JP5033482B2 - Projection display device - Google Patents

Description

  The present invention relates to a projection display apparatus, and is particularly suitable when a laser light source is used as a light emission source.

  Recently, a projection display apparatus (hereinafter referred to as “projector”) using a laser light source as a light emitting source has been proposed. In this type of projector, since the energy density of the laser light source is high, it is necessary to pay sufficient attention to the influence on the human body due to the laser light irradiation.

  For example, if a problem occurs in the lens group constituting the illumination system during use, the spread of the laser beam becomes insufficient, and the energy density of the projection light may increase undesirably. If the human body is accidentally irradiated with laser light in this state, burns or damage may occur, and in the worst case, it may lead to a reduction in visual acuity or blindness. When designing a projector, it is necessary to take sufficient measures to prevent such a situation.

In Patent Document 1 shown below, the laser output is stopped or the laser power is attenuated according to abnormality detection (for example, lens displacement) in the illumination optical system, thereby causing harm to the viewer. The technology to prevent is described. Here, a configuration for detecting an abnormality by arranging a detection means outside the effective image area on the screen, a configuration for detecting an abnormality by arranging a detection means on the projection lens cover, and a part of the effective light by the beam splitter The structure which isolate | separates and detects abnormality from the intensity | strength change is shown.
JP 2000-267621 A

  Among the configurations described in Patent Document 1, in the configuration in which the detection unit is arranged on the screen, the screen is indispensable as a component, and therefore, the application target is limited to a projector that integrally includes the screen, such as a rear projection television. .

  Further, in the configuration in which the detection means is arranged on the lens cover, the lens cover is essential as a component, and the application target is limited to a projector having the lens cover. Also, in this configuration example, the abnormality of the laser beam cannot be detected with the lens cover removed. For example, when an abnormality occurs unexpectedly during normal operation, this abnormality is detected. I can't.

  Further, in the configuration in which an abnormality is detected by separating a part of the effective light, there is an inconvenience that the intensity of the projection light is lowered and the light use efficiency is lowered because the effective light needs to be separated.

  The present invention has been made in view of the above-described matters, and provides a projector capable of smoothly detecting an abnormality of a laser beam without impairing the light use efficiency and without having a screen or a lens cover. This is the issue. In addition, this invention makes it the further subject to enable it to identify smoothly the location which contributed to the abnormality of a laser beam.

  A projection display apparatus according to the present invention includes a laser light source, a light modulation element that modulates incident laser light based on a video signal, and an illumination optical system that guides the laser light emitted from the laser light source to the light modulation element. A projection unit that projects light modulated by the light modulation element onto a projection surface, and an optical path of the laser light that is disposed between the laser light source and the projection unit and travels from the laser light source to the projection unit. A light detection unit that receives the light that has deviated, an abnormality determination unit that determines abnormality of the laser beam based on a signal from the light detection unit, and an output of the laser light source based on a determination result in the abnormality determination unit And a laser control unit for controlling.

  According to the present invention, since the abnormality of the laser beam is determined using the light deviating from the optical path, the utilization efficiency of the laser beam does not decrease as in the technique of Patent Document 1 described above. Further, since the present invention has a configuration in which a light detection unit is arranged between the laser light source and the projection unit, it is possible to detect an abnormality in the laser light even when a screen or a lens cover is not provided.

  In the present invention, when the illumination optical system includes a fly-eye lens, the light detection unit may be configured to include a first light detector disposed at a position for detecting sidelobe light generated by the fly-eye lens. . The side lobe light is a part of the light transmitted through one cell of the fly-eye lens on the incident side of the pair of fly-eye lenses, and leaks into cells around the corresponding cell of the fly-eye lens on the output side. This is the light that is generated. The light leaking into the surrounding cells is not irradiated to the effective area of the light modulation element, but is guided to a position outside the effective area. Sidelobe light is unnecessary light that normally occurs when a fly-eye lens is used.

  In addition, when the light modulation element is a reflection type light modulation element such as a DMD (digital micro-mirror device) element that expresses the gradation of each pixel by switching the reflection direction of the light at each pixel position. The unit may be configured to include a first photodetector arranged at a position for receiving light reflected by the light modulation element in a direction deviating from the projection unit.

  Furthermore, the light detector is a second light detector arranged at a position for detecting scattered light from the laser light source or scattered light emitted from the laser light source and scattered outside the optical path before entering the illumination optical system. May be configured to include a vessel. In this way, if the second detector is disposed in the vicinity of the light source in addition to the position where the sidelobe light is received or the unnecessary light is reflected by the DMD element, either the light source or the illumination optical system will cause an abnormal laser light. It is possible to smoothly determine whether the contribution has been made.

  When a plurality of laser light sources are arranged, the second photodetector is arranged at a position corresponding to one light source group of one laser light source or a plurality of laser light sources. Can do. At this time, the abnormality determination unit identifies the laser light source in which the abnormality has occurred based on the detection signal from the second photodetector, and the laser control unit is configured to adjust the output of only the laser light source in which the abnormality has occurred. Can be done. In this way, the output of the laser light source without any abnormality can be continued, and the image projection can be continued smoothly even after the abnormality is detected.

