JP2002341280A - Projection type display device and light beam projection preventing method for the same device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device which has its safety enhanced by preventing a light beam from being projected in the beam state to the outside of the projection display device at need without incorporating any new device. SOLUTION: The projection display device is equipped with scanning means 102 and 104 which include a scanning mirror 104 whose attitudes can be controlled. The scanning means 102 and 104 make a scan with the light beam from a light source 101 to form video on a projection object body. The attitude- controllable scanning mirror 104 is controlled to specific attitudes at need to prevent the light beam from being projected in the beam state to the outside of the projection display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device having a scanning means including a scanning mirror capable of controlling the attitude, and scanning a light beam with the scanning means to form an image on a projection object. A first scanning mirror that scans the light beam in the scanning line direction and a second scanning mirror that scans the light beam in a direction perpendicular to the scanning line direction. The present invention relates to a projection display device formed on a projection body. In this specification, scanning in the scanning line direction is referred to as horizontal scanning,
Scanning in a direction perpendicular to the scanning line direction may be referred to as vertical scanning for convenience, but the scanning line direction may be vertical.

[0002]

2. Description of the Related Art As one of projection type display devices, a laser display which forms an image on a projection object by two-dimensionally scanning a light beam is known. FIG. 3 shows the configuration. Dichroic mirror 304 (reflects the red beam and deflects its optical axis at right angles) from the red laser 301, green laser 302, and blue laser 303, dichroic mirror
305 (reflects the green beam and deflects its optical axis at a right angle, but transmits the red beam and goes straight), dichroic mirror 306 (reflects the blue beam and deflects its optical axis at a right angle, And a green beam is transmitted and travels straight), and the color combined beam is horizontally scanned by a polygon mirror 307 rotating in one direction, and vertically scanned by a galvano mirror 308 which is an oscillating one-sided mirror. The scanned light beam is f
An image is formed on the screen 313 by the -θ lens 312. Each laser 3
Gas lasers are used as 01, 302, and 303, and light intensity modulators 309, 310, and 311 are used for modulation based on image information of a light beam from each laser. In FIG. 3, the shaded area shows the state of scanning of the light beam.

[0003] Since the laser beam is two-dimensionally scanned at a high speed and diffused on a screen, there is little danger in normal operation. However, for example, when the mirror scanning system fails, the laser beam becomes stationary, and when the beam enters the eye directly or by reflection, there is a high risk.

[0004] The projection display device disclosed in Japanese Patent Application Laid-Open No. 2000-194302 incorporates a light blocking device in order to enhance safety in the event of an abnormality as described above. FIG. 3 shows a mounting position of the light blocking device 314 in the projection display device. The light blocking device 314 is located between a polygon mirror 307 which is a horizontal scanning mirror and a galvano mirror 308 which is a vertical scanning mirror (in the projection type display device disclosed in JP-A-2000-194302, the vertical scanning mirror is also used). Using polygons). When an error occurs in beam scanning due to a malfunction of the mirror scanning system, or when a foreign object such as a human body enters between the laser emitting unit and the screen of the projection display device, the light blocking device 314 becomes a dotted line. To stop the laser beam emission. At this time, the scanning abnormality is detected by a signal from a light receiving element mounted near the scanning start position of the laser beam. The entry of the human body or the like into the beam optical path is detected by a pyroelectric infrared sensor that detects infrared rays emitted by the human body or the like by converting the infrared rays into heat.

[0005]

However, the incorporation of a light blocking device as in the above-mentioned conventional device is problematic from the viewpoint of reducing the size and cost of the projection display device.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to prevent a light beam from being emitted out of a projection display device in a beam state when an abnormality or the like is necessary without incorporating a new device. It is an object of the present invention to provide a projection-type display device with an improved height and a method for preventing light beam emission in the device. Here, the light beam is a highly directional light beam having a high optical power density so as to cause harm to a human body or the like in a small cross section.

[0007]

In order to solve the above-mentioned problems, a projection display apparatus according to the present invention includes a scanning unit including a scanning mirror capable of controlling the attitude, and scans a light beam by the scanning unit to form an image. A projection mirror on a projection object, and when necessary, sets the scanning mirror capable of controlling the attitude to a predetermined attitude in order to prevent the light beam from being emitted out of the projection display in a beam state. It is configured to be controlled.

As a result, the safety can be improved without adding a new bulky component. The projection type display device to which the present invention can be applied is not limited as long as it includes a scanning unit including a scanning mirror capable of controlling the attitude, and deflects and scans a light beam to form an image on a projection target. It may be something.

