JP2009204903A - Scanning device and failure detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display for detecting a failure resulting from reduction in reflectivity or optical axis shifting of a mirror, and a failure detection method therefor. <P>SOLUTION: The optical scanning device includes a light source 101; an optical system including one or two or more mirrors 1, 104, which displays an image by deflecting light emitted from the light source 101; an optical sensor 106 which receives light passed through the optical system with the reflecting surface of each mirror 1, 104 being fixed at a predetermined position, and measures the intensity of the light; and a determination means 113 which compares the intensity of the light measured by the optical sensor 106 with a reference intensity and determines presence/absence of error according to the comparison result. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an optical scanning device that displays an image by deflecting light from a light source and an abnormality detection method thereof.

In recent years, development of microactuators using micromechanics technology has been active.
For example, an optical scanning device including a vibrating mirror supported to be torsionally rotated by a pair of elastic support portions (torsion bars) has been developed as a device capable of forming an image display device with a simple configuration. (See Patent Document 1).
JP 2005-169553 A

In such an optical scanning device, a decrease in the reflectance of one or more mirrors that deflect light, an optical axis shift, and the like are directly connected to a display abnormality. Therefore, when putting these optical scanning devices into practical use, it is desirable to be able to detect such abnormalities before actually displaying an image.

The present invention has been made in view of the above circumstances, and one of its purposes is to provide a display device capable of detecting an abnormality caused by a decrease in mirror reflectivity, an optical axis deviation, and the like, and an abnormality detection method thereof. There is to do.

In order to achieve the above object, an optical scanning device of the present invention includes a light source, an optical system including one or more mirrors that display an image by deflecting light emitted from the light source, and each mirror. The light sensor that receives the light that has passed through the optical system with the reflecting surface fixed at a predetermined position and measures the intensity of the light is compared with the intensity of the light measured by the light sensor and the reference intensity. And
Determining means for determining the presence or absence of an error according to the comparison result.

In the above configuration, light that has passed through the optical system is received by the optical sensor in a state where the reflecting surface of each mirror is fixed at a predetermined position, and the intensity of the light is measured. Then, the determination means compares the light intensity measured by the optical sensor with the reference intensity, and determines the presence or absence of an error according to the comparison result. For example, when there is a decrease in mirror reflectivity or an optical axis shift, the light intensity measured by the optical sensor decreases. Therefore, if the difference between the light intensity and the reference intensity is within the specified value range, it is determined that there is no error, and if the difference between the two is outside the specified value range, it is determined that there is an error.
Thereby, an abnormality is detected without actually displaying it.

The optical sensor is provided at a position different from the light emission port to the outside. This prevents light leakage to the outside during the abnormality detection process.

The camera further includes a shutter that controls opening and closing of the light emission port to the outside, and the optical sensor is provided inside the shutter. Thus, during the abnormality detection process, the optical sensor is provided at a position overlapping the light emission port, and leakage of light to the outside during the abnormality detection process is prevented.

Furthermore, in order to achieve the above object, the abnormality detection method for an optical scanning device according to the present invention is an optical scanning for displaying an image by deflecting light from a light source using an optical system including one or more mirrors. A method for detecting an abnormality of an apparatus, wherein at the time of start-up, a step of emitting light from a light source toward an optical system with a reflecting surface of each mirror fixed at a predetermined position, and light that has passed through the optical system including the mirror And a step of comparing the measured light intensity with a reference intensity and determining the presence or absence of an error according to the comparison result.

In the above configuration, the intensity of light that has passed through the optical system is measured with the reflecting surface of each mirror fixed at a predetermined position. Then, the measured light intensity is compared with the reference intensity, and the presence or absence of an error is determined according to the comparison result. For example, when there is a decrease in mirror reflectivity or an optical axis shift, the measured light intensity decreases. Therefore, if the difference between the light intensity and the reference intensity is within the allowable range, it is determined that there is no error, and if the difference between the two is outside the specified value range, it is determined that there is an error. Thereby, an abnormality is detected without actually displaying it.

