JP2004207420A - Laser equipment and display unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect easily the state of each required laser beams when the beams outputted from a plurality of lasers are inputted into a common optical fiber. <P>SOLUTION: When the beams outputted from the plurality of lasers are inputted into the common optical fiber, a sensor is arranged on the output side of the common optical fiber in order to detect the state of each operated laser beam. Synchronizing with a laser operation period, the amount of the beam is measured by using the sensor, thereby detecting the state of each laser beam. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a laser device for inputting light output from a plurality of lasers to one optical fiber and an image display device using the laser device as a light source.
[0002]
[Prior art]
As a conventional method of detecting a laser failure, there is described a method of detecting a laser failure and controlling the operation of the laser when the laser is used as a light source of a projection display apparatus. (For example, Patent Document 1)
[0003]
[Patent Document 1]
JP-A-2000-267621 (pages 3 and 4, FIG. 1)
[0004]
[Problems to be solved by the invention]
In the technique disclosed in Patent Document 1 described above, when a plurality of semiconductor lasers are used, the state of each of the semiconductor lasers is not detected. When used, not only is there useless power consumption, but also the amount of heat generated increases, which may cause safety problems.
[0005]
An object of the present invention is to provide a laser device for easily detecting the state of each laser when light output from a plurality of lasers is input to one optical fiber, and an image display device using the laser device. It is in.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problem, a laser device of the present invention includes a laser light output unit that obtains a single light output from a plurality of laser generation units that generate laser light, and an output side of the laser light output unit. Detecting means for detecting the light amount on or near the optical path, wherein the detecting means operates the plurality of laser generating units in a time-division manner and detects the light amount in synchronization with the laser operation period. Features.
[0007]
According to this laser device, by measuring the amount of light using a sensor in synchronization with the laser operation period, when the light output from a plurality of lasers is input to a common optical fiber, each laser or optical system The state can be easily detected by a single sensor.
[0008]
An image display device according to the present invention is characterized in that a laser beam emitted from a laser device configured based on the above is spatially modulated using a spatial modulation element and displayed on a screen.
[0009]
According to this video display device, it is possible to easily detect the state from the laser emitting light source to the projection lens by measuring the light amount using the sensor in synchronization with the laser operation period.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram for explaining a first embodiment of the laser device of the present invention. In FIG. 1, 11a to 11e are semiconductor lasers, 12a to 12e and 14 are optical components, and 13a to 13e and 15 are optical fibers. The optical components 12a to 12e and 14 include a lens and an optical waveguide.
[0011]
Light output from the semiconductor lasers 11a to 11e is input to one ends of the optical fibers 13a to 13e via the optical components 12a to 12e, respectively. Light input to each of the optical fibers 13a to 13e is output from the other end, combined through the optical component 14, and input to one end of the optical fiber 15. The light input to the optical fiber 15 is output from the other end.
[0012]
Reference numeral 16 denotes a sensor for measuring the amount of light output from the optical fiber 15, such as a photodiode or a CCD. Reference numeral 17 denotes a microcomputer that obtains data from the sensor 16 and controls laser driving. Reference numeral 18 denotes a laser driving unit that drives the semiconductor lasers 11a to 11e based on a control signal of the microcomputer 17.
[0013]
Next, a method for detecting the state of each semiconductor laser will be described with reference to FIGS. Each of FIGS. 2 and 3 will be described with reference to an example in which all the semiconductor lasers are normal, and FIG. 2B will be described with an example in which the semiconductor laser 11d has failed.
[0014]
In the detection method of FIG. 2, the semiconductor lasers 11 a to 11 e are sequentially operated and stopped, and the amount of light output from the optical fiber 15 is measured using the sensor 16 during the operation period. By synchronizing the operation periods of the semiconductor lasers 11a to 11e with the measured values of the light amounts, the states of the semiconductor lasers 11a to 11e can be detected.
[0015]
FIG. 3 shows another example of the detection method. In this detection method, the states of the semiconductor lasers 11a to 11e are detected by sequentially operating the semiconductor lasers 11a to 11e and calculating the difference between the measured values of the light amounts.
[0016]
As described above, the states of the semiconductor lasers 11a to 11e are detected by the method shown in FIG. 2 or FIG. 3, and if the light amount is equal to or less than the specified value, the operation of the corresponding semiconductor laser is stopped. This eliminates unnecessary power consumption by eliminating the supply of electric power to the failed semiconductor laser, and also ensures safety.
[0017]
FIG. 4 is a configuration diagram for explaining a second embodiment of the laser device of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the cores of the optical fibers 13a to 13e shown in FIG. Elements 41a to 41e are attached, and a common reflection element 42 is attached to the other ends of the fiber lasers 131a to 131e to be opposed to the optical component 14.
