JP2011090030A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device by which an image is two-dimensionally displayed, wherein the operation of a device which two-dimensionally scans a luminous flux is easily stabilized. <P>SOLUTION: The image display device obtains the actual oscillation frequency of a first reflection mirror 140 in a first scanner 120, obtains a target oscillation frequency of a second reflection mirror 180 in a second scanner 122 on the basis of the actual oscillation frequency, generates a saw tooth wave signal on which the obtained target oscillation frequency is reflected, performs a filtering process on the generated saw tooth wave signal so that the natural resonance frequency band which the second reflection mirror has is trapped, and obtains the driving signal for driving the second scanner on the basis of the saw tooth wave signal after filtered. The image display includes a heat movement promotion means 128 provided so that the movement of heat is promoted between the first scanner and the second scanner. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image display apparatus that displays an image two-dimensionally, and more particularly to a technique for stabilizing the operation of a device that scans a light beam two-dimensionally.

  An image display apparatus that displays an image two-dimensionally is already known. This type of image display device generally includes a light source that emits a light beam and an optical scanner device that two-dimensionally scans the light beam incident from the light source, as disclosed in, for example, Patent Document 1. Composed.

  Here, in the “optical scanner device”, the light beam is scanned in the first direction (main scanning direction) by swinging around the first axis of the first reflecting mirror, and the scanned light beam is rotated around the one axis of the second reflecting mirror. There is a type of scanning in the second direction (sub-scanning direction) intersecting the first direction by swinging.

  In this type of optical scanner device, in general, the first scanner includes a first reflection mirror that reflects the light beam incident from the light source, a first beam connected to the first reflection mirror, and a first drive signal. And a first drive source that swings the first reflecting mirror in the first direction in a resonance mode by torsionally vibrating the first beam portion.

  In this form, the second scanner further includes a second reflecting mirror that reflects the light beam incident from the first reflecting mirror, a second beam connected to the second reflecting mirror, and a second drive signal. And a second drive source that swings the second reflecting mirror in the non-resonant mode in the second direction by electromagnetic driving.

  There is another type of optical scanner device. In this type, the light beam is scanned two-dimensionally by swinging the same reflecting mirror about two axes.

  In general, an optical scanner device of this type includes a reflection mirror that reflects a light beam incident from a light source, a first beam connected to the reflection mirror, and a torsional vibration of the first beam based on a first drive signal. A first drive source that causes the reflection mirror to swing in the first direction in a resonance mode, a movable frame coupled to the first beam portion, and a second beam portion coupled to the movable frame; A fixed frame connected to the second beam portion, and a second drive source that swings the reflecting mirror in the non-resonant mode in the second direction via the movable frame by electromagnetic drive based on a second drive signal And is configured to include.

  In any type of optical scanner device, it is important to control the drive source so that the reflection mirror does not resonate when the light beam is scanned in the second direction (sub-scanning direction) by swinging the reflection mirror.

  For this reason, the drive signal supplied to the drive source is filtered so as not to include a component having the same frequency as the resonance frequency unique to the reflection mirror. In the filtering process, the removal band in which the frequency component is removed from the drive signal is set so as to include the same frequency as the resonance frequency unique to the reflection mirror.

JP 2004-258158 A

  In the above-described conventional optical scanner device, regardless of the type, the second drive source electromagnetically drives the second reflecting mirror or the movable frame in order to scan the light beam in the second direction. . Therefore, the second drive source generates Joule heat, and as a result, a mechanical portion of the optical scanner device that operates to scan the light beam in the second direction (hereinafter referred to as “second scanner for convenience of explanation”). "). Heat is generated.

  However, in the conventional optical scanner device, the second scanner emits the generated heat mainly by thermal radiation, and the heat is released by heat conduction that can realize more effective cooling than the thermal radiation. It was not like that.

  On the other hand, the resonance frequency inherent to the reflecting mirror is not always constant, and varies depending on, for example, the elastic coefficient of the reflecting mirror and the beam connected to the reflecting mirror, and the elastic coefficient depends on the temperature of the reflecting mirror and the beam. It depends on.

  As described above, the drive source for driving the reflection mirror may generate heat during its operation, and in this case, the resonance frequency of the reflection mirror decreases due to the temperature rise of the device.

  When the resonant frequency of the reflection mirror decreases due to the temperature rise of the device, the frequency of the component that should be removed in the drive signal is decreased, and as a result, the frequency deviates from the filtering processing removal band. There is a possibility that.

  This possibility is particularly remarkable when Joule heat is generated in the electromagnetic coil during operation because the driving source uses the electromagnetic coil.

  Against the background described above, the present invention provides an image display apparatus that displays an image two-dimensionally and that can easily stabilize the operation of a device that scans a light beam two-dimensionally. It was made as an issue.

  The following aspects are obtained by the present invention. Each aspect is divided into sections, each section is given a number, and is described in a form that cites other section numbers as necessary. This is to facilitate understanding of some of the technical features that the present invention can employ and combinations thereof, and the technical features that can be employed by the present invention and combinations thereof are limited to the following embodiments. Should not be interpreted. That is, it should be construed that it is not impeded to appropriately extract and employ the technical features described in the present specification as technical features of the present invention although they are not described in the following embodiments.

  Further, describing each section in the form of quoting the numbers of the other sections does not necessarily prevent the technical features described in each section from being separated from the technical features described in the other sections. It should not be construed as meaning, but it should be construed that the technical features described in each section can be appropriately made independent depending on the nature.

(1) An image display device for displaying an image two-dimensionally,
A light source that emits a light beam having an intensity according to an image signal;
A first scanner that scans a light beam incident from the light source in a first direction;
A second scanner that scans a light beam scanned by the first scanner in a second direction intersecting the first direction;
The first scanner includes:
A first reflecting mirror for reflecting the incident light beam;
A first beam connected to the first reflecting mirror;
A first drive source that swings the first reflecting mirror in the first direction in a resonance mode by torsionally vibrating the first beam portion based on a first drive signal;
The second scanner
A second reflecting mirror for reflecting the light beam incident from the first reflecting mirror;
A second beam connected to the second reflecting mirror;
A second drive source that swings the second reflecting mirror in the non-resonant mode in the second direction by electromagnetic drive based on a second drive signal;
The image display device further includes:
A sensor for detecting a swinging state of the first reflecting mirror;
Based on an output signal of the sensor, an actual vibration frequency acquisition unit that acquires an actual vibration frequency of the first reflection mirror;
A target vibration frequency acquisition unit that acquires a target vibration frequency of the second reflection mirror based on the acquired actual vibration frequency of the first reflection mirror;
A sawtooth signal generator that generates a sawtooth signal reflecting the obtained target vibration frequency;
A filter that performs a filtering process on the generated sawtooth signal so that a specific resonance frequency band of the second reflection mirror is trapped;
A drive signal acquisition unit for acquiring the second drive signal based on the filtered sawtooth signal;
An image display device comprising: heat transfer promoting means provided so as to promote heat transfer between the first scanner and the second scanner.

  In this image display device, when the temperature of the second scanner rises, the resonance frequency inherent to it decreases. Therefore, in order to avoid resonance of the second scanner, the frequency band to be removed from the drive signal supplied to the second scanner tends to deviate from the removal band of the filter.

  However, in this image display device, since heat is promoted from the second scanner to the first scanner, the temperature of the first scanner also rises due to the temperature rise of the second scanner. As a result, the resonance frequency of the first scanner also decreases, and its actual vibration frequency also decreases. On the other hand, when the actual vibration frequency decreases, the target vibration frequency of the second scanner also decreases.

  Decreasing the target vibration frequency means that the removal band of the filter shifts in the direction in which the frequency decreases. For this reason, the removal band of the filter shifts in the same direction as the direction in which the resonance frequency of the second scanner changes due to the generation of heat, and as a result, the second scanner has no change in the resonance frequency of the second scanner. The supplied drive signal is unlikely to contain a component having the same frequency as the actual resonance frequency.

  Therefore, according to this image display device, the operation of the second scanner is stabilized despite the temperature rise of the second scanner, and as a result, the quality of the displayed image is improved and stabilized.