In the step of emitting light, the reflecting surface of each mirror is fixed at a position where the light that has passed through the optical system is not emitted to the outside. This prevents leakage of light to the outside during the abnormality detection process.

The step of emitting light is performed in a state where the light emission port to the outside is closed by a shutter. Thereby, leakage of light to the outside during the abnormality detection process is surely prevented.

The optical scanning device includes a plurality of light sources that emit light having different wavelength bands, and the step of emitting light and the step of measuring the intensity of light are performed separately for each light source. Thereby, when there are a plurality of light sources, it is possible to detect an optical axis shift for each light source.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a plan view showing an example of a vibrating mirror used in the optical scanning device according to the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG.

The vibrating mirror 1 includes a movable plate 11, a support frame 12, and a pair of elastic support portions 13 that support the movable plate 11 with respect to the support frame 12 so as to be torsionally rotated. The movable plate 11, the support frame 12, and the elastic support portion 13 are integrally formed, for example, by etching a silicon substrate.

A reflective film 21 is formed on the movable plate 11. A magnet 22 is joined to the movable plate 11 on the side opposite to the reflective film 21. The magnet 22 is magnetized in a direction orthogonal to the axis X that is the rotation center axis of the movable plate 11 when the movable plate 11 is viewed in plan. That is, the magnet 22
Has a pair of magnetic poles of opposite polarities facing each other via the axis X. The support frame 12 is joined to the holder 20, and a coil 23 for driving the movable plate 11 is disposed on the holder 20.

In the vibrating mirror 1, a periodically changing current (alternating current) is supplied to the coil 23.
As a result, the coil 23 alternately generates a magnetic field directed upward (movable plate 11 side) and a magnetic field directed downward. As a result, one of the pair of magnetic poles of the magnet 22 approaches the coil 23 and the other magnetic pole moves away, and the movable plate 11 rotates around the X axis while twisting and deforming the elastic support portion 13. Be moved.

FIG. 1 shows a drive-type vibrating mirror using electromagnetic force between the magnet 22 and the coil 23. However, the present invention may adopt a method using electrostatic attraction or a method using piezoelectric elements. For example, in the case of a method using electrostatic attraction, the magnet 22 is unnecessary,
Instead of the coil 23, one or a plurality of electrodes facing the movable plate 11 are installed. And
By applying an alternating voltage that periodically changes between the movable plate 11 and the electrode, the movable plate 11
While the elastic support 13 is twisted and deformed by applying an electrostatic attractive force between the electrode and the electrode, the movable plate 1
1 is rotated around the X axis.

FIG. 3 is a schematic configuration diagram of an optical scanning device including the vibrating mirror 1 described above. The optical scanning device shown in FIG. 3 uses the vibrating mirror 1 shown in FIG. 1 as a horizontal mirror.

The optical scanning device illustrated in FIG. 3 includes a laser light source 101, a dichroic mirror 102, a photodiode 103, and a vertical mirror 104 in addition to the vibrating mirror 1. The optical system of the present invention includes the dichroic mirror 102, the vibrating mirror 1, and the vertical mirror 104.

The laser light source 101 includes a red laser light source 101R that emits red laser light, a blue laser light source 101B that emits blue laser light, and a green laser light source 101 that emits green laser light.
G. However, laser light sources of two colors or less or four colors or more may be used.

The dichroic mirror 102 includes a dichroic mirror 102R that reflects red laser light from the red laser light source 101R, a dichroic mirror 102B that reflects blue laser light and transmits red laser light, and reflects green laser light and blue laser light and red. A dichroic mirror 102G that transmits laser light. By these three kinds of dichroic mirrors 102, the combined light of the red laser light, the blue laser light, and the green laser light is converted into the vibrating mirror 1
Is incident on.

