JP2021135411A - Head-up display - Google Patents

Abstract

To uniformize a scan pitch over the entire arrangement surface of a plurality of optical elements without sacrificing brightness.SOLUTION: A head-up display comprises: emission means; a plurality of optical elements regularly arrayed in a first direction and a second direction perpendicular to each other in an arrangement surface, and dispersing laser beams; and scanning means scanning the laser beams in a spot diameter smaller than the size of the optical element. The scanning means generates a control signal so that the laser beams emitted from the emission means travels in a reciprocating manner between one end and the other end of a scan range in the first direction while deviated in the second direction. The emission means emits the laser beams so that the entire display image can be formed on the basis of a predetermined scan range part, of the scan range by the control signal, where the plurality of optical elements are irradiated with the laser beams. The predetermined scan range part is a part of the scan range deviated to one side in the first direction.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a head-up display.

Laser light is incident on a plurality of optical elements regularly arranged at a predetermined pitch along a plane forming a scanning surface, and can be visually recognized by the driver based on the light emitted from the plurality of optical elements. A technique for displaying a clear display image is known.

Japanese Unexamined Patent Publication No. 2015-225216

However, in the above-mentioned conventional technique, it is difficult to make the scanning pitch at the time of scanning the laser beam uniform over the entire array of a plurality of optical elements without sacrificing the brightness. In the normal raster scan method, the scanning pitch can be made uniform by using only one of the outward path and the return path, but the brightness is sacrificed.

Therefore, it is an object of the present disclosure to make the scanning pitch uniform over the entire arrangement surface of a plurality of optical elements without sacrificing brightness.

On one side, it is a heads-up display that displays a visible display image.
An emission means that emits laser light according to the image,
A plurality of optical elements that are regularly arranged in the array plane in the first direction and the second direction that are orthogonal to each other and diffuse the laser beam.
A scanning means for scanning a laser beam with a spot diameter smaller than the size of each of the plurality of optical elements is provided.
The scanning means generates a control signal so that the laser beam emitted from the emitting means reciprocates between one end and the other end of the scanning range in the first direction while shifting in the second direction. ,
The emitting means emits a laser beam so that the entire display image is formed based on a predetermined scanning range portion within the scanning range of the control signal.
A head-up display is disclosed in which the predetermined scanning range portion is a portion of the scanning range biased to one side in the first direction.

According to the present disclosure, it is possible to make the scanning pitch uniform over the entire arrangement surface of a plurality of optical elements without sacrificing brightness.

It is a figure which shows roughly the vehicle-mounted state of the head-up display by one Example in the vehicle side view. It is the schematic which shows the structure of the head-up display. It is the schematic which shows an example of the arrangement of the microlenses which form a screen. It is explanatory drawing which shows the scanning pattern for upper side and the scanning pattern for lower side by one Example. It is explanatory drawing of the principle that two kinds of display images are generated by the scan pattern for upper side and the scan pattern for lower side. It is explanatory drawing of the control signal for controlling a MEMS scanner by a scanner control unit. It is a figure which shows the characteristic example of a MEMS scanner. It is explanatory drawing of the scanning pattern when the swell does not occur. It is explanatory drawing of the scanning pattern when swell occurs. It is a figure which shows the relationship between the scanning range, and the predetermined scanning range part which generates the upper image signal. It is a figure which shows the relationship between the scanning range, and the predetermined scanning range part which generates the lower image signal. It is a figure which shows the relationship between the scanning range, and the predetermined scanning range part which generates a specific image signal. It is explanatory drawing of the modification.

Hereinafter, examples will be described in detail with reference to the accompanying drawings. In addition, in FIG. 3 and the like, for the sake of easy viewing, there are cases where a reference reference numeral is only partially attached to a plurality of parts or parts having the same attribute.

[Head-up display configuration]
FIG. 1 is a diagram schematically showing a vehicle-mounted state of the head-up display 1 according to one embodiment in a vehicle side view. FIG. 2 is a schematic view showing the configuration of the head-up display 1. FIG. 3 is a schematic view showing an example of the arrangement of the microlenses 41 forming the screen 40. In FIG. 2, the driver's face P1 when the viewpoint is relatively in the upper eyebox and the driver's face P2 when the viewpoint is in the relatively lower eyebox. Is schematically shown. The upper and lower eye boxes may be eye boxes that are continuous in the vertical direction, or may be separate eye boxes that are separated vertically. Further, in FIG. 2, the dotted arrows R0 to R4 schematically show the flow of electric signals.