More specifically, the following embodiments are possible. The scanning means typically includes a first scanning mirror that scans a light beam in a scanning line direction, and a second scanning mirror that scans a light beam in a direction perpendicular to the scanning line direction, which is the attitude controllable scanning mirror. , And two-dimensionally scan the light beam to form an image on the projection target.

The attitude controllable scanning mirror can be configured to be controlled to the predetermined attitude when an abnormality occurs. In this case, the abnormal time is an abnormal time of the scanning system of the first scanning mirror, and the abnormality is detected by the detecting means, and the scanning mirror is automatically controlled to the predetermined posture based on the abnormality. It can be configured as follows. Further, when an abnormality such as a person enters the optical path of the light beam, the abnormality is detected by the detecting means, and the scanning mirror is automatically controlled to the predetermined posture based on the abnormality. obtain.

Further, the scanning mirror capable of controlling the attitude is
A scanning mirror having a light absorbing portion formed on the back surface, such that when necessary or abnormal, the scanning mirror is rotated by about 90 degrees or more from a normal state so that the light absorbing portion receives and absorbs a light beam; Can be configured. Using a scanning mirror having a light diffusion portion formed on the back surface, such that the scanning mirror is rotated by approximately 90 degrees or more from a normal state and receives and diffuses a light beam at the light diffusion portion, when necessary or abnormal. It may be configured.

As a result, the angle control accuracy of the scanning mirror capable of controlling the attitude at the time of light shielding can be greatly reduced.

Further, a light absorbing portion is provided on an inner surface of a housing for accommodating components of the apparatus, and the scanning mirror capable of controlling the attitude is controlled to the predetermined attitude when necessary or abnormal when the light beam is controlled. Can be configured to reflect the light, guide the light to the light absorbing portion, and absorb the light. A light diffusing unit is provided on the inner surface of the housing that accommodates the components of the apparatus, and the scanning mirror capable of controlling the attitude reflects the light beam by controlling the predetermined attitude when necessary or abnormal, and reflects the light beam. You may comprise so that it may guide | induce and diffuse to a light-diffusion part. When the inner surface of the housing is a rough surface, the light diffusing portion may use the rough surface as it is.

Thus, the magnitude of the movement angle of the scanning mirror whose posture can be controlled at the time of shading is suppressed, and the selection range is widened.

A semiconductor light emitting element can be used as a light source of the light beam, and a resonance type galvano mirror manufactured by a semiconductor manufacturing process can be used as a first scanning mirror. Thus, the size and cost of the device can be reduced.

Further, in order to solve the above-mentioned problem, a light beam emission preventing method according to the present invention comprises a scanning means including a scanning mirror capable of controlling a posture, and scans a light beam with the scanning means to project an image. In a projection display device formed on a body, a light beam emission prevention method for preventing the light beam from being emitted out of the projection display device in a beam state when necessary, wherein the attitude controllable scanning mirror is provided when necessary Is controlled to a predetermined posture to prevent the light beam from being emitted out of the projection display device in a beam state. In the light beam emission prevention method, various more specific modes are possible in accordance with the more specific modes of the projection display device.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In one embodiment of the present invention,
Provide a light absorbing portion inside the projection display device, when abnormal, for example, when scanning is stopped by stopping the horizontal scanning mirror,
The light beam from there is irradiated to the light absorbing section by controlling the vertical scanning mirror, which is a normal galvano mirror capable of controlling the attitude with a current, to a predetermined attitude, and is absorbed inside the projection display device, and is emitted to the outside. Prevent emission of light beam. The vertical scanning mirror has a large mirror size (typically 1 cm or more) because it needs to receive the light beam scanned horizontally by the horizontal scanning mirror, and is large enough to block or receive the abnormally stopped light beam. With. Further, since the operating frequency is low (typically 100 Hz or less), angle control is easy.

The light absorbing portion is formed by matte black coating or the like. It is also possible to use a diffused surface of a ground glass or the like whose surface is roughly polished. In this case, the diffused light is emitted from the projection display device, but is not in a beam state, so that the danger is small.

