JP2015125834A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device which detects abnormalities such as breakage and the like of individual optical fibers even during the operation, by light quantity measurement for an output light flux of integrated radiation light from all optical fibers, not from individual optical fibers.SOLUTION: A light source device has a plurality of element light sources each consisting of a unit comprising a light-emitting element, a drive circuit thereof, and an optical fiber, and forms and outputs an output light flux. An inspection target element light source and a variation correction element light source are selected from the element light sources. Then, feedback control to the drive circuit belonging to the variation correction element light source is performed so as to cancel a change in light quantity measurement data caused by a change in an output power correlation amount Qu while controlling the drive circuit belonging to the inspection target element light source so as to gradually change the output power correlation amount Qu by +ΔQu. When a change amount for changing an output power correlation amount Qv of the variation correction element light source is -ΔQv, a ratio ΔQv/ΔQu is evaluated to detect abnormalities of the inspection target element light source.

Description

  The present invention relates to a light source device using a light emitting element such as a semiconductor laser and an optical fiber, which can be used in an optical device such as a projector.

For example, high-intensity discharge lamps (HID lamps) such as xenon lamps and ultra-high pressure mercury lamps have been used in image display projectors such as DLP (TM) projectors and liquid crystal projectors, and photomask exposure apparatuses. I came.
As an example, the principle of the projector will be described with reference to FIG. 4, which is a diagram for explaining one form of a part of a conventional projector related to the projector of the present invention (reference: Japanese Patent Application Laid-Open No. 2004-252112, etc.).

As described above, light from the light source (SjA) composed of a high-intensity discharge lamp or the like is obtained with the help of a light condensing means (not shown) composed of a concave reflecting mirror, a lens, or the like. FmA) is input to the incident end (PmiA) and output from the exit end (PmoA).
Here, as the light homogenizing means (FmA), for example, a light guide can be used, which is also called a name such as a rod integrator or a light tunnel, and is a light transmissive material such as glass or resin. In accordance with the same principle as that of an optical fiber, the light homogenizing means (FmiA) repeats total reflection on the side surface of the light homogenizing means (FmA). By propagating through FmA), even if the distribution of light input to the incident end (PmiA) is uneven, the illuminance on the exit end (PmoA) is sufficiently uniformed. Function.

  As for the light guide just described, in addition to the above-described prisms made of a light-transmitting material such as glass and resin, a hollow square tube, the inner surface of which is a reflecting mirror, Similarly, there are some which perform the same function by propagating light while repeating reflection on the inner surface.

The illumination lens (Ej1A) is arranged so that a square image of the emission end (PmoA) is formed on the two-dimensional light amplitude modulation element (DmjA), and is output from the emission end (PmoA). The two-dimensional light amplitude modulation element (DmjA) is illuminated with light.
However, in FIG. 4, a mirror (MjA) is disposed between the illumination lens (Ej1A) and the two-dimensional light amplitude modulation element (DmjA).
Then, the two-dimensional light amplitude modulation element (DmjA) modulates the light so as to be directed to the direction in which the light is incident on the projection lens (Ej2A) or not to be incident on each pixel according to the video signal. An image is displayed on the screen (Tj).

  The two-dimensional light amplitude modulation element as described above is sometimes called a light valve. In the case of the optical system shown in FIG. 4, the DMD (TM) (digital) is generally used as the two-dimensional light amplitude modulation element (DmjA).・ Micromirror devices are often used.

  In addition to the above-described light guide, there is also a light uniformizing means called a fly eye integrator. As an example of a projector using this light uniformizing means, a conventional projector related to the projector of the present invention is used. The principle will be described with reference to FIG. 5, which is a diagram for explaining one form of one kind (reference: JP-A-2001-142141, etc.).

The light from the light source (SjB) composed of a high-intensity discharge lamp or the like is made into a uniform light beam by a fly-eye integrator with the help of collimator means (not shown) composed of a concave reflecting mirror or lens. Is input to the incident end (PmiB) of the converting means (FmB) and output from the exit end (PmoB).
Here, the light uniformizing means (FmB) is configured by a combination of an incident-side front stage fly-eye lens (F1B), an exit-side rear stage fly-eye lens (F2B), and an illumination lens (Ej1B).
Both the front fly-eye lens (F1B) and the rear fly-eye lens (F2B) are formed by arranging a large number of rectangular lenses having the same focal length and the same shape in the vertical and horizontal directions.

Each lens of the front-stage fly-eye lens (F1B) and the corresponding lens of the rear-stage fly-eye lens (F2B) in the subsequent stage constitute an optical system called Koehler illumination. A large number of optical systems are arranged vertically and horizontally.
In general, the Kohler illumination optical system is composed of two lenses. When the front lens collects light and illuminates the target surface, the front lens does not form a light source image on the target surface, but the center of the rear lens. A light source image is formed on this surface, and the rear lens is arranged so as to form an image of the quadrangle of the outer shape of the front lens on the target surface (surface to be illuminated), thereby uniformly illuminating the target surface.
The function of the latter lens is to prevent the phenomenon that the illuminance around the square of the target surface falls depending on the size when the light source is not a perfect point light source but has a finite size if it is not Thus, the rear lens can make the illuminance uniform to the periphery of the square of the target surface without depending on the size of the light source.

Here, in the case of the optical system of FIG. 5, since it is basically based on the input of a substantially parallel light beam to the light uniformizing means (FmB), the front fly-eye lens (F1B) and the rear fly-eye lens ( The distance from F2B) is set to be equal to the focal length thereof, and thus an image of the target surface of uniform illumination as the Kohler illumination optical system is generated at infinity.
However, since the illumination lens (Ej1B) is disposed at the rear stage of the rear fly-eye lens (F2B), the target surface is drawn toward the focal plane of the illumination lens (Ej1B) from infinity.
Since many Koehler illumination optical systems arranged in the vertical and horizontal directions are parallel to the incident optical axis (ZiB) and the light fluxes are input substantially axially symmetrically with respect to the respective central axes, the output light flux is also substantially axially symmetric. Because of the nature of the lens, that is, the Fourier transform action of the lens, all rays incident on the lens surface at the same angle are refracted toward the same point on the focal plane regardless of the incident position on the lens surface. The output of the Koehler illumination optical system is imaged on the same target surface on the focal plane of the illumination lens (Ej1B).

As a result, all the illuminance distributions on the respective lens surfaces of the preceding fly-eye lens (F1B) are superposed, so that the illuminance distribution becomes more uniform than in the case of a single Koehler illumination optical system. A square image is formed on the incident optical axis (ZiB).
By disposing a two-dimensional light amplitude modulation element (DmjB) at the position of the composite square image, the two-dimensional light amplitude modulation element (DmjB) that is an object to be illuminated by light output from the emission end (PmoB). Is illuminated.
However, for illumination, a polarizing beam splitter (MjB) is disposed between the illumination lens (Ej1B) and the two-dimensional light amplitude modulation element (DmjB), so that light is transmitted to the two-dimensional light amplitude modulation element ( DmjB) is reflected.
The two-dimensional light amplitude modulation element (DmjB) rotates the polarization direction of light by 90 degrees for each pixel according to the video signal, or modulates and reflects the light so that only the rotated light is reflected. Then, the light passes through the polarizing beam splitter (MjB) and is incident on the projection lens (Ej3B) to display an image on the screen (Tj).

In the case of the optical system of FIG. 5, generally, LCOS ™ (silicon liquid crystal device) is often used as the two-dimensional light amplitude modulation element (DmjA).
In the case of such a liquid crystal device, since only the light component in the specified polarization direction can be effectively modulated, normally the component parallel to the specified polarization direction is transmitted as it is, but only the component perpendicular to the specified polarization direction is polarized. A polarization alignment function element (PcB) for rotating the direction by 90 degrees and, as a result, enabling effective use of all light, is inserted, for example, in the rear stage of the rear fly-eye lens (F2B).
For example, a field lens (Ej2B) is inserted immediately before the two-dimensional light amplitude modulation element (DmjB) so that substantially parallel light is incident thereon.

  As for the two-dimensional optical amplitude modulation element, in addition to the reflective type as shown in FIG. 5, a transmissive liquid crystal device (LCD) is also used with an optical arrangement suitable for it (reference: 10-133303 etc.).

  By the way, in a normal projector, in order to display an image in color, for example, a dynamic color filter such as a color wheel is disposed after the light uniformizing means, and R, G, B (red and green, blue) The two-dimensional light amplitude modulation element is illuminated as a color sequential light beam, and color display is realized by time division, or a dichroic mirror or dichroic prism is arranged at the subsequent stage of the light uniformizing means, and R, G, B A dichroic mirror and a dichroic prism are used to illuminate a two-dimensional light amplitude modulation element provided independently for each color with light separated into the three primary colors, and to perform color synthesis of modulated light beams of the three primary colors of R, G, and B. However, in order to avoid complication, it is omitted in FIGS.