In the head-up display 1, as shown in FIG. 1, when the windshield WS is irradiated with the display light, the driver who drives the vehicle VC sees the display obtained by the irradiation in front of the windshield WS. Image (virtual image display) VI can be seen. As a result, the driver can visually recognize the display image VI by superimposing it on the front scenery. Therefore, the driver can grasp the vehicle information and the like in a mode in which the line-of-sight movement is small as compared with the case of looking at the meter in the instrument panel 9, and the convenience and safety are improved. In the modified example, a combiner or the like may be used instead of the windshield WS.

As shown in FIG. 2, the head-up display 1 includes a laser unit 10 (an example of emitting means), a dichroic mirror unit 20, a condenser lens 28, a MEMS (Micro Electro Mechanical Systems) scanner 30, and a screen 40. , And the control device 50.

The laser unit 10 includes laser irradiation devices 11, 12, and 13 for each color of red, blue, and green. The laser irradiation device 11 emits laser light in the red wavelength region. The laser irradiation device 12 emits laser light in a blue wavelength region. The laser irradiation device 13 emits laser light in the green wavelength region. In this embodiment, since the laser beams of these three colors can be emitted, a full-color display image VI can be generated. However, in the modified example, the variation of the displayable color may be small.

The dichroic mirror unit 20 has dichroic mirrors 21, 22, and 23 corresponding to the laser irradiation devices 11, 12, and 13, respectively. The dichroic mirror 21 reflects only the red wavelength region. Therefore, the dichroic mirror 21 can reflect only the laser light incident from the laser irradiation device 11 toward the condenser lens 28. The dichroic mirror 22 transmits the red wavelength region and reflects the blue wavelength region. Therefore, the dichroic mirror 22 can reflect the laser light incident from the laser irradiation device 12 toward the condenser lens 28 while transmitting the laser light incident from the dichroic mirror 21. Similarly, the dichroic mirror 23 transmits the red and blue wavelength regions and reflects the green wavelength region. Therefore, the dichroic mirror 23 can reflect the laser light incident from the laser irradiation device 13 toward the condenser lens 28 while transmitting the laser light incident from the dichroic mirror 22.

As described above, the condenser lens 28 collects the laser light (laser light of each color of red, blue, and green) incident from the dichroic mirror unit 20 and emits it toward the MEMS scanner 30.

In the condenser lens 28, the laser light incident from the dichroic mirror unit 20 is projected onto the screen 40 with a spot diameter (diameter) smaller than the size of each of the plurality of microlenses 41 (described later) forming the screen 40. It is configured and arranged so as to. For example, the spot diameter is adapted so that the following relational expression holds.
Spot diameter ≤ lens pitch / number of viewpoints Here, the lens pitch is the pitch of the arrangement of a plurality of microlenses 41 described later (see PT1 and PT2 in FIG. 3), and the number of viewpoints is the display image VI by changing the viewpoint. Corresponds to the number of appearances of the display image VI when the appearance of the image changes, and in this embodiment, it is "2" as an example.

The MEMS scanner 30 projects the laser beam incident from the condenser lens 28 onto the screen 40. The MEMS scanner 30 includes a MEMS mirror that can rotate around two orthogonal axes. The projection position of the laser beam on the screen 40 changes according to the orientation of the MEMS mirror. Therefore, the MEMS scanner 30 can arbitrarily change the projection position of the laser beam on the screen 40.

The screen 40 extends in a plane. In this embodiment, as an example, the screen 40 extends in the horizontal plane, but may be arranged in a direction slightly inclined with respect to the horizontal plane. As shown in FIG. 3, the screen 40 includes a plurality of microlenses 41 (an example of an optical element) that are regularly arranged in a plane. That is, the screen 40 includes a two-dimensional microlens array. The plurality of microlenses 41 typically have the same form, and in this embodiment, as an example, when viewed in the direction perpendicular to the screen 40, the outer shape is rectangular (square), but the outer shape is hexagonal. It may have other outer shapes such as. The screen 40 may have an incident surface having a convex shape relating to the plurality of microlenses 41, and the exit surface may be a flat surface (see FIG. 5).

