JP4460384B2 - Laser projector - Google Patents

Description

  The present invention relates to a laser projector that presents visual information composed of characters and images on an object in the field of view of an observer.

There is a see through head mounted display (hereinafter referred to as an HMD) as an apparatus that can be visually recognized by an observer by overlapping visual information of characters and images with an object. This HMD is literally attached to the observer's head as an example, and projects visual information at a specific depth position in front of the object so that it can be visually recognized by the observer's eyes.
The HMD is also a device that realizes augmented reality technology as a display means based on ubiquitous computing that has been attracting attention recently, and can be noted as a device that can present visual information as ubiquitous information anytime and anywhere.

However, when visual information and an object are visually recognized using the HMD, the visual information or the object is simultaneously viewed because at least one of the visual information and the object is viewed when the observer visually recognizes the visual information and the object. I can't see it clearly. That is, in the conventional HMD, strictly, only a single target can be visually recognized at each time point, and the fact that the observer must frequently change the focus is a heavy burden during observation.
As a method for solving such a problem, there are techniques shown in Patent Documents 1 and 2 in which visual information is projected onto an object itself. In Patent Document 1, when an observer is diagnosed or cared for by a robot instead of an operator, the observer who is diagnosed or cared for wears the HMD and projects the operator's visual information onto the robot. It is disclosed that the sense of incongruity is eliminated, and in Patent Document 2, the real object is concealed by a shielding material, so that the real object and the virtual object that is visual information are correctly shielded to present a highly realistic virtual space. Is disclosed. However, the techniques shown in Patent Documents 1 and 2 do not provide brightness that can be visually recognized by an observer due to scattering of projection light on the object, etc., so that retroreflection that reflects only the incident direction on the object is possible. A material has to be applied, and it is generally impossible to apply a retroreflective material to this object, especially when it can be applied to the object.

Therefore, there is a demand for an HMD that projects visual information onto an object without frequently changing the focus of the observer and does not apply a retroreflecting material on the object.
On the other hand, although it is not an HMD, Non-Patent Document 1 irradiates a surgical site of a patient by scanning with laser light as a device that projects visual information onto an object and does not apply a retroreflective material onto the object. For example, a laser projection technique is disclosed in which a surgical site is trimmed with laser light and the site is clearly indicated to an observer. However, in this case, the direction of the observer's line of sight does not coincide with the direction of laser light irradiation, so if there is a surgical part inside, the observer's viewpoint position and the three-dimensional shape and position of the surgical part are measured. Therefore, it is necessary to change the projection of the laser light in real time. Considering the burden and cost of arithmetic processing based on this three-dimensional measurement, this laser projection technology is in a situation where it is unavoidable to be an expensive product with a complicated apparatus configuration.
JP 2000-218575 A JP 2000-122176 A ND Glossop, Z.Wang; Laser projection augmented reality system for computer assisted surgery, International Congress Series 1256, pp65-71, Elsevier Science (2003)

As described above, the laser projection technique shown in Non-Patent Document 1 has a problem in that the apparatus configuration related to the arithmetic processing becomes complicated and the apparatus becomes expensive, and this problem is minimized. In order to solve the problem, it is necessary that the direction of the observer's line of sight coincides with the irradiation direction of the laser beam. On the other hand, even if the direction of the observer's line of sight and the irradiation direction of the projection light can coincide with each other as in the case of the HMD, in order to frequently perform the focus changing operation by the observer and visually recognize the visual information as the display means Requires application of a retroreflecting material to the object.
The present invention has been invented in view of the above-mentioned problems, and after making the direction of the observer's line of sight coincide with the irradiation direction of the laser light, performing the focus changing operation by the observer and the object. It is an object of the present invention to provide a laser projector that forms visible visual information on an object without applying a retroreflecting material.

  In order to achieve the above object, the present invention provides a laser that draws on an object by scanning a laser beam from a laser light source with an optical scanning unit and swinging the emission direction of the laser beam horizontally and vertically. The projector includes a coupling unit that places the center position of the scanning of the laser beam in the optical scanning unit and the viewpoint position at a conjugate position so that the emission direction of the laser beam from the optical scanning unit matches the direction of the line of sight. Features.