  The “heat transfer promoting means” in this section is, for example, means for increasing heat conduction between the first scanner and the second scanner, and, for example, between the first scanner and the second scanner. On the other hand, it is a means for transferring the generated heat to the other by heat conduction.

  In addition, the “first drive source” in this section can be, for example, an electromagnetic drive type as in the case of the second drive source, or other types, for example, a piezoelectric type that generates less heat than the electromagnetic drive type. It is.

(2) The image display device according to (1), wherein the heat transfer promoting unit includes a connecting member that connects the first beam portion and the second beam portion to each other.

  According to this image display device, the first reflection mirror, the first beam portion, the connecting member, the second beam portion, and the second reflection mirror cooperate with each other to form one physical continuum. To do. Accordingly, heat transfer between the first scanner and the second scanner is promoted using heat conduction of the connecting member.

(3) The connection member includes a base frame common to the first reflection mirror and the second reflection mirror,
In the base frame, the first reflection mirror and the second reflection mirror are arranged in a plane,
The image display apparatus according to (2), wherein both the first beam portion and the second beam portion are coupled to the base frame.

(4) The image display device according to (2) or (3), wherein at least the connection member is made of metal.

  According to this image display apparatus, since the connecting member is made of a metal that is a material having a higher thermal conductivity than that of the synthetic resin, heat transfer between the first scanner and the second scanner is easily promoted. be able to.

(5) The first scanner further includes a substrate to which the first beam portion is connected,
The substrate is connected to the first reflecting mirror via the first beam portion,
The first reflecting mirror, the first beam portion, and the substrate are all made of metal, whereby the first scanner is configured as a metal scanner,
The first drive source is mounted on the substrate, and the first reflection mirror is swung in a resonance mode via the substrate and the first beam portion by vibration generated in the first drive source. ,
The image display device further includes a base frame common to the first scanner and the second scanner,
The base frame is connected to the substrate and the second beam portion, and is made of metal.
The image display device according to (1), wherein at least the base frame, the substrate, the first beam portion, and the first reflecting mirror each function as the heat transfer promoting unit.

  According to this image display device, the first scanner and the second scanner are connected to each other by a base frame that is common to them and made of metal that is a material having a higher thermal conductivity than synthetic resin.

  Further, according to the image display device, the first scanner is configured as a metal scanner including the first reflecting mirror and the first beam portion, and a substrate to which the first beam portion is connected, and further, The first reflecting mirror, the first beam portion, and the substrate are all made of a metal that is a material having a higher thermal conductivity than the synthetic resin.

  In the first scanner, vibration generated in the first drive source is transmitted to the first reflection mirror via the substrate and the first reflection mirror, thereby exciting the resonance of the first reflection mirror.

  Therefore, according to this image display device, heat transfer between the first scanner and the second scanner is further enhanced by the base frame, the substrate, the first beam portion, and the first reflecting mirror, all of which are made of metal. Can be easily promoted.

  In one embodiment of the image display device according to this section, the base frame, the substrate, the first beam portion, and the first reflecting mirror are made of, for example, stainless steel, and the first drive source mainly includes, for example, a piezoelectric element. To do.

(6) Furthermore,
Including a temperature sensor installed in the connecting member;
The image display device according to any one of (1) to (5), wherein the temperature detected by the temperature sensor is used as a temperature representative of both the first scanner and the second scanner.

(7) Furthermore,
A second sensor for detecting a swinging state of the second reflecting mirror;
An error determining unit that determines whether an error occurring in the swing of the second reflecting mirror exceeds an allowable value based on an output signal of the second sensor;
The filter does not update the characteristics of the filter processing when the error determination unit determines that the error does not exceed the allowable value, but the error is not updated by the error determination unit. The image display device according to any one of the items (1) to (6), wherein the characteristic of the filtering process is updated when it is determined that the threshold value is exceeded.

  According to this image display device, when the error occurring in the swing of the second reflecting mirror is small, the generation of the sawtooth signal and the filtering process are omitted. Therefore, regardless of the magnitude of the error, The signal processing load is reduced as compared with the case where the generation of the sawtooth signal and the filter processing are performed.

  In this section, the error occurring in the oscillation of the second reflecting mirror is the magnitude of the inherent resonance frequency component that the second reflecting mirror has.

(8) An image display device for displaying an image two-dimensionally,
A light source that emits a light beam having an intensity according to an image signal;
A two-dimensional scanner that two-dimensionally scans a light beam incident from the light source in a first direction and a second direction intersecting each other;
The two-dimensional scanner
A reflection mirror for reflecting the incident light beam;
A first beam connected to the reflecting mirror;
A first drive source that swings the reflection mirror in the first direction in a resonance mode by torsionally vibrating the first beam portion based on a first drive signal;
A movable frame coupled to the first beam portion;
A second beam connected to the movable frame;
A fixed frame connected to the second beam portion;
A second drive source for causing the reflecting mirror to swing in the second direction in a non-resonant mode through the movable frame by electromagnetic drive based on a second drive signal;
The image display device further includes:
A sensor for detecting a swinging state of the reflecting mirror;
Based on an output signal of the sensor, an actual vibration frequency acquisition unit that acquires an actual vibration frequency of the reflection mirror in the first direction;
A target vibration frequency acquisition unit for acquiring a target vibration frequency in the second direction of the reflection mirror based on the acquired actual vibration frequency;
A sawtooth signal generator that generates a sawtooth signal reflecting the obtained target vibration frequency;
A filter that performs a filtering process on the generated sawtooth signal so that a unique frequency band of the reflection mirror is trapped;
A drive signal acquisition unit for acquiring the second drive signal based on the filtered sawtooth signal;
An image display device comprising: heat transfer promoting means provided so as to promote heat transfer between the first beam portion and the second beam portion.

  In this image display device, the temperature of the first beam part affects the resonance frequency of the vibration in the first direction (main scanning direction) of the reflection mirror, while the temperature of the second beam part is affected by the temperature of the reflection mirror. This affects the resonance frequency of vibration in the second direction (sub-scanning direction). This will be explained in comparison with the image display device described in (1) above. The temperature of the “first beam portion” in this section corresponds to the temperature of the “first scanner” in the section (1). In addition, the temperature of the “second beam portion” in this section corresponds to the temperature of the “second scanner” in the section (1).

  And in the image display apparatus which concerns on this term, the movement of the heat | fever between a 1st beam part and a 2nd beam part is accelerated | stimulated. Therefore, according to this image display device, the same operation effect as that of the image display device according to the item (1) can be obtained while the light beam is two-dimensionally scanned by two-dimensional swing of the same reflecting mirror. .

(9) The heat transfer accelerating means is configured such that at least the adjacent portion of the movable frame adjacent to the first beam portion and the fixed frame is made of metal. The image display device according to item (8), wherein the heat transfer between the second beam portion is promoted.

  According to this image display device, the first beam portion and the first beam portion are left on the movable frame while leaving a portion that is not made of metal, that is, a portion that generally does not have magnetism (hereinafter referred to as a “nonmagnetic portion”). Heat transfer between the two beams is promoted.

  Therefore, even when the second drive source is of a type that dislikes contact with a magnetic body (for example, an electromagnetic coil), the second drive source (for example, an electromagnetic coil) is installed in a nonmagnetic part of the movable frame. The movable frame can be forcibly swung by the electromagnetic drive by the second drive source.

1 is a system diagram schematically showing an image display device according to a first embodiment of the present invention. It is a disassembled perspective view which shows the optical scanner apparatus shown in FIG. It is a longitudinal cross-sectional view which shows the optical scanner apparatus shown in FIG. FIG. 2 is a functional block diagram conceptually showing a control unit shown in FIG. 1 together with peripheral devices. 6 is a flowchart conceptually showing a drive signal generation program executed by a computer of the control unit shown in FIG. 5 is a flowchart conceptually showing a target drive frequency acquisition program executed by a computer of the control unit shown in FIG. 4. 6 is a graph for explaining execution of the drive signal generation program shown in FIG. 5. It is a flowchart for demonstrating the effect acquired by the said 1st Embodiment, and the reason which the effect is acquired. It is a perspective view which shows the two-dimensional scanner of the image display apparatuses according to 2nd Embodiment of this invention.