[0018]
The reflection elements 41a to 41e transmit the light output from the semiconductor lasers 11a to 11e and reflect the light generated from the fiber lasers 131a to 131e. The reflection element 42 reflects part of the light generated from the fiber lasers 131a to 131e and transmits part of the light.
[0019]
Next, the operation will be described. Light output from the semiconductor lasers 11a to 11e is input to the corresponding fiber lasers 131a to 131e via the optical components 12a to 12e, respectively. The input light is absorbed by the fiber lasers 131a to 131e as excitation light, and the fiber lasers 131a to 131e generate light, respectively. The generated light forms a resonator between the reflection elements 41a to 41e and 42, becomes laser light, and is output from the reflection element 42 side. Each of the fiber lasers 131a to 131e becomes a fiber laser, and its output light is combined by the optical component 14 and input to the optical fiber 15.
[0020]
FIG. 5 is a configuration diagram for explaining a third embodiment of the laser device of the present invention, and the same components as those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the core of the optical fiber 15 shown in FIG. 1 is provided with a fiber laser 151 doped with a laser active substance, and a reflection element 51 is attached to one end of the fiber laser 151 facing the optical component 14. A common reflecting element 52 is attached to the other end of the optical component 14 so as to face the optical component 14.
[0021]
In the case of the configuration of FIG. 5, the light output from the semiconductor lasers 11a to 11e is combined through the optical components 12a to 12e, the optical fibers 13a to 13e, and the optical component 14, and then enters the optical fiber 15 as excitation light. , A resonator is formed between the reflection elements 51 and 52.
[0022]
Laser light generated by the fiber laser 151 is output from the reflection element 52 side. Since the sensor 16 measures the output light of the fiber laser 151, the sensor 16 measures the fiber laser light.
[0023]
As described above, even when the optical fibers 131a to 131e and the optical fiber 151 are fiber lasers, the detection operation is the same as that in FIG. 2 or FIG. Is stopped, and the same effect as in FIG. 1 is achieved.
[0024]
In each of the above-described embodiments, the sensor 16 measures the output of the optical fiber 15, and is not due to a defect of the semiconductor laser, but to a defect of the optical coupling system in the process of propagating from the semiconductor laser to the optical fiber 15. In some cases, the amount of light has decreased. Even in this case, it is preferable to stop the semiconductor laser in order to reduce power consumption and ensure safety, and it is preferable that the sensor 16 measures the output of the optical fiber 15 in order to detect the state of both the semiconductor laser and the optical system. .
[0025]
If the influence of the optical component 14 and the optical fiber 15 is to be excluded, the sensor 16 may be arranged near the output side of the optical fiber 13, and the output light of all the optical fibers of the plurality of optical fibers 13 is received. If possible. The operation in FIG. 2 or FIG. 3 may be performed at the start of the operation of the laser device, or may be performed at regular intervals of driving of the semiconductor laser. Alternatively, the operation of FIG. 2 or FIG. 3 may be performed only when the total output of the laser device is equal to or less than the specified value, and a failed semiconductor laser or optical system may be detected.
[0026]
FIG. 6 is a configuration diagram for explaining an embodiment of the video display device of the present invention, which is applied to a projection type video display device.
In FIG. 6, reference numerals 61 to 63 denote optical modules, and show components excluding the sensor 16, the microcomputer 17, and the laser control unit 18 from FIGS. 1, 4, and 5. The optical modules 61 to 63 are set so that the oscillation wavelengths of the semiconductor lasers 11a to 11e of FIG. 1 are red, green, and blue, respectively. In the case of FIG. The laser active material added to the optical fiber and the oscillation wavelength of the semiconductor laser are set so that red, green, and blue laser beams can be obtained by the fiber laser 151, respectively.
[0027]
64 to 66 are optical fibers attached to the optical module and output generated laser light, 67 is a lens, 68 is a video input terminal, 69 is a liquid crystal driving unit, 70 is a liquid crystal panel, 71 is a projection lens, and 72 is a screen. Show.
[0028]
First, the operation of the video display device will be described. Light output from the end faces of the optical fibers 64 to 66 becomes parallel light by the lens 67 and enters the liquid crystal panel 70. On the other hand, a video signal is input from a video signal input terminal 68, and a liquid crystal driving section 69 drives a liquid crystal panel 70 based on the video signal. Thus, the light incident on the liquid crystal panel 70 is spatially modulated in accordance with the video signal. The spatially modulated light forms an image on a screen 72 via a projection lens 71.
[0029]
Reference numeral 73 denotes a sensor that measures the amount of light projected from the projection lens 71, and is disposed at a location that does not obstruct image display at a corner of the screen, for example. A microcomputer 74 acquires data from the sensor 73 and controls laser driving. A laser driving unit 75 drives the laser based on a control signal of the microcomputer 74.
