WO2004051344A1

WO2004051344A1 - Image display device

Info

Publication number: WO2004051344A1
Application number: PCT/JP2003/014227
Authority: WO
Inventors: Mitsuyoshi Watanabe; Shoji Yamada
Original assignee: Brother Kogyo Kabushiki Kaisha
Priority date: 2002-11-29
Filing date: 2003-11-07
Publication date: 2004-06-17

Abstract

An image display device (1) for displaying an image by scanning a light flux and projecting an image on a retina of an observer. The device includes an emission section (10) for emitting a light flux according to a video signal representing an image, a scan section (50) for scanning the light flux emitted from the emission section, and a control section (110). When a setting condition is established without depending on the observer operation during image display, the control section (110) controls the emission section to emit a light flux at a low output level preset to a level lower than the normal level but greater than 0.

Description

Image display device

TECHNICAL FIELD The present invention relates to a method for projecting a light beam into a pupil of an observer and projecting an image on a retina of the observer with the incident light beam, whereby a virtual image is displayed in front of the pupil.

The present invention relates to an image display device that allows an observer to recognize.

Rice field

Background art

• A retinal scanning display is already known as an example of an image display device. In this type of image display device, a light beam corresponding to an image is generated and emitted by a light source, and the emitted light beam is reflected by a reflection surface of a scanning unit, so that the image is scanned into an image-projectable state. You. The scanned light beam enters the pupil of the observer, and an image is projected on the retina of the observer by the light beam thus incident on the pupil. Thereby, the observer can recognize that the virtual image is displayed in front of the pupil. The scanning unit in this type of image display device usually has a reflecting surface for reflecting a light beam, and the reflecting surface is changed by repeating the operation of changing the direction of the reflecting surface with respect to the light beam incident on the reflecting surface. It is configured to scan the light beam reflected from the camera so that it can be projected as an image. In this way, since the light beam is scanned by repeating the operation of changing the direction of the reflecting surface of the scanning unit, the mechanism for changing the direction of the reflecting surface normally operates due to some kind of trap. Otherwise, the light beam may enter the pupil of the observer without being scanned normally. The luminous flux incident on the pupil in this manner is not a luminous flux that has been normally scanned for image display, and thus may give an observer discomfort such as glare and flicker.

In Japanese Patent Publication No. 07-121212, a conventional example of this type of image display device is described. In this conventional example, when a mechanical trouble occurs in the image display device, for example, when the light beam scanning by the scanning unit is not performed normally, the light beam is emitted to the pupil. It is configured not to be incident at all. Specifically, when such a trouble occurs, the emission (generation) of the light beam from the light source is stopped, or the path of the light beam is deviated from the pupil. Disclosure of the invention

According to the conventional image display device described above, when the scanning unit does not scan the light beam normally, the light beam does not enter the pupil of the observer, so that the observer may be dazzled or flicker. Is prevented from being uncomfortable.

However, in the conventional image display device, when the scanning of the light beam by the scanning unit is not performed normally, the process of simply preventing the light beam from entering the pupil is simply performed. In other words, for the observer, the virtual image that has been viewed until now suddenly disappears without any information being given, and therefore, there is a possibility that the observer may feel uneasy. there were.

Against this background, an object of the present invention is to provide an image display device capable of changing a display mode of a virtual image without giving a sense of anxiety to an observer when the display mode of the virtual image is automatically changed. Is to do.

The following aspects are obtained by the present invention. Each aspect is divided into terms, and each term is numbered. Numbers shall be added, and numbers shall be quoted from other sections as necessary. This is to facilitate understanding of some of the technical features that can be adopted by the present invention and combinations thereof, and the technical features and the combinations thereof that can be adopted by the present invention are limited to the following embodiments. Should not be construed as That is, it should be construed that the technical features not described in the following embodiments but described in the present specification are appropriately extracted and adopted as the technical features of the present invention.

Furthermore, listing each section in a form that quotes the number of the other section does not necessarily prevent the technical features described in each section from being separated from and independent of the technical features described in the other sections. It should not be construed as meaning that the technical features described in each section can be made independent as appropriate according to their nature.

(1) An image display device that displays an image by projecting the image on the retina of an observer by running a light beam,

A video signal representing the image is input, and an output unit that outputs the light flux based on the input video signal;

A scanning unit that scans a light beam emitted from the emission unit;

When the setting conditions are satisfied without depending on the operation of the observer during the display of the image, the light flux from the emission unit is set to a low value which is set in advance so as to be lower than the normal output level but larger than 0. A control unit for controlling the emission unit so as to emit light at an output level;

In this image display device, the display mode of the image is automatically changed when the set condition is satisfied without depending on the operation of the observer during the display of the image. By this change, the output level of the light beam emitted from the emission unit for displaying an image is reduced to a low output level lower than the normal output level. However, since the low output level is not 0, the image displayed by the low output level luminous flux is Although the brightness is lower than that of the video signal, it does not disappear from the observer against the content of the video signal.

Therefore, according to this image display device, when the display mode of the image is automatically changed, the image does not disappear, so that anxiety caused by the change in the display mode does not need to be given to the observer. Even if it gives a sense of anxiety, it can be alleviated.

The “output level” in this section and each of the following sections can be defined to mean, for example, the intensity of a light beam emitted from the emission section. Furthermore, when a device whose light emission amount changes depending on power consumption, for example, a laser diode is used for the emission unit, the power supplied to the emission unit for emitting the light flux (for example, the maximum power supplied to the device) , Average power, and effective power) can be defined.

(2) The image display device according to (1), wherein the set condition includes an abnormal condition establishment condition that is satisfied when an error occurs in the scanning unit.

According to this image display device, when an abnormality occurs in the scanning unit, the output level of the light beam is automatically reduced within a range that does not cause anxiety to the observer.

(3) The scanning unit comprises:

At least one reflecting surface for reflecting the light beam;

A drive unit for driving the reflection surface such that the reflection surface angle, which is an angle of the reflection surface with respect to a light beam incident on the reflection surface, changes periodically.

Including

The image display device according to (2), wherein the abnormal condition is satisfied when an actual cycle in which the reflection surface angle changes deviates from a set range.

According to this image display device, the actual cycle in which the reflection surface angle of the scanning unit changes is abnormal. In the event of an occurrence, the output level of the luminous flux is automatically reduced within a range that does not cause anxiety to the observer.

(4) The abnormal condition

When at least one of the reflection surface and the driving unit has an abnormal site in the scanning unit, the first condition is satisfied regardless of the abnormal site; and A second condition that is satisfied when an abnormality occurs in the surface, and a third condition that is satisfied at least when an abnormality occurs in the driving unit.

(3) The image display device according to the above (3).

According to this image display device, the abnormality that occurs in the scanning unit is defined as the abnormality that is related to the reflection surface of the scanning unit and the abnormality that is related to the driving unit (for example, the motor, the actuator, and the motion transmitting unit). Regardless of which, it is possible to discover. Further, it is possible to identify an abnormality occurring in the scanning unit as either an abnormality relating to the reflection surface or an abnormality relating to the driving unit.

(5) The scanning section is a rotating body having a plurality of the reflecting surfaces arranged side by side along a circumference coaxial with a rotation axis, the scanning section being rotated about the rotation axis by the driving section. Including

The control unit detects the reflection surface angles individually for the plurality of reflection surfaces, and the first condition is that, among the plurality of reflection surface angles respectively detected for the plurality of reflection surfaces, The second condition is satisfied when there is a reflection surface angle that deviates from the first set range, and the second condition is a case where the first condition is satisfied. Is established when there is a reflective surface angle whose deviation from the average value of the reflective surface angle exceeds the second set range.

The third condition is a case where the first condition is satisfied, and a case where there is no reflection surface angle whose deviation exceeds the second setting range among the plurality of reflection surface angles. The image display device according to the above mode (4).

The image display device according to the above mode (4), wherein the scanning unit comprises: a plurality of reflecting surfaces; and a rotating body in which the plurality of reflecting surfaces are arranged along a circumference coaxial with the rotation axis. And a driving unit for rotating the rotating body about a rotation axis.

In this aspect, when an abnormal reflection surface angle is present among the plurality of reflection surface angles detected for each of the plurality of reflection surfaces, the scanning unit relates to the reflection surface or the drive unit. Regardless of this, it is possible to determine that there is an abnormality. Further, in this aspect, when it is determined that there is some abnormality in the scanning unit, the deviation from the average value of the plurality of reflection surface angles is abnormal among the plurality of reflection surface angles. If there is a certain reflection surface angle, it is possible to determine that some reflection surfaces are abnormal.

Furthermore, in this aspect, when it is determined that there is some abnormality in the running section, and when there is no reflection surface angle having the above-mentioned deviation among a plurality of reflection surface angles, Rather than determining that all reflecting surfaces have the same abnormality, it is more appropriate to determine that there is an abnormality in the drive unit itself that can have the same effect on all reflecting surfaces.

Based on the knowledge described above, according to the image display device of this section, it is possible to determine whether the abnormality occurred in the scanning unit is an abnormality related to a part of the reflecting surface or an abnormality related to the driving unit. It becomes.

(6) Further, the beam detector includes a beam detector for detecting that the light beam scanned by the scanning unit has entered a set position, and the former control unit detects the cycle based on an output signal of the beam detector. It is determined whether the abnormal condition is satisfied based on the detected cycle. (2) The method according to any one of (2) to (5), Image display device.