However, the high-intensity discharge lamp described above has drawbacks such as low conversion efficiency from input power to optical power, that is, a large heat loss or a short life.
In recent years, solid light sources such as LEDs and semiconductor lasers have attracted attention as alternative light sources that have overcome these drawbacks.
Among them, the LED has a smaller heat loss and a longer life than the discharge lamp, but the emitted light has no directivity like the discharge lamp. However, in applications where only light in a specific direction can be used, there is a problem that the light use efficiency is low.

On the other hand, the semiconductor laser has a drawback that speckle is generated due to its high coherence, but it can be overcome by various technical improvements such as using a diffusion plate. Advantages of high light utilization efficiency even in applications where only light in a specific direction can be used, such as the projectors and exposure apparatuses described above, because of low heat loss, long life, and high directivity There is.
In addition, the high directivity makes it possible to perform optical transmission with high efficiency, so it is possible to separate the installation location of the semiconductor laser from the location where the light is used, such as a projector. The degree of freedom can be increased.

However, even when the same current flows, the brightness of the semiconductor laser changes due to environmental temperature change or temperature rise due to self-heating, and deterioration due to increase in cumulative energization time, so when applying this to a projector, It is desirable to perform feedback control in order to stabilize the light amount.
In order to realize this, means for measuring the amount of light is essential, and in particular, an optical sensor for measuring the amounts of light of R, G, and B at the entrance of light to the projector, that is, at the exit end of the optical fiber. It is desirable to install.

By the way, the optical fiber is disadvantageous in that it has a risk of breaking because it is made of fragile glass such as quartz, although it is convenient as described above.
For example, when a projector having a brightness of 10,000 ANSI lumens is to be realized, it is necessary to transmit optical power of about 200 W through an optical fiber, depending on the efficiency of the optical system.
For this reason, even if it is divided into six optical fibers and transmitted, it is necessary to transmit optical power of 30 W or more per one.
Incidentally, if the number of optical fibers is further increased, the power per one can be reduced. However, since the cost is increased, the number of optical fibers cannot be increased without any darkness.
When an optical fiber that transmits such a large power breaks, the optical power leaks from the broken portion and is absorbed by the coating material provided to mechanically protect the optical fiber, and the coating material may burn out. For this reason, if the optical fiber breaks, a safety measure is required to detect this and turn off the semiconductor laser.

Techniques for detecting optical fiber breakage have been developed in the past, from those with high power applications where there is a possibility of such member burning to those with low power applications such as communication.
For example, in Japanese Patent Laid-Open No. 06-050841, a light having a wavelength to be transmitted and a monitoring light having a wavelength different from that are transmitted from a transmitting side to a communication optical fiber, and a monitoring side is used on a receiving side. A technique is described that includes a filter that reflects and returns light, and detects the breakage of the optical fiber by monitoring whether the monitoring light returns on the transmission side.

  Further, for example, in Japanese Patent Application Laid-Open No. 09-269248, the presence or absence of breakage of the optical fiber is detected based on the waveform of the return light when the pulse light is incident mainly on the communication optical fiber, and is broken. In this case, a technique for calculating the distance to the breaking point is described.

  Further, for example, in Japanese Patent Application Laid-Open No. 10-038751, an optical sensor for detecting stray light in a lens system is provided in the vicinity of each of the lens systems on the incident end side and the output end side, mainly for a high power optical fiber for laser processing. A technique for detecting breakage of an optical fiber by comparing the amounts of light detected by both optical sensors is described.

  Further, for example, in JP-A-11-005187, a high-power optical fiber for laser processing is mainly provided with a protective tube for covering it, and a plurality of sensors for detecting laser light leaking from the optical fiber are arranged inside. A technique for placing and detecting the breakage of an optical fiber is described.

  Further, for example, in Japanese Patent Application Laid-Open No. 11-344417, a high-power optical fiber for laser processing is sent from the transmission side together with light of a wavelength to be transmitted from the transmission side together with light of a wavelength to be transmitted. Describes a technique for detecting breakage of an optical fiber by monitoring the presence or absence of light for monitoring.

  Furthermore, for example, in Japanese Patent Application Laid-Open No. 2002-350694 and Japanese Patent Application Laid-Open No. 2004-219244, a conductive coating is provided on the outer peripheral surface of an optical fiber for communication or laser processing, and the incident end side and the output end side are provided. A technique for detecting the breakage of an optical fiber by monitoring a conduction state between them is described.

  Further, for example, in Japanese Patent Application Laid-Open No. 2003-279444, a high-power optical fiber for laser processing is installed along a cable in which a large number of thermal fuses are connected in series, and the optical fiber is broken by melting the thermal fuse. The technology to detect is described.

  Further, for example, in Japanese Patent Application Laid-Open No. 2006-064399, the presence or absence of breakage of an optical fiber is detected based on the phase difference of return modulated light when modulated light is incident on a communication optical fiber. A technique for calculating the distance to the breaking point when it is broken is described.

  Further, for example, in Japanese Patent Application Laid-Open No. 2012-147860, a technique for detecting breakage of an optical fiber mainly based on a ratio of an incident light quantity and a return light quantity measured on the light incident end side with respect to an optical fiber for endoscope illumination. Is described.

However, it has not been advantageous to apply these conventional techniques when a semiconductor laser is applied as the projector light source as described above.
This is because, when a plurality of optical fibers are used in combination, it is expensive to apply some device such as a monitor light source or a break detection mechanism to each optical fiber.
As described above, for the purpose of stabilizing the light amount, if an optical sensor for measuring the respective light amounts of R, G, and B is installed at the output end of the optical fiber, this can be used for detecting the breakage of the optical fiber. It is desirable that this can be diverted.
However, even in a light source device having a plurality of optical fibers and a plurality of drive circuits, it is possible to separate and measure the amount of light of each optical fiber in the same manner as described above. Moreover, it is not necessary to achieve stabilization of the light amount of the light beam supplied to the projector, and it is sufficient if the total light amount from all the optical fibers can be measured for each color.
However, under such conditions where only the total amount of light from all optical fibers can be measured, the optical fiber breakage cannot be detected correctly.
The reason is that even if one optical fiber breaks, light is supplied from the other plural optical fibers. If the deterioration of the light emitting element has not progressed, the light amount stabilization feedback control This is because the total light amount from all the optical fibers is maintained at the target value.

Therefore, in order to investigate the state of individual optical fibers under the condition that only the total amount of light from all the optical fibers can be measured, the light-emitting elements that have guided light to each optical fiber have been individually turned on. It was unavoidable to use a method in which the measurement result of the total light amount from all the optical fibers at that time was compared and analyzed, for example, by controlling the state to the off state (or dimming state).
However, in the case of a light source device that supplies a light beam to a projector, for example, an optical fiber break detection sequence that involves intentional increase or decrease in the amount of light that passes through the optical fiber will adversely affect the projected image if performed while the projector is in operation. It was possible to carry out only within a limited period immediately after the start of operation and before the start of video projection.
For example, rather than starting the light-emitting elements that are guiding the light to each optical fiber all at once, starting them one by one in order, and the total light quantity from all the optical fibers is the expected stepped shape Anomaly detection is tried depending on whether or not the light is increased.
Even during operation, if there is a period during which no image is projected, if information to that effect is transmitted from the projector to the light source device, it can be performed during that period, but it is still not possible to monitor constantly during operation. was there.

Japanese Patent Laid-Open No. 06-050841 JP 09-269248 A Japanese Patent Laid-Open No. 10-038751 JP 11-005187 A JP-A-11-344417 JP 2002-350694 A JP 2004-219244 A JP 2003-279444 A JP 2006-064399 A JP 2012-147860 A

  The problem to be solved by the present invention is that the individual optical fibers are broken even during operation by measuring the amount of light emitted from all the optical fibers instead of the individual optical fibers. It is an object of the present invention to provide a light source device and a projector that can detect abnormalities such as the above.

  The light source device according to the first aspect of the present invention includes one or more light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) And the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...). A driving circuit (P1a, P1b,..., P2a, P2b,...) And a condensing optical system (Ec1) that condenses light emitted from the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...). , Ec2,...) And the light collected by the condensing optical system (Ec1, Ec2,...) Is received and guided by the incident ends (Ei1, Ei2,...) And emitted from the exit ends (Eo1, Eo2,...). A unit including the radiating optical fibers (Ef1, Ef2,...) As one element light source (U1, U2,...), And a plurality of the element light sources (U1, U2,...), Each said optical fiber (U1, U2,...) f1, Ef2,...)) is a light source device that outputs radiation light from the emission ends (Eo1, Eo2,...) as a single output light beam (Fo). Further, a light sensor (A) and a light amount measuring circuit (H) for receiving a signal from the light sensor (A), measuring a light amount incident on the light sensor (A), and generating light amount measurement data (Sh) A control circuit (Mc) for receiving the light quantity measurement data (Sh) and setting and controlling the output power correlation amount for each of the drive circuits (P1a, P1b,..., P2a, P2b,...). And the light source device combines light emitted from the emission ends (Eo1, Eo2,...) Of the optical fibers (Ef1, Ef2,...) Of the element light sources (U1, U2,...). At least a part of one luminous flux By irradiating the light sensor (A), the control circuit (Mc) can acquire the light amount measurement data (Sh) correlated with the light amount of the output light beam (Fo). The control circuit (Mc) selects one inspection target element light source and one or more variation correction element light sources from the element light sources (U1, U2,...), And then performs the control. The circuit (Mc) gradually changes the output power correlation amount Qu that combines the entire drive circuits that drive the light emitting elements belonging to one wavelength band belonging to the inspection target element light source from Quo to Quo + ΔQu. While controlling the drive circuit belonging to the inspection target element light source, the change in the light quantity measurement data corresponding to the wavelength band due to the change in the output power correlation amount Qu is canceled out. Feedback control is performed on the drive circuit belonging to the fluctuation correction element light source to change an output power correlation amount Qv that is a total of the drive circuits that drive the light emitting elements belonging to the wavelength band that belong to the fluctuation correction element light source. In addition, when the change in the output power correlation amount Qv with respect to the change in the output power correlation amount Qu from Quo to Quo + ΔQu is from Qvo to Qvo−ΔQv, the output power with respect to the change in the output power correlation amount Qu. A change ratio acquisition sequence for acquiring a value of the change ratio ΔQv / ΔQu taking the ratio of the change in the correlation amount Qv is performed, the change ratio ΔQv / ΔQu is evaluated, and the element light source of the inspection target light source It is characterized by detecting an abnormality.