As the horizontal scanning mirror, a micromirror manufactured by a semiconductor manufacturing process in which a Si substrate is patterned and etched to form a mirror is used. The resonance type galvanometer mirror, which is such a micromirror, resonates with a small drive signal having a resonance frequency and vibrates at high speed. Normally, the displacement by DC drive is small, and it is not possible to control the attitude to an arbitrary angle. An example of a micromirror is described in the “Silicon Microoptical Scanner” in the Journal of the Japan Society of Applied Physics, Micro-Optical Research Group, Vol. 14, No. 3, pages 13-17. Such a micromirror has an angle detection function using a detection coil for the stability of driving the mirror, and can be used for detecting the stop of scanning. For detecting the stop of scanning, it is also possible to use a signal used to establish a drawing timing of a beam modulated based on image data. This signal is generated by a light receiving element installed near the end of the scanning range of the light beam.

The operation of blocking or reflecting the light beam by the vertical scanning mirror is performed by the scanning control unit of the display device based on the above detection signal. A predetermined current is applied to the electromagnetic coil for driving the mirror to bring the vertical scanning mirror into a predetermined angle posture, or a predetermined current is applied to an electromagnetic coil different from the electromagnetic coil used for mirror driving at normal time to set the vertical scanning mirror to a predetermined position. Angle posture.

As the light source, a semiconductor laser or a light emitting diode can be used. Any light source can be used as long as it can emit a highly directional light flux having a somewhat high light intensity in a small cross section. The beam modulated based on the image data may be created by directly modulating the light source based on the image data, or the unmodulated beam emitted from the light source may be modulated by an external modulator based on the image data. May be created.

As the vertical scanning mirror, a normal galvanometer mirror (oscillating one-sided mirror) whose attitude can be controlled is used. If a small stepping motor is used as the driving unit, the size can be reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, more specific embodiments will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a view showing a first embodiment of the projection display apparatus of the present invention. The projection display apparatus includes a light source 101, a horizontal scanning mirror 102, a vertical scanning mirror 103 having a relatively large size whose attitude can be controlled, a light absorbing portion 104 formed on the back surface of the mirror 103, and a projection for housing these elements. It has a housing 105 of the type display device. Here, only the components necessary for describing the present invention are described. FIG. 1A shows a state in which the horizontal scanning mirror 102 normally deflects and scans a beam, and FIG.
This shows a state where scanning is stopped for some reason. In FIG. 1 (a), the shaded area indicates the deflection of the light beam.
The state of scanning is shown.

In this embodiment, a light absorbing portion 104 is provided on the back surface of the mirror surface of the vertical scanning mirror 103, and when the emission of the light beam is stopped, the vertical scanning mirror 103 is rotated from the normal state by 90 degrees or more. The absorber 103 is directed toward the horizontal scanning mirror 102, and receives and absorbs a light beam from the mirror. The rotation angle may be such that the light absorbing unit 103 hits the light beam. About 90 to 270 degrees is appropriate. The stop of the scanning of the horizontal scanning mirror 102 is detected by a detection coil used for driving stability of the mirror or by a light receiving element installed near an end of a scanning range of the light beam. In the latter case, it is sufficient to detect that no light comes to the light receiving element within a predetermined time. Based on this detection, the control unit sends a drive signal to the scanning system of the vertical scanning mirror 103 to rotate the mirror by 90 degrees or more.

In this embodiment, since the light beam is absorbed by the vertical scanning mirror itself, it is not necessary to set the angle of the vertical scanning mirror 103 at the time of shading. Therefore, a predetermined current is supplied to the mirror driving electromagnetic coil to bring the vertical scanning mirror 103 into a predetermined angle posture, or a predetermined current is supplied to an electromagnetic coil different from the electromagnetic coil used for mirror driving in a normal state to perform vertical scanning. The mirror 103 may be set to a predetermined angle posture.
In this case, it is not suitable to use a small stepping motor as the driving unit.

In the present embodiment, the light absorption unit 103 is directed to the horizontal scanning mirror 102 side when the scanning of the horizontal scanning mirror 102 is stopped. However, the abnormality is not limited to this. May be entered. This can be detected by a pyroelectric infrared sensor or the like, and a detection signal is input to the control unit, and a drive signal is sent to the scanning system of the vertical scanning mirror 103 to rotate the mirror about 180 degrees. Furthermore, when it is necessary to prevent the light beam from being emitted for some reason, the operator of the apparatus manually operates the vertical scanning mirror 10.
It is also possible to operate the scanning control unit 3 to rotate the mirror by about 90 degrees or more.

The control unit includes a CPU, a RAM, a ROM in which a program for controlling the entire display device is stored, and the like. The control unit performs various controls and image data processing, modulates the beam based on the processed image data, and causes the scanning system to scan the beam two-dimensionally in synchronization with the timing, thereby displaying the image on the screen. Project.