In general, an image display device is configured to include a beam detector that detects the angle of a reflecting surface of a scanning unit using light reflected from the reflecting surface in order to synchronize the scanning of a light beam by the scanning unit. You.

This beam detector can detect, for each reflecting surface, the travel time required for one scan of the light beam, so that the actual reflecting surface angle changes for each reflecting surface. It is possible to detect the period.

Therefore, this beam detector can be used for both synchronization of scanning and detection of the change period of the reflection surface angle.

Therefore, according to the image display device of this section, since the change period of the reflection surface angle is detected using the beam detector, for example, by using the same beam detector to suppress an increase in the number of parts, Thus, it is possible to perform both scanning synchronization and detection of a change cycle of the reflection surface angle.

(7) The setting condition includes any one of (1) to (6), including a long-time display condition that is satisfied when a continuous display time of the image display device exceeds the set time. Image display device.

In general, the longer the continuous display time of the image display device is, the longer the observer keeps watching the image, and the more fatigue the observer feels in the eyes. On the other hand, even if the observer observes an image for the same time, the darker the image is, the less fatigue the observer feels in the eyes.

Based on such knowledge, in the image display device according to this section, when the continuous display time by the image display device exceeds the set time, the output level of the luminous flux automatically becomes uneasy for the observer. It can be reduced within a range that does not give a feeling.

Therefore, according to this image display device, the fatigue of the eyes of the observer is not imposed on the observer. Without any pleasure, it is possible to automatically reduce the amount.

(8) The control unit detects the continuous display time based on the elapsed time from the start of operation of the scanning unit, and establishes the long-time display based on the detected continuous display time. The image display device according to the mode (7), wherein it is determined whether or not the condition is satisfied.

(9) The observer can understand that the control unit is in the state where the output level of the light beam emitted from the emission unit is reduced to the low output level because the setting condition is satisfied. The image display device according to any one of (1) to (8), wherein the emission unit is controlled such that a predetermined message image is projected on the retina.

According to this image display device, when the output level of the luminous flux is automatically reduced, the observer can know that the phenomenon is expected through the message image as a medium. In this case, the observer does not have to feel anxious due to the automatic decrease in the output level of the luminous flux.

(10) The image display device according to (9), wherein the message image is represented by at least one of a character, a symbol, and a figure.

According to this image display device, the meaning that the output level of the luminous flux was reduced as expected is not caused by the actual decrease in the brightness of the image viewed by the observer, but by the language itself or a communication function equivalent to the language. It is possible to reliably transmit to the observer through the image that fulfills the above.

(11) The control unit, when the setting condition is not satisfied, controls the emission unit in a normal mode in which the emission unit emits a light beam at the normal output level, while the setting condition is satisfied. In this case, the image display device according to any one of (1) to (10), wherein the emission unit controls the emission unit in a low output mode in which the emission unit emits a light beam at the low output level. (12) The low output level is a luminous flux output level at which the observer can visually recognize the image, and does not cause discomfort to the observer even if the same position on the retina is continuously irradiated. The image display device according to any one of (1) to (11), wherein In this image display device, the low output level of the luminous flux is set from the viewpoint of avoiding or reducing the discomfort that may be given to the observer by the continuous irradiation on the retina.

(13) An image display device that displays an image by projecting the image on the retina of an observer by scanning a light beam,

(A) at least one reflecting surface for reflecting the emitted light beam, and (b) an angle of the reflecting surface with respect to the light beam incident on the reflecting surface for scanning the light beam emitted from the emitting portion. A scanning unit having a driving unit that drives the reflection surface so that a certain reflection surface angle periodically changes;

The actual period at which the reflection surface angle changes is optically detected, and when the detected period deviates from the set range, the light flux from the emission unit is lower than the normal output level but larger than 0. A control unit that controls the emission unit so as to emit light at a low output level set in advance in a state where the output level of a light beam emitted from the emission unit is reduced to the low output level. The emission unit is controlled so that a predetermined message image is projected on the retina so that an observer can understand that the state is in the state.

An image display device including:

According to this image display device, when an abnormality occurs in the actual cycle in which the reflection surface angle of the scanning unit changes, the output level of the luminous flux is automatically set to a level that does not cause anxiety to the observer. Lowered within the enclosure.

Furthermore, according to this image display device, when the output level of the light beam is automatically reduced, the observer can know through a message image that the phenomenon is expected. This also eliminates the need for the observer to feel uneasy due to the automatic decrease in the output level of the luminous flux.

(14) An image display device for displaying an image by projecting the image on a retina of an observer by running a light beam,

It has a light emitting portion that generates a light beam corresponding to the image and emits the generated light beam, and a reflecting surface that reflects the light beam emitted from the emitting portion, and the direction of the reflecting surface is within a predetermined angle range. A scanning unit that scans the light beam reflected by the reflecting surface by periodically changing

A guiding unit that guides the light beam scanned by the scanning unit to the pupil of the observer and causes the pupil to enter the pupil;

A cycle detection unit that is arranged in an area where the light beam scanned by the scanning unit reaches, receives the light beam that has reached the area, and detects a cycle in which the scanning unit changes the direction of the reflection surface;

When the cycle detected by the cycle detection unit deviates from a predetermined range, the operation mode of the emission unit is changed from the normal mode in which the light flux is emitted at a first level to the emission unit. Switching command means for commanding to switch to a low output mode for emitting the light beam at a second level lower than the level and at a level visible to an observer.

An image display device including:

According to this image display device, when the change period of the reflection surface angle detected by the period detection unit deviates from a predetermined range, the operation unit outputs a low output of the operation mode to the emission unit. Switching to the mode is commanded by the switch command means.

The cycle detection unit detects a repetition cycle when the scanning unit changes the direction of the reflection surface (the angle of the reflection surface with respect to the light beam). Therefore, as the “predetermined range” to be referred to when the switching command means issues a command to switch the operation mode, a range in which the repetition period when the light beam is normally scanned by the scanning unit can be set. For example, when the light beam is no longer scanned normally, the emission unit is instructed to switch the operation mode to the low output mode.

When the operation mode of the emission unit is switched to the low output mode in response to this command, the emission unit has an output level lower than the first level for emitting the light beam in the normal mode and is visible to the observer. The luminous flux will be emitted at the second level. Thus, in the low output mode, the output level of the light beam incident on the pupil of the observer is within the range that the observer can see, and is at the second level lower than in the normal mode.

Therefore, in the image display device according to this section, when the scanning of the light beam by the scanning unit is not performed normally, the virtual image displayed so far does not suddenly disappear, and the virtual image The display (a state in which the observer can visually recognize the virtual image) is maintained.

Therefore, according to the image display device of this section, when the scanning of the light beam by the scanning unit is not performed normally, anxiety is given to the observer due to sudden disappearance of the virtual image. You don't have to.

(15) The scanning unit includes:

By periodically changing the angle of the first reflection surface that reflects the light beam with respect to the light beam within a predetermined angle range, the first light beam that is reflected from the first reflection surface is scanned in the first direction. Scanning means; By periodically changing the angle of the second reflection surface that reflects the light beam with respect to the light beam within a predetermined angle range, the light beam reflected from the second reflection surface can be changed to the second direction that intersects the first direction. Second scanning means for scanning in the direction of 2,

The image display device according to (14), further comprising: a relay optical system that relays a light beam between the first scanning unit and the second scanning unit.

(16) The scanning unit performs main scanning for scanning the light beam in the main scanning direction and sub-scanning for scanning in a sub-scanning direction that intersects the main scanning direction, using a common reflecting surface. The image display device according to the above mode (14).

(17) The image display device according to any one of (14) to (16), wherein the guiding unit includes a relay optical system that guides the light beam scanned by the scanning unit to a pupil of an observer.

(18) The image display according to any one of (14) to (17), wherein the guiding unit guides the light beam scanned by the scanning unit directly to the pupil of the observer without passing through an optical element. apparatus.

(19) The switching command unit, when the cycle detected by the cycle detection unit returns from the state beyond the predetermined range to within the range, operates the emission unit with respect to the emission unit. The image display device according to any one of (14) to (18), which issues a command to switch the mode from the low output mode to the normal mode.

(20) The low output mode is an operation mode in which the output level of the light beam emitted from the emission section is immediately changed from the first level to the second level. The image display device as described in the above.

(21) The low output mode is an operation mode in which the output level of the light beam emitted from the emission section is gradually reduced from the first level to the second level. An image display device according to any one of the above. In this section, one example of the mode of “gradually changing the output level” is a mode of changing stepwise, and another mode is a mode of changing continuously.

(22) Further, when the operation mode of the emission unit is switched to the low output mode, emission of a light beam corresponding to a notification image for notifying an observer that the mode has been switched to the low output mode. To the emission unit. The emission unit generates a light flux corresponding to the notification image based on the cycle detected by the cycle detection unit, and emits the generated light flux. The image display device according to any one of (14) to (21).

According to this image display device, when the operation mode of the emission unit is switched to the low output mode, a light beam for forming a notification image is emitted from the emission unit that has been instructed by the notification instruction unit. The notification image is an image for notifying the observer that the operation mode has been switched to the low output mode, and the notification image is recognized by the observer as a virtual image.