The photodiode 103 detects the amounts of red laser light, green laser light, and blue laser light that are transmitted without being reflected by the dichroic mirrors 102R, 102G, and 102B.

The vibrating mirror 1 scans the laser beam sent from the dichroic mirror 102 in the horizontal direction (the vertical direction of the axis X). As described above, the vibrating mirror 1 is a resonant mirror formed by MEMS.

The vertical mirror 104 scans the laser beam reflected by the vibration mirror 1 in the vertical direction.
The vertical mirror 104 is configured by a galvanometer mirror, for example. A galvanometer mirror is a deflector in which a mirror is provided with an axis so that the rotation angle of the mirror can be changed according to an electric signal. An image is displayed by horizontal scanning of the laser beam by the vibrating mirror 1 and vertical scanning of the laser beam by the vertical mirror 104.

The optical scanning apparatus according to the present embodiment further includes a laser driving unit 110 that drives the laser light source 101 as a drive control system for the laser light source 101, the vibrating mirror 1, and the vertical mirror 104.
A horizontal mirror driving unit 111 that drives the vibrating mirror 1 as a horizontal mirror, a vertical mirror driving unit 112 that drives the vertical mirror 104, and a control unit 11 that controls the overall operation.
3 and storage means 114.

The storage unit 114 includes, for example, a ROM that stores various programs, a RAM that stores variables, and the like, and a nonvolatile memory. In the present embodiment, the storage unit 114 holds a reference strength described later.

The control means 113 is based on image information sent from various video sources 115 such as a personal computer or a mobile phone, and displays these images by means of a laser drive means 110, a horizontal mirror drive means 111, a vertical mirror drive means. The operation of 112 is controlled. Moreover, the control means 113 performs the abnormality detection process mentioned later at the time of starting.

FIG. 4 is a schematic configuration diagram illustrating an abnormality detection mechanism of the optical scanning device.
As shown in FIG. 4, a housing 1 that houses an optical system including a vibrating mirror 1 and a vertical mirror 104.
An optical sensor 106 is installed inside 05.

The optical sensor 106 is provided at a position different from the light emission port 107 provided in the housing 105, in other words, a position that does not overlap the light emission port 107. The optical sensor 106 is made of a photodiode, for example. As the optical sensor 106, it is preferable to use a photodiode having sensitivity in all the wavelength bands of RGB. Thereby, the abnormality detection process of all the RGB laser light sources 101 can be performed using one optical sensor 106.

The vibrating mirror 1 is fixed at the reference position during the abnormality detection process. This reference position is the position of the oscillating mirror 1 when the elastic support portion 13 does not cause torsional vibration.

As shown by the dotted line in the drawing, the vertical mirror 104 is placed at a predetermined position, in other words, the reflection surface has a predetermined angle so that the light reflected by the vertical mirror 104 is coupled to the optical sensor 106, as indicated by a dotted line in the drawing. Fixed to. Note that, during normal operation, the vertical mirror 104 reflects light toward the light exit 107 as indicated by a solid line in the drawing.

The control unit 113 executes the process of the determination unit of the present invention. Based on the output from the optical sensor 106, the control unit 113 detects the presence / absence of an abnormality such as a decrease in reflectance of the vibrating mirror 1 and the vertical mirror 104 and an optical axis shift.

Next, an abnormality detection method for the optical scanning device according to the present embodiment will be described with reference to the flowchart of FIG. In the present embodiment, the processing shown in FIG. 5 is performed separately for each of the RGB laser light sources 101R, 101G, and 101B when the optical scanning device is activated.

First, the control unit 113 controls the driving units 111 and 112 to fix the oscillating mirror 1 at the reference position and fix the vertical mirror 104 at a predetermined position (step ST1). The angle of the reflecting surface of each mirror in the abnormality detection process is as described with reference to FIG.