  However, in the above description, one wavelength band, and the wavelength band, when the light source device of the present invention includes only a light emitting element belonging to only one wavelength band, the wavelength band to which the light emitting element belongs, In addition, when the light source device of the present invention includes a light emitting element belonging to a plurality of wavelength bands, it refers to one of the wavelength bands of interest, and in the description below It is the same.

  In the light source device according to a second aspect of the present invention, the control circuit (Mc) drives the light emitting element belonging to the wavelength band belonging to the element light source selected as the inspection target element light source. When there are a plurality of drive circuits, one of them is further selected, and only the output power correlation amount of the selected drive circuit is changed, thereby changing the total output power correlation amount Qu of the drive circuit. And executing the change ratio acquisition sequence in sequence over all of the driving circuits that drive the light emitting elements belonging to the wavelength band, belonging to the selected element light source, and acquired. The largest value of the change ratios ΔQv / ΔQu is evaluated to detect an abnormality of the optical fiber belonging to the selected element light source to be inspected. Is.

  In the light source device according to a third aspect of the present invention, the control circuit (Mc) drives the light emitting element belonging to the wavelength band belonging to the element light source selected as the inspection target element light source. When there are a plurality of drive circuits, one of them is further selected, and only the output power correlation amount of the selected drive circuit is changed, thereby changing the total output power correlation amount Qu of the drive circuit. And executing the change ratio acquisition sequence in sequence over all of the driving circuits that drive the light emitting elements belonging to the wavelength band, belonging to the selected element light source, and acquired. The largest value of the change ratios ΔQv / ΔQu is set as the change ratio reference value for the inspection target element light source, and the obtained change ratio ΔQv / ΔQu is the previous value. Evaluating the value of the ratio of change in ratio reference value, and is characterized in that to detect the set of anomalies of the corresponding drive circuit and the light emitting element connected to it.

  In the light source device according to a fourth aspect of the present invention, the control circuit (Mc) drives the light emitting element belonging to the wavelength band belonging to the element light source selected as the variation correction element light source. When there are a plurality of drive circuits, one of them is further selected, and only the output power correlation amount of the selected drive circuit is changed to change the total output power correlation amount Qv of the entire drive circuit. The change ratio acquisition sequence is executed, and when one of the drive circuits is selected, the one that gives the change ratio ΔQv / ΔQu having the smallest value is selected. .

  In the light source device according to a fifth aspect of the present invention, when there are a plurality of element light sources that can be selected as the variation correction element light source, the control circuit (Mc) has the smallest change ratio ΔQv / The one that gives ΔQu is selected.

  In the light source device according to a sixth aspect of the present invention, at the start of the change ratio acquisition sequence, the control circuit (Mc) uses the same element light source belonging to the wavelength band as a variation correction element light source. The change ΔQu of the output power correlation amount Qu set in the acquisition sequence is characterized in that a change ΔQu of the opposite sign is set.

  In the light source device according to a seventh aspect of the present invention, the control circuit (Mc) sets the change ΔQu of the output power correlation amount Qu to a negative value during the change ratio acquisition sequence, and serves as the fluctuation correction element light source. A change ΔQv of the output power correlation amount Qv is given by a plurality of the drive circuits belonging to the selected element light source.

  In the light source device according to an eighth aspect of the present invention, the control circuit (Mc) selects all of the active element light sources (U1, U2,...) As the inspection target element light sources one by one in order, A sequence for performing a change ratio acquisition sequence and trying to detect an abnormality of the inspection target element light source is periodically performed.

  In the light source device according to a ninth aspect of the present invention, when the control circuit (Mc) performs feedback control on the drive circuit belonging to the variation correction element light source, the light quantity measurement data and a target value thereof are calculated. The output power correlation amount Qv is changed so as to reduce the difference.

  In the light source device according to a tenth aspect of the present invention, the light emitting element (Y1a, Y1b,..., Y2a, Y2b,...) Includes a light emitting wavelength belonging to a plurality of different wavelength bands, and the optical sensor. (Ax, Ay,...) Includes a plurality of spectral filters (Erx, Ery,...) That selectively transmit light corresponding to the wavelength band. A total of radiation beams of a plurality of types of wavelength bands from the emission ends (Eo1, Eo2,...) Of the optical fibers (Ef1, Ef2,...) Of the element light sources (U1, U2,...) By irradiating at least a part of each of the plurality of photosensors (Ax, Ay,...) With the light flux, the control circuit (Mc) can generate the light flux (Fo). For the amount of light in each wavelength band The light quantity measurement data (Shx, Shy,...) Can be received, and when the change ratio acquisition sequence is executed, the output power correlation amount Qu is changed. The light amount measurement data of the photosensor corresponding to the wavelength band to which the light emitting element connected to the drive circuit belongs is acquired, and connected to the drive circuit in which the output power correlation amount Qu is changed. The output power correlation amount Qv is changed by selecting from among the drive circuits to which the light emitting elements belonging to the same wavelength band as the wavelength band to which the light emitting elements belong is connected.

  According to an eleventh aspect of the present invention, there is provided a projector for projecting and displaying an image using the light source device according to any one of the first to tenth aspects.

  Light source that enables detection of abnormalities such as breakage of individual optical fibers even during operation by measuring the amount of light emitted from all the optical fibers instead of individual optical fibers. An apparatus and a projector can be provided.

The block diagram which simplifies and shows the light source device of this invention is represented. The block diagram which simplifies and shows the light source device of this invention is represented. The figure which simplifies and shows one form of the Example of the light source device of this invention is represented. The figure explaining one form of one part of the kind of the conventional projector concerning the projector of this invention is represented. The figure explaining one form of one part of the kind of the conventional projector concerning the projector of this invention is represented.

First, the form for implementing this invention is demonstrated using FIG. 1 which is a block diagram which simplifies and shows the light source device of this invention.
The light emitting elements (Y1a, Y1b,...) Provided in the element light source (U1) are driven by a drive circuit (P1a, P1b,...) To emit light. The light is condensed on the incident end (Ei1) of the optical fiber (Ef1) by the system (Ec1), propagates through the core of the optical fiber (Ef1), and is emitted from the emission end (Eo1).
Here, in order to simplify the description, it is assumed for the time being that the light source device of the present invention includes only light emitting elements belonging to only one wavelength band.
A case where light emitting elements belonging to a plurality of wavelength bands are included will be described later.

For the light emitting elements (Y1a, Y1b,...), Here, for example, semiconductor laser or wavelength conversion of the emitted light of the semiconductor laser is performed using a nonlinear optical phenomenon such as harmonic generation / optical parametric effect. A plurality of such light sources are connected in series, in parallel, or in series-parallel, and can be driven by a single drive circuit (P1a, P1b,...). .
In addition, the drive circuits (P1a, P1b,...) Are here DC / DC converters configured by a circuit of a method such as a step-down chopper or a step-up chopper, which is fed by a DC power supply (not shown). Yes, it is assumed that prescribed power can be applied to the light emitting elements (Y1a, Y1b,...).

The light source device of the present invention has a plurality of element light sources similar to the element light source (U1), and the emission ends of the optical fibers (Ef1, Ef2,...) Of these element light sources (U1, U2,...). The radiated light from (Eo1, Eo2,...) Is combined and output as one output light beam (Fo) from the light source device of the present invention.
As a comprehensive method of radiated light from the plurality of emission ends (Eo1, Eo2,...), The simplest method is to align the emission ends (Eo1, Eo2,...) On the same plane. This can be realized by bundling the emission ends of the optical fibers (Ef1, Ef2,...).