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

  FIG. 1 conceptually shows an image display device 10 according to the first embodiment of the present invention. This image display device 10 is a retinal scanning type, projects a light beam on the retina through the pupil of the observer's eye, and scans the light beam on the retina, thereby projecting an image directly on the retina. To do. In FIG. 1, the eye is indicated by reference numeral 12, the pupil is indicated by reference numeral 14, and the retina is indicated by reference numeral 15.

  This image display device 10 is a head mount type, and as shown in FIG. 1, a mounting unit 16 that is mounted on the head of an observer and a light source unit 18 carried by the observer are physically connected. Provided independently of each other. The mounting portion 16 and the light source unit 18 are optically connected to each other by a flexible optical fiber 20 as an optical transmission means.

  The wearing unit 16 is a glasses type, and is held on the observer's head using the observer's nose and both ears in the same manner as normal glasses. The light source unit 18 is used by being attached to the observer on the waist or back of the observer using, for example, a fixing tool such as a belt.

  The image display apparatus 10 is a monocular system, and projects an image on the retina 15 of one eye 12 of the observer. Therefore, as shown in FIG. 1, the image display apparatus 10 includes a scanning unit 40 that scans the light beam in the mounting unit 16, and the scanned light beam is incident on one eye 12 and projected onto the retina 15. A projection tool 42 is provided. The mounting portion 16 is connected to the optical fiber 20 in the scanning unit 40.

  As shown in FIG. 1, the projection tool 42 is of a reflective type, and reflects the light beam scanned by the scanning unit 40 to enter the retina 15. Specifically, the projection tool 42 is configured by using a half mirror having a shape similar to each lens in normal glasses. In the projection tool 42, the surface facing the observer is a reflection surface 44, and as shown in FIG. 1, the light beam incident on the reflection surface 44 from the scanning unit 40 is reflected by the reflection surface 44 and reflected by the eye 12. Is incident on.

  In addition to the reflection function described above, the projection tool 42 also has a transmission function that allows light incident from the front of the projection tool 42 to pass through and enter the eye 12. Therefore, the observer can visually recognize the image transmitted from the image display device 10 by superimposing it on the actual scene in front of the eye that has passed through the projector 42. That is, the image display device 10 is a see-through type.

  In FIG. 1, the light source unit 18, the optical fiber 20, and the scanning unit 40 are shown in an optical path diagram.

  The light source unit 18 is configured to include a light source unit 50, a converging unit 52, and a control unit 54.

  The light source unit 50 includes a laser device 60 that generates a red (R) laser beam, a laser device 62 that generates a green (G) laser beam, and a blue (B And a laser device 64 for generating a laser beam. Each of the laser devices 60, 62, and 64 is composed mainly of a semiconductor laser, for example.

  The intensity of the laser beam generated from the laser devices 60, 62, and 64 is controlled by the control unit 54 for each pixel based on an image signal representing an image to be projected on the retina 15.

  On the other hand, the converging unit 52 is provided to focus the three laser beams generated from the three laser devices 60, 62, and 64. For example, for each laser device 60, 62, and 64, Collimating lenses 70, 72, and 74 for collimating the generated laser beam and dichroic mirrors 80, 82, and 84 are included.

  The laser beam focused by the focusing unit 52 is converged by the converging lens 90, and the converged laser beam passes through the optical fiber 20 and enters the scanning unit 40.

  As shown in FIG. 1, the scanning unit 40 includes a collimating lens 98 for collimating the laser beam emitted from the optical fiber 20, and a first direction and a second direction in which the laser beam emitted from the collimating lens 98 intersects each other. And an optical scanner device 100 that scans two-dimensionally in the direction.

  In the present embodiment, the collimating lens 98 causes the laser beam to enter the optical scanner device 100 as parallel light. The laser beam emitted from the optical scanner device 100 is incident on the reflecting surface 44 of the projection tool 42 and is reflected there to reach the retina 15.

  As shown in FIG. 1, a drive unit 110 is electrically connected to the optical scanner device 100. The drive unit 110 drives the optical scanner device 100 based on a drive signal supplied from the control unit 54 via the optical fiber 20 or an electric wire that is a different path.

  The optical scanner device 100 is of a parallel structure type, and includes an upstream high-speed scanner (hereinafter also referred to as “HS”) 120 and a downstream low-speed scanner (hereinafter referred to as “LS”). 122) on the same plane. The high-speed scanner 120 and the low-speed scanner 122 are driven by the drive unit 110.

  The high-speed scanner 120 causes the laser beam incident thereon to be fast in a first mode (also referred to as “main scanning direction”, for example, one of a horizontal direction and a vertical direction) in a resonance mode (by resonance of a reflection mirror 140 described later). Scan. In contrast, the low-speed scanner 122 applies the laser beam incident from the high-speed scanner 120 in a second direction (also referred to as “sub-scanning direction”, for example, the other of the vertical direction and the horizontal direction) that intersects the first direction. The scanning is performed at a low speed in the non-resonant mode (by forced swinging of a reflection mirror 180 described later).

  Therefore, in the present embodiment, the high-speed scanner 120 is an example of the “first scanner” in the item (1), and the low-speed scanner 122 is an example of the “second scanner” in the item.

  Since the basic configuration of the optical scanner device 100 is disclosed in detail in Japanese Patent Application Laid-Open No. 2005-181666 relating to the applicant's patent application, redundant description is omitted in this specification. The publication is incorporated herein by reference in its entirety.

  2 shows the optical scanner device 100 in an exploded perspective view, while FIG. 3 shows the optical scanner device 100 in a longitudinal sectional view. The optical scanner device 100 is configured by covering the surface of the vibrating body 124 with a cover 126.

  The vibrating body 124 includes a thin metal base frame 128 shared by the high-speed scanner 120 and the low-speed scanner 122. The base frame 128 is configured with a plate made of SUS304 (an example of a material classified as metal) having a thickness of about 30 to 50 μm as a base material.

  By etching the base material, the base frame 128 and the vibration part of the high-speed scanner 120 are integrally formed with the vibrating body 124. The high-speed scanner 120 scans the laser beam incident thereon in the first direction as the vibrating part (oscillating part), and a pair of beam parts 150 facing each other with the reflecting mirror 140 interposed therebetween. , 150.

  That is, in the present embodiment, the reflecting mirror 140 constitutes an example of the “first reflecting mirror” in the item (1), and the pair of beam portions 150 and 150 is an example of the “first beam portion” in the same term. It is composed.

  For the reflecting mirror 140 and the beam portion 150, a portion of the base frame 128 that surrounds the beam portion 150 adjacent to the beam portion 150 functions as a fixed frame. The beam unit 150 connects the reflection mirror 140 and the base frame 128 to each other.

  The high-speed scanner 120 has a first swing axis in a direction in which the pair of beam portions 150 and 150 face each other. Further, a drive source (for example, a piezoelectric element) 160 is attached to each of the pair of beam portions 150 and 150, and each drive source 160 causes the corresponding mirror portion 150 to torsionally vibrate to cause the reflection mirror 140 to resonate. Is swung around the first swing axis (in the first direction).

  As shown in FIG. 2, in the present embodiment, two beam portions 150 and 150 exist at two positions facing each other across the reflection mirror 140, and the drive source 160 is provided in each beam portion 150. It is installed.

  The beam portions 150 and 150 are each given displacement from the respective driving sources 160 so as to be displaced in the thickness direction in opposite directions. As a result, the beam portions 150 and 150 jointly cause the reflection mirror 140 to swing around the first swing axis in the same direction.

  In the present embodiment, in the high-speed scanner 120, the reflection mirror 140 and the beam portion 150 are made of a thin metal plate, but may be manufactured using a lighter material (for example, silicon).

  As shown in FIG. 1, the drive unit 110 is provided with a drive circuit 162 for driving a drive source 160 of the high-speed scanner 120. The drive circuit 162 is designed to supply necessary power to the drive source 160 based on a drive signal (for example, a sine wave signal) supplied from the control unit 54.