Therefore, according to this image display device, the observer can know that the operation mode of the emission unit has been switched to the low output mode using the notification image as a virtual image as a medium.

In this image display device, a light beam for forming a notification image is generated by the emission unit based on the repetition period detected by the period detection unit. Therefore, according to this image display device, even if the repetition period is not normal, the notification image is displayed as close to normal as possible. That is, the notification image is displayed in a state where the deformation of the image derived from the abnormal repetition period is suppressed.

The “notification image” in this section is an image for notifying the observer that the operation mode of the emission unit has been switched to the low output mode. Displays a message directly indicating that the mode has been switched, a message indicating that the repetition cycle detected by the cycle detection unit has exceeded a predetermined range, a message indicating that some trouble has occurred in the scanning unit, etc. Image.

(23) Further, a time detecting unit for detecting an elapsed time from when the scanning unit starts operating, and

When the elapsed time detected by the time detection unit exceeds a predetermined range, the switching instruction unit instructs the emission unit to switch the operation mode to the low output mode (14) The image display device according to any one of (1) to (22). In this image display device, the operation mode of the emission unit is switched to the low output mode when the elapsed time from when the scanning unit starts operating exceeds a predetermined range.

In this image display device, the length of the above-mentioned “predetermined time” is set to, for example, the length of time during which it is expected that the observer will not give a great feeling of fatigue even if the observer continues to observe the virtual image. It is possible to carry out in an aspect. In this embodiment, when the elapsed time from the start of the operation of the scanning unit exceeds a predetermined range, the output level of the light beam incident on the pupil of the observer is reduced to the above-described second level. However, it is possible to suppress the fatigue of the observer's eyes while maintaining the state in which the virtual image is displayed.

(24) The second level is an output level that can be visually recognized by an observer, and is determined so as not to cause discomfort to the observer even when the scanning unit continues to enter the pupil when scanning of the light beam is stopped. The image display device according to any one of (14) to (23), wherein the output level is the obtained output level.

In this image display device, in the low output mode, the output level of the light beam entering the pupil of the observer continues to enter the pupil when the scanning unit stops scanning the light beam. However, the output level is reduced to a level determined so as not to cause discomfort to the observer.

Therefore, according to this image display device, it is possible to maintain the state in which the virtual image is displayed and to prevent the observer from feeling unpleasant such as glare or flicker. In this section, `` the output level determined so as not to cause discomfort to the observer even if the light beam continues to enter the pupil when the scanning unit stops moving '' is, for example, sufficiently visible to the observer Power level of 10 nW or more, and the JIS standard (JISC6802) stipulates that there is no problem even if the light continues to be incident on the retina through the pupil at one point. A light flux of 0 nW or more and 3900 nW or less can be considered.

(25) An image display device that displays an image by projecting the image on the retina of an observer by scanning a light beam,

An emission unit that generates image light that is a light flux corresponding to the image, and emits the generated light flux;

A scanning surface having a reflecting surface for reflecting the light beam emitted from the light emitting portion, and repeating the operation of changing the direction of the reflecting surface within a predetermined angle range, thereby scanning the light beam reflected by the reflecting surface. Department and

A guiding unit that guides the light beam reflected by the reflecting surface of the scanning unit to the pupil of the observer and makes the pupil enter the pupil;

The scanning unit is disposed in an area where the light beam scanned by the scanning unit reaches, and receives the light beam reaching the area to detect a repetition period when the scanning unit changes the direction of the reflection surface. Period detector and

An image display program executed by a computer to control an image display device including:

When the repetition period detected by the period detection unit exceeds a predetermined range, The operation mode of the emission unit is changed from a normal mode in which the light flux is emitted at a first output level, which is a predetermined output level, to a lower level than the first level, and an observer visually recognizes the operation mode. An image display program including a switching instruction step of instructing switching to a low output mode for emitting the light beam at a second level that is a possible level.

If the image display program according to this section is executed by a computer, (1)

It is possible to achieve the same operation and effect as the device according to the item 4).

(26) Further, when the operation mode of the emission unit is switched to the low output mode, the emission unit emits a light beam corresponding to a notification image for notifying that the mode has been switched to the low output mode. Including a notification instruction means for instructing

The image display program according to (25), wherein the emission unit generates a light flux corresponding to the notification image based on a cycle detected by the cycle detection unit, and emits the generated light flux.

If the image display program according to this section is executed by a computer, (2)

It is possible to achieve the same operation and effect as the device according to the item 2).

(27) Further, a time detecting unit for detecting an elapsed time from when the scanning unit starts operating, and

When the elapsed time detected by the time detection unit exceeds a predetermined range, the switching instruction unit instructs switching of the operation mode to the low output mode (2).

5) or the image display program described in (26).

It is possible to achieve the same operation and effect as the device according to the item 3).

Note that some of the image display programs described above are directly or separately connected to the image display device via a communication network such as a recording medium Internet such as an FD, CD-ROM, or memory card. It is possible to provide indirectly via the device. Examples of the computer that executes the image display program include a computer built in the image display device, and a computer connected to the image display device so as to be able to perform data communication via a wireless or wired communication path.

(28) It has a reflecting surface capable of reflecting a light beam, and by repeatedly performing an operation of changing the direction of the reflecting surface within a predetermined angle range, the light beam reflected by the reflecting surface can be displayed as an image. A light beam scanning unit that scans in a state,

A pupil entrance for causing a light beam reflected by the reflection surface of the light beam scanning unit to enter a user's pupil;

Image light emission that generates image light, which is a light flux corresponding to an image, and emits the generated image light along a path that reaches the user's pupil via the light beam scanning unit and the pupil entrance unit. Department and

An image display device capable of visually recognizing a situation in which a virtual image is displayed in front of a pupil of a user by projecting an image on a retina by the image light incident on the pupil by the pupil incidence unit,

A repetition period when the light beam scanning unit changes the direction of the reflection surface by being disposed in a region scanned by the light beam reflected by the reflection surface of the light beam scanning unit and receiving the light beam that scans the region. A cycle detection unit that detects

When the repetition period detected by the period detection unit exceeds a predetermined range, the operation mode of the image light emission unit is changed to a first level which is a predetermined output level for the image light emission unit. To switch from a first mode for emitting the image light to a second mode for emitting the image light at a second level lower than the first level and at a level that is visible to a user. An image display device, comprising: switch command means for commanding.

(29) When the operation mode of the image light emitting unit is switched to the second mode And a notification command means for instructing the image light emission unit to generate and emit image light corresponding to a notification image for notifying that the image light emission unit has been switched to the second mode. The method according to (28), wherein: generating image light corresponding to the notification image based on the repetition period detected by the period detection unit, and emitting the generated image light. Image display device.

(30) a time detecting unit for detecting an accumulated time since the light beam scanning unit started operating,

The switching command means is characterized in that when the accumulated time detected by the time detecting unit exceeds a predetermined range, the switching command means commands the switching of the operation mode to the second mode (28) or (29) The image display device according to the above (29).

(31) The second level is an output level that can be visually recognized by the user, and is determined to be a level at which there is no problem even if the second level continues to enter the pupil when the light beam scanning unit stops scanning the light beam. The image display device according to any one of (28) to (30), wherein the image display device has a reduced output level. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a system diagram showing an image display device according to the first embodiment of the present invention.

FIG. 2 is a flowchart conceptually showing the contents of an image display program executed by the computer of the control unit in FIG.

FIG. 3 is a front view showing an example of a message image displayed by execution of steps S220 and S230 in FIG.

FIG. 4 is a front view showing some examples of images displayed when the scanning time of the image display device shown in FIG. 1 by the polygon mirror becomes long.

FIG. 5 is displayed by performing steps S240 and S280 in FIG. FIG. 7 is a front view showing some examples of message images to be displayed.

FIG. 6 is a flowchart conceptually showing the contents of an image display program executed by the computer of the control unit in the image display device according to the second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, some of the more specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 systematically shows an image display device 1 according to a first embodiment of the present invention. The image display device 1 enters a light beam into a pupil E of an observer (that is, a user of the image display device 1), and projects an image on the observer's retina by the incident light beam, whereby This device allows the observer to recognize that a virtual image is displayed in front of the pupil E. This is a so-called retinal scanning display.

As shown in FIG. 1, the image display device 1 includes an emission unit 10 that generates and emits image light that is a light flux corresponding to an image. The emission unit 10 generates the image light by appropriately modulating the image light. That is, the emission unit 10 is a unit that generates image light in the image display device 1.

The image display device 1 further includes an optical fiber 20 for transmitting the image light emitted from the emission unit 10, and a collimating optics for converting the image light emitted from the optical fiber 20 into a parallel light flux (parallel light). System 30.

The image display device 1 further includes a scanning unit 50 that scans the image light collimated by the collimating optical system 30 so that the image light can be projected as an image, and an image light scanned by the scanning unit 50. And a guiding unit 70 for guiding the pupil E of the observer to enter. The image display device 1 further includes a period detection unit 100 that detects a repetition period when the scanning unit 50 scans the image light, and a control unit 110 that controls the operation of the entire image display device 1. The control device 110 is mainly configured by a computer 112, and the computer 112 is configured to include a processor 114 and a memory 116.

