JP2000194302A - Projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the projection display device which uses laser light of high power density enabling projection on a large screen and is equipped with a means for improving the safety. SOLUTION: This device projects and displays an image while scanning a screen by polygon mirrors 17 and 18 by sending a signal from a control part 40 according to image data inputted to an image input part 47 and making laser light emitting units of three colors provided for a laser scanner part 10 emit lights. If the entry of foreign body into an optical path or abnormality of the scanning is detected by a human body sensor part 30, a pyroelectric sensor 31 that a laser scanner part 10 is equipped with, a horizontal scanning beam sensor 19, or a vertical scanning beam sensor 20, the scanner control part 12 electrically stops the laser light emitting units from emitting the lights and an optical path cutting-off device 61 mechanically stops the scanning light from being projected to completely prevent unexpected danger to a human body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display apparatus which projects a laser beam and scans the laser beam to display it on a screen, and more particularly to a projection display apparatus having a scanning stop means.

[0002]

2. Description of the Related Art Conventionally, JP-A-1-245780, JP-A-3-65916, and JP-A-4-1812 have been known.
A projection display device which projects a laser beam as described in JP-A-89-1989 onto a screen and two-dimensionally scans the laser beam to display an image or the like on the screen has been proposed. Such a projection display device has an advantage that a laser beam having a high power density is used, and a small projection device can project a large screen brightly. The laser beam projected on the screen has a high power density, but if it is a reflective screen, it is irregularly reflected on the screen, and if it is a transmissive screen, the luminous flux is diffused by a translucent screen. It does not affect the human eye. Furthermore, this laser beam is constantly scanned two-dimensionally at high speed by a polygon mirror or the like. Even if the laser beam enters the eyes of one person, the power is not concentrated on one point of the retina for a long time. Has little effect. What's more, it doesn't shut your eyes, turn your face away, or irradiate the retina for long periods of time, because even if it gets into the human eye for a moment, it feels so dazzling.

[0003]

However, it is difficult to completely eliminate the failure of the device, and it is difficult to deflect the laser.
There is a possibility that the scanning mechanism may not be normal, and the laser may be illuminated at one point without being scanned while being turned on.
In such a case, if the power of the laser beam having a high power density is concentrated, there is a problem that the stationary laser beam may be stared at the laser beam for a long time, particularly on a transmissive screen, which may adversely affect the eyes. On the other hand, if the projection display device is a large-sized projection display device with an open structure between the screen and the projection device, a person may accidentally enter the laser beam projection optical path. It can be dangerous if done. Even if a person does not enter the optical path of the laser light, if a material such as glass that is easily specularly reflected is mistakenly present on the optical path of the laser light, the reflected light flux having a high power density is output to the human eye. A similar problem can occur if the problem occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and provides a projection display apparatus using a laser beam having a high power density and capable of projecting even on a large screen. For that purpose.

[0005]

In order to achieve this object, in a projection display apparatus according to the first aspect of the present invention, a light emitting means for emitting a laser beam for scanning, and a light emitting means for emitting light by the light emitting means are provided. A light emission control unit that controls the light amount by modulating the light amount based on image data, a scanning unit that scans a screen by projecting a light beam emitted by the light emission unit, and a scanning unit that detects infrared rays between the screen and the light emission unit. A monitoring unit for detecting foreign matter, and a scanning stop unit for stopping scanning by the laser beam when the foreign matter is detected by the monitoring unit.

[0006] The projection display apparatus according to this configuration is provided with monitoring means for detecting a human body or the like, and the scanning stop means is arranged between the screen and the light emitting means, and foreign matter enters the vicinity of the optical path of the laser beam by the monitoring means. In this case, the scanning by the laser beam can be stopped. In particular, since the scanning is stopped before the foreign matter actually comes into contact with the optical path of the laser beam, danger can be prevented beforehand.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the monitoring means includes a pyroelectric sensor.

In the projection display apparatus according to this configuration, a pyroelectric infrared sensor is used as the sensor and reacts sensitively to infrared rays emitted by humans, so that the projection display apparatus has an effect that it has a high detection capability especially for human invasion. . In addition, since the operating temperature and the wavelength band that can be detected are wide, stable operation is possible and reliability is high. In the case of infrared rays, it is considered that foreign substances other than humans are often moved by humans. By detecting the humans at an early stage and stopping laser beam scanning, foreign substances other than humans are similarly detected. There is an effect that intrusion can also be avoided before danger. In addition, since it is possible to detect infrared rays even to a power source such as an engine or a motor, it is possible to detect foreign substances moved by the infrared rays.

[0009] In the projection display device according to the third aspect of the present invention,
A light emitting unit for emitting a scanning laser beam, a light emitting control unit for modulating and controlling the amount of light emitted by the light emitting unit based on image data, and a screen for projecting a light beam emitted by the light emitting unit. Scanning means for scanning, scanning timing detecting means for detecting scanning timing by the scanning means, comparing means for comparing the scanning timing detected by the scanning timing detecting means with a predetermined time, and scanning timing by the comparing means. A scanning stop unit for stopping scanning by the laser light when the predetermined time is different from the predetermined time.