  As apparent from the above description, the high speed scanner 120 is formed integrally with the base frame 128, whereas the low speed scanner 122 is formed independently of the base frame 128. A rectangular recess (or through hole) 170 is formed in the base frame 128 on the downstream side of the high-speed scanner 120, and the low-speed scanner 122 is attached to the recess 170.

  As shown in FIG. 2, the low-speed scanner 122 separates the reflection mirror 180 from the reflection mirror 180 as a vibration unit (oscillation unit) in order to scan the laser beam incident from the high-speed scanner 120 in the second direction. And a pair of beam portions 182 and 182 facing each other, and a fixed frame 184 to which the beam portions 182 and 182 are connected.

  That is, in the present embodiment, the reflecting mirror 180 constitutes an example of the “second reflecting mirror” in the item (1), and the pair of beam portions 182 and 182 is an example of the “second beam portion” in the item. It is composed.

  The reflecting mirror 180, the pair of beam portions 182 and 182 and the fixed frame 184 are integrally formed by etching a silicon wafer (an example of a nonmagnetic material) which is a base material. The low-speed scanner 122 has a second swing axis in a direction in which the pair of beam portions 182 and 182 face each other.

  The low-speed scanner 122 is classified as a so-called galvanometer mirror. Since the basic configuration of the galvanometer mirror is well known, detailed description is omitted here. In the low-speed scanner 122, a driving source 186 (not shown in FIGS. 1 to 3 but only shown in FIG. 4 which is a functional block diagram) is mounted on the back surface of the reflecting mirror 180. An example of the drive source 186 is a printed wiring that functions as an electromagnetic coil. The low-speed scanner 122 includes a permanent magnet 188 (not shown in FIGS. 1 to 3 but only shown in FIG. 4 which is a functional block diagram) at a position facing the driving source 186. The permanent magnet 188 forms a static magnetic field.

  The driving source 186 of the low-speed scanner 122 cooperates with the permanent magnet 188 to torsionally vibrate the pair of beam portions 182 and 182 so that the reflection mirror 180 is rotated around the second oscillation axis in the non-resonant mode (the second direction). ) Forcibly swing.

  In addition, in this embodiment, as shown in FIG. 2, a single beam portion 182 that connects the reflecting mirror 180 and the fixed frame 184 so as to be relatively swingable with respect to each other is provided with respect to the position of the reflecting mirror 180. It is arranged on each side.

  As shown in FIG. 1, the drive unit 110 is provided with a drive circuit 190 for driving a drive source 186 of the low-speed scanner 122. The drive circuit 190 is designed to supply necessary power to the drive source 186 based on a drive signal (for example, a signal obtained by correcting a linearly changing sawtooth signal) supplied from the control unit 54. .

  As shown in FIG. 1, the scanning unit 40 further includes a beam detector 194 (indicated as “BD” in FIG. 1) at a fixed position. The beam detector 194 is provided for detecting the laser beam deflected by the high-speed scanner 120 (that is, the laser beam scanned in the first direction). An example of the beam detector 194 is a photodiode.

  The beam detector 194 outputs a signal indicating whether the laser beam has reached a predetermined position (a signal that changes between an on state and an off state) to the control unit 54 as a BD signal. In response to the BD signal output from the beam detector 194, the control unit 54 waits for a set time to elapse from the time when the beam detector 194 detects the laser beam, and sends the necessary drive signal to each laser device 60, 62, 64. Thereby, the image display start timing is determined for each scanning line, and the image display is started at the determined image display start timing.

  The control unit 54 further counts the period of the BD signal supplied thereto (for example, the interval between two adjacent edge portions in the BD signal based on a faster clock such as a system clock). The actual vibration frequency of the reflection mirror 140 of the high-speed scanner 120 is acquired based on the (acquired period). The use of this actual vibration frequency will be described in detail later.

  As shown in FIG. 1, the scanning unit 40 further includes a swing state sensor 196 that detects the swing state of the reflection mirror 180 of the low-speed scanner 122. The swing state sensor 196 is, for example, a piezoelectric element attached to each beam portion 182, and is used to detect the swing state of the reflection mirror 180 and ringing by detecting distortion of each beam portion 182. Is done. Here, “ringing” means an unnecessary resonance component that appears in the reflection mirror 180 in a form superimposed on the swing of the reflection mirror 180 according to the drive signal.

  As shown in FIG. 2, the cover 126 is configured such that the vertical wall portion 202 extends from the peripheral edge of the plate portion 200. The cover 126 includes an entrance-side transmission unit 204 to allow the laser beam to be incident from the outside, while the exit-side transmission unit 206 is configured to allow the laser beam to exit to the outside. I have.

  As shown in FIG. 3, the laser beam is incident on the high-speed scanner 120 through the entrance-side transmission part 204 while the laser beam is emitted obliquely from the low-speed scanner 122 through the exit-side transmission part 206.

  As shown in FIGS. 2 and 3, a fixed mirror 210 is mounted on the both surfaces of the plate unit 200 facing the high speed scanner 120 and the low speed scanner 122 (that is, the back surface). The fixed mirror 210 is mounted at a fixed position. The fixed mirror 210 reflects the laser beam emitted from the high speed scanner 120 toward the low speed scanner 122.

  The configuration of the image display device 10 has been schematically described above. Next, portions of the image display device 10 that need to be described in order to understand the present invention, particularly the high-speed scanner 120 and the low-speed scanner 122. This control will be described in more detail.

  FIG. 4 conceptually shows the configuration of the control unit 54 in a functional block diagram. The control unit 54 generates a drive signal to be supplied to the drive circuit 190 of the low-speed scanner 122 and a first drive signal generation unit 220 for generating a drive signal to be supplied to the drive circuit 162 of the high-speed scanner 120. The second drive signal generator 222 is provided.

  The first drive signal generation unit 220 generates a drive signal necessary for the high-speed scanner 120 to resonate and supplies the drive signal to the drive circuit 162. The vibration frequency (resonance frequency) inherent to the high-speed scanner 120 is uniquely determined mainly by the mass and elastic coefficient of the reflection mirror 140 and the beam portion 150.

  However, the elastic coefficient of the reflecting mirror 140 and the beam part 150 (particularly the elastic coefficient of the beam part 150) is such that the elastic coefficient decreases as the temperature of the high-speed scanner 120 increases (particularly the temperature of the beam part 150). There are characteristics. Therefore, the high-speed scanner 120 also has a temperature characteristic that the resonance frequency decreases as the temperature thereof increases.

  Therefore, the first drive signal generation unit 220 monitors the deflection angle of the reflection mirror 140 based on the output signal from the beam detector 194 during the operation of the high-speed scanner 120, whereby the reflection mirror 140 is in a resonance state. And a drive signal (sine wave signal) is generated so that the reflection mirror 140 is maintained in a resonance state.

  As a result, the reflection mirror 140 is maintained in a resonance state despite its temperature change. Therefore, the actual vibration frequency of the reflection mirror 140 may fluctuate.

  On the other hand, the second drive signal generation unit 222 generates a drive signal necessary for forcibly swinging the low-speed scanner 122 in the non-resonant mode in synchronization with the vibration of the high-speed scanner 120 to the drive circuit 190. Supply.

  In the present embodiment, for the high-speed scanner 120, it is necessary to swing the reflection mirror 140 at high speed in the resonance mode in order to realize high-speed scanning, but for the low-speed scanner 122, low-speed scanning is sufficient. It is not necessary to swing the reflection mirror 180 at high speed in the resonance mode.

  However, since the reflection mirror 180 of the low-speed scanner 122 also has its own vibration frequency, the drive signal supplied to the drive circuit 190 for oscillating the reflection mirror 180 is substantially equal to the natural vibration frequency. If the frequency components having the same frequency are included in the reflection mirror 180, the reflection mirror 180 resonates unexpectedly in addition to the oscillation according to the drive signal. A large error occurs in the movement of the reflection mirror 180, and a large ringing occurs. Therefore, also in the low-speed scanner 122, it is necessary to consider the resonance frequency of the reflection mirror 180.