In order to generate light quantity measurement data (Sh) that correlates with the light quantity of the output light beam (Fo), a part of the radiated light from the emission end (Eo1, Eo2,...) As with the output light beam (Fo). The output light beam (Fo ′) for measurement is generated and irradiated to the optical sensor (A), and the signal (Sg) of the optical sensor (A) is required to be amplified or AD converted by the light amount measuring circuit (H). Then, the light quantity measurement data (Sh) is generated.
The measurement output light beam (Fo ′) may be generated by being divided from the output light beam (Fo), or may be stray light that is generated when the output light beam (Fo) is generated and cannot be used effectively. Any light can be used as long as it has a light quantity correlated with the light quantity of the output light beam (Fo).
Then, the control circuit (Mc) can acquire the generated light quantity measurement data (Sh), and further via the drive circuit control signals (J1a, J1b,..., J2a, J2b,...) (P1a, P1b,..., P2a, P2b,...) Are controlled independently and correlated with the input power to the respective light emitting elements (Y1a, Y1b,..., Y2a, Y2b,. The circuit (P1a, P1b,..., P2a, P2b,...) Is configured so that data corresponding to the output power correlation amount can be set.

As the output power correlation amount mentioned here, a power value defined by the product of the voltage applied to each of the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) And the flowing current is adopted. Of course, a simpler index, for example, when the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) Are a plurality of semiconductor lasers connected in series, the voltage ( By utilizing the fact that the forward voltage is substantially constant, it is possible to obtain a current value to flow through them.
In addition, when different numbers of series connections are mixed, for example, an alternative value obtained by multiplying the current value by the number of series may be adopted as the output power correlation amount so that the correlation with the power value is improved. .

In order to examine the presence or absence of abnormality of the light source device of the present invention, the control circuit (Mc) first, the element light source to be inspected for abnormality from the element light sources (U1, U2,...), That is, One element light source to be inspected is selected, and further, one element light source that performs the function of correcting the light quantity so that the inspection action does not change the light quantity of the output light beam (Fo), that is, one fluctuation correction element light source or Select multiple.
Then, the control circuit (Mc) drives the drive belonging to the inspection target element light source so as to gradually change the output power correlation amount Qu of the entire inspection target element light source from an initial value Quo to Quo + ΔQu. In parallel with this, while controlling the circuit, the light quantity of the output light flux (Fo) does not change due to the change of the output power correlation amount Qu, that is, the change in the light quantity measurement data is canceled. Feedback control is performed on the drive circuit belonging to the fluctuation correction element light source so that the output power correlation amount Qv for the whole fluctuation correction element light source is integrated.
Then, when the change of the output power correlation amount Qu to Quo + ΔQu is finished, the output power correlation amount Qv changes from the initial value Qvo to Qvo−ΔQv, and the change of the output power correlation amount Qu. The value of the change ratio ΔQv / ΔQu is calculated and obtained by taking the ratio of the change in the output power correlation amount Qv to the minutes.

The sequence from the start of gradually changing the output power correlation amount Qu of the element light source to be inspected from the initial value Quo until the value of the change ratio ΔQv / ΔQu is obtained, This is called a fraction acquisition sequence.
In the light source device of the present invention, the change ratio ratio ΔQv / ΔQu acquired by the change ratio acquisition sequence can be evaluated to detect an abnormality of the inspection target element light source, and the reason will be described below.

For simplicity, each of the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) Included in each of the element light sources (U1, U2,...) Has all conversion efficiency from input power to optical power. The element light source (U1, Uc1, Ec2,...) And the light utilization efficiency of the light reaching the output light beam (Fo) through the optical fibers (Ef1, Ef2,. Suppose that there is no difference for each of U2,.
When the element light source (U2) is selected as the element light source to be inspected and the element light source (U1) is selected as the variation correction element light source, the drive circuits (P2a, P2b included in the element light source (U2)) ,...), The drive circuit (P2a) is further selected as a drive circuit for use in an operation that gives a change in the output power correlation amount Qu, that is, a change operation target drive circuit, and is included in the element light source (U1). Among the drive circuits (P1a, P1b,...) To be used for the operation of adjusting the output power correlation amount Qv to correct the change, that is, the drive circuit (P1a) as a correction operation target drive circuit. Assume further selection.

The control circuit (Mc) continuously monitors the light quantity measurement data (Sh) in parallel with gradually increasing the output power correlation amount Qu of the drive circuit (P2a) by ΔQu, The output power correlation amount Qv of the drive circuit (P1a) is continuously adjusted so that the value, that is, the brightness of the output light beam (Fo) does not change.
In order to increase the output power correlation amount Qu of the drive circuit (P2a), naturally, the output power correlation amount Qv of the drive circuit (P1a) is decreased so that the value of the light quantity measurement data (Sh) does not change. There must be.
Thus, at the stage where the output power correlation amount Qu has been increased by ΔQu, under the above-described simplified assumption, the decrease amount ΔQv of the output power correlation amount Qv is equal to ΔQu, and therefore ΔQv = ΔQu. After all, ΔQv / ΔQu = 1 should be obtained. In other words, if the value of the change ratio ΔQv / ΔQu is evaluated and ΔQv / ΔQu = 1 is confirmed, it is understood that the value is normal.

On the contrary, the optical fiber (Ef2) of the element light source (U2) is completely broken, and the light use efficiency of the element light source (U2) is zero. Assume that the change ratio acquisition sequence described above is performed.
Under this assumption, even if the output power correlation amount Qu of the drive circuit (P2a) is increased, the light emitted from the light emitting element (Y2a) is completely transmitted from the emission end (Eo2) of the optical fiber (Ef2). Of course, since the control circuit (Mc) does not change the output power correlation amount Qv of the drive circuit (P1a), the value of the light quantity measurement data (Sh) does not change.
Therefore, since ΔQv = 0 and eventually should be ΔQv / ΔQu = 0, conversely, if the change ratio ΔQv / ΔQu is evaluated and the result ΔQv / ΔQu = 0 is obtained, It turns out that it is abnormal.

Further, it is assumed that the optical fiber (Ef1) of the element light source (U1) is completely broken and the light use efficiency of the element light source (U1) is zero, which is completely abnormal and simplified. Consider that the change ratio acquisition sequence described above is performed.
Under this assumption, no matter how much the output power correlation amount Qv of the drive circuit (P1a) is changed, the light emitted from the light emitting element (Y1a) is emitted from the emission end (Eo1) of the optical fiber (Ef1). Since it does not appear at all, naturally, the change in the value of the light quantity measurement data (Sh) caused by the change in the output power correlation amount Qu of the drive circuit (P2a) given by the control circuit (Mc) can be canceled. Can not.
This symptom can be found early without changing the output power correlation amount Qu of the drive circuit (P2a) from the initial value Quo without changing it to ΔQu. The ratio acquisition sequence may be stopped.
If this situation is expressed mathematically corresponding to the above-mentioned example, ΔQv = ∞, which should eventually become ΔQv / ΔQu = ∞. In other words, the value of the change ratio ΔQv / ΔQu Even if the result of ΔQv / ΔQu = ∞ is obtained by evaluating the above, it is understood that it is abnormal.
However, in this case, it is not an abnormality of the element light source to be inspected for the presence or absence of abnormality, and special treatment is required.
Specifically, for example, when this situation is detected, the change ratio acquisition sequence is immediately stopped to return to the original state, and the light source device having three or more element light sources in operation In this case, it is preferable to reselect the variation correction element light source.

As described above, it can be understood that the presence or absence of abnormality of the element light sources (U1, U2,...) Can be detected by executing the change ratio acquisition sequence and evaluating the change ratio ratio ΔQv / ΔQu.
Naturally, in the actual light source device, the simplified condition assumed here is not strictly applied, and the change ratio ΔQv / ΔQu is not necessarily exactly 1 or 0, ∞. Therefore, it is necessary to devise a method for determining and evaluating a threshold value for determining an abnormality.

Here, it should be noted that the brightness of the output light beam (Fo) is not changed by the above-described change ratio acquisition sequence, whether normal or abnormal.
As is apparent from the above description, the reason for this is that the control circuit (Mc) sets the output power correlation amount Qv of the drive circuit (P1a) so that the brightness of the output light beam (Fo) does not change. This is because the feedback control is intentionally performed. Due to this feature, when the light source device of the present invention is used as a light source for a projector, for example, the change ratio acquisition sequence is periodically performed even during image projection. Thus, it becomes possible to constantly monitor the presence or absence of abnormality of the light source device.

In the above description, it has been described that the output power correlation amount Qu of the element light source to be inspected is changed gradually, that is, at a slow speed. The reason is that if the change is too fast, the output luminous flux (Fo This is because the light amount of the output light beam (Fo) fluctuates without the feedback control of the fluctuation correction element light source catching up so that the light amount of () does not change.
Therefore, with respect to the degree of slowness in changing the output power correlation amount Qu, the above-described feedback control sufficiently catches up, and the output light flux (Fo) required in light of the use of the light source device, for example, for projectors. ) As long as the accuracy with respect to the stability of the light quantity can be achieved.

The sign of the amount ΔQu that changes the output power correlation amount Qu can be either positive or negative.
On the other hand, if the magnitude of ΔQu, that is, the absolute value is too small, accurate evaluation / determination cannot be performed. Therefore, the low detection error probability related to abnormality detection required in light of the use of the light source device is It is necessary to give an appropriate size to the extent that a dynamic range and an SN ratio (signal-to-noise ratio) necessary for achieving it can be realized, but specifically, it may be determined experimentally.