In this embodiment, the light absorbing section 104 may be replaced with a light diffusing section. As a result, the light beam is diffused and goes out of the housing 105 when necessary, for example, when an abnormality occurs.

(Second Embodiment) FIG. 2 is a diagram showing a second embodiment of the projection display apparatus of the present invention. The components are the same as in the first embodiment. The difference is that the light absorbing unit 201 is mounted inside the housing 105. FIG. 2A shows a horizontal scanning mirror 1.
02 indicates the state when beam deflection and scanning are normal,
FIG. 2B shows a state where the beam is guided to the light absorbing unit 201. In FIG. 2A, the shaded area shows how the light beam is deflected and scanned.

In this embodiment, when the light absorbing unit 201 is mounted inside the housing 105 of the projection display device and the light emission is stopped, the light beam reflected by the vertical scanning mirror 103 impinges on the light absorbing unit 201. The angle of the vertical scanning mirror 103 is controlled as described above. The angle of the mirror 103 at the time of stopping the injection is set in the scanning control unit in advance. This may be performed in the same manner as in the first embodiment. Since the diameter of the light beam is about 1 mm, if the size of the light absorbing section 201 is set to about 1 cm, the accuracy of this setting is not so required.

In this embodiment, when it is necessary to guide the beam to the light absorbing portion 201, it is not necessary to change the angle of the vertical scanning mirror 103 from a normal state, so that a normal galvanomirror whose attitude can be controlled is used. Is possible.

Also in this embodiment, the light absorbing section 201 may be replaced with a light diffusing section. In this case, when the inner surface of the casing 105 is rough and is used as it is as a light diffusion surface, it is not necessary to provide a special light diffusion portion.

[0034]

According to the present invention, in a projection type display device for forming an image by scanning with a light beam, a light beam is emitted from the housing of the device in a beam state when necessary, for example, when horizontal scanning is stopped. Can be prevented without adding a new bulky component. Thus,
It is possible to reduce the size and cost while maintaining the safety of the projection display device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a projection display apparatus according to the present invention.

FIG. 2 is a view showing a second embodiment of the projection display apparatus according to the present invention.

FIG. 3 is a view showing a conventional light beam scanning projection display device.

[Explanation of symbols]

 101: Light source 102: Horizontal scanning mirror 103: Vertical scanning mirror 104, 201: Light absorbing part 105: Housing 301: Red laser 302: Green laser 303: Blue laser 304, 305, 306: Dichroic mirror 307: Polygon mirror 308: Galvanometer mirrors 309, 310, 311: Light intensity modulator 312: f-θ lens 313: Screen 314: Light blocking device

Claims (22)