Next, the control means 113 drives one of the three laser light sources 101R, 101G, and 101B to emit laser light. As a result, the laser light emitted from the laser light source 101 is reflected by the vibrating mirror 1 and the vertical mirror 104, and the optical sensor 10.
6 and the light intensity is measured by the optical sensor 106 (step ST2). The control means 113 inputs a signal corresponding to the light intensity received from the optical sensor 106.

Next, the control means 113 uses the reference intensity previously stored in the storage means 114 and the optical sensor 10.
6 is compared to determine whether or not the difference between the two is within a specified value range (step ST3). Here, the reference intensity indicates the light intensity when the laser is incident on the optical sensor 106 under the same conditions in the initial optical scanning device.

When the reflectivity of the vibrating mirror 1 or the vertical mirror 104 decreases, the intensity of light measured by the optical sensor 106 decreases. Even when the optical axis shift of the laser light source occurs, the intensity of light measured by the optical sensor 106 becomes small. Therefore, if the difference between the measured light intensity and the reference intensity is outside the specified value range, an error determination is made on the assumption that there is an abnormality due to a decrease in reflectivity or an optical axis deviation (step) ST4). If an error determination is made, the operation of the optical scanning device is stopped. In addition, the user is notified of the error using means such as an alarm, blinking of a lamp, and writing to a display area.

If the difference between the two light intensities is within the specified value range, a normal display operation is started (step S).
T5). However, as in this embodiment, the three laser light sources 101R, 101G, and 101B are used.
If all the laser light sources are processed and it is determined that there is no abnormality, the normal display operation is started.

As described above, according to the optical scanning device according to the present embodiment, the vibrating mirror 1 is activated at the time of activation.
Further, by measuring the intensity of the light reflected by the vertical mirror 104, it is possible to detect an abnormality such as a decrease in the reflectivity of the mirror and an optical axis shift.

In addition, an optical sensor 106 for measuring the intensity of light is provided at a position that does not overlap the light emission port 107, and the light is reflected toward the optical sensor 106 by the vibrating mirror 1 and the vertical mirror 104, thereby performing abnormality detection processing. In some cases, it is possible to prevent light from leaking from the light exit 107 to the outside. This is because, in a state where each mirror is fixed, laser light having a high light intensity is irradiated toward one point, and it is preferable not to emit the laser light at this time to the outside from the viewpoint of safety.

(Second Embodiment)
FIG. 6 is a diagram illustrating an abnormality detection mechanism of the optical scanning device according to the second embodiment.

The optical scanning device according to the present embodiment includes a shutter 108 that can open and close the light emission port 107, and shutter driving means 116 that drives the shutter 108.

In the present embodiment, the light exit 107 is closed by the shutter 108 during the abnormality detection process. That is, before moving to step ST1 in FIG. 5, the control unit 113 controls the shutter driving unit 116 to close or keep the shutter 108 closed. Other basic abnormality detection processing steps are the same as those in the first embodiment.

According to the present embodiment, even when stray light other than the reflected light (indicated by the dotted line in the figure) assumed by the positions of the reflecting surfaces of the oscillating mirror 1 and the vertical mirror 104 is generated, these lights are reliably detected. Thus, it is possible to reliably prevent light from leaking from the light emission port 107 to the outside during the abnormality detection process. Therefore, safety can be improved as compared with the first embodiment.

(Third embodiment)
FIG. 7 is a diagram illustrating an abnormality detection mechanism of the optical scanning device according to the third embodiment.

The optical scanning device according to the present embodiment includes a shutter 108 that can open and close the light emission port 107, and shutter driving means 116 that drives the shutter 108, and an optical sensor 106 is provided inside the shutter 108. It is what.

In the present embodiment, during the abnormality detection process, the shutter 108 is the same as in the second embodiment.
Thus, the light emission port 107 is closed. In addition, in step ST1 of the abnormality detection process, the reflection surface of the vertical mirror 104 is fixed so that the reflected light from the vertical mirror 104 is coupled to the optical sensor 106. Other basic abnormality detection processing steps are the same as those in the first embodiment.