In the simplified example described above, it has been described that a completely broken optical fiber does not emit any light from the exit end. However, in an actual light source device, depending on the state of breakage, attenuated light may be emitted. It can come out.
In addition, only weak light may be emitted due to deterioration of the light emitting element or failure of the drive circuit.
Here, a method of distinguishing and detecting when there are a plurality of the drive circuits in the inspection target element light source will be described.

When the element light source (U2) selected as the inspection target element light source includes a plurality of the drive circuits (P2a, P2b,...), One of them is selected as the change operation target drive circuit. And changing the output power correlation amount of the selected drive circuit to change the total output power correlation amount Qu of the entire drive circuit, and performing the change ratio acquisition sequence. Are sequentially executed over all of the drive circuits (P2a, P2b,...) Belonging to.
In this way, the change ratio ΔQv / ΔQu is obtained corresponding to each of the drive circuits (P2a, P2b,...), The largest value is selected and examined, and the threshold value defined by it is determined. When it is evaluated that it does not satisfy, it can be considered that an abnormality such as a break has been detected in the optical fiber (Ef2) belonging to the inspection target element light source.
The reason for this is that when a certain optical fiber is broken, all light passing through the optical fiber is attenuated regardless of which light emitting element emits the light, so that the light emitting element that has not progressed most deteriorates. This is because it is sufficient to evaluate by the inspection according to the above, that is, by evaluating with the largest value of the change ratio ΔQv / ΔQu.
Of course, an abnormality may be detected due to all deterioration of the light emitting elements (Y2a, Y2b,...) Of the element light source (U2) or all failures of the drive circuits (P2a, P2b,...). Although, in principle, it cannot be eliminated, as mentioned above, optical fiber breakage can lead to serious accidents such as burnout of the coating material. It is not a big problem because it only results in activating safety measures such as partial stoppage of only the inspection target element light source.

Further, the value of the largest change ratio ΔQv / ΔQu extracted as described above is used as the change ratio reference value in the inspection target element light source, and each of the drive circuits (P2a, P2b,...) Is changed operation target drive circuit. The value of the ratio with respect to the change ratio reference value for the change ratio ΔQv / ΔQu obtained by selecting the above, that is, the maintenance index is calculated.
When these are examined one by one and if it is found that they are evaluated as not satisfying the prescribed threshold value, it is considered that an abnormality in the pair of the corresponding driving circuit and the light emitting element connected thereto is detected. be able to.
The reason for this is that light-emitting elements belonging to the same wavelength band originally have little individual difference in the conversion efficiency from input power to optical power. Therefore, in the combination of the drive circuit and the light-emitting element with a small maintenance index, the drive circuit or light emission This is because one or both of the elements are considered to be deteriorated.
Only the information obtained here cannot identify which abnormality of the drive circuit and the light emitting element, but for the set in which this abnormality is detected, safety such as stoppage of the operation of the drive circuit is possible. Can be implemented.

Now, the handling when there are a plurality of the drive circuits in the element light source to be inspected has been described, but here the handling when there are a plurality of the drive circuits in the variation correction element light source will be described.
The specially treated phenomenon described in the simplified example described above may occur not only due to breakage of the optical fiber, but also due to deterioration of the light emitting element in the fluctuation correction element light source or failure of the drive circuit.
When selecting one of the drive circuits for changing the output power correlation amount Qv for the entire drive circuit of the fluctuation correction element light source, the drive circuit or the light emitting element connected thereto is completely broken. Of course, it is not necessary to select a device that does not emit light at all, and the drive circuit that is opposite to such a device is healthy with as little deterioration as possible, that is, with high conversion efficiency from input power to optical power. It is preferable to select a combination of the light emitting element and the light emitting element.

That is, when the element light source (U1) selected as the variation correction element light source includes a plurality of the drive circuits (P1a, P1b,...), One of them is the correction operation target drive circuit described above. Changing the output power correlation amount of the selected drive circuit, and changing the output power correlation amount Qv for the entire drive circuit, and performing the change ratio acquisition sequence. This is executed in order over all the drive circuits (P1a, P1b,...) Belonging to the element light source.
However, one appropriate inspection target element light source for performing the change ratio acquisition sequence is selected in advance.
By doing this, the change ratio ΔQv / ΔQu is obtained corresponding to each of the drive circuits (P1a, P1b,...), And the drive circuit that gives the smallest value among them can be selected. .
The reason is that the higher the conversion efficiency from input power to optical power, the smaller the change in the output power correlation amount Qv necessary for canceling the change in the light quantity measurement data caused by the change in the applied output power correlation amount Qu. Because.

The method just described implements the sequence as described in order to select one of the drive circuits from the variation correction element light source.
However, even if such a sequence is not specifically performed, the change ratio ΔQv / ΔQu is obtained corresponding to each of the drive circuits in the element light source to be inspected, and the largest value among them is obtained. If it is evaluated that it does not meet the prescribed threshold value, a sequence for detecting an abnormality such as a break in the optical fiber belonging to the element light source to be inspected is changed to the element light source (U1). What is necessary is just to select the said drive circuit which gave the value of the largest variation | change_quantity ratio (DELTA) Qv / (DELTA) Qu acquired when implementing as said inspection object element light source.
The reason is that the drive circuit corresponds to a set of the drive circuit and the light emitting element having the highest conversion efficiency from input power to optical power.

When selecting one of the fluctuation correction element light sources from the whole of the element light sources (U1, U2,...), The optical fiber is completely broken and no light comes out from the emission end, In order not to select the fluctuation correction element light source for light that is attenuated by breakage, the transmission efficiency from the output light amount of the light emitting element to the light amount of the output light beam (Fo) is as high as possible. It is preferred to select an element light source.
However, in order to enable measurement of this transmission efficiency, for example, it is necessary to be able to measure the amount of light input to each of the optical fibers (Ef1, Ef2,...), Which increases the cost. Instead, on the assumption that each of the element light sources (U1, U2,...) Has a high conversion efficiency from input power to optical power as much as possible in each element light source (U1, U2,...) Among the element light sources (U1, U2,...), The element light source including the combination of the drive circuit and the light emitting element having the conversion efficiency from the highest input power to optical power is selected as the variation correction element light source. do it.

This means that the element light source that can be selected as the fluctuation correction element light source may be selected as the element that gives the change ratio ΔQv / ΔQu with the smallest value.
As described above, the reason is that the higher the conversion efficiency from input power to optical power, the higher the output power correlation amount Qv necessary to cancel the change in the light quantity measurement data caused by the change in the applied output power correlation amount Qu. The change is small.
Therefore, in the end, the drive circuit and the light emission from which the largest output power correlation amount Qu is obtained in the entire set of the drive circuit and the light emitting element included in the entire element light source (U1, U2,...). It can be seen that the element light source including the pair with the element may be selected as the variation correction element light source.
After the selection of the fluctuation correction element light source is completed, a combination of the drive circuit and the light emitting element having the highest conversion efficiency from input power to optical power is selected as a correction operation target drive circuit. In addition, for example, a pair of the drive circuit and the light emitting element having the second highest conversion efficiency from input power to optical power is added as a correction operation target drive circuit, or the third is input power. A combination of the drive circuit and the light emitting element having high conversion efficiency from light to optical power may be added.

  Therefore, in the element light source to be inspected as described above, the change ratio ΔQv / ΔQu is obtained corresponding to each of the drive circuits, the largest value is selected and examined, and the threshold value defined by it is determined. If it is evaluated as not satisfying, in the optical fiber belonging to the element light source to be inspected, a sequence for detecting an abnormality such as a break or a combination of the drive circuit and the light emitting element connected thereto is detected. It is preferable to determine the variation correction element light source by one large sequence, that is, the element light source scanning comprehensive inspection sequence, and an example of this element light source scanning comprehensive inspection sequence will be described below.

First, an appropriate one of the element light sources (U1, U2,...), For example, the first element light source (U1), is selected as a temporary fluctuation correction element light source, and the drive circuit (P1a) included therein is selected. , P1b,...), An appropriate one, for example, the first drive circuit (P1a) is selected as a correction operation target drive circuit.
Next, the second element light source (U2) of the element light sources (U1, U2,...) Is selected as an inspection target element light source, and all of the light emitting elements (Y2a, Y2b,...) Included in this element light source are selected. Then, in order from the first drive circuit (P2a), the change operation ratio is obtained by selecting the change operation target drive circuits one by one and performing the change ratio acquisition sequence to acquire the change ratio ΔQv / ΔQu. A sequence of values R21, R22,... Of the ratio ΔQv / ΔQu is generated.
Then, the maximum value Rm2 in this column is extracted as the change ratio reference value for this element light source, and each value in the change ratio column R21, R22,... Is divided by the maximum value Rm2. Generate a sequence of values, ie, maintenance indices R21 / Rm2, R22 / Rm2,.
Therefore, if any of the maintenance index columns does not satisfy the prescribed threshold value, an abnormality in the set of the drive circuit corresponding to the maintenance index value and the light emitting element connected thereto is detected. .

Then, the same processing as that performed for the element light source (U2) just described is applied to all the remaining element light sources of the third and subsequent element light sources (U1, U2,...). One by one is selected and executed in sequence, and a sequence of change ratio reference values Rm2, Rm3,... Is generated.
By this alone, information on the element light source (U1) selected as the temporary fluctuation correction element light source is lacking, so this time, an appropriate one of the element light sources excluding the element light source (U1), for example, The second element light source (U2) is selected as a temporary fluctuation correction element light source, and one of the drive circuits (P2a, P2b,...) Included therein, for example, the change ratio reference value is included. The drive circuit given Rm2 is selected as the correction operation target drive circuit.
Then, the element light source (U1) is selected as the inspection target element light source, and the same processing as that performed for the element light source (U2) is performed to obtain the change ratio reference value Rm1 ′. .
Furthermore, an appropriate one as a comparison target, for example, the third element light source is selected as an inspection target element light source from the entire element light sources excluding the element light source (U1) and the element light source (U2), and the change amount is changed. When the ratio reference value Rm3 ′ is obtained, the ratio of Rm3 to Rm3 ′ is a change obtained by using the element light source (U1) as the fluctuation correction element light source with respect to the change ratio obtained by using the element light source (U2) as the fluctuation correction element light source. Since the ratio of the fraction is given,
Rm1 = Rm1 '・ Rm3 / Rm3'
Thus, a change ratio reference value for the element light source (U1) that can be compared with the other is obtained, and a sequence of change ratio reference values Rm1, Rm2, Rm3,.

Then, the maximum value Rg in this column is extracted as a total change ratio reference value, and each value of the above-described change ratio reference value column Rm1, Rm2, Rm3,... Is divided by the total change ratio reference value Rg. That is, the values calculated as above, that is, the overall maintenance indexes Rm1 / Rg, Rm2 / Rg, Rm3 / Rg,.
Therefore, if any of the total maintenance index columns does not satisfy the specified threshold value, an abnormality such as a break in the optical fiber belonging to the element light source corresponding to the value of the total maintenance index is detected.

  The element light source scanning comprehensive inspection sequence described above tries to detect an abnormality in the set of the drive circuit and the light emitting element connected to the drive circuit, and detect an abnormality such as a break in the optical fiber. The drive circuit that gives the change ratio reference value is determined for each light source, and the element light source that gives the maximum change ratio reference value, which is the maximum value, is determined. Therefore, the element light source scanning comprehensive inspection sequence is performed intermittently. In the period between them, based on the determined information, selection of the variation correction element light source, selection of the correction operation target drive circuit, selection of the change operation target drive circuit from the inspection target element light source, A simplified inspection sequence may be used.

First, the output power correlation amount Qu of the inspection target element light source is gradually changed from the initial value Quo to Quo + ΔQu, and the output power of the fluctuation correction element light source is not changed so that the light quantity of the output light beam (Fo) does not change. It was described that the correlation amount Qv is changed from the initial value Qvo to Qvo−ΔQv to obtain the value of the change ratio ΔQv / ΔQu.
At that time, the processing after acquisition of the change ratio was not mentioned, but the output power correlation amounts Qu and Qv of the inspection object light source and the fluctuation correction element light source are returned to the original state before being changed. However, if there is no particular inconvenience, it is possible to obtain an advantage that processing time can be saved by performing the processing without returning to the original state.
However, in the case of this process, at the start of the change ratio acquisition sequence, the output power correlation amount Qu set to the inspection target element light source in the previous change ratio acquisition sequence in which the same element light source is the fluctuation correction element light source. It is preferable to set the change ΔQu having the opposite sign to the change ΔQu of the next to the selected element light source to be inspected, that is, to set the positive change and the negative change alternately.

The reason is that, for example, if a change in the output power correlation amount Qu in a negative or decreasing direction is given to the inspection target element light source, the fluctuation correction element light source increases the output power correlation amount Qv. If the change of the output power correlation quantity Qu in the same decreasing direction is repeated for the next element light source to be inspected without returning this to the original state, the output power of the fluctuation correcting element light source As a result, the correlation amount Qv continues to increase, and as a result, the capacity limit is reached and processing cannot be continued, or the power balance between the element light sources (U1, U2,. This is because inconvenience such as loss of balance occurs.
This inconvenience occurs even when a positive change is given.
For the same reason, when paying attention to one drive circuit of the element light source to be inspected, if the same drive circuit is selected as the change operation target drive circuit, the positive and negative output power correlations for the change ratio acquisition sequence It is preferred to provide a change in the quantity Qu alternately.

In addition, after the acquisition of the change ratio, the output power correlation amounts Qu and Qv of the inspection target element light source and the variation correction element light source are returned to the original state before the start of the change ratio acquisition sequence. There is also a method of returning to a short jump by setting the values Quo and Qvo, but in this case, a discontinuity in the total light quantity of the output light beam (Fo) may occur due to a sudden change in the heat generation state of the light emitting element Therefore, it is preferable to restore the original state by gradually giving a change opposite to the change given for the change ratio acquisition sequence.
This is the same when returning to the original state in the case of the special handling described above.

As described above, the magnitude of the change ΔQu of the output power correlation amount Qu in the change ratio acquisition sequence should be given an appropriate size that can realize the necessary dynamic range and SN ratio. Even if the sign of ΔQu is set to either positive or negative, it is necessary to increase power in either the inspection target element light source or the fluctuation correction element light source.
Therefore, to give a large ΔQu (absolute value), the pair of the drive circuit and the light emitting element needs to have a large margin for increasing the power. For example, the light emitting element (Y1a, Y1b,..., Y2a, Y2b,.

However, in the change ratio acquisition sequence, the change ΔQu of the output power correlation amount Qu in the inspection target element light source is set to be negative, and belongs to the element light source selected as the variation correction element light source. If the change ΔQv of the output power correlation amount Qv is given by a plurality of drive circuits, a plurality of power increases in the fluctuation correction element light source corresponding to the power reduced in the element light source to be inspected are plural. Thus, the correction operation target drive circuit can share and supply the power, so that the power increase per one correction operation target drive circuit is small, and the problem can be solved.
The plurality of correction operation target drive circuits responsible for power increase may be selected from one element light source selected as the fluctuation correction element light source, or a plurality of correction operation target drive circuits selected as the fluctuation correction element light source. You may make it select from these element light sources.
When selecting the correction operation target drive circuit, it is preferable to select from the drive circuits that have the highest possible maintenance index.

As an embodiment of the change ratio acquisition sequence in the light source device of the present invention, all of the element light sources (U1, U2,...) That are in operation are selected as the inspection target element light sources one by one in order, It is preferable to periodically execute the ratio acquisition sequence to try to detect the abnormality of the inspection target element light source, that is, the inspection target element light source scanning sequence, but as the regular embodiment just described, For example, it can be set as the form implemented intermittently every 10 minutes, or the form implemented continuously without interruption.
Of course, the element light source scanning comprehensive inspection sequence described above is also a kind of the inspection object light source scanning sequence described above.

In general, the light source device is required to have stability of the light amount. However, in the light source device of the present invention, when stabilizing the light amount, the light amount of the output light beam (Fo), that is, the light amount measurement data, An operation for performing feedback control so as to increase or decrease the output power of the entire element light sources (U1, U2,...), That is, a light amount stabilization feedback control operation, so as to reduce the difference from the target value, that is, the inspection object. It can be realized by inserting it between periodic implementations of the element light source scanning sequence.
However, when the inspection target element light source scanning sequence is periodically performed in the light source device of the present invention, the operation mode described above in the change ratio acquisition sequence is caused by the change in the output power correlation amount Qu described above. As a kind of operation mode for realizing an operation mode for performing feedback control on the drive circuit belonging to the fluctuation correction element light source so that the change in the light amount measurement data is canceled, the difference between the light amount measurement data and its target value is reduced. Further, by adopting an operation mode in which the output power correlation amount Qv is changed, the inspection target element light source scanning sequence can also serve as the light amount stabilization feedback control operation described above.
In this case, for example, after acquiring the change ratio, the output power correlation amounts Qu and Qv of the inspection target element light source and the variation correction element light source are returned to the original state before the start of the change ratio acquisition sequence. In the returning operation, it can be devised to optimize the distribution of the power burden given to each of the drive circuits (P1a, P1b,..., P2a, P2b,...), For example.

  The present light source device shown in FIG. 1 has been assumed to include only a light emitting element belonging to only one wavelength band so far. R color main light source device, monochromatic G color main light source device in which only G color light emitting elements are mounted, and monochromatic B color main light source device in which only B color light emitting elements are mounted, that is, a total of 3 For example, a projector capable of color display can be configured by using the single light source device of R, G, and B colors.

Specifically, for example, in the projector optical system having a structure as shown in FIG. 4, the first light source device for the first R color shown in FIG. 1 is provided at the incident end (PmiA) of the first light uniformizing means (FmA). The output light beam (Fo) is input to illuminate the first two-dimensional light amplitude modulation element (DmjA) with R color, and R is formed by reflected light from the two-dimensional light amplitude modulation element (DmjA). Similarly to the first optical system for generating a color image, the output light beam (Fo) of the second G color light source device is similarly applied to the incident end (PmiA) of the second light uniformizing means (FmA). ) To illuminate the second two-dimensional light amplitude modulation element (DmjA) with G color, and generate a G color image formed by the reflected light from the two-dimensional light amplitude modulation element (DmjA). The second optical system and the incident light of the third light homogenizing means (FmA) (PmiA) is inputted with the output light beam (Fo) of the third B-color light source device to illuminate the third two-dimensional light amplitude modulation element (DmjA) with B color, and the two-dimensional light amplitude A third optical system that generates a B-color image formed by reflected light from the modulation element (DmjA), and synthesizes the generated three-color images of R, G, and B to produce a projection lens ( What is necessary is just to comprise so that it may project on a screen (Tj) using Ej2A).
In the three light source devices described above, the control circuit (Mc) can be common.

Next, the further form for implementing this invention is demonstrated using FIG. 2 which is a block diagram which simplifies and shows the light source device of this invention.
So far, the case where the light source device includes only light emitting elements belonging to only one wavelength band has been described. However, the case where the light source device includes light emitting elements belonging to a plurality of wavelength bands has been described so far. The above operation may be performed independently for each wavelength band.

The light emitting elements included in the element light sources (U1, U2,...) Shown in FIG. 2 include those whose emission wavelengths belong to a plurality of different wavelength bands such as R, G, and B.
Similarly to what has been described with reference to FIG. 1, the radiated light in which a plurality of types of wavelength bands from the emission ends of the optical fibers (Ef1, Ef2,...) Of the element light sources (U1, U2,. It is output from the light source device of the present invention as one, for example, white output light beam (Fo).
Of course, for each of the optical fibers (Ef1, Ef2,...), Light of one wavelength band may be guided to one optical fiber, or a plurality of wavelength bands may be guided to one optical fiber. The light may be mixed and guided, for example, as white light.

Then, in order to generate light quantity measurement data (Shx, Shy,...) That correlates with the light quantity of the output light beam (Fo) for each wavelength band, a plurality of types from the emission end are generated in the same manner as the output light beam (Fo). A measurement output light beam (Fo ′) in which a part of the radiated light having a mixed wavelength band is combined is generated and irradiated to the optical sensor (Ax, Ay,...), And the optical sensor (Ax, Ay,. The signal (Sgx, Sgy,...) Is subjected to necessary processing such as amplification and AD conversion by the light quantity measurement circuit (Hx, Hy,...) To generate the light quantity measurement data (Shx, Shy,...).
However, a spectral filter (Erx, Ery,...) That selectively transmits light corresponding to the wavelength band is placed in front of the optical sensor (Ax, Ay,...).

The control circuit (Mc) selects the drive circuit to which the light emitting element belonging to the wavelength band selected to be applied to the change ratio acquisition sequence included in the element light source selected as the inspection target element light source is connected. Further, the drive circuit to which the light emitting element belonging to the same wavelength band as the wavelength band selected to be applied to the change ratio acquisition sequence included in the element light source selected as the fluctuation correction element light source is connected is selected. After that, the change ratio acquisition sequence is performed in the same manner as described above.
At this time, the control circuit (Mc) can receive the generated light amount measurement data (Shx, Shy,...) For each wavelength band, but when the change ratio acquisition sequence is performed, the optical sensor ( Ax, Ay,...), Only the light amount measurement data of the optical sensor corresponding to the wavelength band to which the light emitting element connected to the drive circuit in which the output power correlation amount Qu is changed belongs. Just get it.
The change ratio acquisition sequence is performed in the order of R, G, B, for example, over all of a plurality of wavelength bands included in the light source device.
However, in the case where each optical fiber guides white light and only the presence / absence of breakage of the optical fiber needs to be detected, one wavelength band for each of the element light sources (U1, U2,...). Only the change ratio acquisition sequence may be executed.

  If there is a difference in photodetection sensitivity due to wavelength bands, variations among the photosensors (Ax, Ay,...), Or differences in spectral sensitivity, the gain of the light quantity measurement circuit (Hx, Hy,...) The difference may be absorbed by setting or the like.

Incidentally, when the spectral characteristics of the spectral filters (Erx, Ery,...) Are not perfectly matched with the emission wavelength band of the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...), For example, When light of only one wavelength band is emitted, in the light quantity measurement data (Shx, Shy,...), A phenomenon in which data of two colors appears and color data mixing occurs. Then, there is a problem that correct processing cannot be performed.
In such a case, the control circuit (Mc) can avoid the problem by performing color correction to correct light quantity measurement data by linear calculation of the light quantity measurement data (Shx, Shy,...) For each color.

Specifically, assuming that the signal values of the R, G, and B colors of the light quantity measurement data (Shx, Shy,...) Are Vr, Vg, and Vb, the signal values Vx, Vy, and Vz for each wavelength band that have been color corrected. Is the following linear calculation formula: Vx = K11 · Vr + K12 · Vg + K13 · Vb
Vy = K21 · Vr + K22 · Vg + K23 · Vb
Vz = K31 · Vr + K32 · Vg + K33 · Vb
It can be obtained by
Here, K11, K12,..., K32, K33 are constant coefficients for linear calculation, and a combination that corrects the color data mixture described above may be obtained experimentally.
Incidentally, when the above-mentioned color data mixing does not occur, it is only necessary to set the values other than the diagonal components K11, K22, and K33 to 0 in the above-described linear arithmetic expression.

  With the configuration as described above, the light source device of the present invention shown in FIG. 2 is configured as described above even if the output light beam (Fo) in which light of a plurality of different wavelength bands is mixed is generated. By executing the change ratio acquisition sequence, the element light sources (U1, U2,...) Are abnormal, or the drive circuits (P1a, P1b,..., P2a, P2b,...) And the light emitting elements ( Y1a, Y1b,..., Y2a, Y2b,.

Next, referring to FIG. 3 which is a diagram showing a simplified form of an embodiment of the light source device of the present invention, the light source device of the present invention is used as a mode for carrying out the present invention. A more specific configuration of the projector, particularly after the optical fiber and its emission end, will be described.
This light source device corresponds to the three primary colors of R, G, and B, and a plurality of optical fibers of each color, that is, optical fibers for R color light sources (EfR1, EfR2,...) And optical fibers for G color light sources (EfG1, EfG2). ,..., B-color light source optical fibers (EfB1, EfB2,...) Are configured as fiber bundles that are bundled with their output ends aligned, and the output ends of these three fiber bundles are respectively connected to collimator lenses ( The luminous flux converted to an infinite image by EsR, EsG, EsB) is color-synthesized using a mirror (HuR) and a dichroic mirror (HuG, HuB) to generate an output luminous flux (Fo) of the light source device. It is configured.

The output light beam (Fo) is input to the condenser lens (Eu), and the incident end (Pmi) of the light uniformizing means (Fm) by the rod integrator is passed through the diffusion element (Edm) for removing speckle. ).
The optical system after the emission end (Pmo) of the light uniformizing means (Fm) is the same as that described above with reference to FIG.
Naturally, the light source device of the present invention can also be used in the projector described above with reference to FIG. 5 using light uniformizing means by a fly eye integrator.

The dichroic mirror (HuB) is formed so as to transmit as much R / G color light as possible and reflect as much B color light as possible. There are a lot of transmitted light of B and B colors, and these lights are usually discarded as stray light. However, in the light source device of FIG. 3, an output light beam (Fo ′) for measurement is obtained by utilizing this effectively. It is.
The measurement output light beam (Fo ') is a spectral filter (ErR, ErG) that selectively transmits each of R, G, and B colors via a diffusion element (Eds) for suppressing measurement variations due to speckle effects. , ErB) can be measured by the optical sensors (AR, AG, AB) in front of each color of R, G, B.
The component ratio of each color light of R, G, and B of the measurement output light beam (Fo ′) thus generated is not necessarily the same as that of the output light beam (Fo), but the optical sensor (AR , AG, AB) can be corrected by setting the gain of the light quantity measuring circuit for each color described above with reference to FIG.

Regarding the installation of the optical sensors (AR, AG, AB), in addition to the method shown in FIG. 3, the light beams at three positions immediately after the collimator lens (EsR, EsG, EsB) are semi-transmissive. It is also possible to divide a part by inserting a mirror or the like, and to irradiate each of the divided light beams onto the optical sensors (AR, AG, AB) separately.
In the case of this configuration, the above-described semi-transmission mirror for splitting the light beam is additionally required, but the spectral filters (ErR, ErG, ErB) are unnecessary.
Incidentally, this configuration corresponds to the case of using the three single-color R, G, and B light source devices as described above.

  The present invention can be used in an industry for designing and manufacturing a light source device using a light emitting element such as a semiconductor laser and an optical fiber, which can be used in an optical device such as a projector.

A Optical sensor AB Optical sensor AG Optical sensor AR Optical sensor Ax Optical sensor Ay Optical sensor DmjA Two-dimensional optical amplitude modulation element DmjB Two-dimensional optical amplitude modulation element Ec1 Condensing optical system Ec2 Condensing optical system Edm Diffusing element Eds Diffusing element Ef1 Light Fiber Ef2 Optical fiber EfB1 Optical fiber for B color light source EfB2 Optical fiber for B color light source EfG1 Optical fiber for G color light source EfG2 Optical fiber for G color light source EfR1 Optical fiber for R color light source EfR2 Optical fiber for R color light source Ei1 Incident end Ei2 Entrance end Ej1A Illumination lens Ej1B Illumination lens Ej2A Projection lens Ej2B Field lens Ej3B Projection lens Eo1 Output end Eo2 Output end ErB Spectral filter ErG Spectral filter ErR Spectral filter Erx Spectral filter Er Spectral filter EsB Collimator lens sG collimator lens EsR collimator lens Eu condenser lens F1B front stage fly eye lens F2B rear stage fly eye lens Fm light uniformizing means FmA light uniformizing means FmB light uniformizing means Fo output light flux Fo 'output light flux H light quantity measuring circuit HuB dichroic Mirror HuG Dichroic mirror HuR Mirror Hx Light quantity measurement circuit Hy Light quantity measurement circuit J1a Drive circuit control signal J1b Drive circuit control signal J2a Drive circuit control signal J2b Drive circuit control signal LCD Liquid crystal device Mc Control circuit MjA Mirror MjB Polarization beam splitter P1a Drive circuit P1b Drive circuit P2a Drive circuit P2b Drive circuit PcB Polarization alignment functional element Pmi incident end PmiA incident end PmiB incident end Pmo exit end PmoA exit end PmoB exit end Sg signal Sgx signal Sgy signal No. Sh Light quantity measurement data Shx Light quantity measurement data Shy Light quantity measurement data SjA Light source SjB Light source Tj Screen U1 Element light source U2 Element light source Y1a Light emitting element Y1b Light emitting element Y2a Light emitting element Y2b Light emitting element ZiB Incident optical axis

Claims (11)

  One or more light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) And driving circuits (P1a, P1b,..., P2a) for driving the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,. , P2b,..., A condensing optical system (Ec1, Ec2,...) For condensing light emitted from the light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...), And the condensing optical system. Optical fibers (Ef1, Ef2,...) That receive and guide the light collected by (Ec1, Ec2,...) At the incident ends (Ei1, Ei2,...) And radiate from the outgoing ends (Eo1, Eo2,. , And a plurality of element light sources (U1, U2,...), Each of the element light sources (U1, U2,...) The exit end (Eo) of the optical fiber (Ef1, Ef2,...) , Eo2,...), A light source device that collectively outputs the light emitted as one output light beam (Fo). The light source device further includes an optical sensor (A) and the optical sensor. A light amount measurement circuit (H) that receives a signal from (A), measures the amount of light incident on the optical sensor (A) and generates light amount measurement data (Sh), and receives the light amount measurement data (Sh). And a control circuit (Mc) for setting and controlling an output power correlation amount for each of the drive circuits (P1a, P1b,..., P2a, P2b,...), And the light source device includes the element light source ( U1, U2,...) Of the optical fibers (Ef1, Ef2,...) Of the respective optical fibers (Ef1, Ef2,. Is applied to the optical sensor (A). Thus, the control circuit (Mc) is configured to acquire the light quantity measurement data (Sh) correlated with the light quantity of the output light beam (Fo), and the control circuit (Mc) After selecting one inspection target element light source and one or more variation correction element light sources from among the element light sources (U1, U2,...), The control circuit (Mc) The output power correlation amount Qu that combines the entire drive circuits that drive the light-emitting elements belonging to one wavelength band belonging to the light source belongs to the inspection target element light source so as to gradually change from Quo to Quo + ΔQu. While controlling the drive circuit, the drive circuit belonging to the fluctuation correction element light source is controlled so that the change in the light quantity measurement data corresponding to the wavelength band caused by the change in the output power correlation amount Qu is canceled. Feedback control is performed to change the output power correlation amount Qv of the entire drive circuit that drives the light emitting element belonging to the wavelength band belonging to the fluctuation correction element light source, and the output power correlation amount Qu When the change in the output power correlation amount Qv with respect to the change from Quo to Quo + ΔQu is from Qvo to Qvo−ΔQv, the ratio of the change in the output power correlation amount Qv to the change in the output power correlation amount Qu A change ratio acquisition sequence for acquiring a change ratio ΔQv / ΔQu value obtained by taking is performed, and the change ratio ΔQv / ΔQu is evaluated to detect an abnormality of the inspection target element light source. Light source device.   The control circuit (Mc), when there are a plurality of the drive circuits for driving the light emitting elements belonging to the wavelength band belonging to the element light source selected as the inspection target element light source, One is further selected, and only the output power correlation amount of the selected drive circuit is changed, thereby changing the output power correlation amount Qu for the entire drive circuit and performing the change ratio acquisition sequence. , Sequentially executed over all of the drive circuits that drive the light emitting elements belonging to the wavelength band belonging to the selected element light source, and the largest value of the obtained change ratios ΔQv / ΔQu The light source device according to claim 1, wherein an abnormality of the optical fiber belonging to the selected inspection target element light source is detected.   The control circuit (Mc), when there are a plurality of the drive circuits for driving the light emitting elements belonging to the wavelength band belonging to the element light source selected as the inspection target element light source, One is further selected, and only the output power correlation amount of the selected drive circuit is changed, thereby changing the output power correlation amount Qu for the entire drive circuit and performing the change ratio acquisition sequence. , Sequentially executed over all of the drive circuits that drive the light emitting elements belonging to the wavelength band belonging to the selected element light source, and the largest value of the obtained change ratios ΔQv / ΔQu Is the change ratio reference value for the element light source to be inspected, and the ratio value with respect to the change ratio reference value for the obtained change ratio ΔQv / ΔQu is evaluated. The light source device according to claim 1, characterized in that to detect a set of abnormality in the light emitting element connected the driving circuit corresponding and it 2.   The control circuit (Mc), when there are a plurality of the drive circuits for driving the light emitting elements belonging to the wavelength band belonging to the element light source selected as the variation correction element light source, By further selecting one and changing only the output power correlation amount of the selected drive circuit, the output power correlation amount Qv for the entire drive circuit is changed, and the change ratio acquisition sequence is executed. 4. The light source device according to claim 1, wherein when one of the drive circuits is selected, the one that gives the change ratio ΔQv / ΔQu with the smallest value is selected. 5.   When there are a plurality of element light sources that can be selected as the variation correction element light source, the control circuit (Mc) selects the one that gives the change ratio ΔQv / ΔQu with the smallest value. The light source device according to claim 1.   At the start of the change ratio acquisition sequence, the control circuit (Mc) sets the output power correlation amount Qu set in the previous change ratio acquisition sequence in which the same element light source belonging to the wavelength band is the variation correction element light source. The light source device according to claim 1, wherein a change amount ΔQu of an opposite sign is set as the change amount ΔQu of.   In the change ratio acquisition sequence, the control circuit (Mc) sets the change ΔQu of the output power correlation amount Qu to be negative, and belongs to the element light source selected as the variation correction element light source. 4. The light source device according to claim 1, wherein a change amount ΔQv of the output power correlation amount Qv is given by a plurality of the output power correlation amounts Qv.   The control circuit (Mc) selects all of the element light sources (U1, U2,...) That are in operation as the inspection target element light sources one by one, and performs a change ratio acquisition sequence to perform the inspection target The light source apparatus according to claim 1, wherein a sequence of trying to detect an abnormality of the element light source is periodically performed.   When the control circuit (Mc) performs feedback control on the drive circuit belonging to the variation correction element light source, the output power correlation amount Qv so that the difference between the light quantity measurement data and its target value is reduced. The light source device according to claim 1, wherein the light source device is changed.   The light emitting elements (Y1a, Y1b,..., Y2a, Y2b,...) Include elements whose emission wavelengths belong to a plurality of different wavelength bands, and the photosensors (Ax, Ay,...) The light source device includes a plurality of spectral filters (Erx, Ery,...) That selectively transmit light corresponding to the element light sources, and each of the element light sources (U1, U2,...). A plurality of types of radiated light from the emission ends (Eo1, Eo2,...) Of the optical fibers (Ef1, Ef2,...) Are combined into a single light beam, and at least a part thereof is obtained. By irradiating each of the plurality of photosensors (Ax, Ay,...), The control circuit (Mc) correlates with the light quantity in each wavelength band of the output light beam (Fo). Measurement data (Shx, Sh ,... Can be received, and when the change ratio acquisition sequence is performed, the light emitting element connected to the drive circuit in which the output power correlation amount Qu is changed Obtaining the light amount measurement data of the photosensor corresponding to the wavelength band to which the light emitting element belongs, and the wavelength band to which the light emitting element connected to the driving circuit in which the output power correlation amount Qu is changed belongs to 10. The light source device according to claim 1, wherein the output power correlation amount Qv is changed by selecting from the drive circuits to which the light emitting elements belonging to the same wavelength band are connected.   An image projector is projected and displayed using the light source device according to claim 1.

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