The above-described emission unit 10 includes a B laser 11 and a B laser driver 12 that drives the B laser 11 in order to generate a blue light flux, and a G laser in order to generate a green light flux. A laser 13 and a G laser driver 14 for driving the G laser 13 are provided, and further, an R laser 15 and an R laser 15 for driving the R laser 15 for generating a red light beam are provided. And a laser driver 16.

The emitting section 10 further includes a dichroic mirror 17 for combining three light beams generated from the three lasers 11, 13, and 15 into one image light, and a dichroic mirror for the dichroic mirror. And a coupling optical system 18 for guiding one image light coupled by 17 to the optical fiber 120.

The emission unit 10 displays the image to an observer by driving each of the lasers 11, 13, and 15 by each of the laser drivers 12, 14, 16 based on the color signal output from the control unit 110. Image light corresponding to the image to be generated is generated with the required intensity modulation and emitted to the optical fiber 120.

The emitting unit 10 switches the operation mode of the emitting unit 10 itself between a normal mode and a low output mode, which are different from each other with respect to the output level of the light beam emitted from the emitting unit 10, in response to a command from the control unit 110. Designed to. In the present embodiment, the term “output level” is defined to mean the intensity of the light beam emitted from the emission unit 10.

Here, the “normal mode” means that the emission unit 10 is configured to emit the lasers 11, 13, 15 This is an operation mode in which the luminous flux whose sum at each instant of the output level from is less than 1 / W is generated and emitted as image light. In the present embodiment, the output level at which the emission unit 10 emits the light beam in the normal mode is set, for example, within a range from 0 to.

On the other hand, the “low-power mode” means that the emission unit 10 images the luminous flux whose sum of the output levels from the lasers 11, 13, and 15 at each instant does not exceed 200 nW. This is an operation mode in which light is generated and emitted.

In the low power mode, the output level of the light beam emitted from the emission unit 10 is determined by the JIS standard (JISC6802) as a level that does not cause any problem even if it continues to enter the retina through the pupil at one point. It is less than the standard value of 390 nW. However, in the low output mode, the output level of the light beam emitted from the emission unit 10 is equal to or more than 10 nW, which is an output level that can be visually recognized by an observer.

In the present embodiment, the output level at which the emission unit 10 emits the light beam in the low output mode is set, for example, within a range from 0 to 200 nW.

The scanning section 50 scans the image light incident from the collimating optical system 30 so that the image light can be projected as an image. The scanning unit 50 scans the image light in the horizontal direction (main scanning direction or first direction) and the horizontal scanning image light in the vertical direction (sub scanning direction or second direction). And vertical scanning for scanning.

In order to realize horizontal scanning, as shown in FIG. 1, the scanning unit 50 includes a polygon mirror 51 that scans the image light incident from the collimating optical system 30 in the horizontal direction, and a polygon mirror 51 thereof. A horizontal scanning motor 52 that is driven to rotate, and a horizontal scanning drive circuit 53 that receives a command (horizontal synchronization signal) from the control unit 110 and drives the horizontal scanning motor 52 are provided.

As shown in FIG. 1, the scanning section 50 further includes a polygon for realizing vertical scanning. Mirror 54 that scans and outputs the light beam scanned by the mirror 51 in the vertical direction, a vertical drive actuator 55 that drives the galvanomirror 54, and commands from the control unit 110 And a vertical scanning driving circuit 56 for driving the vertical scanning actuator 55 in response to the synchronization signal.

The scanning unit 50 further includes a first relay optical system 57 for relaying a light beam between the polygon mirror 51 and the galvanomirror 54, as shown in FIG.

In the first relay optical system 57, the position where the light beam incident from the collimating optical system 30 is incident on the polygon mirror 51 and the center position on the reflecting surface of the galvano mirror 54 have an optically predetermined positional relationship. The optical system is arranged as follows.

As shown in FIG. 1, the polygon mirror 51 has a rotating body 51b in which a plurality of reflecting surfaces 51a are arranged along a circumference coaxial with the rotation axis. The rotating body 51b is rotated around the rotation axis by the horizontal scanning motor 52, so that the light flux reflected from each reflection surface 51a periodically rotates within a predetermined angular range on a plane intersecting the rotation axis. Is scanned.

In the scanning unit 50 described above, the light beam incident on the scanning unit 50 from the collimating optical system 30 is scanned in the horizontal direction by the polygon mirror 51, and then scanned in the vertical direction by the galvanometer mirror 54. After that, head to the guidance section 70.

The guiding unit 70 is a relay optical system that guides a light beam incident on the guiding unit 70 from the running unit 50 to the pupil E of the observer. The guiding section 70 is arranged so that the center position of the reflecting surface 54a of the galvanomirror 54 and the position of the pupil E (the position corresponding to the pupil E) in the observer have a predetermined optical relationship. Are located.

The above-described period detection unit 100 is configured such that one of the plurality of reflecting surfaces 51 a of the polygon mirror 51 on which the image light is incident is referred to as one of the reflecting surfaces 51 a (hereinafter referred to as “selective reflecting surface 51 a”). The angle region where the image light is reflected from, that is, the polygon mirror 51 And is arranged in an area where the image light is scanned. The cycle detection unit 100 is an example of a light receiving element that outputs a signal according to incident light. More specifically, in the present embodiment, the cycle detection unit 100 is configured as a beam detector that detects a light beam, which is image light scanned by the polygon mirror 51, at a specific position. Each time the direction of the selective reflection surface 5 la of the polygon mirror 51 (the angle of the selective reflection surface 51 a with respect to the light beam) changes periodically, the periodic detection unit 100 0, that is, the beam detector, 1 Receives image light reflected from a.

When receiving the image light, the cycle detector 100 configured as a beam detector supplies a signal indicating that the image light has been received to the controller 110. Then, based on the signal, the control unit 110 performs timing for the emission unit 10 to emit the image light with respect to the horizontal scanning (that is, the start timing of each horizontal scanning line in the rectangular area where the image is displayed). To determine. Hereinafter, focusing on the output signal of the beam detector, the signal is referred to as a BD (Beam Detector) signal.

The control unit 110 further controls the actual running cycle of the polygon mirror 51 (that is, for example, the start timing of horizontal scanning using a certain selective reflection surface 51 a and the next selection reflection surface 5). It also has the function of detecting the time interval between the start of horizontal scanning using 1a). Specifically, the control unit 110 detects the interval at which the image light is received, so that the polygon mirror 51 can direct the selected projection surface 51 a (the angle of the selective reflection surface 5 la with respect to the image light). The repetition period when changing is detected.

An image display program is stored in the memory 1 16 of the computer 1 12 of the control unit 110. This image display program is executed by the processor 114, whereby the overall operation of the image display device 1 is controlled and the image display processing is executed.

Figure 2 conceptually shows the contents of the image display program in a flowchart. ing. This image display program is repeatedly executed after the image display device 1 is started by turning on the power and until the image display device 1 is stopped by turning off the power.

In each execution of the image display program, first, in step S110, it is waited that the input of an external video signal is started. If the input of the video signal is started, the determination in step S110 becomes YES, and the flow shifts to step S120.

In this step S120, the operations of the polygon mirror 51 and the galvanometer mirror 54 are started. Specifically, in this step S120, the supply of the horizontal synchronization signal to the horizontal scanning drive circuit 53 is started, that is, the horizontal synchronization signal is transmitted from the control unit 110 to the horizontal scanning drive circuit 53. By being repeatedly output to the drive circuit 53, the operation of the polygon mirror 51 is started by the horizontal scanning motor 52.

In parallel with the horizontal scanning, the supply of the vertical synchronization signal to the vertical scanning drive circuit 56 is started, that is, the vertical synchronization signal is repeatedly output from the control unit 110 to the vertical scanning drive circuit 56. As a result, the operation of the galvanomirror 54 is started by the vertical scanning actuator 55.

As a result, the polygon mirror 51 periodically changes the angle of each reflecting surface 51 a with respect to the image light within a predetermined angle range, and thereby, is reflected by each reflecting surface 51 a of the polygon mirror 51. A state in which the light beam is scanned in the horizontal direction is realized. On the other hand, the galvanomirror 54 vertically scans the light reflected by the reflecting surface 54 a by periodically changing the angle of the reflecting surface 54 a with respect to the image light within a predetermined angle range. Is realized.

After the execution of step S130 described above is completed, the operation proceeds to step S130. Then, in step S110, generation of color signals for forming an image represented by the video signal whose input has been started is started for each of the red, green, and blue laser beams. Further, the output of the generated various color signals to the emission unit 10 is started.

In this step S130, each time a BD signal is input from the cycle detector 100, various color signals for one horizontal scan (one horizontal scan line) of an image are generated and output. . In the emitting section 10 to which the various color signals are input, the laser drivers 12, 14, and 16 drive the lasers 11, 13, and 15 based on the various color signals. Light beams of each color are generated from each of the lasers 11, 13, and 15. As shown in FIG. 1, the three color light beams generated in this way are combined into one image light by a dichroic mirror 17, and then are passed through a coupling optical system 18 to an optical fiber 120. Direction La.