In the example shown in FIG. 3, the plurality of microlenses 41 are arranged in a plane (arrangement plane) including the X direction (an example of the first direction) and the Y direction (an example of the second direction), and the plurality of microlenses 41 are arranged. Are preferably regularly arranged at a constant pitch, as shown in FIG. In FIG. 3, the pitches PT1 and PT2 in the X direction and the Y direction are the same, but may be different. In this embodiment, as an example, the plurality of microlenses 41 are arranged in 5 rows in the X direction and 4 rows in the Y direction, but the number of rows in the X direction and the Y direction is arbitrary. The X direction and the Y direction are also shown in FIG. 2 above in association with the screen 40.

The control device 50 may be realized by a computer such as an ECU (Electronic Control Unit). The control device 50 includes a laser control unit 51 and a scanner control unit 52. In this embodiment, the laser control unit 51 cooperates with the above-mentioned laser unit 10 to form an example of the emitting means, and the scanner control unit 52 cooperates with the above-mentioned MEMS scanner 30 to scan. Form an example of means.

The laser control unit 51 controls the laser unit 10 based on an image signal for generating a display image VI (see arrows R1 to R3 in FIG. 2). In this embodiment, as an example, the image signals are an upper image signal for generating a display image VI visible from the upper viewpoint (see P1 in FIG. 2) (an example of the first viewpoint) and a lower viewpoint (FIG. 2). 2 includes a lower image signal for generating a display image VI that can be seen from (see P2 of 2) (an example of a second viewpoint). The upper image signal and the lower image signal may be generated by an external ECU and given to the control device 50 (see arrow R0 in FIG. 2), or may be generated by the control device 50 by itself. ..

In the following, for the sake of distinction, the display image VI that can be visually recognized from the upper viewpoint (see P1 in FIG. 2) is also referred to as “display image VI1” and can be visually recognized from the lower viewpoint (see P2 in FIG. 2). The display image VI is also referred to as "display image VI2". Further, in the following, unless otherwise specified, the “display image VI (including the display image VI1 and the display image VI2)” refers to the entire display image VI, and represents the entire output range related to the display image VI. For example, when the display image VI relates to a character representing a speed, the display image VI does not refer only to the character portion but to the entire output range including the character portion.

The upper image signal and the lower image signal may be the same signal or different signals. In this embodiment, as an example, the upper image signal and the lower image signal are different signals. In this case, display images VI1 and display images VI2 that are different from each other can be formed.

For example, the display image VI1 may include navigation-related information (eg, map information), and the display image VI2 may include meter-related information. In this case, the driver has two types of natural line-of-sight movements in line with the relationship between the general meter position (meter position in the instrument panel 9) and the display position of the display image VI of the head-up display 1. The displayed images VI1 and VI2 can be selectively viewed (see the upper side of FIG. 2).

The upper image signal is, for example, a signal representing a pixel value (luminance or color) of each pixel of an image having a predetermined size and a predetermined resolution. The lower image signal is, for example, a signal representing a pixel value (luminance or color) of each pixel of an image having a predetermined size and a predetermined resolution. In this case, the predetermined size and the predetermined resolution may be the same for the upper image signal and the lower image signal. Each pixel of the image is associated with each position of the screen 40 (each position on the scanning surface). For example, each pixel of the image may be associated with each position of the screen 40 (each position on the scanning surface) in a one-to-one relationship. Each position of the screen 40 is associated with each orientation of the MEMS mirror of the MEMS scanner 30.

When the laser control unit 51 controls the laser unit 10 based on the upper image signal, each pixel from the laser unit 10 at a timing corresponding to each pixel based on the pixel value of each pixel included in the upper image signal. The laser unit 10 is controlled so that the laser beam of the color corresponding to the value is emitted. The same applies to the lower image signal.

The scanner control unit 52 controls the MEMS scanner 30 (see arrow R4 in FIG. 2). That is, the scanner control unit 52 scans the laser beam on the screen 40 by controlling the orientation of the MEMS mirror of the MEMS scanner 30. Here, "scanning the laser beam on the screen 40" means changing the projection position of the laser beam on the plane of the screen 40 (the projection position when viewed perpendicular to the plane of the screen 40). Point to. Further, in the following, the “scanning pattern” refers to the locus of the projection position (the locus of the projection position of the laser beam on the plane of the screen 40). Further, the plane related to the screen 40 (that is, the plane on which a plurality of microlenses 41 are arranged) is also referred to as a “scanning surface”.

Specifically, the scanner control unit 52 cooperates with the laser control unit 51 to scan the laser beam (an example of the first laser beam) corresponding to the upper image signal with the upper scanning pattern, and scans the lower image. The laser beam corresponding to the signal (an example of the second laser beam) is scanned by the lower scanning pattern. That is, when operating based on the upper image signal, the scanner control unit 52 sets the laser unit 10 at each position on the scanning surface corresponding to each pixel based on the pixel value of each pixel included in the upper image signal. The MEMS scanner 30 is controlled so that the laser beam from the source is projected. The same applies to the lower image signal.

[Upper scanning pattern and lower scanning pattern]
Next, with reference to FIGS. 4 to 5, some preferable examples of the upper scanning pattern and the lower scanning pattern will be described.

FIG. 4 is an explanatory view showing an upper scanning pattern and a lower scanning pattern according to an embodiment, and is a diagram showing the screen 40 in a plan view. FIG. 5 is an explanatory diagram of the principle that the display images VI1 and VI2 are generated by the upper scanning pattern and the lower scanning pattern. In FIG. 4, the X1 side and the X2 side in the X direction are defined, and the Y1 side and the Y2 side in the Y direction are defined. In FIG. 5, with respect to the screen 40, only three microlenses 41 arranged in the Y direction are taken out and shown in a cross-sectional view. The Y direction corresponds to the vehicle front-rear direction when the screen 40 is located in the horizontal plane. At this time, the X direction corresponds to the vehicle lateral direction (vehicle width direction). In FIG. 5, the direction perpendicular to the paper surface is the X direction.

In the example shown in FIG. 4, the upper scanning pattern includes a plurality of upper scanning portions L401, and the lower scanning pattern includes a plurality of lower scanning portions L402. The upper scanning portion L401 and the lower scanning portion L402 pass through each of the microlenses 41 and are offset from each other by a predetermined offset amount (= α + β) in the Y direction. In other words, the upper scanning portion L401 is offset in the Y direction Y1 side by a predetermined amount α with respect to the center O of each microlens 41, and the lower scanning portion L402 is offset with respect to the center O of each microlens 41. Offset to the Y2 side in the Y direction by a predetermined amount β.

According to such an upper scanning pattern and a lower scanning pattern, the display image VI1 can be generated by the laser light (laser light corresponding to the upper image signal) scanned by the upper scanning pattern, and the lower scanning pattern. The display image VI2 can be generated by the laser light (laser light corresponding to the lower image signal) scanned by.

More specifically, as shown in FIG. 5, the laser beam scanned by the upper scanning pattern (laser beam corresponding to the upper image signal) is a predetermined amount on the Y1 side in the Y direction with respect to the center O of the microlens 41. It is incident at a position deviated by α (see arrow R51). In this case, the microlens 41 emits light in a direction corresponding to the shape (spherical shape) of the incident surface of the microlens 41 (see arrow R511). On the other hand, as shown in FIG. 5, the laser light scanned by the lower scanning pattern (laser light corresponding to the lower image signal) is only a predetermined amount β on the Y2 side in the Y direction from the center O of the microlens 41. It is incident at a deviated position (see arrow R52). In this case, the microlens 41 emits light in a direction corresponding to the shape (spherical shape) of the incident surface of the microlens 41 (see arrow R521). At this time, the incident position (spot position) in one microlens 41, the incident position related to the laser light (laser light corresponding to the upper image signal) scanned by the upper scanning pattern, and the lower scanning pattern. The incident position related to the laser light (laser light corresponding to the lower image signal) scanned by the microlens 41 is located on the opposite side in the Y direction with the center O of the microlens 41 interposed therebetween. Therefore, the emission direction of the laser light from the microlens 41 and the emission direction (see arrow R511) related to the laser light (laser light corresponding to the upper image signal) scanned by the upper scanning pattern and the lower side. The emission direction (see arrow R521) related to the laser light (laser light corresponding to the lower image signal) scanned by the scanning pattern is inclined (non-parallel) with respect to each other as schematically shown in FIG. Will be). Therefore, the region R510 in which the laser light from the microlens 41 in the windshield WS is incident and is related to the laser light (laser light corresponding to the upper image signal) scanned by the upper scanning pattern and the lower side. It is separated from the region R520 related to the laser light (laser light corresponding to the lower image signal) scanned by the scanning pattern. Specifically, the regions R510 and R520 are offset in the vertical direction in the windshield WS. As a result, as schematically shown in FIG. 2, since the laser beam can be projected from the vertically offset regions R510 and R520 to the driver side, the display images VI1 and VI2 can be generated. The predetermined offset amount correlates with the distance between the upper viewpoint (the viewpoint where the display image VI1 can be seen) and the lower viewpoint (the viewpoint where the display image VI2 can be seen) in the vertical direction. The predetermined amounts α and β may be adapted according to the desired positions of the regions R510 and R520 (and thus the desired positions of the displayed images VI1 and VI2).

It should be noted that one scan is realized by a scanning pattern that combines the upper scanning pattern and the lower scanning pattern, or the generation of the upper image signal by the upper scanning pattern and the lower image by the lower scanning pattern. When the signal generation is realized in close time, the display images VI1 and VI2 can be generated substantially at the same time. Therefore, the driver moves the viewpoint in the vertical direction, such as moving the viewpoint relatively upward when he / she wants to see the display image VI1, and moving the viewpoint relatively downward when he / she wants to see the display image VI2. The displayed images VI1 and VI2 can be continuously visually recognized just by making the display images VI1 and VI2 visible. In this way, according to the present embodiment, it is possible to generate the display images VI1 and VI2 in an appropriate manner in a configuration in which the visible display images VI1 and VI2 are changed only by changing the viewpoint in the vertical direction. It becomes.

Further, in this embodiment, as an example, the display images VI1 and VI2 may be generated substantially at the same time regardless of the driver's current viewpoint without detecting the driver's viewpoint with a camera or the like. .. Therefore, even if the driver's viewpoint changes, the driver can visually recognize the display image VI1 or VI2 without delay.

In this embodiment, as described above, the display images VI1 and VI2 are generated, but only one of them may be generated, which is different from the display images VI1 and VI2. The configuration may be such that one or more other display images are generated.

[Uniformization of scanning pitch]
Next, a method for realizing the above-mentioned upper scanning pattern and lower scanning pattern with a uniform scanning pitch will be described with reference to FIGS. 6 and later. Since the method described below is suitable for generating the display images VI1 and VI2 as described above, it is also suitable for generating only one of the display images VI1 and VI2.

FIG. 6 is an explanatory diagram of a control signal for controlling the MEMS scanner 30 by the scanner control unit 52, and the upper side is a signal component for changing the projection position of the laser beam on the plane of the screen 40 in the X direction. The time series (hereinafter, also referred to as “horizontal signal component”) is shown, and the lower side is a signal component for changing the projection position of the laser beam on the plane of the screen 40 in the Y direction (hereinafter, “vertical signal component”). ”) Is shown. The control signal may be formed by the combined wave of these two signal components. That is, the signal component may be formed by superimposing the vertical signal component on the horizontal signal component (or superimposing the horizontal signal component on the vertical signal component).

As shown in FIG. 6, the horizontal signal component (an example of the first signal) is a signal vibrating at a predetermined frequency Fr1 (for example, a sine wave signal). The predetermined frequency Fr1 may be appropriately determined according to the characteristics of the MEMS scanner 30 (see FIG. 7). As described above, the horizontal signal component is a signal component for changing the projection position of the laser beam on the plane of the screen 40 in the X direction, and the MEMS mirror of the MEMS scanner 30 is mounted on the first rotation axis (shown). It is a signal component for rotating around.

As shown in FIG. 6, the vertical signal component (an example of the second signal) is a signal (for example, a serrated signal) that vibrates at a predetermined frequency Fr2. The predetermined frequency Fr2 corresponds to the frame period of the image related to the upper image signal or the lower image signal. As described above, the vertical signal component is a signal component for changing the projection position of the laser beam on the plane of the screen 40 in the Y direction, and the MEMS mirror of the MEMS scanner 30 is mounted on the second rotation axis (shown in the figure). It is a signal component for rotating around. The second rotation axis is orthogonal to the first rotation axis.

FIG. 7 is a diagram showing a characteristic example of the MEMS scanner 30. In FIG. 7, a frequency is taken on the horizontal axis and a gain is taken on the vertical axis, and the vibration characteristic 1001 around the first rotation axis and the vibration characteristic 1002 around the second rotation axis are shown.

In FIG. 7, the vibration characteristic 1001 has a peak value at around 30,000 Hz. That is, the vibration characteristic 1001 around the first rotation axis has a resonance point in the vicinity of 30,000 Hz. Therefore, in this case, by setting the predetermined frequency Fr1 to around 30,000 Hz, the MEMS mirror can be efficiently rotated (vibrated) around the first rotation axis.

By the way, as shown in FIG. 7, the vibration characteristic 1002 around the second rotation axis has a peak value at 5000 Hz or less, but has a slight gain value even at around 30,000 Hz (see point 1003 in FIG. 7). Therefore, when the MEMS mirror is vibrated around the first rotation axis at a predetermined frequency Fr1 near 30,000 Hz, the MEMS mirror vibrates slightly around the second rotation axis. Hereinafter, such vibration generated around the second rotation axis due to the horizontal signal component is also referred to as “waviness”.

FIG. 8A is an explanatory diagram of a scanning pattern when swell does not occur, and FIG. 8B is an explanatory diagram of a scanning pattern when swell occurs. 8A and 8B schematically show a change (scanning locus) in the projection position of the laser beam on a plane (corresponding to a plane related to the screen 40) defined in the X and Y directions, as in FIG. 4 above. Expressed as In addition, in FIG. 8A and FIG. 8B, the black circle represents the position on the scanning locus.

When no waviness occurs, the scan pattern is symmetrical with respect to the center of the scan range in the X direction, as shown in FIG. 8A. Specifically, in the scanning pattern, the projection position of the laser beam on the plane of the screen 40 reciprocates in the X direction while changing in the Y direction due to the vertical signal component. Therefore, the scanning pitch Pc at the center in the X direction and the scanning pitch Pe at the end in the X direction have a relatively large difference. As described above, in the case of the scanning pattern in which the swell does not occur, it is difficult to make the scanning pitch uniform over the entire scanning range.

Therefore, when the upper image signal or the lower image signal is generated during the reciprocating motion by using the scanning pattern when the swell does not occur, the display image is caused by the "unevenness" of the scanning pitch as described above. The quality of VI1 and VI2 may deteriorate.

On the other hand, even when the scanning pattern in the case where the swell does not occur is used, if the upper image signal or the lower image signal is generated only in the outward path or the return path in the reciprocating motion, the scanning pitch as described above becomes ". "Unevenness" is substantially eliminated. This is because, as shown in FIG. 8A, for example, when used only on the outward path or the return path, the scanning pitch Pc'at the center in the X direction and the scanning pitch Pe'at the end in the X direction are substantially the same. Is.

However, when the upper image signal or the lower image signal is generated only on the outward route or the return route, on the other hand, the brightness is lowered as compared with the case where the upper image signal or the lower image signal is generated on both the outward route and the return route. The inconvenience of getting rid of it occurs.

On the other hand, when waviness occurs, as shown in FIG. 8B, the scanning pattern becomes asymmetric with respect to the center of the scanning range in the X direction due to the waviness. In this case, the scanning pitch Pc at the center in the X direction has a relatively large difference from the scanning pitch Pe1 at the end on the X1 side in the X direction, but the scanning pitch at the end on the X2 side in the X direction. There is a relatively small difference with respect to Pe2. In the scanning pattern shown in FIG. 8B, the scanning pitch Pe on the X direction X1 side is substantially larger and the scanning pitch Pe on the X direction X2 side is smaller than the scanning pattern shown in FIG. 8A (FIG. 8B). Then it became almost 0). As a result, the projection position of the laser beam is substantially the same on the outward path and the return path on the X2 side in the X direction with respect to the center in the X direction. As a result, the scanning pitch is made uniform on the X2 side in the X direction with respect to the center in the X direction.