In the projection display apparatus according to this structure, the scanning timing detecting means always monitors the actually emitted laser beam while monitoring the scanning abnormality, and the comparing means uses the main scanning polygon mirror and the sub-scanning polygon mirror. The malfunction of the device is detected at an early stage based on the slight abnormality of the rotation as well as the stop of the rotation of the laser, and the scanning of the laser beam is stopped by the scanning stop means, and the laser beam is continuously emitted at one point. This has the effect of preventing accidents such as accidents.

[0011] In the projection display device according to the fourth aspect of the invention,
In addition to the configuration of the projection display device according to claim 3, further comprising the monitoring means according to claim 1 or 2, wherein the scanning is stopped by the scanning stop means even when the foreign matter is detected by the monitoring means. Characterized by making it possible

In the projection display apparatus according to this structure, the scanning timing detecting means constantly monitors the actually emitted laser beam while monitoring the abnormality of the scanning, and the comparing means detects the malfunction of the scanning and detects the malfunction of the human body. The scanning by the laser beam can be stopped even when a foreign substance has entered near the optical path of the laser beam by the monitoring means for detecting the laser beam.

According to a fifth aspect of the present invention, in addition to the configuration of the projection display device according to any one of the first to fourth aspects, the scanning stop means interrupts light emitted from the light emitting means. It is characterized by having an optical path blocking means.

In the projection display apparatus according to this configuration, the scanning is stopped by mechanically interrupting the optical path of the detected foreign matter or the abnormality of the scanning by the optical path interrupting means. Even in this case, the scanning can be reliably stopped.

In the projection display device according to the invention according to claim 6,
In addition to the configuration of the projection display device according to any one of claims 1 to 5, the scanning stop means stops light emission of the light emitting means.

In the projection display apparatus according to this configuration, the detected foreign matter or the scanning abnormality is promptly responded to the abnormality by a method of softly stopping light emission by the control unit.
Even when physically blocking the optical path by the optical path blocking means does not operate due to some malfunction, it is possible to reliably stop scanning and perform safe control.

In the projection display apparatus according to the invention according to claim 7,
According to a fifth aspect of the present invention, in addition to the configuration of the projection display device, the light path blocking unit is disposed between the light emitting unit and the scanning unit.

In the projection display apparatus according to this configuration, the optical path of the laser beam emitted from the light emitting means is cut off at a position where there is no movement of the optical path before passing through the scanning means, which is scanned by the scanning means and the movement of the optical path occurs. So you can
The optical path can be quickly interrupted by the optical path interrupting means with a small moving distance.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a projection display device according to the present invention will be described by way of a preferred embodiment with reference to the accompanying drawings. Here, FIG. 1 is a schematic diagram illustrating a main configuration of a projection display device 1 according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing the configuration of the main body 2 of the projection display device 1 in detail. First, an outline of the configuration of the projection display device 1 according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 1, the projection display device 1 includes a laser scanner section 10, a human body sensor section 30, a control section 40,
It comprises an optical path blocking unit 60, an image input unit 47, a screen 50, and the like.

The projection display apparatus 1 transmits a signal from the control section 40 to the scanner control section 12 based on the image data input to the image input section 47, and outputs the red laser light emitting device 13R provided in the laser scanner section 10. , Green laser emitter 1
The 3G, blue laser light emitting device 13B (see FIG. 3, hereinafter collectively referred to as a laser light emitting device 13) emits light, and projects while scanning the screen 50 to form an image. Then, as shown in FIG. 2, the pyroelectric sensor 31, the main scanning beam sensor 19, and the sub-scanning beam sensor 2 provided in the human body sensor unit 30 and the laser scanner unit 10.
0 (see FIG. 3), when the entry of a foreign matter into the optical path or the detection of a scanning abnormality is detected, the scanner control unit 12 electrically stops the emission of the laser light emitter 13 or the optical path blocking device 61. Thus, safety is enhanced so that the projection of the scanning light is not mechanically stopped, so that an unexpected danger is not given to the human body. Hereinafter, the configuration of the projection display device 1 will be described in more detail.

The control unit 40 includes a CPU (not shown) and a RAM (not shown).
And a well-known computer having a ROM. A program for controlling the entire projection display device 1 is stored in the ROM, and the laser scanner unit 10 performs input processing and data development and uses the data developed.
Is projected while modulating the light emission of the laser light emitter 13 based on image data, and the screen of the screen 50 is two-dimensionally scanned to display an image on the screen 50.

FIG. 3 is a schematic diagram for explaining the laser scanner unit 10 and the screen 50. Hereinafter, the structure and operation of the laser scanner unit 10 will be described with reference to FIG. First, the laser emitter 13 includes a laser oscillator,
He-Ne laser is used for the red laser light emitting device that emits red light, and He is used for the blue laser light emitting device that emits blue light.
An Ar laser is preferably used for a green laser light-emitting device in which a Cd laser emits green light.