  According to the present invention, it is possible to perform high-intensity rendering of visual information on an object by scanning laser light from a laser light source, and it is as if this laser light is emitted from the observer's viewpoint. With this configuration, it is possible to form an overlay drawing of visual information visible on the object without performing a focus changing operation by the observer and without applying a retroreflecting material to the object.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
FIG. 1 is a block diagram of a laser projector according to a first embodiment of the present invention. In FIG. 1, a laser light source 1 is a small laser light source that emits visible light. Laser light (laser beam) from the laser light source 1 is incident on an optical scanning body 3 such as a galvanometer mirror constituting a part of the optical scanning unit 2. The optical scanning body 3 is driven in a horizontal direction or a vertical direction by a horizontal scanning motor (referred to as a first motor) 4 and a vertical scanning motor (referred to as a second motor) 5 so that incident laser light is horizontally and vertically driven. The rotation is controlled so as to scan in the direction. The laser beam scanned by the optical scanning body 3 is reflected by a coupling portion 6 such as a half mirror, for example, and is applied to an object (not shown). Here, the coupling unit 6 matches the observer's line of sight with the laser beam so that the scanning center of the optical scanning body 3 and the observer's viewpoint 7 are at the same distance from the coupling unit 6. That is, they are arranged so as to be conjugate. Accordingly, the laser light scanned by the optical scanning body 3 behaves as if it is emitted from the viewpoint 7 of the observer, and an overlay image based on the scanning of the laser light can be obtained on the object.

  The oscillation control of the laser light source 1 and the drive control of the first motor 4 and the second motor 5 are based on image information in the image memory 8, for example. In other words, an image memory 8 (image information that is visual information projected on an object) stored therein (which can be identified with a computer memory in ubiquitous computing) is connected to the readout processing unit 9. The readout processing unit 9 generates a pixel signal so as to control the beam spot of the laser light source 1 corresponding to the pixel based on the readout of the image information, and a control signal to the scanning unit 2 synchronized with the readout of the image information. Is generated. Although the digital system including the image memory 8 and the readout processing unit 9 is shown here, it is possible to generate an analog pixel signal and a synchronization control signal to the scanning unit 2.

In FIG. 1, the readout processing unit 9 is connected to the laser control unit 10, and the laser control unit 10 obtains a laser drive control signal based on the pixel signal from the readout processing unit 9. Further, the laser control unit 10 is connected to the laser light source 1 and controls the oscillation of the laser light source 1 by a laser drive control signal. In this way, the laser light source 1 emits laser light (laser spot) corresponding to the pixel in synchronization with reading of the image information recorded in the image memory 8.
On the other hand, the read processing unit 9 is in the scanning unit 2 and is connected to the scan control unit 12. The scan control unit 12 generates drive control signals for controlling the first motor 4 in the horizontal direction and the second motor 5 in the vertical direction in synchronization with the reading of one frame of image information in the image memory 8. That is, the drive control signal is generated in synchronization with the reading of the image information by the first motor 4 so as to swing the optical scanning body 3 in the horizontal direction, and the optical scanning body 3 is swung in the vertical direction. The second motor 5 is generated in synchronization with the reading of the image information. As a result, laser light emitted from a position conjugate with the observer's viewpoint is imaged as a beam spot on the surface of the object, which is a screen, and the visual information is overlaid on the object by scanning it at high speed. Present as an image. Therefore, an overlay image, which is visual information, is drawn on the object after matching the direction of the observer's line of sight and the direction of emission of the laser beam. Objects and overlay images can be visually recognized. Furthermore, since the overlay image is irradiated and projected as a laser beam spot on the object, the observer can also visually recognize the overlay image not only to the viewer but also to the person who sees the object nearby.

  Here, when the overlay image is presented on the object, the brightness of the overlay image can be high as follows. The drive control signal for controlling the first motor 4 and the second motor 5 is a drive control signal for swinging the optical scanning body 3 limited to a scanning range greatly reduced from the entire scanning range of the optical scanning body 3. Yes, an image in a limited scanning range is projected onto the object. In general, in the case of a point light source, it is well known that the brightness of an image on an object becomes 1/4 when the distance from the point light source to the object is doubled. Therefore, an overlay image can be obtained on the object with high luminance.