[Claims] 1. A projection display device comprising a scanning means including a scanning mirror capable of controlling an attitude, wherein the scanning means scans a light beam to form an image on an object to be projected. A projection display apparatus characterized in that the scanning mirror capable of controlling the attitude is controlled to a predetermined attitude in order to prevent a beam from being emitted out of the projection display apparatus in a beam state. 2. The apparatus according to claim 1, wherein the scanning unit scans the light beam in a scanning line direction, and scans the light beam in a direction perpendicular to the scanning line direction, the scanning mirror being the attitude controllable scanning mirror. 2. The projection display device according to claim 1, further comprising: a scanning mirror configured to scan the light beam two-dimensionally to form an image on the projection target. 3. The projection type display device according to claim 1, wherein the scanning mirror capable of controlling the attitude is configured to be controlled to the predetermined attitude when an abnormality occurs. 4. The scanning mirror capable of controlling the attitude, when an error occurs in the scanning system of the first scanning mirror, the abnormality is detected by a detecting means, and based on the abnormality, the scanning mirror is automatically controlled to the predetermined attitude. 4. The apparatus according to claim 3, wherein
13. The projection display device according to claim 1. 5. The scanning mirror capable of controlling the attitude, when an abnormality is detected when foreign matter enters the optical path of the light beam, the abnormality is detected by a detecting means, and based on the abnormality, the scanning mirror is automatically controlled to the predetermined attitude. The projection type display device according to claim 3, wherein the projection type display device is configured to be configured as follows. 6. The scanning mirror whose attitude can be controlled is a scanning mirror having a light absorbing portion formed on a back surface thereof. When the scanning mirror is required or abnormal, the scanning mirror is rotated by about 90 degrees or more from a normal state. 6. The projection type display device according to claim 1, wherein the light absorbing portion is configured to receive and absorb a light beam. 7. The scanning mirror whose attitude can be controlled is a scanning mirror having a light diffusing portion formed on a back surface thereof. When the scanning mirror is required or abnormal, the scanning mirror is rotated by about 90 degrees or more from a normal state. 6. The projection display device according to claim 1, wherein the light diffusion unit receives and diffuses a light beam. 8. A light absorbing portion is provided on an inner surface of a housing for housing elements of the apparatus, and the scanning mirror capable of controlling the attitude is controlled to the predetermined attitude when necessary or abnormal, and the light beam is controlled to the predetermined attitude. The projection type display device according to claim 1, wherein the projection type display device is configured to reflect the light, guide the light to the light absorbing unit, and absorb the light. 9. A light diffusion unit is provided on an inner surface of a housing for housing elements of the apparatus, and the scanning mirror capable of controlling the attitude is controlled to the predetermined attitude when necessary or abnormal when the light beam is controlled. 6. The projection type display device according to claim 1, wherein the projection type display device is configured to reflect the light and guide the light to the light diffusing unit to diffuse the light. 10. An inner surface of a housing accommodating elements of the apparatus is a rough surface, and the scanning mirror capable of controlling the attitude is controlled to the predetermined attitude when necessary or abnormal to reflect the light beam. The projection type display device according to claim 1, wherein the projection type display device is configured to be guided to the rough surface and diffused. 11. The projection type display device according to claim 1, wherein a semiconductor light emitting element is used as a light source of said light beam. 12. The projection display according to claim 2, wherein said first scanning mirror is a resonance type galvanometer mirror. 13. A projection type display device comprising scanning means including a scanning mirror capable of controlling the attitude, wherein the scanning means scans a light beam to form an image on a projection target.
A light beam emission preventing method for preventing the light beam from being emitted out of a projection display device in a beam state, wherein, when necessary, the position controllable scanning mirror is controlled to a predetermined posture to change the light beam to a beam state. A light beam emission preventing method, wherein the light beam is prevented from being emitted outside the projection display device. 14. A scanning means for scanning a light beam in a scanning line direction, and a second scanning means for scanning the light beam in a direction perpendicular to the scanning line direction which is the attitude controllable scanning mirror. 14. The light beam emission prevention method according to claim 13, further comprising the step of: scanning the light beam two-dimensionally to form an image on the projection target. 15. The light beam emission preventing method according to claim 13, wherein the scanning mirror capable of controlling the attitude is controlled to the predetermined attitude when an abnormality occurs. 16. The scanning mirror capable of controlling the attitude, when an error occurs in the scanning system of the first scanning mirror, the abnormality is detected by a detecting means, and based on the abnormality, the scanning mirror is automatically controlled to the predetermined attitude. The method for preventing light beam emission according to claim 15, wherein: 17. The scanning mirror capable of controlling the attitude, when an abnormality is detected when foreign matter enters the optical path of the light beam, the abnormality is detected by a detecting means, and based on the abnormality, the scanning mirror is automatically controlled to the predetermined attitude. The method for preventing light beam emission according to claim 15, wherein: 18. The scanning mirror whose attitude can be controlled is a scanning mirror having a light absorbing portion formed on a back surface thereof.
18. The light beam emission preventing method according to claim 13, wherein the light absorbing section receives the light beam by being rotated by more than degrees and absorbs the light beam. 19. The scanning mirror whose attitude can be controlled is a scanning mirror having a light diffusing portion formed on the back surface.
18. The light beam emission preventing method according to claim 13, wherein the light beam is rotated by more than one degree to receive and diffuse the light beam in the light diffusion unit. 20. A scanning mirror, wherein a light absorbing portion is provided on an inner surface of a housing accommodating elements of the apparatus, and the attitude controllable scanning mirror comprises:
18. The light beam emission prevention according to claim 13, wherein the light beam is reflected under the predetermined posture and guided to the light absorbing portion to absorb the light beam when necessary or abnormal. Method. 21. A light-diffusing section is provided on an inner surface of a housing for accommodating elements of the apparatus, and the scanning mirror capable of controlling the attitude is:
The light beam emission prevention according to any one of claims 13 to 17, wherein the light beam is reflected and guided to the light diffusing unit under the control of the predetermined posture when the light beam is necessary or abnormal. Method. 22. An inner surface of a housing accommodating elements of the apparatus is a rough surface, and the scanning mirror capable of controlling the attitude reflects the light beam under the predetermined attitude when necessary or abnormal. 18. The light beam emission prevention method according to claim 13, wherein the light beam is guided to the rough surface and diffused.