The laser beams LB (R), LB (G), LB emitted from these three laser emitters
(B) is combined into a laser beam LB having one optical axis by a first laser beam combiner 14A and a second laser beam combiner 14B (hereinafter referred to as laser beam combiner 14). First, the red laser emitter 13R and the green laser emitter 13G are combined by the first laser beam combiner 14A. The first laser beam combiner 14A is composed of a dichroic mirror that transmits a specific wavelength or reflects a specific wavelength. The first laser beam synthesizer 14A transmits the laser beam LB (R) emitted from the red laser light emitter 13R, but transmits the laser beam LB (R). Green laser beam LB emitted from laser emitter 13G
(G) is made of a material that reflects light depending on the wavelength of the output light. Therefore, the first laser beam combiner 14A
The red laser beam LB (R) and the green laser beam LB (G) respectively emitted from the red laser light emitter 13R and the green laser light emitter G, which are arranged orthogonally, have a red laser beam LB (R). After passing through the dichroic mirror and proceeding straight, the green laser beam LB (G) is reflected by the dichroic mirror and its optical axis is deflected at right angles. Therefore, both optical axes are aligned in the same direction, and the same optical axis is aligned. It is adjusted to have.

Similarly, the second laser beam combiner combines the red laser beam LB (R) and the green laser beam LB (G) with a blue laser light emitting device 13.
The blue laser beam LB (B) emitted by B is combined, and the original input color can be reproduced. Note that these three laser beams LB (R), LB (G), LB
The composition of (B) may be a composition in which light beams are combined by a prism using a difference in refractive index depending on the wavelength, and may be any as long as three light beams can be combined into one.

The laser beam LB thus synthesized
The optical path is mechanically interrupted by an optical path interrupting device 61 provided on the optical path. This light path blocking device 61
Is to mechanically cut off the optical path and stop the projection reliably even when the light emission of the laser emitter cannot be stopped electrically. The configuration of the light path blocking device 61 will be described later in detail.

The laser beam LB emitted from the laser emitter 13 and combined into one light beam by the laser beam combiner 14 contacts a main scanning polygon mirror (rotating polygon mirror) 17 rotating at high speed. The main scanning polygon mirror 17 has a regular hexagonal prism shape having a height lower than the bottom surface as shown in FIG. 3, and is disposed at a position where the rotation axis is horizontal and the line perpendicular to the laser beam LB is translated upward. Therefore, the laser beam LB is reflected downward by the six plane mirrors rotating about the rotation axis, and the direction of the optical axis is changed by the rotation of the main scanning polygon mirror 17 to the optical axis of the laser beam LB before reflection. And so as to increase the internal angle with.

At this time, the laser beam control unit 15 provided in the scanner control unit 12 and the polygon mirror control unit 15 control the laser beam LB reflected by the main scanning polygon mirror 17 so that the laser beam LB is not projected outside the predetermined angle range. Controlled by the unit 16. Further, in order to harmonize the control by the laser emitter control unit 15 and the polygon mirror control unit 16, the optical axis of the laser beam LB reflected by the main scanning polygon mirror 17 is changed to the luminous flux of the laser beam LB at the position where the main scanning starts. The main scanning beam sensor 19 is located near the position where
Is provided, the actual position of the laser beam LB is detected, and the emission timing of the laser emitter 13 is adjusted to the rotation of the main scanning polygon mirror 17.

Here, the light received by the main scanning beam sensor 19 is sent to the control unit 40 as a signal, and this signal is hereinafter referred to as a main scanning SOS (Start Of Scanni).
ng) signal. The control unit 40 that has detected the main scanning SOS signal sends a laser emission signal modulated based on image data to the laser light emitting unit control unit 15 based on the scanning start position calculated based on this signal. Send out.
The signal modulated by the data for one column in this manner is transmitted to the laser emitter 13 by the laser emitter controller 15 which is the driving means (driver) of the laser oscillator, and the laser beam LB is transmitted to the sub-scanning polygon. The light is reflected by the mirror 18 and scanned on the screen 50 in the X direction in FIG. 3, and a row of images is projected on the screen.

On the other hand, the laser beam LB reflected and deflected by the main scanning polygon mirror 17 is reflected toward the sub-scanning polygon mirror 18 located therebelow in FIG. The sub-scanning polygon mirror 18 has a shape of a slender hexagonal prism having six plane mirrors and a height higher than the bottom surface, and its rotation axis is horizontal, parallel to the screen, and closer to the screen than the main scanning polygon mirror 17. The main scanning polygon mirror 1 is disposed at a position slightly displaced in the opposite direction to the main scanning polygon mirror 1.
The longitudinal direction of the plane mirror is arranged in the same direction as the direction deflected by 7. The sub-scanning polygon mirror 18
Rotates in a direction in which the upper end approaches the screen 50. Therefore, the laser beam LB reflected from the main scanning polygon mirror 17 is further deflected in the direction of the screen 50 so that the internal angle to be deflected increases with time, that is, the laser beam LB is deflected from above the screen 50 to below. The direction changes in the direction in which the LB moves.