Since the current execution of step S130 is the first execution after the activation of the image display device 1, the emission unit 10 starts operating in the normal mode. After that, the image light emitted from the emission unit 10 is scanned by the scanning unit 50 so that it can be projected as an image, and the scanned image light enters the pupil E of the observer via the guidance unit 70. I do. In this manner, the image light incident on the pupil E is projected on the retina as an image so that the observer can recognize that a virtual image is displayed in front of the pupil E of the observer. Become.

After the execution of step S130 described above is completed, in step S140, it is determined whether or not the input of the video signal started in step S110 continues.

In this case, assuming that the input of the video signal is not continued, the determination in step S140 is NO, and in step S150, the execution of step S120 is performed. The operations of the polygon mirror 51 and the galvanomirror 54, which have been started, are stopped.

Specifically, in step S150, the supply of the horizontal synchronization signal to the horizontal drive circuit 53 is stopped, so that the operation of the polygon mirror 51 by the horizontal scan motor 52 is stopped. Stopped. Further, the supply of the vertical synchronization signal to the vertical scanning drive circuit 56 is stopped, so that the operation of the galvanomirror 54 by the vertical scanning actuator 55 is stopped.

This completes one execution of the image display program.

On the other hand, in this case, assuming that the input of the video signal is continued, the determination in step S140 is YES, and initialization is performed in step S160. In the present embodiment, the same number n and the variable T as the number n of the reflecting surfaces 51 a in the polygon mirror 51 are prepared. Each variable T is provided for temporarily storing the period detected by the control unit 110 based on the BD signal output from the period detection unit 100 for each reflection surface 51a.

Each value t of the plurality of variables T is stored in the memory 116 in association with each of the variables T. However, there is no fixed correspondence between the plurality of variables T and the plurality of reflection surfaces 51a, and as described later, the control unit 1 uses the BD signal of the cycle detection unit 100 10 The latest one of the plurality of cycles sequentially detected by 0 is equal to the number n of the reflective surfaces 51a, and is associated with each variable T in the same order as the detected order. Are stored sequentially.

The initialization of the variable T described above is performed in step S160. Specifically, all the variables T [1] to T [n] (n: the number of the reflecting surfaces 51a) are set. Set to 0. Hereinafter, for convenience of description, the value given to each variable T [i] is represented by a value t [i]. When the execution of step S160 is completed, in step S170, the period in which the BD signal is repeatedly output from the period detecting unit 100 in response to the image light being repeatedly incident on the period detecting unit 100 from the polygon mirror 51. As the interval, the control unit 110 detects a cycle in which the direction of each reflecting surface 51 a changes. That is, the change period of the direction of each reflecting surface 51a is detected as the time interval between two adjacent BD signals among the plurality of BD signals repeatedly output from the period detection unit 100. .

In step S170, when the i-th cycle T is detected, the i-th variable T [i] is set to be equal to the detected value, and the (i + 1) -th cycle T Is detected, the (i + 1) th variable T [i + 1] is set to be equal to the detected value. When the detection of a series of n periods T, that is, a set of periods T is completed in this way, the respective detected values of the next set of periods T are respectively n n in the same order as the detection order of each period T. Stored in variables T [1] through T [n] sequentially. As a result, the values t [i] of the n variables T [1] to T [n] are updated to be equal to the detected values of the latest n periods T and stored in the memory 1 16 It will be.

When the execution of step S170 is completed, in step S180, the ratio R between the value t [i] and the reference value t0 is set in n variables [1] to T [n]. It is determined whether there is a variable T that deviates from the range. It is determined whether there is a variable T whose ratio R is above or below the set range. Here, the “reference value t 0” is an average scan per one reflecting surface 51 a of the polygon mirror 51 in a normal state where the image light is normally scanned in the horizontal direction by the polygon mirror 51. This is a value representing a predetermined time as the inspection time.

In the present embodiment, the ratio R is a value obtained by dividing the reference value tO by the value t [i]. That is, it is defined as t oZ t. That is,

R = t 0 / t

It is defined to be expressed by the following expression. Further, the above setting range is defined, for example, as a range from 0.95 to 1.05.

In this case, assuming that there is no variable T in which the ratio R is out of the set range, the determination in step S180 becomes NO, and the process returns to step S140. On the other hand, if it is assumed that there is a variable T whose ratio R deviates from the set range, the determination in step S180 becomes YES, and the process proceeds to step S190.

In step S190, a command is issued to emission section 10 to switch the operation mode to the low output mode. Upon receiving the command, the emitting unit 10 switches the operating mode of the emitting unit 10 itself from the normal mode to the low output mode, and as a result, the output level of the luminous flux generated from each of the lasers 11, 13, and 15 is changed. The luminous flux is generated and emitted at a predetermined low output level such that the maximum value of the sum is 200 nW or less.

Here, the “low output level” can be obtained, for example, by multiplying the normal output level in the normal mode by a fixed coefficient smaller than 1. Specifically, it can be obtained by multiplying the normal output level determined for each pixel and each color by the above-described fixed coefficient based on the video signal. Therefore, even in the low-power mode, the output level of the luminous flux generated from each of the lasers 11, 13, and 15 should be different for each pixel constituting the image according to the video signal, as in the normal mode. Is possible.

After step S190 is executed in this way, in step S200, an average value taVe of n variables T [1] to T [n] is calculated. The average value tave is tave = (t [1] + t [2] + · ·-+ t [n]) / n.

Then, in step S210, the deviation Δt from the average value taVe calculated in step S200 is set to a value greater than or equal to the threshold value ΔtTH among n variables T [1] to T [n]. It is determined whether a certain variable T exists.

In the present embodiment, the deviation At of each variable T [i] is defined as a value obtained by subtracting the average t ave from the value t [i] power of each variable T [i]. Therefore, the deviation Δt is

A t = t— t a v e

It can be represented by the following formula. Thus, the deviation At increases as the value t [i] increases from the average value t ave. Further, in the present embodiment, the threshold value ΔtTH is set to be equal to, for example, 0.3 XtaVe. As described above, the value t of each variable T is set to be equal to the detection value at the time of scanning when the image light is scanned in the horizontal direction, and the deviation Δt is smaller than the threshold Δt TH. The existence of the large value t of the variable T indicates that the scanning time is abnormally long for a part of the plurality of reflecting surfaces 51a of the polygon mirror 51 but not for the whole.

To consider the reason why the scanning time locally becomes abnormally long for a part of the plurality of reflecting surfaces 51a of the polygon mirror 51, as one example, one of the plurality of reflecting surfaces 51a is considered. It is conceivable that the part has been damaged such as cracks or that dirt or other dirt has adhered. If these causes exist, the polygon mirror 51 cannot locally reflect the image light in the normal direction on some of the reflection surfaces 51a, so that, for example, the light from two adjacent reflection surfaces 51a is not reflected. The image light is simultaneously incident on the period detection unit 100. As a result, There is a possibility that the detection value of the period T based on the output signal of the period detection unit 100 represents the scanning time for two reflection surfaces 51a.

Therefore, if there is a variable T in which the deviation At is larger than the threshold value Δt TH, the polygon mirror 51 can normally scan the image light locally on the reflection surface 51 a of the part. It may be gone.

On the other hand, when there is no variable T in which the deviation Δt is larger than the threshold value Δt TH, the deviation Δt is almost uniformly distributed over the n variables T. The scanning time is abnormally long or short for all of the plurality of reflecting surfaces 51a. This means that an abnormality has occurred in the plurality of reflecting surfaces 51a as a whole. Considering the cause of the abnormality, the drive unit for rotating the rotating body 51b of the polygon mirror 51, that is, the horizontal scanning motor 52 and the horizontal drive circuit 53 at least partially failed. It is reasonably inferred that the polygon mirror 51a cannot scan the image light normally on all of the plurality of reflecting surfaces 51a.

In this case, assuming that there is a variable T in which the deviation Δt is larger than the threshold value Δt TH, the determination in step S210 is YES, and in step S220, the reflection surface 5 of the polygon mirror 51 is determined. Image data for displaying a reflection surface abnormality notification image, which is a message screen for notifying an observer that an abnormality has occurred in 1a, is read from the memory.

The image data is stored in the memory 116 in advance. In the present embodiment, the reflection surface abnormality notification image represented by the image data is, in one frame of the image, an image display area inserted by a light beam scanned during one rotation of the polygon mirror 51. It is displayed superimposed on the original image.

In the present embodiment, a part of the reflection surface 51 a of the polygon mirror 51 is locally When an abnormality occurs, it is assumed that an abnormality occurs in only one of a plurality of combinations of two adjacent reflecting surfaces 51a among the n reflecting surfaces 51a. ing. Therefore, the reflection surface abnormality notification image is drawn by (n−2) horizontal scanning lines horizontally scanned by the (n−2) reflection surfaces 51 a adjacent to each other.

When the execution of step S222 is completed, in step S230, various color signals for displaying the image of the reflecting surface abnormality notification image read out in step S220 are displayed based on the image data representing the image. (Red, green, and blue luminous fluxes) are started, and output of the generated color signal to the emission unit 10 is started.

Specifically, in this step S230, first, the time interval between the latest two BD signals input adjacent to each other in time from the period detector 100 (ie, the polygon mirror 51) Of the luminous flux due to the selective reflection surface 51 a of the variable t) 1 Of the n variables T, the variable T determined at step S 210 to have a deviation Δt that is equal to or greater than the threshold Δt TH It is expected that it will be equal to the value t (hereinafter referred to as “outlier tab”). That is, of the n reflective surfaces 51a, the reflected light from two adjacent reflective surfaces 51a in which an abnormality has occurred is transmitted to the beam detector that is the period detector 100. We have to wait for it to be incident.