  Therefore, the second drive signal generation unit 222 has a sawtooth signal having a frequency that is uniquely determined according to the frequency (drive frequency) of the drive signal supplied to the drive circuit 162 of the high-speed scanner 120 (a linearly changing period). The fundamental signal is subjected to filter processing (digital filter processing) on the fundamental signal, and the resonance frequency (primary resonance frequency f1 and secondary resonance) inherent to the low-speed scanner 122 is obtained from the fundamental signal. The component having the same frequency as that including the frequency f2 is removed.

  As shown in FIG. 4, in the second drive signal generation unit 222, basic signals are stored in advance as dot data in the first storage unit (memory) 230. The reading unit 232 reads data from the first storage unit 230 at the first clock frequency, and the filter unit 234 performs a filtering process on the read data.

  As shown in FIG. 4, in the second drive signal generation unit 222, the target drive frequency acquisition unit 235 further calculates the actual vibration frequency of the high-speed scanner 120 based on the output signal of the beam detector 194. The target drive frequency of the low-speed scanner 122 is acquired by dividing the actual vibration frequency by a predetermined integer value n corresponding to the total number of scanning lines per frame.

  The actual vibration frequency of the high-speed scanner 120 is acquired based on the period of the output signal of the beam detector 194. Therefore, in the present embodiment, the beam detector 194 constitutes an example of the “sensor that detects the swinging state of the first reflecting mirror” in the item (1).

  The filter processing characteristics of the filter unit 234 are determined based on parameters (including a cutoff frequency and a center frequency of a trap frequency band described later). The parameter is determined by the parameter determination unit 236 based on the output signal of the swing state sensor 196.

  The filtered signal is temporarily stored in the second storage unit (memory) 238 as dot data. The D / A converter 240 reads data from the second storage unit 238 at a second clock frequency equal to the first clock frequency, and converts the read data into an analog signal. The converted analog signal is supplied to the drive circuit 190 of the low-speed scanner 122 as a drive signal.

  In addition, in the description of the present embodiment, the first clock signal having the first clock frequency and the second clock signal having the second clock frequency are used separately from each other for convenience of description. This is because the purpose for which each clock signal is used is different from each other, but physically it may be a common clock signal.

  The filtering process includes a primary filter process for attenuating the basic signal in a frequency band equal to or higher than the secondary resonance frequency f2 of the low-speed scanner 122, and a signal after the filter process is performed on the primary resonance frequency f1 of the low-speed scanner 122 And second-order filter processing for attenuating in a frequency band centered on.

  The primary filter process is a low-pass filter process, for example, a Bessel type 18th-order low-pass filter process. On the other hand, the secondary filter process includes a preceding secondary low-pass filter process and a subsequent secondary notch filter process.

  Regarding the secondary filter processing, the characteristics of the low-pass filter processing are determined by parameters such as the cutoff frequency, and the cutoff frequency is set according to the secondary resonance frequency f 2 of the low-speed scanner 122. On the other hand, the characteristic of the notch filter processing is based on the parameter of the center frequency of the frequency band to be trapped by the notch filter processing (hereinafter, also referred to as “trap frequency band” or “removal band”) in the processing target signal. The center frequency of the trap frequency band is set according to the primary resonance frequency f 1 of the low-speed scanner 122.

  In the present embodiment, when the primary filter process is performed on the basic signal, the basic signal is converted into the primary signal, and when the secondary filter process is performed on the primary signal, When the primary signal is converted into a secondary signal and D / A conversion is performed on the secondary signal, the secondary signal is converted into a final drive signal.

  The control unit 54 shown in FIG. 4 operates when a computer (not shown) (having a processor and a memory) executes a predetermined program. The predetermined program includes a drive signal generation program and a target drive frequency acquisition program in order to realize the function of the second drive signal generation unit 222.

  FIG. 5 schematically shows a drive signal generation program in a flowchart.

  This drive signal generation program is repeatedly executed by the computer. When executing each time, first, in step S101, the target drive frequency fd of the low-speed scanner 122 is acquired. This acquisition is performed by executing the target drive frequency acquisition program (described in detail later).

  Next, in step S102, the acquired target drive frequency fd is set as the first clock frequency, and a first clock signal having the set first clock frequency is generated.

  Subsequently, in step S103, by using the generated first clock signal, data representing the sawtooth signal that is the basic signal is read from the first storage unit 230 at the first clock frequency. As a result, a sawtooth signal (basic signal to be processed by the filter unit 234) is generated.

  In the present embodiment, the part that executes steps S104 and S105 in the computer constitutes the reading unit 232 shown in FIG.

  Thereafter, in step S104, it is determined whether or not a predetermined condition is satisfied. Specifically, the condition is when the drive signal generation program is executed for the second time or later, that is, after the operation of the low-speed scanner 122 is started as a result of execution of step S111 described later. The case holds.

  If it is assumed that the above condition has not been satisfied yet (this execution is the first time, not the second and subsequent times), the determination in step S104 is NO and the process proceeds to step S107.

  In step S107, the parameters for setting the characteristics of the filtering process are determined based on the swing state of the low-speed scanner 122 detected based on the output signal of the swing state sensor 196. For example, a parameter corresponding to the detected value of the swinging state of the reflecting mirror 180 is determined by referring to a table (stored in advance in the memory) set in advance between the swinging state and the parameter. The

  In the present embodiment, the portion of the computer that executes steps S106 and S107 constitutes the parameter determination unit 236 shown in FIG.

  Thereafter, in step S108, the filtering process (including the primary filtering process and the secondary filtering process) is performed on the generated sawtooth signal (basic signal) based on the determined parameters. Is done. The secondary filter processing includes the notch filter processing.

  In the present embodiment, the part that executes step S108 of the computer constitutes the filter unit 234 shown in FIG.

  Subsequently, in step S <b> 109, the sawtooth wave signal (secondary signal) subjected to the filtering process is temporarily stored in the second storage unit 238.

  Thereafter, in step S110, a second clock signal having the same frequency as the first clock signal is generated. Subsequently, in step S111, by using the generated second clock signal, data representing the filtered sawtooth signal (secondary signal) is transferred from the second storage unit 238 to the second clock frequency. Then, it is read out. The read sawtooth signal is D / A converted to generate a final drive signal.

  In this embodiment, the part which performs step S111 among the said computers comprises the D / A converter 240 shown in FIG.

  This completes one execution of the drive signal generation program.

  This time, it is assumed that the condition is not satisfied (this execution is the first time, not the second time or later), but the condition is satisfied (the current execution is after the second time). ), The determination in step S104 is YES.

  In this case, after that, in step S105, based on the output signal of the oscillation state sensor 196 for the low-speed scanner 122, the size (amplitude) of the ringing (oscillation having a natural resonance frequency) of the reflection mirror 180 is performed. Is detected.

  Subsequently, in step S106, it is determined whether or not the detected ringing magnitude exceeds an allowable value.

  Here, considering one of the main causes of the increase in the ringing of the reflection mirror 180 of the low-speed scanner 122, when the temperature of the low-speed scanner 122 rises and its resonance frequency decreases, the resonance frequency is reduced by the filtering process. It will be out of the removal band. Nevertheless, if the filtering process is performed without updating the parameters, a component having the same frequency as the resonance frequency remains in the drive signal supplied to the low-speed scanner 122. As a result, the movement of the reflecting mirror 180 deviates from the constant angular velocity fluctuation, which causes ringing.

  If it is assumed that the ringing magnitude of the reflection mirror 180 of the low-speed scanner 122 exceeds the allowable value this time, the determination in step S106 is YES, and the process proceeds to step S107.

  This time, it is assumed that the ringing (error) of the reflection mirror 180 of the low-speed scanner 122 is large. If not, the determination in step S106 is NO.

  In this case, step S107 is skipped, and then the process proceeds to step S108. Therefore, this time, the filter process is performed in step S108 without updating the filter characteristic parameters.

  FIG. 6 schematically shows the target drive frequency acquisition program in a flowchart.

  This target drive frequency acquisition program is repeatedly executed by the computer. When executing each time, first, in step S201, a BD signal is captured from the beam detector 194 for the high-speed scanner 120.