  Furthermore, a high-intensity image can be obtained on the object by the scanning method using the optical scanning body 3. That is, as shown in FIG. 1B, the scan control unit 12 includes a raster scanning unit 121 and a vector scanning unit 122, which are connected to the first motor 4 and the second motor 5, respectively. The first motor 4 and the second motor 5 are scan-controlled based on a scan or a vector scan. Specifically, in a television receiver that performs interlaced scanning at 1/30 second per frame, a beam of one pixel is generally used to scan all pixels in one frame by so-called raster scanning and scan the entire screen uniformly. The irradiation time is short, so the screen as a whole tends to be a dark screen, but in the so-called vector scan, the beam is moved at high speed only in a bright area and only this area is scanned repeatedly to increase the beam irradiation time only in that area. Thus, high brightness can be obtained. The scanning method can be selected by a switching circuit (not shown) built in the scan control unit 12. Thus, by utilizing the difference in the scanning method, these methods are switched according to the area to be scanned. For example, a vector scan is used for moving the scanning range limited to the entire scanning range of the optical scanning body 3. By performing raster scanning for image scanning within a limited scanning range, higher brightness of the overlay image can be achieved. Note that when a rough image is presented in a limited scanning range, higher brightness can be obtained by performing vector scanning.

In this way, the observer can view the overlay image projected on the surface of the object by focusing on the object at the same time as the object regardless of the position and depth of the object. For example, even if there is a step on the surface of the object, the projected image can be viewed as a continuous pattern without interruption, and by using a laser beam, vector scanning with movement is possible. A high-intensity image in a limited scanning range can be obtained by selecting raster scanning for image scanning.
In addition, handling an image of this limited scanning range is in line with augmented reality application technology in ubiquitous computing. In other words, in the presentation of overlay images on an object with ubiquitous information, the emphasis will be on viewing the object in the real field of view, so an overlay image that actually covers the entire field of view is projected. It is not necessary to do so, but rather it is important that a small amount of image information is presented stably at an accurate position on the object in the field of view. Therefore, instead of laser projection projection that covers a large field of view, it is sufficient to present the necessary image information by sequentially scanning a plurality of small areas individually, and the wattage of the laser spot light quantity is relatively small. It will be suppressed. This makes it possible to avoid a shortage of light intensity in laser projection, which has been a problem in the past.
[Second Embodiment]
FIG. 2 is a block diagram showing a second embodiment of the present invention. In FIG. 2, the same parts as those in FIG. That is, the laser light from the laser light source 1 is scanned by the optical scanning body 3 that is driven in the horizontal direction and the vertical direction by the first motor 4 and the second motor 5, and is connected to the observer's line of sight 6. The object is folded and irradiated at. In the present embodiment, the photodetector 13 is provided at a position conjugate with the laser light source 1 with respect to the scanning center of the optical scanning body 3. That is, a half mirror 14 is placed between the laser light source 1 and the optical scanning body 3, the laser light from the laser light source 1 is guided to the optical scanning body 3 by the half mirror 14, and the beam of the object is passed through the coupling unit 6. On the other hand, when the scattered light from the beam spot on the object goes backward while the spot is imaged, it passes through the half mirror 14 via the coupling unit 6 and the optical scanning body 3 and is projected onto the object by the photodetector 13. The scattered light of the beam spot is detected.

In the light detection by the photodetector 13, for example, when it has light propagation information that can be modulated by the object itself, this light propagation information is put on the scattered light returning from the optical path by irradiating the object with laser light. Then, the information can be detected by the photodetector 13, and information transmission from the object can be performed.
Therefore, by connecting the detection processing unit 15 to the photodetector 13 and connecting the display 16 to the detection processing unit 15 as shown in FIG. 2, it is possible to display the light propagation information from the object. Become. In this case, the detection processing unit 15 includes, for example, a demodulator when the object itself is a signal source that emits modulated light or outputs active light propagation information accompanied by a modulated reflectance change. This is a signal processing unit 151. On the other hand, information transmission from the object may be so-called passive change information by laser light such as state information of the object itself. In this case, the detection processing unit 15 is also a mere signal conversion unit, for example.

  In addition, as a method of using the photodetector 13, it is possible to measure the position of the laser light projection area on the object or the location of the light propagation information of the object. That is, by detecting the scanning position of the optical scanning body 3 in a state where the scattered light of the laser light projected on the object is detected by the return light detector 13, this scanning position of the laser light is detected. Based on this, the above-described position measurement can be performed. Therefore, the detection processing unit 15 has a measuring unit 152. The measuring unit 152 extracts the drive control signals of the first motor 4 and the second motor 5 based on the light detection from the photodetector 13, and uses the drive control signal. The scanning angle can be determined and the position can be measured.