In this step S230, when the time interval between the BD signals becomes equal to the abnormal value tab, thereafter, every time the BD signal is input from the period detector 100, the original image represented by the video signal is displayed. Various color signals for forming a composite image projected on the pupil E during one rotation of the polygon mirror 51 are generated in order to display a composite image in which the reflection surface abnormality notification image is superimposed on the image. It is output to each laser driver 12, 14, 16.

Thereafter, image light for forming a composite image is emitted from the emission unit 10 and the emission is performed. The image light thus obtained enters the pupil E of the observer through the running section 50 and the guiding section 70 in this order. The incident image light projects an image on the retina, so that the observer can recognize that the reflective surface abnormality notification image is displayed as a virtual image in front of the pupil E. .

FIG. 3 shows an example of the reflection surface abnormality notification image. According to this example, the message image represented by the text “An error occurred on the running surface” is normal among the n reflecting surfaces 51 a of the polygon mirror 51 (n− 2) It is displayed using the reflective surfaces 51a. As a result, as shown in FIG. 3, in the image display region where one frame of the image is displayed, the image of the reflective surface abnormality notification cannot properly transmit the image light among the n reflective surfaces 51a. It is displayed at a position avoiding the horizontal scanning line H corresponding to the individual reflecting surfaces 51a.

In addition, in addition, in the example shown in Fig. 3, the reflection surface abnormality notification image is displayed only once per frame of the image, but the reflection surface abnormality notification image is displayed each time the polygon mirror 51 rotates once. The present invention can be implemented as displayed. As described above, the case where the variable T in which the Δt deviation is equal to or larger than the threshold value Δt TH exists in the n variables T has been described. If the variable T does not exist, the step S 210 in FIG. If the determination is NO, the process moves to step S240.

In this step S240, image data representing a drive unit abnormality notification image for notifying an observer that an abnormality has occurred in the aforementioned drive unit of the polygon mirror 51 is read from the memory 116. . The image data representing the drive unit abnormality notification image is stored in the memory 116 in advance.

In the present embodiment, a plurality of types of image data representing the drive unit abnormality notification image are stored in the memory 1 16 according to the ratio r between the average value ta V e and the reference value t 0. In S240, the drive unit abnormality corresponding to the current value of the ratio r The image data of the notification image is selected and read. In the present embodiment, the value is defined as a value obtained by dividing the specific force reference value t0 by the average value taVe, that is, t0Ztave. That is,

r = t 0 / t a v e

It is defined to be expressed by the following expression.

Hereinafter, the reason why a plurality of types of image data of the drive unit abnormality notification image are prepared will be described in detail with reference to FIGS. However, in Fig. 4 (a) and (b), images in which four perfect circles are arranged at the four vertices of a square are shown in the normal display state and the abnormal display state, respectively. . FIGS. 5 (a) to 5 (c) show image data of three types of drive unit abnormality notification images, respectively.

When an abnormality in the drive unit of the polygon mirror ₅ 1 occurs, as long as the speed of the vertical scanning by the galvano mirror 5 4 (operation speed) does not change, is formed by the image light scanned by run查部5 0 If the time required for one horizontal scan by the polygon mirror 51, that is, the period T is long, that is, if the horizontal scan speed is low (as shown in FIG. 4 (b)), the drive unit is normal. In the case (as shown in Fig. 4 (a)), the pitch d between the horizontal scanning lines is longer.

Therefore, when an abnormality occurs in the driving unit of the polygon mirror 51, the image formed by the image light scanned by the scanning unit 50 is, as shown in FIG. The image has fewer horizontal scanning lines than normal (see Fig. 4 (b)).

An image in which the number of horizontal scanning lines is smaller than that in the normal state because the pitch d between the horizontal scanning lines is long is displayed in a state extended in the vertical direction (up and down direction in FIG. 4) with respect to the image in the normal state.

The timing at which the light beam is emitted from the emission unit 10 (for example, the color of the image light, (The timing at which the degree is modulated) does not change. Therefore, when the horizontal scanning speed is reduced, the image is displayed in a compressed state in the horizontal direction with respect to the normal image, as shown in Fig. 4 (b). You.

Displaying such a deformed image may not be able to accurately convey the image, that is, the content represented by the virtual image, to the observer, that is, the amount of information transmitted in the image may be insufficient. There is. Furthermore, if the image is stretched and displayed in the vertical direction, the lower region of the image (the region that protrudes below the rectangular frame in Fig. 4 (b)) may not be displayed.

By the way, the image visually recognized by the observer is expanded in the vertical direction as the number of horizontal scanning lines is smaller because the horizontal scanning speed of the scanning unit 50 is slow. However, even when the actual horizontal scanning speed is low, if the temporal change of the image light incident on the scanning unit 50 is synchronized with the actual horizontal scanning speed, the image viewed by the observer may change. You don't have to. Specifically, if the time change of the image light is made slower in the horizontal direction as the horizontal scanning speed is slower, the image observed by the observer may also decrease in the number of horizontal scanning lines due to the decrease in the horizontal scanning speed. Regardless, it is maintained, and consequently, the amount of information transmitted in the image.

For this reason, in this embodiment, as shown in FIGS. 5A to 5C, image data of three types of drive unit abnormality notification images to be selected according to the horizontal scanning speed are prepared. Have been. However, the image data of the three types of drive unit abnormality notification images is not shown as the same image as the image actually observed by the observer when the drive unit is abnormal, and the laser driver 12 , 14 and 16 are shown as image data corresponding to the drive signals supplied. That is, in FIG. 5, the image data is not shown along the time axis for the observer, but is shown along the time axis for the laser drivers 12, 14, and 16. -ing Therefore, these three types of drive unit abnormality notification images are displayed when they are actually displayed. According to the corresponding horizontal scanning speed, each character shown in FIG. 5 is expanded in the vertical direction and displayed in a compressed state in the horizontal direction.

Specifically, Fig. 5 (a) shows the pattern A to be selected when the ratio r is within the first range, which is slightly smaller than 1, because the horizontal running speed is slightly lower than normal. The image data of the section abnormality notification image is shown. This image data is the same as the original image data (the image data required for display when the same image is displayed to the observer while the drive unit is normal). The image data is defined so as to extend in the horizontal direction when the image data is reproduced in a state where the drive unit is abnormal.

If the image data defined in this way is reproduced by using the running unit 50 including the polygon mirror 51 in which the driving unit is abnormal, the observer can see each character shown in FIG. 5 (a). This is observed as a drive unit abnormality notification image that is expanded in the vertical direction and compressed in the horizontal direction. In the observed drive unit abnormality notification image, the size of each character is displayed so as to have the same size both vertically and horizontally. In this embodiment, the first range is:

0. 7 5 <= r <1

It is defined by the following inequality.

Fig. 5 (b) shows that the driving error of pattern B should be selected when the ratio r is within the second range, which is slightly smaller than the first range, because the horizontal scanning speed is slightly lower than normal. The image data of the notification image is shown. This image data is defined so that the same relationship as the above case is established with the original image data. When the image data defined in this way is reproduced, the observer is notified to the observer that the characters shown in Fig. 5 (b) are expanded in the vertical direction and compressed in the horizontal direction. Observed as an image. In the present embodiment, the second range is: 0. 5 <= r <0. 7 5

It is defined by the following inequality.

Further, FIG. 5 (c) shows that the driving error of the pattern C to be selected when the ratio r is within the third range, which is slightly smaller than the second range, because the horizontal running speed is much slower than normal. The image data of the notification image is shown. This image data is defined so that the same relationship as the above case is established with the original image data. When the image data defined in this way is reproduced, the observer is notified of the abnormalities of the drive unit while each character shown in Fig. 5 (c) is expanded in the vertical direction and compressed in the horizontal direction. It is observed as a knowledge image. In the present embodiment, the third range is:

0. 2 5 <= r <0.5

It is defined by the following inequality.

Furthermore, in the present embodiment, when the ratio r is within the fourth range, which is slightly smaller than the third range, because the horizontal running speed is much lower than the normal range, the drive unit abnormality notification image of the pattern D Is selected. In the present embodiment, the fourth range is:

0 <= r <0. 2 5

It is defined by the following inequality.

In the present embodiment, when the ratio r is within the fourth range, the display of the image based on the video signal is stopped as described later. Is set so that no information is displayed to the user.

Therefore, the image data for the pattern D is not stored in the memory 116. When this pattern D is selected, the computer 112 cannot read the image data from the memory 116 for the drive unit abnormality notification image. When the execution of step S240 is completed, in step S250, the image data of any type of drive unit abnormality notification image is read in step S240. It is determined whether it has been done. Specifically, since the image data of the drive unit abnormality notification image in any of the patterns A to C has been read, it is necessary to execute the following steps for displaying the drive unit abnormality notification image. Is determined. In this case, no image data was read in step S240, that is, assuming that the drive unit abnormality notification image of pattern D was selected this time, the determination in step S250 was NO. It becomes.