  Thereafter, in step S202, based on the captured BD signal, the actual vibration frequency f0 of the reflection mirror 140 of the high-speed scanner 120 is detected as described above.

  Subsequently, in step S203, the detected actual vibration frequency f0 is divided by the predetermined integer value n to obtain the target drive frequency fd of the low-speed scanner 122.

  Thereafter, in step S204, the acquired target drive frequency fd or information related thereto (for example, a frequency division ratio, etc.) is stored in the memory of the computer for subsequent use. When step S102 (or S110) shown in FIG. 5 is executed, the latest target drive frequency fd is read from the memory.

  This completes one execution of the target drive frequency acquisition program.

  In the present embodiment, a portion of the computer that executes the target drive frequency acquisition program constitutes a target drive frequency acquisition unit 235 shown in FIG.

  As apparent from the above description, in the present embodiment, when the ringing of the reflection mirror 180 of the low-speed scanner 122 is large because the temperature of the low-speed scanner 122 is greatly increased and the resonance frequency thereof is greatly decreased, The parameters that determine the characteristics of the filtering process are updated to reflect the actual swaying state of the low speed scanner 122 (eg, related to its resonant frequency), after which the filtering process is performed.

  On the other hand, when the ringing of the reflection mirror 180 of the low-speed scanner 122 is small, the filtering process is performed without updating the parameters that determine the characteristics of the filtering process, and thereby the final drive signal is Generated.

  That is, when the ringing of the reflection mirror 180 of the low-speed scanner 122 is small, a drive signal for the low-speed scanner 122 is generated without updating the filter processing characteristics, thereby reducing the load on the computer. It is.

  In this embodiment, the frequency band removed from the final drive signal is shifted so as to follow the decrease in the resonance frequency of the low-speed scanner 122. As a result, the same frequency as the resonance frequency is obtained from the final drive signal. The reason for this will be explained below.

  Similar to the case of the high-speed scanner 120, the resonance frequency inherent in the low-speed scanner 122 also has temperature dependency. As the temperature of the low-speed scanner 122 increases, the resonance frequency inherent to the low-speed scanner 122 decreases.

  Here, the temperature characteristic of the resonance frequency of the low-speed scanner 122 will be considered in more detail. As described above, the low-speed scanner 122 is a type in which the drive source 186 swings the reflection mirror 180 using an electromagnetic coil (electromagnetic drive). Method). Therefore, Joule heat is generated in the electromagnetic coil during the operation of the low-speed scanner 122, and as a result, the low-speed scanner 122 is more likely to generate heat than the high-speed scanner 120 that does not generate Joule heat. The temperature change greatly affects the elastic characteristics of the beam or the like that supports the low-speed scanner 122. Therefore, the resonance frequency that is easily affected by the elastic characteristics is likely to decrease.

  When the actual resonance frequency of the low-speed scanner 122 decreases, the resonance frequency may deviate from the removal band of the above-described notch filter processing.

  Even if such a shift exists between the resonance frequency and the removal band of the low-speed scanner 122, if the notch filter processing is performed while ignoring this, the signal after the notch filter processing (the low-speed scanner as the drive signal) The frequency component that should originally be removed is not actually removed. When the low-speed scanner 122 is driven using such a drive signal, ringing occurs in the movement of the reflecting mirror 180 that is oscillating (ideally, strictly constant angular velocity movement).

  Therefore, the present inventor has studied a measure (a measure for improving heat dissipation) in the optical scanner device 100 for promoting the heat dissipation from the low-speed scanner 122 in order to suppress the temperature rise of the low-speed scanner 122.

  As a result of the research, the present inventor found that the base frame 128 surrounding the low-speed scanner 122 is made of a metal having a higher thermal conductivity than a synthetic resin such as silicon, so that the heat dissipation of the low-speed scanner 122 is achieved. I realized it was effective for improvement.

  The present inventor has further noticed the following regarding the notch filter processing.

  The signal to be subjected to notch filter processing is subjected to primary filter processing (for example, 18th-order low-pass filter processing) on a basic signal, that is, a sawtooth signal (a signal that varies linearly) that has not been modified at all. However, the frequency (drive frequency) of the primary signal, which is the signal obtained by processing the basic signal, is the actual vibration frequency of the high-speed scanner 120 (ideally matches the actual resonance frequency f0). It is set so as to follow the fluctuation of.

  In the notch filter processing, the frequency (drive frequency) of the primary signal is set by dividing the actual vibration frequency of the high-speed scanner 120 by the predetermined integer value n. Therefore, the driving frequency of the primary signal depends on the actual vibration frequency of the high-speed scanner 120.

  Further, in the notch filter processing, the center frequency of the removal band should ideally be set variably so as to follow the actual resonance frequency of the low-speed scanner 122. However, when the temperature of the low-speed scanner 122 rises and the resonance frequency thereof decreases, a divergence (which is difficult to accept) frequently occurs between the resonance frequency and the center frequency of the removal band.

  However, if the temperature of the low-speed scanner 122 rises and the resonance frequency of the low-speed scanner 122 decreases, the present inventor takes measures to increase the temperature of the high-speed scanner 120 and decrease its actual vibration frequency so as to follow it. When taken, it was noticed that the actual removal band in the secondary signal, which is the filtered signal of the primary signal, shifts in the same direction as the direction in which the resonant frequency of the low speed scanner 122 changes.

  Hereinafter, this will be specifically described with reference to FIG.

  When the sawtooth signal that is the primary signal is Fourier-transformed, the sawtooth signal is decomposed into a plurality of harmonic components that are integer multiples of the drive frequency, as shown in FIG. In FIG. 7, “θ” represents the amplitude of the sawtooth signal, “t” represents time, “Gain” represents the gain of the frequency spectrum, and “fr” represents the frequency.

  In the present embodiment, the notch filter processing is designed such that the center frequency of its removal band depends on the drive frequency of the sawtooth signal (hereinafter simply referred to as “drive frequency”). The center frequency of the removal band is obtained by multiplying the drive frequency by m (m> 1). Here, as an example, a notable harmonic of interest among a plurality of harmonic components is selected as a harmonic having a frequency four times the driving frequency, and is set as the center frequency of the removal band.

  In addition, it is desirable that the drive signal that causes the reflecting mirror 180 of the low-speed scanner 122 to move at an equal angular velocity includes the highest order harmonics of the sawtooth signal. Therefore, it is desirable that the value of m is sufficiently larger than the value of m in the above example, that is, 4 and, for example, the value of m is selected so that the low-speed scanner 122 satisfies m> 10. It is common.

  Here, it is assumed that the driving frequency (first and second clock frequencies) is 60 Hz at time t1, and the driving frequency (first and second clock frequencies) is 55 Hz at time t2. From time t1, at time t2, the temperature of the high-speed scanner 120 rises and the resonance frequency thereof decreases, so that the drive frequency (first and second clock frequencies) decreases.

  As shown in FIG. 7B, the center frequency (harmonic frequency) of the removal band is 60 Hz as the driving frequency (in this figure, “fl” in the meaning of “frame rate”). In some cases, the frequency is 240 Hz. On the other hand, when the drive frequency fl is 55 Hz, the frequency is 220 Hz.

  When a notch filter process in which the center frequency of the removal band is set to 240 Hz is performed on a sawtooth signal (primary signal) having a driving frequency fl of 60 Hz, as shown in FIG. Moreover, the harmonics of 240 Hz are removed from the sawtooth signal (primary signal) by the notch filter processing.

  Here, when the notch filter process having the same characteristics is executed for the same primary signal with the drive frequency fl set to 55 Hz (both the first and second clock frequencies are set to 55 Hz), the sawtooth signal (1 The frequency component having a frequency 220 Hz that is four times the driving frequency fl is removed from the next signal. In other words, the center frequency of the actual removal band of the notch filter processing depends on the drive frequency fl.

  Thus, even if the parameter of the notch filter processing is not updated so as to follow the resonance frequency of the low-speed scanner 122, if the drive frequency fl decreases, the center frequency of the removal band automatically decreases.