  In addition, the light detection unit may be configured to include a third light detector disposed at a position for detecting light scattered outside the optical path by the surface of the optical element constituting the illumination optical system. In this way, it is possible to specify in which optical path section in the illumination optical system an abnormality has occurred.

  In the present invention, when an abnormality is detected in the laser beam, adjustment is performed such as stopping the laser output completely or lowering the laser drive current below the laser oscillation threshold. However, when adjustment is performed on all the laser light sources during image projection, the projected image is suddenly cut off, and when adjustment is performed on some of the laser light sources, the brightness of the image suddenly decreases. Users who face this may be confused by sudden changes in the projected image. This inconvenience can be avoided by notifying the outside of the fact at the time of abnormality determination.

  Therefore, in the present invention, it is preferable to provide a means for notifying the outside when the abnormality is determined. At this time, if the abnormal location is also notified, the repair work after the occurrence of the abnormality can be facilitated. In addition, the structure regarding these alerting | reporting is described in Claim 7 and 8.

  According to the present invention, it is possible to provide a projector capable of smoothly detecting an abnormality of a laser beam without impairing light utilization efficiency and without including a screen or a lens cover. In addition, the output of the laser light source is appropriately adjusted according to the detection of the abnormality of the laser beam, thereby preventing harm to the user. Furthermore, according to the present invention, it is possible to specify a location that has contributed to the abnormality of the laser beam, and by notifying this to the user, the repair work after the occurrence of the abnormality can be facilitated.

The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an example when the present invention is implemented, and the meaning of the term of the present invention or each constituent element is limited to that described in the following embodiment. Is not to be done.

  FIG. 1 shows an optical system of a projector according to the embodiment.

  In the figure, reference numeral 11 denotes a laser array in which a plurality of laser light sources are arranged in an array on the YZ plane. On the YZ plane, light emitting units of laser light sources that emit light in the red wavelength band, the green wavelength band, and the blue wavelength band are arranged according to a predetermined rule. The laser light emitted from each light emitting unit has the polarization direction aligned in one direction.

  Laser light of each wavelength emitted from the laser array 11 is converted into parallel light having a predetermined beam diameter by a dispersion angle control lens 12 composed of a concave lens and a convex lens, and then enters a fly eye integrator 13.

  The fly-eye integrator 13 includes first and second fly-eye lenses composed of eyelet-shaped lens groups, and dispersion angle control is performed so that the light quantity distribution when entering the liquid crystal panels 18, 21, and 27 is uniform. A lens action is given to the light incident from the lens 12. That is, the light that has passed through one lens cell on the first fly-eye lens passes through the corresponding lens cell on the second fly-eye lens, so that the liquid crystal panels 18, 21 and 27 receive these liquid crystals. Incident light is spread with a panel aspect ratio (for example, 16: 9).

  Note that the light transmitted through one lens cell on the first fly-eye lens does not all enter the corresponding lens cell on the second fly-eye lens, and the light at the peripheral portion is around this lens cell. Leak into the lens cell at. The light leaking into the surrounding lens cells in this way is guided as a side lobe light to a position outside the effective area of the liquid crystal panels 18, 21 and 27 as shown in FIG.

  Here, the side lobe light is guided to all the areas around the liquid crystal panels 18, 21 and 27 as shown in FIG. This is because light transmitted through one lens cell on the first fly-eye lens leaks into each lens cell around the corresponding lens cell on the second fly-eye lens.

  The condenser lens 14 condenses light incident from the fly eye integrator 13.

  The dichroic mirror 15 reflects, for example, only light in the red wavelength band (hereinafter referred to as “R light”) out of the light incident from the condenser lens 14, and a blue wavelength band (hereinafter referred to as “B light”). It transmits the green wavelength band (hereinafter referred to as “G light”). The mirror 16 reflects the R light reflected by the dichroic mirror 15 so as to enter the lens 17.

  The lens 17 collimates the R light and makes it incident on the liquid crystal panel 18. The liquid crystal panel 18 is driven according to a red driving signal, and modulates R light according to the driving state. The R light transmitted through the lens 17 is incident on the liquid crystal panel 18 via an incident side polarizing plate (not shown).

  The dichroic mirror 19 reflects, for example, only G light out of B light and G light transmitted through the dichroic mirror 15. The lens 20 collimates the G light and makes it incident on the liquid crystal panel 18. The liquid crystal panel 21 is driven according to the green driving signal, and modulates the G light according to the driving state. The G light transmitted through the lens 20 is incident on the liquid crystal panel 21 via an incident side polarizing plate (not shown).

  The lenses 22 and 24 impart a lens action to the B light so that the incident state of the B light on the liquid crystal panel 27 becomes equal to the incident state of the R light and the G light on the liquid crystal panels 17 and 20. The mirrors 23 and 25 change the optical path of the B light so that the B light transmitted through the dichroic mirror 19 is guided to the liquid crystal panel 27.