As described above, the sub-scan is performed in the vertical direction while performing the horizontal main scan. This is a scan similar to the horizontal scan and the vertical scan of the CRT. When horizontal scanning is repeatedly performed from the upper end to the lower end in this manner, one screen is displayed. However, since the sub-scanning polygon mirror 18 rotates at a constant speed, the control unit 40 sends a signal at an appropriate interval. . Then, the sub-scanning of the next screen can be performed on the next mirror surface of the rotating sub-scanning polygon mirror 18. This sub-scanning can be performed by using a galvanometer (oscillating single-sided mirror) whose inclination is controlled by a current. It is preferable to use

Strictly speaking, the sub-scanning polygon mirror 18 rotates while the main scanning polygon mirror 17 scans one main scanning line. Scanning polygon mirror 18
Are set in such a manner that the main scanning direction is slightly lowered.

In order to detect the vertical scanning start position, the laser emitter is turned on slightly above the original scanning start position on the screen, and the laser beam LB is emitted without modulation and the main scanning is performed. And sub-scanning. Then, when the laser beam LB is incident on the sub-scanning beam sensor 20 arranged near the scanning start position, a sub-scanning SOS signal is sent from the sub-scanning beam sensor 20 to the control unit 40. The actual scanning start position is calculated, and a control signal is sent to the scanner control unit 12 of the laser scanner unit 10 after a predetermined time calculated, and the scanner control unit 12 sends a drive signal to the laser emitter 13 to reduce the light amount. The modulation is performed, and the main scanning and the sub-scanning are started.

As described above, the image displayed on the screen 50 by the laser beam LB shows a pincushion-like distortion on both sides, causing a gap between the scanning lines in the vertical direction. Therefore, in the control unit 40, it is preferable to control the distortion by controlling the distortion by extending the modulation time for scanning the central part or shortening the modulation time at the upper end and the lower end, or by using an fθ lens or the like. It is desirable to optically correct the distortion by using.

In this embodiment, the scanning of 525 main scanning lines (horizontal scanning lines) for one screen is reduced to 1/3 in this embodiment.
The sub-scanning (vertical scanning) of 0 seconds is performed, and a smooth screen with little flicker can be projected.

The screen 50 can be of either a reflection type or a transmission type. The reflection type screen is provided with fine irregularities such that the laser beam LB having a high power density is not reflected only in one direction when the laser beam is applied, and the surface is dispersed and irregularly reflected in each direction. . In this case, the position at which the viewer views the image with respect to the screen 50 and the position at which the laser beam is irradiated are in the same direction. Therefore, there is a possibility that a foreign matter including a human body enters the optical path by mistake.

On the other hand, the transmissive screen is made of a translucent material so that when the laser beam LB is transmitted, it is sufficiently diffused to reduce the power. Therefore, even if the scanning laser beam is applied to the human body through the transmission type screen 50, the irradiation power per unit area is small, but the laser beam perceived by the viewer is smaller than the reflection type screen. Of course, there is no effect even if the power density is increased and enters the human eyes, but it is not preferable to stare for a long time in a state where scanning is stopped.

The optical path cutoff device 60 is disposed on the optical path of the laser beam LB as described above, and a drive signal is issued from the optical path cutoff device control unit 62 by a signal from the control unit 40, and the optical path of the laser beam LB is changed. This is a mechanical shutoff.

FIG. 4 is a diagram showing an example of the configuration of the light path blocking device 61. Hereinafter, the light path blocking device 61 will be described with reference to FIG. In the optical path blocking device 61, the central portion of the main body 63 is swingably supported by a support 67 provided on the main body 2 by a support shaft 64, and a blocking portion 68 is provided at one end of the main body 63. It is provided so as to be displaceable between a blocking position for blocking the light path of the LB and an open position for opening the light path of the laser beam LB. A permanent magnet 65 is provided at the other end of the main body 63, and an electromagnet 66 made of a coil is provided in the main body 2 so as to face the permanent magnet 65. One end of a spring 69 is locked to the lower end of the main body 63 on the blocking section 68 side, and the other end of the spring 69 is locked to a part of the main body 2 so that the main body 63 is connected to the blocking section 6.
8 urges the laser beam LB in a direction of blocking it. Therefore, when the power is not turned on, the laser beam LB is stopped by the spring 69 at a position where the laser beam LB is blocked by the laser beam LB blocking unit 68. Therefore, even if there is a trouble that power is not supplied to the light path interrupting device 60, if the voltage is not applied to the electromagnet 66, the optical path of the laser beam LB is always interrupted, and the laser beam LB is inadvertently emitted. Safe without any. on the other hand,
When projecting the laser beam LB, by energizing the electromagnet 66, the electromagnet 66 attracts the permanent magnet 65 to open the optical path against the urging force of the spring, and the laser beam LB can be irradiated. It is to be.