According to the present embodiment, even when the optical sensor 106 is provided at a position overlapping the light emission port 107, the abnormality detection process can be executed while preventing leakage of laser light to the outside.
As described above, by using the shutter, it is possible to eliminate restrictions on the arrangement of the optical sensor 106.

The present invention is not limited to the description of the above embodiment.
For example, the structure of the vibrating mirror 1 is not limited. For example, the movable plate 11 may be a polygon other than a circle. In the present embodiment, the vibration mirror 1 of a type that is driven with one-dimensional one-degree-of-freedom is illustrated, but a vibration mirror of a type that is driven two-dimensionally may be used, and it is driven with one-dimensional two-degree-of-freedom. It may be a type of vibrating mirror. When a two-dimensional driving type oscillating mirror is used, the vertical mirror 104 is not necessary.
In addition, various modifications can be made without departing from the scope of the present invention.

It is a top view of a vibration mirror. It is sectional drawing of a vibration mirror. It is a schematic block diagram of an optical scanning device. It is a block diagram which shows the abnormality detection mechanism of an optical scanning device. It is a flowchart of the abnormality detection process at the time of starting of an optical scanning device. It is a block diagram which shows the abnormality detection mechanism of the optical scanning device which concerns on 2nd Embodiment. It is a block diagram which shows the abnormality detection mechanism of the optical scanning device which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vibration mirror, 11 ... Movable plate, 12 ... Support frame, 13 ... Elastic support part, 20 ... Holder, 2
DESCRIPTION OF SYMBOLS 1 ... Reflective film, 22 ... Magnet, 23 ... Coil, 101 ... Laser light source, 101R ... Red laser light source, 101G ... Green laser light source, 101B ... Blue laser light source, 102, 102R, 102
G, 102B ... Dichroic mirror, 103, 103R, 103G, 103B ... Photodiode, 104 ... Vertical mirror, 105 ... Housing, 106 ... Optical sensor, 107 ... Light exit, 108 ... Shutter, 110 ... Laser drive means, 111 ... Horizontal mirror driving means, 112
... vertical mirror driving means, 113 ... control means, 114 ... storage means, 115 ... video source, 1
16 ... Shutter drive means

Claims (7)

A light source;
An optical system including one or more mirrors for displaying an image by deflecting light emitted from the light source;
Receiving light that has passed through the optical system with the reflecting surface of each mirror fixed in place,
An optical sensor for measuring the intensity of the light;
A determination unit that compares the intensity of light measured by the optical sensor with a reference intensity and determines the presence or absence of an error according to the comparison result;
An optical scanning device. The optical sensor is provided at a position different from the light exit to the outside.
The optical scanning device according to claim 1. It further has a shutter that controls the opening and closing of the light outlet to the outside,
The photosensor is provided inside the shutter,
The optical scanning device according to claim 1. An abnormality detection method for an optical scanning device that displays an image by deflecting light from a light source using an optical system including one or more mirrors,
A step of emitting light from the light source toward the optical system in a state where the reflecting surface of each mirror is fixed at a predetermined position at the time of startup;
Measuring the intensity of light that has passed through the optical system including the mirror;
Comparing the measured light intensity with a reference intensity and determining the presence or absence of an error according to the comparison result;
An abnormality detection method for an optical scanning device having In the step of emitting the light, the reflecting surface of each mirror is fixed at a position where the light that has passed through the optical system is not emitted to the outside.
The method for detecting an abnormality of the optical scanning device according to claim 4. The step of emitting the light is performed in a state where the light emission port to the outside is closed by a shutter.
The method for detecting an abnormality of the optical scanning device according to claim 4. The optical scanning device has a plurality of light sources that emit light of different wavelength bands,
The step of emitting the light and the step of measuring the intensity of the light are performed separately for each light source.
The method for detecting an abnormality of the optical scanning device according to claim 4.

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