Although not mentioned in the first embodiment, when specifying a limited scanning range on the object within the entire scannable range by the optical scanning body 3 of the scanning unit 2, for example, the full scannable range. A raster scan scan is performed, and a tag of ubiquitous information as an object is detected by the photodetector 13, and a vector scan is performed by moving a limited scan range on the identified object. It is possible to specify a scanning range and select a scanning method in which raster scanning is performed in the scanning range. Of course, without using the photodetector 13, the observer can input the position of the object in advance as position information, for example, to the scan control unit 12, or store the position information in advance by another method.
[Third Embodiment]
3 and 4 are blocks showing a third embodiment of the present invention. In the example shown in FIG. 1 and FIG. 2, the visual information is imaged using the object as a screen. Therefore, this visual information can be visually recognized in addition to the observer. In this embodiment, An example is shown in some cases where visual information may be concealed except for the observer. 3 and 4, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. In FIG. 3, two laser light sources 1a and 1b are provided, and a half mirror 14 is provided so as to multiplex the laser beams from the laser light sources 1a and 1b. Then, the laser light reflected or transmitted by the half mirror 14 is incident on the optical scanning body 3 scanned by the first motor 4 and the second motor 5, deflected, and observed through the coupling portion 6. The object is irradiated so as to be emitted from the viewpoint 7 of the person. Here, the two laser light sources 1a and 1b are connected to an image signal source 17. The image signal source 17 generates, for example, a positive image and a negative image from image information, and the positive image and the negative image are different. The laser light sources 1a and 1b are controlled. Further, polarizing plates 18a and 18b are provided between the laser light sources 1a and 1b and the half mirror 14, and the polarizing plates 18a and 18b are polarizing plates orthogonal to each other. As a result, the laser spots from the laser light sources 1a and 1b controlled by the image signal source 17 are scanned by the optical scanning body 3 and imaged on the object, but the lasers of the laser light sources 1a and 1b are used. Since the spot is in a relationship between positive and negative, the overlay image on the object is only a bright area having no characteristics combining the positive and negative. In this case, by disposing the same polarizing plate 19 as the polarizing plate 18a or 18b between the coupling portion 6 and the viewpoint 7 of the observer, the observer can view only the positive or negative image associated with one polarized light. Can do.

In FIG. 3, image information presented on an object using a polarizing plate is selectively visible and can be concealed. In the example shown in FIG. 4, the negative image and the positive image are shifted in time instead of polarized light, and so-called time-division modulation is applied to conceal the presented image for the observer. That is, as shown in FIG. 4, a single laser light source 1 is provided, and an image signal source 17 for generating a negative image and a positive image is connected to the laser light source 1. A switching element 20 is interposed between the image signal source 17 and the laser light source 1, and a positive image and a negative image are separated by the switching element 20. In the separation, switching control of the switching element 20 is performed by the switching signal generation unit 22 connected to the image signal source 17. The switching control of both positive and negative image signals by the switching element 20 can be performed by so-called time-division modulation by switching for each pixel or switching at a longer timing cycle. Therefore, the laser spot from the laser light source 1 is periodically composed of a negative image and a positive image, and as a result, the image presented on the object becomes a bright area without features. On the other hand, for example, a liquid crystal shutter 21 is interposed between the coupling unit 6 and the viewpoint 7 of the observer. The shutter 21 is connected to and controlled by the switching signal generation unit 22 and is synchronized with the switching element 20. By the on / off control, the observer can visually recognize only the positive image or the negative image.
[Fourth Embodiment]
In the above description, in order to behave so that the laser beam from the laser light source 1 is emitted from the observer's viewpoint at the coupling unit 6, the laser projector of the present invention is configured to be mounted on the observer's head. Is the most appropriate. FIG. 5 shows an external appearance of an example including the laser light sources 1a and 1b and the polarizing plates 18a and 18b shown in FIG. That is, in FIG. 5, a unit main body 51 is attached to the central portion of the bracket 50 to be attached to the observer's head, and the unit main body 51 exemplified for this FIG. 3 is similar to FIG. Laser light sources (laser diode units) 1a and 1b are attached at right angles to each other, and the first motor 4 and the second motor 5 of the optical scanning unit 2 are further attached. Then, the laser light is emitted from the lower side of the unit main body 51 of FIG. 5 toward the front.