[0030]
A method of detecting individual semiconductor lasers will be described with reference to FIGS. 7A and 8A, (A) shows a state where all the semiconductor lasers are normal, and (B) shows a state where the semiconductor laser of green d has a failure.
[0031]
In the detection method of FIG. 7, red (a) to (e), green (a) to (e), and blue (a) to (e) are sequentially stopped and activated, and the projection lens 71 is operated in accordance with the operation period. Is measured using the sensor 73. The state of each semiconductor laser can be detected by synchronizing the operation period of each semiconductor laser with the measured light amount.
[0032]
FIG. 8 shows another detection method. In the detection method shown in FIG. 8, each of the semiconductor lasers is operated by sequentially operating red (a) to (e), green (a) to (e), and blue (a) to (e), and taking a difference between measured values of light quantity. Is a method of detecting the state of The state of each semiconductor laser is detected by the method shown in FIG. 7 or FIG. 8, and the operation of the semiconductor laser is stopped if the light amount is equal to or less than the specified value. This eliminates unnecessary power consumption by eliminating the supply of power to the failed semiconductor laser, and also ensures safety.
[0033]
Since the sensor 73 measures the output of the projection lens 71, not a failure of the semiconductor laser but any part of the optical system from the semiconductor laser to the projection lens may be defective. In this case as well, it is preferable to stop the semiconductor laser in order to reduce power consumption and ensure safety, and it is preferable that the sensor 73 measures the output of the projection lens 71 in order to detect the state of the entire optical system. When the state of only the optical module is detected, a sensor may be arranged near the output side of the optical fibers 64 to 66, as long as the output light of all the optical fibers of the optical fibers 64 to 66 can be received.
[0034]
The operation in FIG. 7 or FIG. 8 may be performed when the power of the video display device is turned on, or may be performed at regular intervals of driving the semiconductor laser. Alternatively, the operation of FIG. 7 or FIG. 8 may be performed only when the total output of the projection lens is equal to or less than the specified value, and a failed semiconductor laser or optical system may be detected.
[0035]
【The invention's effect】
As described above, according to the laser apparatus of the present invention, the state of each laser or optical system when light output from a plurality of lasers is input to a common optical fiber can be easily detected by a single sensor. It is possible to do.
[0036]
Further, according to the video display device using the laser device of the present invention as a light source, it is possible to easily detect the state from the laser to the projection lens.
[Brief description of the drawings]
FIG. 1 is a configuration diagram for explaining a first embodiment of a laser device of the present invention.
FIG. 2 is an explanatory diagram for describing an example of laser state detection used in the laser device of FIG. 1;
FIG. 3 is an explanatory diagram for describing another example of laser state detection used in the laser device of FIG. 1;
FIG. 4 is a configuration diagram for explaining a second embodiment of the laser device of the present invention.
FIG. 5 is a configuration diagram for describing a third embodiment of the laser device of the present invention.
FIG. 6 is a system configuration diagram for explaining an embodiment of the video display device of the present invention.
FIG. 7 is an explanatory diagram for describing an example of laser state detection used in the embodiment of the video display device in FIG. 6;
FIG. 8 is an explanatory diagram for describing another example of laser state detection used in the video display device of FIG. 6;
[Explanation of symbols]
11a to 11e semiconductor lasers 12a to 12e, 14 optical components 13a to 13e, 15 optical fibers 131a to 131e, 151 fiber laser 16 sensor 17 microcomputer 18 laser control units 41a to 41e, 42, 51, 52 ... Reflection elements 61-63 ... Optical modules 64-66 ... Optical fiber 67 ... Lens 68 ... Video signal input terminal 69 ... Liquid crystal drive unit 70 ... Liquid crystal panel 71 ... Projection lens 72 ... Screen 73 ... Sensor 74 ... Microcomputer 75 ... Laser drive Department

Claims (5)

Laser light output means for obtaining a single light output from a plurality of laser generators for generating laser light,
Detecting means for detecting the amount of light on or near the optical path on the output side of the laser light output means,
The laser device, wherein the detection means operates the plurality of laser generation units in a time-division manner and detects a light amount in synchronization with a laser operation period. 2. The laser device according to claim 1, wherein the detecting unit detects that an output of the laser beam is equal to or less than a specified value among the plurality of laser generating units. 3. The laser device according to claim 1, wherein the plurality of laser generating units are fiber lasers. The laser device according to claim 1, wherein the plurality of laser generation units are excitation light sources of a fiber laser, and the single optical output is an output of a fiber laser. 5. An image display device, wherein a laser beam emitted from a laser device configured according to any one of claims 1 to 4 is spatially modulated using a spatial modulation element, and displayed on a screen.

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