In this case, in order to stop the display of the image based on the video signal, in step S260, generation and output of various color signals based on the video signal are started in step S130. Is stopped. Subsequently, in step S270, the operations of the polygon mirror 51 and the galvanomirror 54, which were started in step S120, are stopped.

Thus, a series of executions of the image display program is completed, and the computer 112 waits for an image display command from the observer again.

On the other hand, in this case, assuming that the image data was read in step S240, that is, if any of the drive unit abnormality notification images of patterns A to C was selected this time, step S2 The judgment of 50 is YES.

In this case, thereafter, in step S280, various color signals (red, green, and blue luminous fluxes) based on the image data of the drive unit abnormality notification image read in step S240 are generated. Then, output of the generated various color signals to the emission unit 10 is started. In this step S280, every time a normal BD signal is input from the cycle detection unit 100, a composite image in which the drive unit abnormality notification image is superimposed on the original image represented by the video signal is displayed. For formation, various color signals are generated and output for one rotation of the polygon mirror 51.

Thereafter, image light for forming a composite image is emitted from the emission unit 10 and the emission is performed. The obtained image light sequentially enters the pupil E of the observer through the scanning unit 50 and the guiding unit 70. The incident image light projects an image on the retina, so that the observer can recognize that the drive unit abnormality notification image is displayed as a virtual image in front of the pupil E. .

When the execution of step S280 is completed, the steps S16 to S310 are executed in steps S290 to S310 in the same manner as when the execution of step S230 is completed. In the same way as 0 to S180, the next abnormality determination for the polygon mirror 51 is performed.

Specifically, in step S290, n variables T are initialized in the same manner as in step S160. As a result, the variables T [1] through T [n] are all set to zero.

Then, in step S300, in the same manner as in step S170, successive detection of the cycle T using the cycle detector 100 and storage of each detected value associated with each variable T [i] Is performed. Specifically, the input interval of the BD signal from the long-term detector 100 is stored in the memory 116 as the cycle T in association with each variable T [i].

Subsequently, in step S310, in the same manner as in step S180, among the n variables [1] to T [n], the variable in which the aforementioned ratio R deviates from the predetermined setting range is set. It is determined whether T exists.

In this case, if it is assumed that there is a variable T whose ratio R has deviated from the set range, the determination in step S310 is YES, the process returns to step S200, and the polygon mirror is operated in the same manner as described above. It is determined whether the abnormality of 51 is caused by an abnormality of some of the reflection surfaces 51a or an abnormality of the driving unit of the polygon mirror 51.

On the other hand, this time, it is assumed that there is no variable T whose ratio R deviates from the set range. Then, the determination in step S310 is NO, and the routine goes to step S330. In this step S330, it is instructed to the emission unit 10 to switch the operation mode to the normal mode. The emitting unit 10 receiving this command switches the operating mode of the emitting unit 10 itself from the low output mode to the normal mode, and as a result, the output level of the luminous flux generated from each of the lasers 11, 13, and 15 Are generated and emitted as image light at a predetermined normal output level such that the sum of the light beams is 1 iW or less.

Thereafter, in step S340, the generation and output of various color signals corresponding to the currently selected one of the reflection surface abnormality notification image and the drive unit abnormality notification image are stopped. As a result, only the generation and output of various color signals based on the video signal, which is the processing started in step S130, is continued. Then, it returns to step S140.

In the image display device 1 configured as described above, the ratio R (= t 0 / t) between the value t of each variable T and the reference value t 0 is set at the time of executing step S 180 in FIG. When there is a variable T outside the range (from 0.95 to 1.05), the emission unit 10 is instructed to switch the operation mode to the low output mode.

Here, the reference value t 0 represents an average scanning time per one reflecting surface 51 a in a state where the scanning of the image light is normally performed by the polygon mirror 51 as described above. On the other hand, the variable T is set to the period when the polygon mirror 51 periodically changes the direction of the reflecting surface 51a.

Therefore, in step S180, the above-described ratio R is set with respect to the period in which the direction of the reflecting surface 51a changes (that is, one horizontal traveling time by one reflecting surface 51a). If the deviation is out of the range, that is, if the polygon mirror 51 does not scan the image light normally, it is necessary to switch the emission unit 10 to the low output mode. Will be ordered.

The emitting unit 10 that has switched the operation mode to the low output mode in response to this command has an output level lower than the output level of the image light emitted in the normal mode, that is,

The image light is emitted at an output level that does not exceed 200 nW and is set to be equal to or higher than the output level that can be visually recognized by the observer, 100 nW.

As described above, in the low output mode, the output level of the image light incident on the pupil E of the observer is lower than that in the normal mode while being within the visible range. Therefore, in a case where the scanning of the light beam by the scanning unit 50 is not performed normally, it is necessary to maintain a state in which the virtual image can be viewed by the observer while suppressing the discomfort given to the observer by the image light. Can be.

That is, if the image display device is designed so that the virtual image suddenly disappears due to the abnormality of the scanning unit 50, the observer may feel uneasy due to that. According to the present embodiment, it is not necessary to give the observer discomfort due to the occurrence of an abnormality in the running section 50 without causing such a possibility.

Further, in the present embodiment, when the emission unit 10 switches the operation mode to the low output mode in response to receiving the switching command by executing step S190 in FIG. By executing step S230 or S290, image light corresponding to the reflection surface abnormality notification image and the drive unit abnormality notification image is generated and emitted based on the image data read from the memory 116. Is done.

These notification images tell the observer that the operation mode of the emission unit 10 has been switched to the low output mode due to an abnormality in some of the reflection surfaces 51a of the polygon mirror 51 or the drive unit. It is an image for announcement. Therefore, by observing the notification images, the observer is informed that some abnormality has occurred in the polygon mirror 51 and that the operation mode of the emission unit 10 has been switched to the low output mode. Can be

In particular, in step S230, if the various color signals for forming the reflection surface abnormality notification image include the variable T in which the deviation Δt is equal to or greater than the threshold value ΔtTH in step S210. Since the image is input to the emission unit 10 after the determination, the reflective surface abnormality notification image is displayed on the image display area with the horizontal scanning line H corresponding to the reflective surface 51 a that cannot scan the image light normally. It is displayed exactly where you avoid it. Therefore, the observer can accurately understand the content to be conveyed to the observer by the reflection surface abnormality notification image.

Further, in the present embodiment, after the operation mode of the emission unit 10 is switched to the low output mode by the execution of step S190 in FIG. 2, the output level of the image light incident on the pupil E becomes Even if the light continues to be incident on one point on the retina through E, the level is lowered so that it does not exceed 200 nW, which is a level determined to have no problem at all. Therefore, according to the present embodiment, after the occurrence of the abnormality in the running section 50, the observer feels discomfort such as glare and flicker due to the abnormal image light while maintaining the state in which the observer can visually recognize the virtual image. Can not be given.

It should be noted that the present invention can be implemented in a form in which various modifications, improvements, and the like are made to the present embodiment.

For example, in the present embodiment, the image display program shown in FIG. 2 is executed by the computer 112 incorporated in the image display device 1. On the other hand, all or some of the steps constituting the image display program are executed by an external computer connected to the image display device 1 via a wireless or wired communication path so as to be able to perform data communication. It is possible to implement the present invention in a form.

Further, in the present embodiment, the memory 116 of the control unit 110 is configured as a storage element (for example, ROM, RAM) which is unremovable with respect to the control unit 110. After being formed, the image display program shown in FIG. 2 is stored in such a memory 1 16. On the other hand, data can be input / output to / from recording media such as FD, CD-ROM, and memory card (including recording media that is removable with respect to the control unit 110). The present invention can be implemented in such a form that the image display program is stored in such a recording medium.

Further, in the present embodiment, the scanning unit 50 includes a polygon mirror 51, a galvano mirror 54, and a first relay optical system 57, and the horizontal scanning and the vertical scanning are independent of each other. la, 5 4 a. On the other hand, the present invention can be implemented in such a form that the scanning unit 50 performs both horizontal scanning and vertical scanning on the light beam emitted from the collimating optical system 30 using the same reflecting surface. It is. If this mode is adopted, the number of parts of the image display device 1 can be easily reduced, and the size of the image display device 1 can be easily reduced.

Furthermore, in the present embodiment, the image light scanned by the scanning unit 50 is incident on the pupil E via the guiding unit 70. On the other hand, the present invention can be implemented in a mode in which the image light scanned by the scanning unit 50 is directly incident on the pupil E.

Further, in the present embodiment, the output unit 10 receiving the operation mode switching command changes the output level of the image light from 1 or less to 200 nW or less, or from 200 nW or less to 1 or less. Is configured to be changed discontinuously. On the other hand, the present invention can be implemented in a mode in which the emission unit 10 that has received the operation mode switching command changes the output level of the image light stepwise or continuously.

Next, a second embodiment of the present invention will be described. However, since this embodiment has elements common to the first embodiment, the common elements will be referred to using the same reference numerals or names, and detailed description will be omitted. only This will be described in detail.

In the image display device 2 according to the present embodiment, unlike the first embodiment, if the time during which images are continuously displayed by the image display device 2 exceeds the set time, a long-time display notification image is displayed. Thus, the observer is notified that the display is continuously performed for a long time.