    In the present embodiment, the projector mounted on the observer's head is exemplified by a structure that suppresses the disturbing movement of the projected image on the object as the observer suddenly turns the head left and right or up and down. . FIG. 6 shows an experiment in which a bracket 50 is attached to the observer's head, and a screen 23 is installed as an object at a position 2.8 m away from the observer's viewpoint. FIG. As the visual information from the laser light source as shown, the overlay image of the Landolt ring 24 is presented on the basis of the fixed point of + mark, and the movement of the overlay image when the observer's head is rotated left and right in this state ( Motion blur (fluctuation of image due to movement) is schematically illustrated. Originally, the alignment of the overlay image and the object on which it is presented within the field of view is important. To prevent this alignment from shifting due to the rotation of the head, the rotation of the head is canceled ( It is required to change the projection position at high speed so as to compensate. However, when this change operation is performed, if the change operation is performed only when updating to another image in units of frames, which is the display unit of the image, a time lag of several tens of ms or more has occurred. There is a phenomenon that the image fluctuates in an unstable manner, for example, the Landolt ring 24 in FIG.

  In this fourth embodiment, as shown in FIG. 7, angular velocity sensors 25 and 26 such as gyros that detect left and right and upper and lower head rotations are attached to the observer, and these angular velocity sensors 25 and 26 are set to -1/2. Connected to the calculator 27, the scanning speed of the first motor 4 or the second motor 5 of the optical scanning body 3 is controlled. That is, the angular velocity of the head is detected by the angular velocity sensors 25, 26, a speed amount of −½ of the angular speed is calculated by the −½ calculator 27, and this speed amount is calculated by the optical scanning body 3. The scanning speed is reduced or increased by adding to the speed of the first motor 4 or the second motor 5. For the speed amount of -1/2,-means the direction opposite to the rotation direction of the head, and 1/2 indicates the change in the direction of light with respect to the rotation angle of the optical scanning body 3 is doubled. It is based on that. By adding this speed to the scanning target speed of the optical scanning body 3 and controlling the first motor 4 and the second motor 5, it is possible to cancel out these fluctuations continuously with almost no time delay during scanning. Was able to do. In this way, it is possible to present an overlay image that is perceptually almost completely stable and stationary with respect to the field of view. In this embodiment, it is appropriate that the angular velocity sensors 25 and 26 for detecting the rotation of the observer's head are directly attached to the observer in the same manner as the bracket 50. However, the gyro 53 shown in FIG. The unit main body 51 may be provided.

FIG. 8 shows the results of the experiment shown in the schematic diagram of FIG. Here, the apparatus worn by the observer uses the conventional HMD and the projector of the present embodiment, and the HMD uses two drawing speeds of a frame rate of 30 Hz and a frame rate of 60 Hz, and the rotational angular velocity of the head is 5 .6 to 70 (deg / s). As a result of comparing the experimental results, the fluctuation width decreased in the order of HMD with a frame rate of 30 Hz, MHD with a frame rate of 60 Hz, and the projector of this embodiment.
FIG. 9 is a graph of virtual visual acuity at a plurality of depths of focus of 0 to 2 m using MHD and the projector according to the present embodiment. The visual acuity is greatly improved in the projector according to the present embodiment as compared with the HMD. Therefore, the improvement of the resolution based on the scanning of the laser beam and the improvement of the resolution based on the suppression of the fluctuation are remarkable. In FIG. 9, the virtual visual acuity of the HMD is standardized for comparison with the projector of this example, and this standardized conversion characteristic matches the highest point (distance 0.9 m) of the HMD characteristic with the characteristic of the projector of this example. It is converted. As shown in the figure, the characteristics of the projector of this example are extremely excellent even when compared with the HMD. Incidentally, the minimum visual acuity of the projector of this example is 0.67.

FIG. 10 is a diagram in which an observer wears the projector of the present invention on the head, draws visual information on the object using a notebook held in the hand as an object, and observes an overlay image on the object. It shows a person visually recognizing with the naked eye.
FIG. 11 shows a specific example of how to use the projector of the present invention, and shows a state in which visual information is drawn with a cow belly as an object. Here, the observer shows visual information as a plurality of objects as a cow belly screen as well as a notebook screen held in his hand. This is possible by changing the scanning angle of the optical scanning body. At this time, the overlay image of the cow's belly can be seen by the surrounding (side) observers. Further, when the body temperature of the cow can be measured by irradiating the cow's belly with the laser beam, the projector can capture the scattered light from the irradiation, and the body temperature can be detected by signal processing based on FIG.