  As described above, in the present embodiment, when the temperature of the low-speed scanner 122 rises and the resonance frequency thereof decreases, the temperature of the high-speed scanner 120 increases and the actual vibration frequency thereof also follows. Decreasing measures are taken.

  Specifically, this countermeasure does not arrange the high-speed scanner 120 and the low-speed scanner 122 so as to be thermally shielded from each other, but makes the high-speed scanner 120 and the low-speed scanner 122 common to them. 120, and promoting heat transfer between the high-speed scanner 120 and the low-speed scanner 122 by an effective form of heat conduction.

  According to this, the reflecting mirror 140 and the reflecting mirror 180 are connected to each other via the base frame 128 as a connecting member, and as a result, one physical continuous body is formed.

  Further, this measure includes that the base frame 128 is made of a metal that is a material having a higher thermal conductivity than that of the synthetic resin, and further, the temperature of the beam portion 150 in the high-speed scanner 120 is easily increased. The beam portion 150 is made of a metal having a higher thermal conductivity than that of the synthetic resin.

  FIG. 8 shows, in time series, the phenomenon that the removal band of the notch filter processing by the filter unit 234 follows due to the temperature rise of the low-speed scanner 122 (LS) in the optical scanner device 100.

  First, when the temperature of the low speed scanner 122 increases in step S1, the resonance frequency of the low speed scanner 122 decreases in step S2. As a result of step S1, heat generated in the low-speed scanner 122 in step S3 is transferred to the high-speed scanner 120 (HS) via the base frame 128. As a result, the temperature of the high-speed scanner 120 rises.

  Following step S3, the resonance frequency of the high-speed scanner 120 decreases in step S4. Subsequently, in step S5, the driving frequency of the low-speed scanner 122 ("target vibration frequency" in the above (1), first clock frequency and Which is also the second clock frequency). Thereafter, in step S6, the removal band of the notch filter processing for the low-speed scanner 122 decreases.

  Steps S2 and S6 work together. As a result, in step S7, the removal band of the notch filter process follows the decrease in the resonance frequency of the low-speed scanner 122.

  In addition, in this embodiment, heat generated during the operation of the low-speed scanner 122 is positively transmitted to the high-speed scanner 120 in this embodiment. As a result, even when the ambient temperature is low, an additional effect that the time required for the temperature of the high-speed scanner 120 to rise to an appropriate temperature range (normal temperature range) is shortened can be obtained.

  This effect makes it easy to reduce the operating temperature range of the entire optical scanner device 100 including the high-speed scanner 20, that is, the temperature range in which normal operation must be ensured, thereby improving the degree of freedom in design. To do.

  As is clear from the above description, in the present embodiment, the portion of the computer that executes steps S201 and S202 shown in FIG. 6 is an example of the “actual vibration frequency acquisition unit” in the above item (1). The portion that configures and executes step S203 constitutes an example of the “target drive frequency acquisition unit” in the same term, and the portion that executes steps S102 and S103 shown in FIG. The part that executes steps S107 to S109 constitutes an example of “filter” in the same term, and the part that executes steps S110 and S111 is an example of “driving signal acquisition unit” in the same term It constitutes.

  Furthermore, in the present embodiment, the base frame 128 constitutes an example of the “heat transfer promoting means” in the item (1) and an example of the “connecting member” in the item (2).

  In addition, in this embodiment, a temperature sensor (not shown) is installed in the base frame 128, and the temperature detected by the control unit 54 is detected by the high-speed scanner 120 and the low-speed scanner 122. It is possible to change so that the operation state of the entire optical scanner device 100 is monitored by using both as representative temperatures.

  In this case, for example, when the temperature detection value exceeds an allowable value, the control unit 54 can be designed to prohibit the continuation of the operation because the optical scanner device 100 may be overheated. It is.

  Next, a second embodiment of the present invention will be described. However, since this embodiment has many elements in common with the first embodiment, the common elements are quoted using the same name or reference numerals, and redundant description is omitted, and only different elements are cited. This will be described in detail.

  As shown in FIG. 2, in the image display device 10 according to the first embodiment, the high-speed scanner 120 and the low-speed scanner 122 are arranged side by side on the same plane and are installed on a base frame 128 common to them. ing.

  In contrast, the image display apparatus 260 according to the present embodiment includes a two-dimensional scanner 270 shown in FIG. 9 instead of the optical scanner apparatus 100. The two-dimensional scanner 270 is configured to two-dimensionally scan the light beam incident on the reflection mirror 272 by swinging one reflection mirror 272 two-dimensionally.

  Since the basic configuration of the two-dimensional scanner 270 is disclosed in Japanese Patent Application Laid-Open No. 2008-191619 related to the applicant's patent application, a duplicate description is omitted. This publication is incorporated herein by reference in its entirety.

  In addition to the reflection mirror 272, the two-dimensional scanner 270 includes a pair of first beam portions 274 and 274 connected to the reflection mirror 272, and a movable frame 276 connected to the pair of first beam portions 274 and 274. The pair of second beam portions 278 and 278 connected to the movable frame 276 and the fixed frame 280 connected to the pair of second beam portions 278 and 278 are provided.

  On the back surface of the reflection mirror 272, the pair of first beam portions 274 and 274 are torsionally vibrated based on the first drive signal to cause the reflection mirror 272 to move in the first direction in the resonance mode (in FIG. 9, around the X axis). ) A first drive source 290 that swings at high speed is installed. The first drive source 290 is an electromagnetic coil.

  The pair of second beam portions 278 and 278 are torsionally vibrated on the movable frame 276 based on the second drive signal, thereby causing the reflecting mirror 272 to move in the second direction in the non-resonant mode via the movable frame 276 (FIG. 9). 2, a second drive source 292 that swings at a low speed (around the Y axis) is provided. The second drive source 292 is also an electromagnetic coil.

  In the present embodiment, an adjacent portion adjacent to the first beam portion of the movable frame 276 is made of metal, whereby a pair of first beam portions 274 and 274 and a pair of second beam portions 278 and 278 are formed. The movement of heat between them is promoted by the movable frame 276.

  In the present embodiment, since the second drive source 292 is an electromagnetic coil that dislikes contact with a magnetic body, a pair of first beam portions 274 and 274 and a pair of first beams are left while leaving a nonmagnetic portion in the movable frame 276. The movement of heat between the two beam portions 278 and 278 is promoted by the movable frame 276. A second drive source 292 is installed in a non-magnetic portion of the movable frame 276, and the movable frame 276 is forcibly swung by the electromagnetic drive of the second drive source 292.

  In this embodiment, heat transfer between the pair of first beam portions 274 and 274 and the pair of second beam portions 278 and 278 is promoted by heat conduction in the movable frame 276.

  The two-dimensional scanner 270 further includes first and second permanent magnets (not shown) at a fixed position facing the first drive source 290 and a fixed position facing the second drive source 292, respectively. The static magnetic field formed by the first permanent magnet is applied to the first drive source 290, while the static magnetic field formed by the second permanent magnet is applied to the second drive source 292.

  The present embodiment will be described in comparison with the high-speed scanner 120 and the low-speed scanner 122 in the first embodiment. A pair of first beam portions 274, 274, a first drive source 290, and the first permanent magnet are mutually connected. The high-speed scanner is jointly configured, and the pair of second beams 278 and 278, the second drive source 292, and the first permanent magnet jointly form a low-speed scanner, and the reflection mirror 272 includes them. Shared by high-speed and low-speed scanners.

  The control unit 54 of the image display device 260 uses the computer to execute the drive signal generation program shown in FIG. 5 and the target drive frequency acquisition program shown in FIG. 6, thereby driving the drive signal to be supplied to the second drive source 292. (An example of the “second drive signal” in the item (1)) is generated.

  Specifically, in the present embodiment, as in the first embodiment, the temperature of the low-speed scanner 302 (for example, the movable frame 276) is greatly increased and the resonance frequency thereof is greatly decreased. When ringing in one direction (main scanning direction) is large, the parameter that determines the characteristics of the filtering process reflects the actual oscillation state of the low-speed scanner 302 (eg, related to its resonance frequency). As updated.