FIG. 6 is a flowchart conceptually showing the content of the image display program executed by the computer 112 of the image display device 2 according to the present embodiment. Hereinafter, the image display program will be described. Steps common to those of the image display program according to the first embodiment are omitted from the drawings or the same reference numerals or names are used as long as they do not interfere with the description. By using and quoting, redundant description will be omitted.

As shown in FIG. 6, the image display program according to the present embodiment has steps S510 to S570 added to the image display program according to the first embodiment.

As shown in FIG. 6, in this image display program, after the operations of the polygon mirror 51 and the galvanometer mirror 54 are started in step S130, the timer is used in step S510. Is started. This timer is provided to measure the elapsed time from the start of the operation of the polygon mirror 51. In the present embodiment, the elapsed time means the length of continuous operation time of the polygon mirror 51, and is reflected in a count value that is incremented by one over time.

Subsequently, in step S140, it is determined whether the input of the video signal is continued. In this case, assuming that the input of the video signal is not continued, the determination in step S140 is NO, and in step S520, the time measurement by the timer is performed. It is stopped, and the counter value is reset to 0. Thereafter, in step S150, the operations of the polygon mirror 51 and the galvanometer mirror 54 are stopped. This completes one execution of the image display program.

On the other hand, in this case, assuming that the input of the video signal is continued, the determination in step S140 is YES, and the process proceeds to step S530. In step S530, it is determined whether the current value of the count value is equal to or greater than a predetermined value. It is determined whether or not the continuous display time by the image display device 1 is equal to or longer than the allowable time. In the present embodiment, the predetermined value is set in advance to a value corresponding to two hours. In this case, if it is assumed that the current value of the count value is not equal to or more than the predetermined value, the determination in step S530 becomes NO and the process proceeds to step S160, and thereafter, the count value does not increase to the predetermined value or more. As long as steps S16, S170, S1

The execution of the loop consisting of 40 and S530 is repeated.

Assuming that the count value has become equal to or greater than the predetermined value while the execution of the loop is repeated, the determination in step S530 becomes YES, and the flow shifts to step S540. In this step S540, the timer is stopped and the count value is reset to 0 in the same manner as in step S520.

After that, in step S550, the emission unit 10 is instructed to switch the operation mode from the normal mode to the low output mode. Then, step

5560, the continuous display time by the image display device 2, that is, a long time for notifying the observer that the elapsed time from the start of the operation of the polygon mirror 51 has exceeded the allowable time. Image data representing the time display notification image is stored in the memory 1 1

Read from 6.

The long-time display notification image is configured as a message image with the characters, for example, "The image has been displayed for a long time. The mode has been switched to low output mode." It is possible to

Subsequently, in step S570, various color signals (red, green, and blue luminous flux) for displaying a long-time display announcement image are generated based on the image data read in step S560. Then, output of the generated various color signals to the emission unit 10 is started.

In this step S570, each time a BD signal is input from the cycle detector 100, a composite image in which the above-described long-time display notification image is superimposed on the original image represented by the video signal is displayed. Therefore, various color signals corresponding to one rotation of the polygon mirror 51 are generated and output.

Thereafter, image light for forming a composite image is emitted from the emission unit 10, and the emitted image light is incident on the pupil E of the observer through the scanning unit 50 and the guiding unit 70 in order. The incident image light projects an image on the retina, so that the observer can recognize that the notification image displayed for a long time in front of the pupil E is displayed as a virtual image. . Subsequently, the flow shifts to step S160.

As is clear from the above description, in the present embodiment, when the time elapsed from the start of the operation of the polygon mirror 51 exceeds the allowable time (2 hours in the present embodiment), the emitting unit 10 Is switched to the low output mode.

Here, if the above-mentioned predetermined value, that is, the above-mentioned permissible time, is given, for example, a value that is not expected to give a great fatigue to the observer even if the observer continuously views the virtual image, From the point in time when it is expected that continued viewing will increase fatigue, the output level of the luminous flux incident on the pupil E is the lower level within the range where the observer can view the object. 0 nW or less.

Therefore, according to the present embodiment, it is possible to suppress the feeling of fatigue given to the observer while maintaining the state in which the observer observes the virtual image. As is clear from the above description, in the present embodiment, the running unit 50 constitutes an example of the “scanning unit” in the above item (1), and the computer 112 includes the step S 19 in FIG. 0, S320, and the part that executes step S550 in Fig. 6 constitute an example of the "switch command means" in the above item (14). Furthermore, in the present embodiment, the part of the computer 112 that executes the steps S230, S280 in FIG. 2 and the step S570 in FIG. It constitutes an example of "notification instruction means".

Further, in the present embodiment, the timer that is considered to measure the time in step S510 of FIG. 6 in the computer 112 is an example of the “time detector” in the above item (23). It is composed.

Further, in the present embodiment, an output level of 1 or less is an example of the “normal output level” in the above item (1), and an output level of 100 nW or more and 200 nW or less is the same. This is an example of “low output level” in the section.

As described above, some of the embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely examples, and based on the knowledge of those skilled in the art, including the embodiments described in the section of [Disclosure of the Invention]. The present invention can be implemented in other forms with various modifications and improvements.

Claims

The scope of the claims

1. An image display device that displays an image by projecting the image on the retina of an observer by scanning a light beam,

A scanning unit that scans a light beam emitted from the emission unit;

When the setting conditions are satisfied without depending on the operation of the observer during the display of the image, the light flux from the emission unit is set to a low value which is set in advance so as to be lower than the normal output level but larger than 0. A control unit for controlling the emission unit so as to emit light at an output level.

2. The image display device according to claim 1, wherein the setting condition includes an abnormal condition that is satisfied when an error occurs in the scanning unit.

3. The running unit is

At least one reflecting surface for reflecting the light beam;

Including

3. The image display device according to claim 2, wherein the abnormal condition is satisfied when an actual cycle in which the reflection surface angle changes deviates from a set range.

4. The abnormal condition is satisfied

When at least one of the reflection surface and the driving unit has an abnormal site in the scanning unit, the first condition is satisfied regardless of the abnormal site; and A second condition that is satisfied when an abnormality occurs on the surface; A third condition that is satisfied at least when an abnormality occurs in the driving unit;

4. The image display device according to claim 3, comprising:

5. The scanning unit is a rotating body having a plurality of the reflecting surfaces arranged side by side along a circumference that is coaxial with a rotation axis, the rotation unit being rotated about the rotation axis by the driving unit. Including

The control unit detects the reflection surface angles individually for the plurality of reflection surfaces, and the first condition is that among the plurality of reflection surface angles detected for the plurality of reflection surfaces, respectively. The second condition is satisfied when the first condition is satisfied, and the second condition is satisfied when there is a reflective surface angle that deviates from the first set range. Is established when there is a reflective surface angle whose deviation from the average value of the reflective surface angles exceeds the second set range,

The third condition is a case where the first condition is satisfied, and is satisfied when there is no reflecting surface angle whose deviation exceeds the second set range among the plurality of reflecting surface angles. Item 5. The image display device according to Item 4.

6. Further, the control unit includes a beam detector that detects that the light beam scanned by the scanning unit is incident on a set position, wherein the control unit detects the cycle based on an output signal of the beam detector, and detects the period. 3. The image display device according to claim 2, wherein it is determined whether or not the abnormal condition establishment condition is satisfied based on the performed cycle.

7. The image display device according to claim 1, wherein the setting condition includes a long-time display condition that is satisfied when a continuous display time of the image display device exceeds a set time.

8. The control unit detects the continuous display time based on the elapsed time from the start of the operation of the scanning unit, and performs the long time display based on the detected continuous display time. The image table according to claim 7, which determines whether or not the condition is satisfied. Indicating device.

9. The observer understands that the control unit is in the state where the output level of the light beam emitted from the emission unit is reduced to the low output level because the setting condition is satisfied. 2. The image display device according to claim 1, wherein the emission unit is controlled such that a predetermined message image is projected onto the retina so that the message image can be projected.

10. The image display device according to claim 9, wherein the message image is represented by at least one of a character, a symbol, and a figure.

11. The control unit controls the emission unit in a normal mode in which the emission unit emits the light beam at the normal output level when the setting condition is not satisfied, and when the setting condition is satisfied. The image display device according to claim 1, wherein the emission unit controls the emission unit in a low output mode in which the emission unit emits a light beam at the low output level.

1 2. The low output level is a luminous flux output level at which the observer can visually recognize the image, and which does not cause discomfort to the observer even when the same position on the retina is continuously irradiated. The image display device according to claim 1.

13. An image display device for displaying an image by projecting an image on a retina of an observer by scanning a light beam, wherein a video signal representing the image is input, and based on the input video signal. An emission unit that emits the light beam;

(A) at least one reflecting surface for reflecting the emitted light beam, and (b) an angle of the reflecting surface with respect to the light beam incident on the reflecting surface for scanning the light beam emitted from the emitting portion. A scanning unit having a driving unit that drives the reflection surface so that a certain reflection surface angle periodically changes; During the display of the image, the actual period at which the reflection surface angle changes is optically detected, and when the detected period deviates from a set range, the light flux from the emission unit is output from the normal output level. Is a control unit that controls the emission unit to emit light at a low output level that is set in advance so as to be larger than 0, and the output level of a light beam emitted from the emission unit decreases to the low output level. In this state, the emission unit is controlled so that a predetermined message image is projected on the retina so that an observer can understand that state.

An image display device including: