim 1, further comprising a calculating unit that calculates   The light source device according to claim 3, further comprising a non-lighting number notifying unit that notifies the non-lighting number calculated by the calculating unit.   5. The supply unit according to claim 1, wherein the supply unit supplies a predetermined current value I and a current value I ′ obtained by changing the current value I by a minute current change amount ΔI to the light source. Light source device.   6. The light source according to claim 1, wherein the initial output difference value is an output difference value detected by the detection means when all of the plurality of semiconductor lasers are turned on. apparatus.   The light source device includes a plurality of semiconductor lasers that emit blue light connected in series as a light source, and a diffusion region that diffuses and transmits the blue light and the blue light as excitation light in the light emission direction of the light source. A phosphor wheel is arranged in which a phosphor region coated with phosphors emitting red and green is arranged on the circumference, and blue light and red light are rotated by rotating the phosphor wheel at a predetermined speed. The light source device according to claim 1, wherein the green light is emitted in a time division manner. A computer having a light source device having a plurality of semiconductor lasers connected in series as a light source;
Supply means for supplying different values of current to the light source;
Detecting means for detecting an output difference value of each of the light sources that has emitted light in accordance with the supply of the currents of different values by the supplying means;
Storage means for storing an initial output difference value detected by the detection means;
Comparing means for comparing the initial output difference value stored in the storage means with the output difference value detected by the detecting means;
A light source defect detection program that functions as a determination unit that determines the presence or absence of a non-lighted laser in the plurality of semiconductor lasers connected in series based on a comparison result of the comparison unit. A light source defect detection method in a light source device having a plurality of semiconductor lasers connected in series as a light source,
A supplying step of supplying different values of current to the light source;
A detection step of detecting an output difference value of each of the light sources that has emitted light in accordance with the supply of the current of the different value in the supply step;
A storage step for storing an initial output difference value detected by the detection step;
A comparison step for comparing the initial output difference value stored in the storage step with the output difference value detected by the detection means;
And a determination step of determining whether or not there is a non-lighted laser in the plurality of semiconductor lasers connected in series based on a comparison result in the comparison step. A projection apparatus for projecting an image by lighting a plurality of light sources having different emission colors in a time-sharing manner, each of the plurality of light sources being composed of a plurality of semiconductor lasers connected in series,
Supply means for supplying different values of current to the light source;
Detecting means for detecting an output difference value of each of the light sources that has emitted light in accordance with the supply of the currents of different values by the supplying means;
Storage means for storing an initial output difference value detected by the detection means;
Comparing means for comparing the initial output difference value stored in the storage means with the output difference value detected by the detecting means;
A projection apparatus comprising: a determination unit configured to determine presence or absence of a non-lighting laser in the plurality of semiconductor lasers connected in series based on a comparison result of the comparison unit.

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