  On the other hand, when the ringing of the reflecting mirror 272 in the second direction (sub-scanning direction) is small, the filtering process is performed without updating the parameters, thereby generating a final drive signal.

  That is, when the ringing in the second direction of the reflection mirror 272 is small, a final drive signal is generated without updating the parameters that determine the characteristics of the filter processing, thereby reducing the load on the computer. It is.

  Although the first embodiment and the second embodiment of the present invention have been described above, the present invention can be implemented in other forms.

  In another embodiment of the present invention, for example, the high-speed scanner 120 shown in FIG. 2 is configured as a metal scanner.

  Since a conventional example of a metal scanner is disclosed in Japanese Patent Application Laid-Open No. 2006-293116, a duplicate description is omitted in this specification, but the publication is entirely incorporated herein by reference. Combined with the calligraphy.

  Since the basic structure of the metal scanner according to the present embodiment is the same as that shown in FIG. 2, common elements are referred to using the same reference numerals, and redundant description is omitted. .

  The metal scanner according to the present embodiment includes a substrate connected to the base frame 128 shown in FIG. 2 and a first beam portion connected to the substrate (for example, one beam like the beam portion 182 shown in FIG. 2). ) And a reflecting mirror 140 connected to the first beam portion.

  In this example of the metal scanner, the base frame 128, the substrate, the first beam portion, and the reflection mirror 140 are connected to each other so as to be arranged in a line in that order. However, the substrate is not rigidly coupled to the base frame 128, but is softly coupled. Specifically, the substrate is connected to the base frame 128 so as to be relatively bendable, for example, via a hinge that is easy to bend because its rigidity is lower than that of the peripheral portion.

  A piezoelectric film (an example of the “first drive source” in the item (1)) is attached to the substrate. The piezoelectric film vibrates when a voltage is applied, and vibrates to the substrate due to the vibration (the vibration direction is parallel to the surface of the substrate, but is perpendicular to the propagation direction of the vibration). A certain vibration) is generated.

  The generated vibration excites a torsional vibration in the first beam portion, and the reflection mirror 140 is oscillated in a resonance mode by the torsional vibration.

  In the present embodiment, the base frame 128, the substrate, the first beam portion, and the reflection mirror 140 are all made of metal (for example, stainless steel).

  Therefore, in the present embodiment, the high-speed scanner 120 configured as a metal scanner and the low-speed scanner 122 are connected to each other by a base frame 128 formed of metal that is a material having higher thermal conductivity than synthetic resin.

  Furthermore, in this embodiment, not only the base frame 128 but also the substrate, the first beam portion, and the reflection mirror 140 are made of a metal that is a material having a higher thermal conductivity than the synthetic resin.

  Therefore, according to the present embodiment, heat transfer between the high-speed scanner 120 and the low-speed scanner 122 can be easily promoted using at least the base frame 128, the substrate, the first beam portion, and the reflection mirror 140 as a medium. .

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

Claims (9)

An image display device for two-dimensionally displaying an image,
A light source that emits a light beam having an intensity according to an image signal;
A first scanner that scans a light beam incident from the light source in a first direction;
A second scanner that scans a light beam scanned by the first scanner in a second direction intersecting the first direction;
The first scanner includes:
A first reflecting mirror for reflecting the incident light beam;
A first beam connected to the first reflecting mirror;
A first drive source that swings the first reflecting mirror in the first direction in a resonance mode by torsionally vibrating the first beam portion based on a first drive signal;
The second scanner
A second reflecting mirror for reflecting the light beam incident from the first reflecting mirror;
A second beam connected to the second reflecting mirror;
A second drive source that swings the second reflecting mirror in the non-resonant mode in the second direction by electromagnetic drive based on a second drive signal;
The image display device further includes:
A sensor for detecting a swinging state of the first reflecting mirror;
Based on an output signal of the sensor, an actual vibration frequency acquisition unit that acquires an actual vibration frequency of the first reflection mirror;
A target vibration frequency acquisition unit that acquires a target vibration frequency of the second reflection mirror based on the acquired actual vibration frequency of the first reflection mirror;
A sawtooth signal generator that generates a sawtooth signal reflecting the obtained target vibration frequency;
A filter that performs a filtering process on the generated sawtooth signal so that a specific resonance frequency band of the second reflection mirror is trapped;
A drive signal acquisition unit for acquiring the second drive signal based on the filtered sawtooth signal;
An image display device comprising: heat transfer promoting means provided so as to promote heat transfer between the first scanner and the second scanner.   The image display apparatus according to claim 1, wherein the heat transfer promoting unit includes a connecting member that connects the first beam portion and the second beam portion to each other. The connecting member includes a base frame common to the first reflecting mirror and the second reflecting mirror;
In the base frame, the first reflection mirror and the second reflection mirror are arranged in a plane,
The image display apparatus according to claim 2, wherein both the first beam portion and the second beam portion are coupled to the base frame.   The image display device according to claim 2, wherein at least the connecting member is made of metal. The first scanner further includes a substrate to which the first beam portion is connected,
The substrate is connected to the first reflecting mirror via the first beam portion,
The first reflecting mirror, the first beam portion, and the substrate are all made of metal, whereby the first scanner is configured as a metal scanner,
The first drive source is mounted on the substrate, and the first reflection mirror is swung in a resonance mode via the substrate and the first beam portion by vibration generated in the first drive source. ,
The image display device further includes a base frame common to the first scanner and the second scanner,
The base frame is connected to the substrate and the second beam portion, and is made of metal.
The image display device according to claim 1, wherein at least the base frame, the substrate, the first beam portion, and the first reflection mirror each function as the heat transfer promoting unit. further,
Including a temperature sensor installed in the connecting member;
6. The image display device according to claim 1, wherein the temperature detected by the temperature sensor is used as a temperature representative of both the first scanner and the second scanner. further,
A second sensor for detecting a swinging state of the second reflecting mirror;
An error determining unit that determines whether an error occurring in the swing of the second reflecting mirror exceeds an allowable value based on an output signal of the second sensor;
The filter does not update the characteristics of the filter processing when the error determination unit determines that the error does not exceed the allowable value, but the error is not updated by the error determination unit. 7. The image display device according to claim 1, wherein when it is determined that the threshold value is exceeded, the characteristics of the filtering process are updated. An image display device for two-dimensionally displaying an image,
A light source that emits a light beam having an intensity according to an image signal;
A two-dimensional scanner that two-dimensionally scans a light beam incident from the light source in a first direction and a second direction intersecting each other;
The two-dimensional scanner
A reflection mirror for reflecting the incident light beam;
A first beam connected to the reflecting mirror;
A first drive source that swings the reflection mirror in the first direction in a resonance mode by torsionally vibrating the first beam portion based on a first drive signal;
A movable frame coupled to the first beam portion;
A second beam connected to the movable frame;
A fixed frame connected to the second beam portion;
A second drive source for causing the reflecting mirror to swing in the second direction in a non-resonant mode through the movable frame by electromagnetic drive based on a second drive signal;
The image display device further includes:
A sensor for detecting a swinging state of the reflecting mirror;
Based on an output signal of the sensor, an actual vibration frequency acquisition unit that acquires an actual vibration frequency of the reflection mirror in the first direction;
A target vibration frequency acquisition unit for acquiring a target vibration frequency in the second direction of the reflection mirror based on the acquired actual vibration frequency;
A sawtooth signal generator that generates a sawtooth signal reflecting the obtained target vibration frequency;
A filter that performs a filtering process on the generated sawtooth signal so that a specific resonance frequency band of the reflection mirror is trapped;
A drive signal acquisition unit for acquiring the second drive signal based on the filtered sawtooth signal;
An image display device comprising: heat transfer promoting means provided so as to promote heat transfer between the first beam portion and the second beam portion.   The heat transfer accelerating means is configured such that at least the adjacent portion of the movable frame and the adjacent portion adjacent to the first beam portion is made of metal, so that the first beam portion and the second frame are made of metal. The image display device according to claim 8, wherein heat transfer between the beam portion and the beam portion is promoted.

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