  The lens 26 collimates the B light to make the liquid crystal panel 27. The liquid crystal panel 27 is driven according to the blue driving signal, and modulates the B light according to the driving state. The B light transmitted through the lens 26 is incident on the liquid crystal panel 27 via an incident side polarizing plate (not shown).

  The dichroic prism 28 is modulated by the liquid crystal panels 18, 21, and 27, synthesizes R light, G light, and B light via an output side polarizing plate (not shown), and enters the projection lens 40.

  The projection lens 40 includes a lens group for forming an image of projection light on a projection surface, and an actuator for adjusting a zoom state and a focus state of a projection image by displacing a part of the lens group in the optical axis direction. It has.

  The optical system shown in FIG. 1 further receives sidelobe light generated by an optical sensor 31 (hereinafter referred to as “light source side sensor”) that receives scattered light from each laser light source and fly eye integrator 13. Optical sensors (hereinafter referred to as “panel side sensors”) 32, 33, and 34 are arranged. The light source side sensor 31 is disposed between the laser array 11 and the dispersion angle control lens 12. The panel side sensors 32, 33 and 34 are arranged around the liquid crystal panels 18, 21 and 27.

  FIG. 3 is a diagram illustrating an arrangement state of the light source side sensor 31 and the panel side sensor 32.

  As shown in FIG. 2A, the light source side sensors 31 are arranged so as to correspond to the laser light sources constituting the laser array 11 on a one-to-one basis. In the figure, 11a is a light emitting point of each laser light source. From each light emitting point 11a, light in the central portion (effective light) that goes straight in the optical axis direction and scattered light scattered outside are emitted. Of these, effective light enters the dispersion angle control lens 12 and is guided to the liquid crystal panels 18, 21, and 27. The light source side sensor 31 is disposed at a position for receiving only scattered light among effective light and scattered light.

  Here, the light source side sensor 31 is disposed between the laser array 11 and the dispersion angle control lens 12 in a state of being held by a holding member having a plurality of openings through which effective light passes, for example.

  As shown in FIG. 5B, only one panel side sensor 32 is arranged around the liquid crystal panel 18. Similarly to FIG. 2B, only one panel side sensor 33, 34 is arranged around the liquid crystal panels 21, 27. As described above, the side lobe light is guided to all the areas around the liquid crystal panels 18, 21, and 27. Therefore, in order to detect the side lobe light, only one panel-side sensor 32, 33, 34 may be arranged around each liquid crystal panel 18, 21, 27 in this way.

  FIG. 4 is a diagram showing a configuration of the projector according to the embodiment.

  In the figure, a laser driver 101 drives each laser light source constituting the laser array 11 in accordance with a command from the control unit 109. The panel driver 102 drives the liquid crystal panels 18, 21, and 27 based on the drive signal supplied from the image signal generation unit 103. The image signal generation unit 103 generates a red drive signal, a green drive signal, and a blue drive signal for driving the liquid crystal panels 18, 21, and 27 based on the input video signal, and supplies the generated signals to the panel driver 102. .

  The display output unit 104 includes display means and performs a predetermined display in response to a command from the control unit 109. The audio output unit 105 includes a speaker and performs predetermined audio output in response to a command from the control unit 109.

  The light source side sensor unit 106 includes the light source side sensor 31 described above, and supplies a detection signal from each light source side sensor 31 to the abnormality determination unit 108. The panel side sensor unit 107 includes the panel side sensors 32, 33, and 34 described above, and supplies detection signals from the panel side sensors 32, 33, and 34 to the abnormality determination unit 108.

  The abnormality determination unit 108 determines the abnormality of the laser beam based on the detection signals supplied from the light source side sensor unit 106 and the panel side sensor unit 107 and supplies the determination result to the control unit 109. The control unit 109 controls each unit according to a predetermined control routine.

  FIG. 5 is a flowchart showing the determination process in the abnormality determination unit 108 and the control process in the control unit 109 when an abnormality is detected.

  When the laser array 11 is driven and image projection is started, the abnormality determination unit 108 monitors the detection signals output from the light source side sensor 31 and the panel side sensors 32, 33, and 34, and among these detection signals. It is determined whether any of them suddenly changes (S101, 102). Here, a sudden change in the detection signal is determined by whether the detection signal has changed greatly beyond a preset fluctuation of the laser intensity when a certain period of time has elapsed. That is, it is determined that the detection signal has suddenly changed when the detection signal changes greatly beyond the fluctuation.

  Note that it is unlikely that only the detection signal from the light source side sensor 31 changes suddenly due to the arrangement of each sensor. That is, when an abnormality occurs in any of the laser light sources, the corresponding detection signal from the light source side sensor 31 changes suddenly. In this case, one of the panel side sensors 32, 33, and 34 is irradiated. Since the intensity of the sidelobe light also changes due to the abnormality of the laser light, the detection signal from the corresponding panel side sensor also changes suddenly in the same manner.