Next, the human body sensor section 30 will be described with reference to FIG. The human body sensor unit 30 includes the pyroelectric sensor 3
1, a filter 32 and a sensor amplifier 33. The pyroelectric sensor 31 is a pyroelectric infrared sensor, and in the present embodiment, a sensor utilizing a characteristic in which electric charge changes in response to a temperature change in the crystal structure of PZT (lead zirconate titanate) is used. Therefore, an arbitrary temperature sensor can be obtained by using an optical filter without wavelength dependency. Note that LiTaO ₃ (lithium tantalate),
A configuration using PVF ₂ (phosphorus vanadium fluoride), PbTaO ₃ (lead tantalate), or the like may be used.

Here, the infrared radiation emitted by the human body is generally 7
It is in the wavelength band from μm to 14 μm. However, since the pyroelectric sensor 31 detects infrared rays emitted into the sensor by converting it into heat, it has a certain sensitivity to a very wide range of electromagnetic waves of 0.2 μm to 20 μm.
If used, it may cause a malfunction. Therefore, in the present embodiment, the filter (window material) 3 is attached to the pyroelectric sensor 31.
2, a silicon / polyethylene / quartz glass or band pass filter is used. The sensor amplifier 33 extracts the surface charge of the pyroelectric element to the outside, and uses a voltage type using a source follower circuit as a transimpedance circuit. Further, as shown in FIG. 2, a horn-shaped recess is provided in a part of the main body 2 so as to increase the directivity so as not to cause a malfunction to a person or the like outside the optical path of the laser beam LB applied to the outside of the apparatus. Since it is formed and the pyroelectric sensor 31 is disposed at the bottom thereof, the entry of noise is prevented.

However, although called the human body sensor unit 30,
The foreign substance to be detected is not limited to the human body, and means a sensor that can detect other foreign substances and detects mainly the human body. In other words, the adjustment of the sensitive band by the filter 32 or the like sets a high sensitivity even for a human body other than a human body, because even a foreign substance other than the human body on the optical path is dangerous if it causes regular reflection of the laser beam LB. Of course, it is possible, but on the other hand, it is not desirable that the safety device works more than necessary and the projection display device 1 stops more than necessary. Therefore, the pyroelectric sensor 31 using the above-described filter or the like is used.
It is desirable to adjust the sensitivity by actually operating it.

The scanner controller 12 includes a laser emitter controller 15 and a polygon mirror controller 16. The laser emitter control unit 15 is a driver that sends a weak signal sent from the control unit 40 to the laser emitter 13 as a drive signal. The polygon mirror control unit 16 is also a driver that receives a weak signal from the control unit 40 and sends out a drive signal for driving a motor that rotates the main scanning polygon mirror 17 and the sub-scanning polygon mirror 18.

The image input section 47 is a buffer for externally inputting and storing image data to be projected, and has a storage means which is also a development place for developing the image data.
As input data, a general RGB video signal is input via the interface 48. The input signal is not limited to this, and a signal of various types may be input.

FIG. 5 is a flowchart for explaining the procedure of the control process for turning off the laser and cutting off the optical path of the projection display device 1. Hereinafter, the procedure of the process of controlling the laser extinguishing and the optical path cutoff will be described with reference to this flowchart.

First, when the power is turned on (start), the rotation of the main scanning polygon mirror 17 is started at a constant speed, and an unmodulated drive signal is applied to the laser emitter 13 from the laser emitter controller 15 to turn on the laser emitter. To emit light (Step 1
(Hereinafter, steps are abbreviated as S.). Next, the value of N stored in the counter memory of the RAM of the control unit 40 (not shown) is reset to 1 (S3). Next, it is determined whether there is no image data to be displayed on the image input unit 47 or whether an end switch (switch) (not shown) has been operated. If the end SW (switch) is operated (S5: YES), the laser light emitter 13 is turned off (S5).
6), the optical path of the laser beam LB is cut off (S7), and the rotation of the polygon mirrors 17, 18 is stopped (S2).
9), end the processing (end).

When there is image data to be displayed in the image input section 47 and the end switch is not operated (S
5: NO), the sub-scanning SOS from the sub-scanning beam sensor 20
It is determined whether the signal has been transmitted to the control unit 40, and if not transmitted, the process waits until the signal is transmitted (S8: NO)
→ S8). If the SOS signal has been sent to the control unit 40 (S8: YES), the process enters a loop of the main scanning process (S9 → S23). The main scan is a loop that performs processing by changing the increment from 1 from N = 1 to N = 525. First, the main scanning beam sensor 19 outputs the main scanning S
It is determined whether the OS signal has been transmitted to the control unit 40. If the signal has not been transmitted (S11: NO), the process waits until the signal is transmitted (S11: NO → S11). If the SOS signal has been sent to the control unit 40 (S11: YES), the scanning timing is detected (S13).