1 is a block diagram illustrating a first embodiment of the present invention. It is a block diagram which illustrates 2nd Embodiment of this invention. It is a block diagram which shows an example of 3rd Embodiment of this invention. It is a block diagram which shows the other example of 3rd Embodiment of this invention. It is an external view of the projector with which the head is mounted. It is explanatory drawing for 4th Embodiment of this invention. It is a block diagram which illustrates 4th Embodiment of this invention. It is a diagram which shows the effect of the specific example of 4th Embodiment of this invention. It is a diagram which illustrates the effect of the present invention. It is a use state figure of an observer. It is a figure which shows the specific example of the use condition of a projector.

Claims (9)

In a laser projector that scans a laser beam from a laser light source in an optical scanning unit and draws on an object by swinging the emission direction of the laser beam horizontally and vertically,
A coupling portion to match the emission direction of the laser beam in the direction of the line of sight from the optical scanning unit and the center position and the viewpoint position of the scanning of the laser beam by the optical scanning unit at a conjugate position,
A photodetector disposed in the laser light source position conjugate with respect to the center position of scanning of the laser beam by the optical scanning unit,
Features and, Relais over The projector in that it has a. In a laser projector that scans a laser beam from a laser light source in an optical scanning unit and draws on an object by swinging the emission direction of the laser beam horizontally and vertically,
A coupling portion to match the emission direction of the laser beam in the direction of the line of sight from the optical scanning unit and the center position and the viewpoint position of the scanning of the laser beam by the optical scanning unit at a conjugate position,
And a light detector arranged on the laser light source position conjugate with respect to the center position of scanning of the laser beam by the optical scanning unit,
The aforementioned optical scanning unit for scanning the laser beam, characterized and, Relais chromatography The projector further comprising a scan control unit for performing at least one of the raster scan or vector scan according to the area of scanning. The optical detector is a laser projector according to claim 1 or 2, characterized in that detecting the light propagation information output object itself actively, or to detect the passive change information of the object itself. Detection processing unit connected to the photodetector, the laser projector according to claim 1 or 2, characterized in that measures positional information of the image to the object based on the drive control signal of the optical scanning element. In a laser projector that scans a laser beam from a laser light source in an optical scanning unit and draws on an object by swinging the emission direction of the laser beam horizontally and vertically,
A first coupling portion to match the direction of the emission direction line of sight of the laser beam from the center position and the viewpoint position of the scanning of the laser beam at a conjugate position the optical scanning unit in the optical scanning unit ,
An image signal source that generates two pieces of feature information that do not appear when combined from visual information to be drawn,
Two laser light sources controlled by the image signal source;
A second coupling unit arranged between the two laser light sources and the optical scanning unit to multiplex the two laser beams;
Means for taking out one feature information arranged between the first coupling portion and the viewpoint;
Features and, Relais over The projector in that it has a. The laser projector according to claim 5 the two laser light based on the feature information is transmitted through the polarizing plate orthogonal to each other, the means for taking one feature information of the which is a polarizing plate. In a laser projector that scans a laser beam from a laser light source in an optical scanning unit and draws on an object by swinging the emission direction of the laser beam horizontally and vertically,
A coupling portion to match the emission direction of the laser beam in the direction of the line of sight from the optical scanning unit and the center position and the viewpoint position of the scanning of the laser beam by the optical scanning unit at a conjugate position,
An image signal source that generates two pieces of feature information that do not appear when combined from visual information to be drawn,
One laser light source controlled by the image signal source;
A switching element that separates the two pieces of feature information and supplies the laser light source;
Les chromatography The projector characterized by having <br/> and optical switching means for taking out a laser beam having a one feature information of the in synchronism with the switching element. Configured to emit by scanning the laser light from the laser light source, a laser projector according to any one of claims 1 to 7, characterized in that a structure to be mounted on the head. A sensor for detecting the rotation of the head; and a calculator for calculating a value half of the detected value based on a value detected by the sensor. The scanning speed of the optical scanning unit is output from the calculator. The laser projector according to claim 8 , wherein the laser projector is controlled to compensate for the rotation of the head.

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