  On the other hand, it is possible that only the detection signals from the panel side sensors 32, 33, and 34 change suddenly without the detection signal from the light source side sensor 31 changing suddenly. That is, when an abnormality occurs in the optical system (illumination optical system) from the dispersion angle control lens 12 to the liquid crystal panels 18, 21, 27, the detection signal from the light source side sensor 31 does not change suddenly and the panel side sensor 32. , 33 and 34 only change the detection signals suddenly.

  Therefore, in the processing flow of FIG. 5, first, in S101, it is determined whether or not a sudden change has occurred in the detection signals from the panel side sensors 32, 33, and 34. Here, when a sudden change occurs in the detection signals from the panel side sensors 32, 33, and 34, it is assumed that an abnormality has occurred in one or both of the laser light source (laser array 11) and the illumination optical system. Is performed.

  In S101, when a sudden change is not detected in the detection signals from the panel side sensors 32, 33, and 34, the control unit 109 executes normal image projection assuming that the laser light source (laser array 11) and the illumination optical system are normal. (S102). On the other hand, if a sudden change is detected in the detection signals from the panel side sensors 32, 33, 34, the control unit 109 has received a signal indicating that the signal from the light source side sensor 32 has changed suddenly from the abnormality determination unit 108. Is determined.

  Here, when there is no sudden change in the signal from the light source side sensor 32 (S103: NO), the controller 109 assumes that an abnormality has occurred in the illumination optical system (S104), and all the laser light sources constituting the laser array 11 are detected. Stop or reduce the drive current applied to each laser light source below the laser oscillation threshold (S105). Thereby, the projection of the image is stopped. At the same time, the control unit 109 stops the processing operation in the image signal generation unit 103.

  Further, the control unit 109 causes the display output unit 104 and the audio output unit 105 to perform processing for notifying that an abnormality has occurred in the laser light (S106). At this time, the user is also informed that the abnormality of the laser beam is caused by the illumination optical system. Thereby, the user can easily perform repair work after the occurrence of an abnormality.

  If it is determined in S103 that the detection signal from the light source side sensor 32 has also suddenly changed (S103: YES), the control unit 109 stops the laser light source corresponding to the light source side sensor 32 in which the detection signal has suddenly changed. (S107). Further, the control unit 109 causes the abnormality determination unit 108 to evaluate whether the output of the panel side sensors 32, 33, 34 after the laser light source is stopped (S108).

  The abnormality determination unit 108 holds the value of the detection signal output from each of the panel side sensors 32, 33, and 34 immediately before the sudden change of the detection signal is determined in S101. The abnormality determination unit 108 refers to the value (Va) of the detection signal in which the sudden change occurs among these values, and stops the laser light source to be stopped in S107 before the sudden change is determined in S101. Then, how the value (Va) changes is predicted, and the value (Vb) of the detection signal after stopping the laser light source is calculated. Then, the calculated value (Vb) is compared with the value (Vc) of the detection signal actually acquired from the corresponding panel-side sensor when the target laser light source is stopped in S107, and the value Vc and the value are compared. If the difference in Vb is less than the predetermined threshold value, it is determined that the output of the panel side sensor is appropriate (S108: YES), and if the difference between the value Vc and the value Vb is equal to or greater than the predetermined threshold value, It is determined that the output is not appropriate (S108: NO).

  The value (Vb) is, for example, the amount of change in the amount of side lobe light (or the rate of change of the signal from the panel-side sensor) when each laser light source is turned off from the fully lit state. It can be calculated by multiplying the value (Va) by holding this correspondingly. Alternatively, the predicted values of the detection signals in the panel-side sensors 32, 33, and 34 when each laser light source is turned off are stored as a table in association with environmental parameters such as the temperature in the apparatus, and the turn-off state of each laser light source The value (Vb) may be held by acquiring a predicted value corresponding to the internal environment of the apparatus from this table.

  When the determination in S108 is NO, the controller 109 determines that an abnormality has occurred in the illumination optical system (S104), stops all the laser light sources constituting the laser array 11, or drives the current applied to each laser light source. Is reduced below the laser oscillation threshold (S105), and the display output unit 104 and the audio output unit 105 perform the above-described output.

  If the determination in S108 is YES, the controller 109 determines that an abnormality has occurred in the laser light source (S109), and drives the other laser light sources while keeping only the laser light source to be stopped in S107 stopped. Is continued (S110). As a result, the brightness of the projected image decreases by the amount that the laser light source is stopped.

  Further, the control unit 109 causes the display output unit 104 and the audio output unit 105 to perform processing for notifying that an abnormality has occurred in the laser light (S111). At this time, it is also notified that the abnormality of the laser beam is caused by the laser light source. Furthermore, it is preferable to notify which laser light source among the laser light sources constituting the laser array 11 has contributed to the abnormality of the laser light. Thereby, the user can easily perform repair work after the occurrence of an abnormality.

  According to the present embodiment, since the abnormality of the laser beam is determined using the scattered light from the laser light source and the sidelobe light generated by the fly eye integrator 13, it is possible to avoid a decrease in the utilization efficiency of the laser beam. However, the abnormality of the laser beam can be detected smoothly. In the present embodiment, since the light source side sensor 31 and the panel side sensors 32, 33, 34 are arranged near the laser light source (laser array 11) and around the liquid crystal panels 18, 21, 27, the projector Even when the lens cover is not provided, the abnormality of the laser beam can be detected smoothly.

  Furthermore, according to the present embodiment, it is possible to specify which of the laser light source and the illumination optical system has contributed to the abnormality of the laser beam, so that the repair work after the occurrence of the abnormality can be facilitated.

  As described above, according to the present embodiment, it is possible to provide a projector capable of smoothly detecting an abnormality in a laser beam without impairing the light use efficiency and without including a screen or a lens cover. . Moreover, the location which contributed to the abnormality of the laser beam can be specified smoothly, and by notifying this to the user, the repair work after the occurrence of the abnormality can be facilitated.

  The embodiment of the present invention can be variously modified in addition to the above.

  For example, in the above embodiment, the light source side sensor 31 and the laser light source are made to correspond one-to-one, but for example, as shown in FIG. A light source side sensor 31 may be arranged.

  FIG. 6A shows an arrangement example in a case where the light source group is a one-to-one correspondence with a group of two upper and lower laser light sources, and FIG. It is an example of arrangement in the case of corresponding one to one. In FIG. 2A, one light source side sensor 31 is arranged at an overlapping portion of scattered light emitted from two upper and lower laser light sources. Further, in FIG. 5B, one light source side sensor 31 is arranged at an overlapping portion of scattered light emitted from four laser light sources in the vertical and horizontal directions.

  When the light source side sensor 31 is arranged as shown in the figure, the abnormality of the laser light source is determined on a light source group basis. Therefore, during the flow process of FIG. 5, the processes of S102, S107, S109, and S110 are performed in units of light sources.

  Further, as shown in FIG. 7, the laser array and the illumination system can be arranged for each color. In the figure, reference numerals 51, 61, and 71 denote laser arrays that emit R light, G light, and B light, respectively. The R light, G light, and B light emitted from the laser arrays 51, 61, and 71 are expanded to the fly-eye integrators 53, 63, and 73 after the beam diameters are expanded by the dispersion angle control lenses 52, 62, and 72, respectively. Incident light is collected by condenser lenses 54, 64 and 74. Thereafter, the R light, G light and B light are incident on the liquid crystal panels 18, 21 and 27 via the lenses 17, 20 and 26.

  In the configuration example shown in the figure, light source side sensors 55, 65 and 75 are arranged in the vicinity of the laser light sources constituting the laser arrays 51, 61 and 71. These light source side sensors 55, 65 and 75 are arranged at positions for receiving scattered light emitted from the laser light source, as in the above embodiment. Here, the arrangement pattern of the light source side sensors 55, 65 and 75 is, for example, the arrangement pattern shown in FIG. The panel side sensors 32, 33, and 34 are arranged at positions for receiving the sidelobe light generated by the fly eye integrators 53, 63, and 73 as in the above embodiment.

<Other embodiments>
In the above embodiment, a transmissive liquid crystal panel is used as the light modulation element, but in the present embodiment, a reflection type light modulation element is used.

  FIG. 8 is a diagram showing an optical system of the projector according to the present embodiment.

  In the figure, reference numeral 81 denotes a laser array in which a plurality of laser light sources emitting R light, G light, and B light are arranged in an array on the same plane. Laser light emitted from the laser array 11 is converted into parallel light by the lens 82, condensed by the condenser lens 83, and incident on the light pipe 84.

  The inner surface of the light pipe 84 is a mirror surface, and the laser light travels through the light pipe 84 while being repeatedly reflected by the inner surface of the light pipe 84. By such multiple reflection, the intensity distribution of the laser light of each color emitted from the light pipe 84 is made uniform. Laser light emitted from the light pipe 84 is incident on the DMD element 86 via the relay optical system 85.

  The DMD element 86 expresses the gradation of each pixel by switching the reflection direction of the light at each pixel position between a first direction toward the projection lens 40 and a second direction deviating from the projection lens 40. . Of the laser light incident on each pixel position, the light reflected in the first direction (ON light) is incident on the projection lens 40 and projected onto the projection surface. Further, the light (OFF light) reflected in the second direction by the DMD element 86 is not incident on the projection lens but is absorbed by the light absorber 87.

  In the optical system shown in the figure, each laser light source constituting the laser array 81 is driven in a time-sharing manner for each color. At the timing when the R light is emitted, the DMD element 86 is driven according to the red driving signal, and modulates the R light according to the driving state. Similarly, at the timing when the G light or B light is emitted, the DMD element 86 is driven according to the red or green drive signal, and modulates the G light or B light according to the drive state.

  In the optical system shown in the figure, a light source side sensor 88 is disposed at a position for receiving scattered light from each laser light source. Here, the arrangement pattern of the light source side sensor 88 is, for example, the arrangement pattern of FIG. Further, in this optical system, a DMD side sensor 89 is disposed on the light absorber 87. The DMD side sensor 89 receives a part of the OFF light reflected by the DMD element 86. More specifically, the DMD side sensor 89 is disposed so as to receive OFF light from a predetermined pixel region in the light modulation region on the DMD element 86.

  FIG. 9 is a diagram showing a configuration of the projector according to the present embodiment.

  In FIG. 4, the panel driver 102 and the panel side sensor unit 107 in FIG. 4 are replaced with a DMD driver 110 and a DMD side sensor unit 111, respectively. Further, a video adaptive illuminance prediction unit 112 is added, and the determination processing in the abnormality determination unit 108 and the processing of the image signal generation unit 103 are different from those in FIG.

  The laser driver 101 drives each laser light source constituting the laser array 11 in accordance with a command from the control unit 109. Here, as each laser light source, laser light sources for R light, G light, and B light are driven in a time-sharing manner.

  The DMD driver 110 drives the DMD element 86 based on the drive signal supplied from the image signal generation unit 103. The image signal generation unit 103 generates a red drive signal, a green drive signal, and a blue drive signal for driving the DMD element 86 based on the input video signal, and supplies the generated signal to the DMD driver 110.

  The light source side sensor unit 106 includes a light source side sensor 88 and supplies a detection signal from each light source side sensor 88 to the abnormality determination unit 108. The DMD side sensor unit 111 includes a DMD side sensor 89 and supplies a detection signal from the DMD side sensor 89 to the abnormality determination unit 108.

  The video adaptive illuminance prediction unit 112 predicts the detection signal value from the DMD side sensor 89 at the timing from the driving state of the DMD element 86 at each timing (the driving signal input to the DMD driver 110), and the predicted detection signal value Is supplied to the abnormality determination unit 108.

  FIG. 10 is a flowchart showing the determination process in the abnormality determination unit 108 and the control process in the control unit 109 when an abnormality is detected.

  When the laser array 81 is driven and image projection is started, the abnormality determination unit 108 monitors the detection signals output from the light source side sensor 88 and the DMD side sensor 89, and any of these detection signals is abnormal. Is determined (S201, 202).

  Here, the abnormality of the detection signal from the DMD side sensor 89 means that the difference between the value of the detection signal from the DMD side sensor 89 and the prediction value of the detection signal supplied from the video adaptive illuminance prediction unit 112 has a predetermined threshold value. It is determined by whether or not it exceeds. When the difference between these values exceeds the threshold value, it is assumed that an abnormality has occurred in the signal from the DMD side sensor 89. The abnormality of the detection signal in the light source side sensor 88 is determined depending on whether the detection signal has changed suddenly as in S103 of FIG.

  If no abnormality is detected in the detection signal from the DMD sensor 89 in S201, the control unit 109 assumes that the laser light source (laser array 81) and the optical system (the optical system from the lens 82 to the DMD element 86) are normal. Then, normal image projection is executed (S102). On the other hand, when a sudden change is detected in the detection signal from the DMD side sensor 89, the control unit 109 determines whether a signal indicating that the signal from the light source side sensor 88 has changed suddenly is supplied from the abnormality determination unit 108.

  Here, when there is no sudden change in the signal from the light source side sensor 88 (S203: NO), the control unit 109 stops all the laser light sources constituting the laser array 11 even if an abnormality occurs in the optical system (S204). Alternatively, the drive current applied to each laser light source is reduced below the laser oscillation threshold (S205). Thereby, the projection of the image is stopped. At the same time, the control unit 109 stops the processing operation in the image signal generation unit 103.

  Further, the control unit 109 causes the display output unit 104 and the audio output unit 105 to perform processing for notifying that an abnormality has occurred in the laser light (S206). At this time, the user is also informed that the abnormality of the laser beam is caused by the optical system. Thereby, the user can easily perform repair work after the occurrence of an abnormality.

  When it is determined in S203 that the detection signal from the light source side sensor 88 has also suddenly changed (S203: YES), the control unit 109 stops the laser light source corresponding to the light source side sensor 88 whose detection signal has suddenly changed. (S207). Further, the control unit 109 causes the abnormality determination unit 108 to evaluate the suitability of the output of the DMD side sensor 89 after the laser light source is stopped (S208).

  The abnormality determination unit 108 causes the video adaptive illuminance prediction unit 112 to predict the value of the detection signal output from the DMD side sensor 89 when the laser light source to be stopped is stopped. Then, the predicted value is compared with the value of the detection signal actually acquired from the DMD side sensor 89 at the timing, and when the difference between these values exceeds a predetermined threshold, the output of the DMD side sensor 89 is not appropriate. (S208: NO).

  When the determination in S208 is NO, the controller 109 determines that an abnormality has occurred in the optical system (S204), stops all the laser light sources constituting the laser array 81, or sets a drive current to be applied to each laser light source. The value is reduced below the laser oscillation threshold (S205), and the display output unit 104 and the audio output unit 105 perform the above-described output.

  When the determination in S208 is YES, the control unit 109 determines that an abnormality has occurred in the laser light source (S209), stops only the laser light source that is the stop target in S207, and continues driving the other laser light sources ( S210). As a result, the brightness of the projected image decreases by the amount that the laser light source is stopped.

  Further, the control unit 109 causes the display output unit 104 and the audio output unit 105 to perform processing for notifying that an abnormality has occurred in the laser light (S211). At this time, it is also notified that the abnormality of the laser beam is caused by the laser light source. Furthermore, it is preferable to notify which laser light source among the laser light sources constituting the laser array 81 contributed to the abnormality of the laser light. Thereby, the user can easily perform repair work after the occurrence of an abnormality.

  According to the present embodiment, since the abnormality of the laser light is determined using the scattered light from the laser light source and the OFF light from the DMD element 86, the laser light can be smoothly smoothed while avoiding a decrease in the utilization efficiency of the laser light. Abnormalities can be detected. In the present embodiment, since the light source side sensor 88 and the DMD side sensor 89 are arranged in the vicinity of the laser light source (laser array 81) and in the vicinity of the DMD element 86, the projector may not include a screen or a lens cover. Therefore, it is possible to smoothly detect the abnormality of the laser beam.

  Furthermore, according to the present embodiment, it is possible to specify which of the laser light source and the optical system has contributed to the abnormality of the laser beam, so that the repair work after the occurrence of the abnormality can be facilitated.

  As described above, according to the present embodiment, it is possible to provide a projector capable of smoothly detecting an abnormality in a laser beam without impairing the light use efficiency and without including a screen or a lens cover. . Moreover, the location which contributed to the abnormality of the laser beam can be specified smoothly, and by notifying this to the user, the repair work after the occurrence of the abnormality can be facilitated.

  In addition, this embodiment can be changed as follows.

  For example, as shown in FIG. 11A, an optical fiber 92 is connected to the exit of each laser unit constituting the laser array 91, and light from each laser unit is transmitted through the optical fiber 92 to a light pipe 93. It can also be guided to. In this case, for example, the light scattered by the surface of the lens 94 (relay optical system) on the light exit side of the light pipe 93 is received by the optical sensor 95, thereby detecting the abnormality of the laser beam. it can. In this configuration example, an abnormality occurring in the optical system from the laser array 91 to the lens 94 can be detected based on an abnormality (abrupt change) in the detection signal from the optical sensor 95.

  In addition to this configuration, light scattered on the surface of the condenser lens 97 disposed in the laser unit can be received by the optical sensor 98 as shown in FIG. In this case, if there is an abnormality in the detection signal from the optical sensor 95 and there is no abnormality in the detection signal from the optical sensor 98, it is determined that there is an abnormality in the optical system from the optical fiber 92 to the lens 94. In FIG. 5B, the scattered light from the surface of the condenser lens 97 is received by the optical sensor 98, but the scattered light emitted from the laser light source 96 is similar to the above embodiment. The light sensor 98 may receive light.

  In the present embodiment, the light pipe 93 is used as the light uniformizing means. However, as shown in FIG. 5C, the laser light from the laser array 91 is sent through the optical fiber 92 to the fly-eye illumination system 99. Thus, the light can be made uniform. In this case, each laser unit constituting the laser array 91 is provided with an optical sensor 98 as shown in FIG. 4B, and thereby an abnormality of each laser light source 96 is detected.

  As mentioned above, although two embodiment which concerns on this invention, and its modification example were demonstrated, the embodiment of this invention can change variously besides these.

  For example, in the above embodiment, the abnormality of the laser beam is detected during the actual operation of image projection, but it is also possible to detect the abnormality of the laser beam before the actual operation. For example, the limit value for each sensor output is held in the abnormality determination unit 108 and laser light is emitted for a certain period before actual operation, and the detection signal output from each sensor at that time exceeds the corresponding limit value. In the case, it is determined that there is an abnormality.

  In this case, for example, in the flowchart of FIG. 5, S101 is changed to “whether the output of the panel side sensor exceeds the limit value”, and S102 is changed to “whether the output of the light source side sensor exceeds the limit value”. , S108 is changed to “whether the output of the panel side sensor exceeds the limit value”. Here, the limit value of S108 is set smaller than the limit value of S101 by the amount that the abnormality target light source is stopped in S107.

  Further, in the flowchart of FIG. 10, S203 is changed to “whether the output of the light source side sensor exceeds the limit value”. In this case, a reference pattern for abnormality detection is drawn on the DMD element 86.

  When detecting an abnormality of the laser beam before the actual operation as described above, it is desirable to close the projection port of the projector with a lens cover or other members as a precaution.

  The arrangement position of the optical sensor is not limited to the above, and may be another position as long as unnecessary light can be detected. For example, as shown in FIG. 12, optical sensors 35, 36, and 37 may be disposed on the upper surface of the dichroic prism 28, and leakage light from the upper surface of the dichroic prism 28 may be detected by these sensors. Further, an optical sensor may be added at a position where light scattered on the surface of the optical element such as the vicinity of the condenser lens 14 or the lens 22 can be received. In this way, it is possible to further finely identify the portion that has contributed to the abnormality of the laser beam.

  When the output level of the laser light source is adjusted according to the video signal, it is necessary to adjust the abnormality determination threshold accordingly. For example, in FIG. 5, the abnormality determination threshold in S101 and S103 is changed according to the output level of the laser light source, and in FIG. 10, the abnormality determination threshold in S210 and 203 is changed according to the output level of the laser light source. Let

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

The figure which shows the optical system of the projector which concerns on embodiment The figure which shows typically the generation | occurrence | production state of the sidelobe light which concerns on embodiment The figure which shows the arrangement | positioning state of the optical sensor which concerns on embodiment The figure which shows the structure of the projector which concerns on embodiment Processing flowchart at the time of abnormality determination according to the embodiment The figure which shows the example of a change of arrangement | positioning of the optical sensor which concerns on embodiment The figure which shows the example of a change of the optical system of the projector which concerns on embodiment The figure which shows the optical system of the projector which concerns on other embodiment. The figure which shows the structure of the projector which concerns on other embodiment. The figure which shows the example of a change of the optical system which concerns on other embodiment Process flowchart for abnormality determination according to another embodiment The figure which shows the example of a change of the arrangement position of the optical sensor which concerns on embodiment

Explanation of symbols

11, 51, 61, 71 ... Laser array 12, 52, 62, 72 ... Dispersion angle control lens 13, 53, 63, 73 ... Fly eye integrator 14, 54, 64, 74 ... Condenser lens 15, 19 ... Dichroic mirror 17 , 20, 22, 24, 26 ... lens 16, 23, 25 ... mirror 18, 21, 27 ... liquid crystal panel 28 ... dichroic prism 31, 55, 65, 75 ... light source side sensor 32, 33, 34 ... panel side sensor 35 , 36, 37 ... optical sensor 40 ... projection lens 81, 91 ... laser array 82 ... lens 83 ... condensing lens 84, 93 ... light pipe 85 ... relay optical system 86 ... DMD
89 ... DMD side sensor 92 ... Optical fiber 94 ... Lens 95 ... Optical sensor 96 ... Laser light source 97 ... Condensing lens 98 ... Optical sensor 99 ... Fly eye illumination system 101 ... Laser driver 104 ... Display output unit 105 ... Audio output unit 106 ... Light source side sensor part 107 ... Panel side sensor part 108 ... Abnormality judgment part 109 ... Control part 111 ... DMD sensor part 112 ... Video adaptive illumination intensity prediction part

Claims (6)

A laser light source, a light modulation element that modulates incident laser light based on a video signal, an illumination optical system that guides the laser light emitted from the laser light source to the light modulation element, and light modulated by the light modulation element A projection unit that projects light onto a projection surface, and a light detection unit that is disposed between the laser light source and the projection unit and that receives light deviating from the optical path of the laser light traveling from the laser light source to the projection unit, that Yusuke an abnormality determination unit that determines an abnormality of the laser light based on a signal from the light detector, a laser controller for controlling the output of the laser light source based on the determination result of the abnormality determination portion, a In a projection display device,
The illumination optical system has a fly-eye lens,
The light detection unit includes a first light detector disposed at a position for detecting sidelobe light generated by the fly-eye lens.
A projection display apparatus characterized by the above. The projection display apparatus according to claim 1,
The light detection unit is disposed at a position for detecting scattered light from the laser light source or scattered light emitted from the laser light source and scattered outside the optical path before entering the illumination optical system. With a photodetector
A projection display apparatus characterized by the above. The projection display apparatus according to claim 2, wherein
A plurality of the laser light sources,
The second photodetector is disposed at a position corresponding to a light source group of one laser light source or a plurality of laser light sources in a one-to-one correspondence.
The abnormality determination unit identifies a laser light source in which an abnormality has occurred based on a detection signal from a photodetector that detects the scattered light,
The laser control unit adjusts the output only for the laser light source in which the abnormality has occurred,
A projection display apparatus characterized by the above. In the projection type video display device according to any one of claims 1 to 3,
The light detection unit includes a third light detector disposed at a position for detecting light scattered outside the optical path by the surface of an optical element constituting the illumination optical system.
A projection display apparatus characterized by the above. In the projection type video display device according to any one of claims 1 to 4,
Having an abnormality notification part for notifying the abnormality determination result in the abnormality determination part to the outside;
A projection display apparatus characterized by the above. The projection display apparatus according to claim 5, wherein
The abnormality determination unit identifies an abnormal location based on a detection signal of the light detection unit,
The abnormality notification unit notifies the abnormality location specified by the abnormality determination unit to the outside.
A projection display apparatus characterized by the above.

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