FIG. 6 is a flowchart showing in detail the procedure of the process of detecting the scanning timing in S13 in FIG. Hereinafter, the procedure of the process of detecting the scanning timing will be described with reference to the flowchart of FIG. First,
In FIG. 5, the main scanning beam sensor 19 outputs the main scanning SOS.
When the signal is sent to the control unit (S11: YES), FIG.
In order to store the time when the SOS signal is present for the purpose of calculating the elapsed time from the previous scan,
After substituting the value of _TN stored as the time when the SOS signal was present from the reference timer (not shown) provided in the control unit 40 at the time of the previous scan into _TN-1 , the value of _TN becomes It is cleared (S151). Then, the time recorded by the reference timer of the SOS signal in S11 is substituted into the value of _TN again.

Here, only in the case of the first main scan, the data _TN-1 of the SOS signal at the time of the main scan of the destination to be compared.
Since there is no T _{N in the} previous round, the data of T _N
Substituting into _{N- 1} is meaningless. Therefore, N = 1
It is determined whether or not N = 1, that is, in the first main scan, because the SOS signal cannot be compared with the previous SOS signal, the process is performed without any abnormality (S158), and the process is terminated (end).

In the case of the second main scanning, the processing is started (started), and the time _TN of the first SOS signal is set to _TN-1.
And the value of _TN is reset once (S151). Then, the time of the reference timer of the second SOS signal is newly assigned to _TN (S152). Also,
Here, since N = 2 and not N = 1 (S15
3: NO), the process proceeds to S154, and the time difference TD becomes ( _TN −
_TN-1 ) (S154). The calculated time difference TD is called a “reference time” stored in the ROM as a standard SOS signal interval time, and the previously calculated time difference and the previous time difference TD, which is the time interval, are equal to TD. / TS (S155), and 0.98 ≦ TD
It is determined whether or not the condition of the formula of /TS≦1.02 is satisfied, that is, whether or not the error is within ± 2% with respect to the reference time TS (S156).

If the value of (TD / TS) is given by the equation (0.9)
8 ≦ TD / TS ≦ 1.02), that is, if the value of the time difference TD is within the error range of ± 2% with respect to TS (S156: YES), “No abnormality” Is determined (S158). On the other hand, the value of (TD / TS)
If the condition of the expression (0.98 ≦ TD / TS ≦ 1.02) is not satisfied, that is, if the value of the time difference TD is not within an error range of ± 2% with respect to TS (S156: N
O), it is determined that there is an abnormality (S157). Therefore,
"No abnormality" (S158) or "Abnormal" (S15
The process is terminated after performing one of the determinations in 7) (end). By the above procedure, S151 to S15 in FIG.
The process up to 8, that is, the process of S13 in FIG.

Next, description will be made with reference to the flowchart of FIG. When the scanning timing detection processing in S13 is completed, the presence or absence of the above is determined (S19), that is, "abnormal" in the above-described flowchart of FIG. 6 (S15).
7) It is determined which of “abnormal” (S158) has been determined (S15), and if “abnormal” has been determined (S15: YES), the laser emitter is controlled by the control unit 40. 13 is stopped (S2).
6) Also, a signal is output to the light path cutoff device control section 60, and the light path is cut off by the light path cutoff device 61 (S27), and the rotation of the main operation polygon mirror 17 and the sub-scanning polygon mirror 18 is stopped (S29). The process ends.

If it is determined that there is no abnormality (S15: N
O) Next, the signal of the pyroelectric sensor 31 (see FIG. 2) is input to the control unit 40 (S17), and the control unit 40 determines the pyroelectric sensor signal and determines that there is "an obstacle". (S1
9: YES), the emission of the laser emitter 13 is stopped by the control of the control unit 40 (S26), and a signal is output to the optical path interrupting device control unit 60, and the optical path is interrupted by the optical path interrupting device 61 (S27). Main operation polygon mirror 17
The rotation of the sub-scanning polygon mirror 18 is stopped (S2
9), end the processing (end).

If it is determined that there is no obstacle (S19:
NO), the image data of the row is read out from the image input unit 47, and a modulation signal is sent from the control unit 40 to the laser oscillator control unit 15 based on the image data, and the modulation signal from the control unit 40 is Based on this, the drive signal (drive signal) modulated by the laser light emitter control unit 15 to the laser light emitter 13 is transmitted and displayed on the screen 50. When the one-line scanning is completed, N is incremented by +1 (S23), and until N = 525, the loop from S9 to S23 is repeated to perform the next main scanning again.
If N is incremented by +1 and becomes N = 526, there is no 526th horizontal scanning line, and the main scanning process is terminated (S25).

If the end switch is not operated and the image data to be displayed next is in the image input section 47 (S5: YES), the next screen scanning step is repeated from S3. Repeat (S7 to S25). If the end switch has been operated or if there is no image data to be displayed in the image input unit 47 (S5: NO), the control unit 40 stops the light emission of the laser emitter 13 (S6). Further, a signal is output to the light path blocking device control unit 60, and the light path is blocked by the light path blocking device 61 (S8).
Main operation polygon mirror 17 / Sub scanning polygon mirror 18
Is stopped (S29), and the process ends.

The present embodiment has the following effects because it has the configuration and effects described above. That is, the main operation beam sensor 19 and the sub-scanning beam sensor 2
0, always monitor the actually emitted laser beam LB, monitor the scanning abnormality, and stop the rotation of the main operation polygon mirror 17 and the sub-scanning polygon mirror 18 as well as the abnormality of the rotation. This has the effect of detecting a malfunction of the apparatus at an early stage and preventing an accident that the laser beam is stopped and emitted beforehand.

Further, a sensor for detecting a human body or the like is provided, and when foreign matter enters near the optical path of the laser beam, emission of the laser beam is stopped before the foreign matter actually contacts the optical path of the laser beam. Alternatively, since the optical path is blocked, danger can be prevented beforehand.

Further, since a pyroelectric infrared sensor is used as the sensor and reacts sensitively to infrared rays emitted by humans, there is an effect that it has a high detection capability especially for human invasion. In addition, since the operating temperature and the wavelength band that can be detected are wide, stable operation is possible and reliability is high. In the case of infrared rays, it is considered that foreign substances other than humans are often moved by humans. By detecting the humans at an early stage and stopping laser beam scanning, foreign substances other than humans are similarly detected. There is an effect that intrusion can also be avoided before danger. In addition, since it is possible to detect infrared rays even to a power source such as an engine or a motor, it is possible to detect foreign substances moved by the infrared rays.

For the foreign matter detected in this way, one method is to softly stop light emission by the control unit 40 and to mechanically cut off the light path by the light path cutoff device 61 under the control of the light path cutoff device control unit 62. Thus, even if one of the two does not operate due to some malfunction, it is possible to surely perform safe control by complementing each other. In addition, in order to operate the light path blocking device 61 at a position where the light path does not move before scanning of the laser beam is performed, the blocking of the light path can be made as close to the light path as possible. There is an effect that the idle distance of the blocking unit 68 can be shortened, and the optical path can be blocked promptly after the abnormality is detected.

As described above, the present invention has been described based on one embodiment. However, the present invention is not limited to the above embodiment, and various improvements can be made without departing from the spirit of the present invention. Needless to say.

[0061]

As is apparent from the above description, claim 1
According to the projection display device of the present invention, a light emitting unit that emits a scanning laser beam, a light emission control unit that controls the amount of light emitted by the light emitting unit based on image data and controls the light emission, Scanning means for projecting light rays emitted by the means to scan the screen, monitoring means for detecting foreign matter between the screen and the light emitting means by detecting infrared rays, and the foreign matter detected by the monitoring means In this case, a scanning stop means for stopping scanning by the laser light is provided, so that a monitoring means for detecting a human body or the like is provided, and the scanning stop means is disposed between the screen and the light emitting means. Further, there is an effect that the scanning by the laser beam can be stopped when a foreign matter enters the vicinity of the optical path of the laser beam by the monitoring means. In particular, since the scanning is stopped before the foreign matter actually contacts the optical path of the laser beam, danger can be prevented beforehand.

According to a second aspect of the present invention, in addition to the effect of the first aspect, the monitoring means is provided with a pyroelectric sensor. This has the effect of sensitively reacting to the infrared rays emitted by the device, and having a high detection capability especially for human invasion. Further, since the operating temperature and the detectable wavelength band are wide, stable operation is possible and reliability is high. In the case of infrared rays, it is considered that foreign substances other than humans are often moved by humans. By detecting the humans at an early stage and stopping laser beam scanning, foreign substances other than humans are similarly detected. There is an effect that intrusion can also be avoided before danger.
In addition, since it is possible to detect infrared rays even to a power source such as an engine or a motor, it is possible to detect foreign substances moved by the infrared rays.

In the projection display device according to the third aspect of the present invention,
A light emitting unit for emitting a scanning laser beam, a light emitting control unit for modulating and controlling the amount of light emitted by the light emitting unit based on image data, and a screen for projecting a light beam emitted by the light emitting unit. Scanning means for scanning, scanning timing detecting means for detecting scanning timing by the scanning means, comparing means for comparing the scanning timing detected by the scanning timing detecting means with a predetermined time, and scanning timing by the comparing means. In the case where the scanning time is different from the predetermined time, a scanning stop means for stopping scanning by the laser light is provided, so that the scanning timing detecting means always performs scanning while always detecting an actually emitted laser beam. Of the main scanning polygon mirror and the sub-scanning polygon mirror are stopped by the comparing means. Early detect a malfunction of the device to slight abnormality such as a clue rotation that the I, the scanning stop means,
There is an effect that laser beam scanning can be stopped. Therefore, it is possible to prevent an accident in which the laser beam is continuously emitted at one point for a long time.

In the projection display device according to the fourth aspect of the present invention,
In addition to the effect of the projection display device according to claim 3, further comprising the monitoring means according to claim 1 or 2, wherein the scanning is stopped by the scanning stop means also when the foreign matter is detected by the monitoring means. Since the scanning timing detecting means always detects the actually emitted laser beam, the scanning abnormality can be monitored, and the scanning means can be detected by the comparing means. is there. Further, there is an effect that the scanning by the laser light can be stopped when a foreign substance enters near the optical path of the laser beam by the monitoring means for detecting the human body or the like.

According to a fifth aspect of the present invention, in addition to the configuration of the projection display device according to any one of the first to fourth aspects, the scanning stop means blocks light emitted from the light emitting means. Since the optical path cutoff means is provided, there is an effect that scanning can be stopped by physically blocking the optical path by the light path cutoff means for a detected foreign substance or abnormal scanning. Therefore, even if it is not possible to stop the light emission by software due to some malfunction, it is possible to surely stop the scanning.

In the projection display apparatus according to the invention according to claim 6,
In addition to the effect of the projection display device according to any one of claims 1 to 5, the scanning stop means stops emission of the light emitting means. In addition, the method of stopping the light emission by software by the control unit has an effect that a quick response to the abnormality can be performed. Therefore, even when physically blocking the optical path by the optical path blocking means does not operate due to some malfunction, there is an effect that the scanning can be surely stopped and the safe control can be performed.

In the projection display apparatus according to the seventh aspect,
In addition to the configuration of the projection display device according to claim 5, the optical path blocking unit is disposed between the light emitting unit and the scanning unit. There is an effect that the optical path of the laser beam emitted from the light emitting unit can be blocked at a position where the optical path does not move before passing through the scanning unit where the movement occurs. Therefore, there is an effect that the optical path can be quickly interrupted by the optical path interrupting means with a small moving distance.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main configuration of a projection display device 1 according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a main body 2 of the projection display device 1 in detail.

FIG. 3 is a schematic diagram illustrating a laser scanner unit 10 and a screen 50.

FIG. 4 is a diagram illustrating an example of a configuration of an optical path blocking device 60.

FIG. 5 is a flowchart illustrating a procedure of a process for controlling laser extinguishing and optical path cutoff of the projection display device 1.

FIG. 6 is a flowchart showing in detail a procedure of a process of detecting a scanning timing in S13 in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Projection display apparatus 2 Main body 10 Laser scanner unit 11 Scanner 12 Scanner control unit 13R, 13G, 13B Laser light emitter 14A, 14B Laser beam synthesizer 15 Laser light emitter control unit 16 Polygon mirror control unit 17 Main operation polygon mirror 18 Sub-scan Polygon mirror 19 Main scanning beam sensor 20 Sub-scanning beam sensor 30 Human body sensor unit 31 Pyroelectric sensor 32 Filter 33 Sensor amplifier 40 Control unit 50 Screen 51 fθ lens 60 Optical path blocking unit 61 Optical path blocking unit 62 Optical path blocking unit control unit 63 Main unit 64 Support shaft 65 Permanent magnet 66 Electromagnet 67 Support base 68 Blocking part 69 Spring

Claims (7)

[Claims] A light emitting unit that emits laser light for scanning; a light emission control unit that modulates and controls the amount of light emitted by the light emitting unit based on image data; and a light emitting unit that emits light emitted by the light emitting unit. Scanning means for projecting and scanning the screen; monitoring means for detecting foreign matter between the screen and the light emitting means by detecting infrared light; and the laser beam when the foreign matter is detected by the monitoring means. And a scanning stop means for stopping the scanning by the projection display device. 2. The projection display device according to claim 1, wherein said monitoring means includes a pyroelectric sensor. 3. A light emitting unit that emits a scanning laser beam, a light emission control unit that modulates and controls the amount of light emitted by the light emitting unit based on image data, and a light emitting unit that emits a light beam emitted by the light emitting unit. Scanning means for projecting and scanning a screen; scanning timing detecting means for detecting scanning timing by the scanning means; comparing means for comparing the scanning timing detected by the scanning timing detecting means with a predetermined time; A projection display device comprising: a scanning stop means for stopping scanning by the laser light when a scanning timing is different from the predetermined time by means. 4. The scanning device according to claim 1, further comprising a monitoring unit configured to stop scanning even when the monitoring unit detects the foreign matter. Item 4. The projection display device according to item 3. 5. The projection display device according to claim 1, wherein said scanning stop means includes an optical path blocking means for blocking a light beam emitted from a light emitting means. 6. The projection display device according to claim 1, wherein said scanning stop means stops light emission of said light emitting means. 7. The projection display device according to claim 5, wherein the light path blocking unit is provided between the light emitting unit and the scanning unit.