From this, while using the control signal that causes swell, a predetermined scanning range portion that is a part of the scanning range (in the case of FIG. 8B, the range on the X direction X2 side of the center in the X direction). It can be seen that if the upper image signal or the lower image signal is generated only by), the deterioration of the quality of the display images VI1 and VI2 due to the "unevenness" of the scanning pitch as described above can be suppressed. Further, in this case, since the upper image signal or the lower image signal can be generated on both the outward path and the return path, the brightness is not sacrificed.

In this way, according to the present embodiment, a predetermined scanning range portion of the scanning range (in the case of FIG. 8B, in the X direction rather than the center in the X direction) by utilizing the characteristic of such “waviness”. Brightness is increased by generating an upper image signal (and a laser beam corresponding to the upper image signal) or a lower image signal (and a laser beam corresponding to the lower image signal accordingly) only in the X2 side range). It is possible to make the scanning pitch uniform without sacrificing.

9A and 9B are diagrams showing the relationship between the scanning range in this embodiment and a predetermined scanning range portion 700 that generates an upper image signal or a lower image signal. FIG. 9A shows the relationship between the scanning range in this embodiment and the predetermined scanning range portion 700 that generates the upper image signal, and FIG. 9B shows the scanning range in this embodiment and the predetermined scanning that generates the lower image signal. The relationship with the range portion 700 is shown.

In FIGS. 9A and 9B, the predetermined scanning range portion 700 is a range in which an upper image signal or a lower image signal is generated, and is a range in which the screen 40 is shown in a plan view. In FIGS. 9A and 9B, the scanning locus when a control signal that causes swell is used is schematically shown within the scanning range 800. The predetermined scan range portion 700 (in this case, the scan range portion corresponding to the entire screen 40) is included in the scan range 800 as shown in FIGS. 9A and 9B. Specifically, the predetermined scanning range portion 700 is biased toward the X direction X2 side (an example of one side of the first direction) of the scanning range 800. The scanning range 800 has a length in the X direction longer than the predetermined scanning range portion 700. The scanning range 800 is a range surrounding the scanning locus according to the scanning patterns shown in FIGS. 9A and 9B.

In FIG. 9A, the control device 50 is a scanning portion of the scanning locus in the scanning range 800 related to the reciprocating paths substantially overlapping each other in the predetermined scanning range portion 700, and the upper image signal portion related to the same image portion. generate. In this case, by generating an upper image signal portion related to the same image portion in the scanning portion related to one outward route and the scanning portion related to the subsequent one inbound route, the upper image signal portion related to the same image portion is generated for the upper side related to the one outward route in FIG. It can be realized that the scanning portion L401 generates the same upper image signal portion. Then, within the predetermined scanning range portion 700, the scanning pitch is made uniform as described above, so that the display image VI1 of good quality can be formed.

Further, in such an example shown in FIG. 9A, since the same upper image signal portion is generated in the scanning portion related to the round-trip path, the brightness can be effectively increased. That is, since the laser beam corresponding to the upper image signal is incident on one microlens 41 twice per frame, the brightness can be effectively increased.

Similarly, as shown in FIG. 9B, a lower image signal is generated in a scanning portion related to one round-trip path (one outward path and one subsequent return path) that substantially overlap each other within a predetermined scanning range portion 700. Therefore, it is possible to realize that the lower scanning portion L402 in FIG. 4 described above generates the same lower image signal. Then, within the predetermined scanning range portion 700, the scanning pitch is made uniform as described above, so that a display image VI2 of good quality can be formed.

Further, as in the case of FIG. 9A, in the example shown in FIG. 9B, since the same lower image signal is generated in the scanning portion related to the round-trip path, the brightness can be effectively increased. That is, since the laser beam corresponding to the upper image signal is incident on one microlens 41 twice per frame, the brightness can be effectively increased.

FIG. 10 is a diagram showing the relationship between the scanning range in this embodiment and a predetermined scanning range portion that generates a specific image signal.

In FIG. 10, a predetermined scanning range portion 700 is a range in which a specific image signal is generated, and is a range in which the screen 40 is shown in a plan view. The specific image signal is generated in place of the upper image signal and the lower image signal. The specific image signal is generated, for example, when the display image VI outputs vehicle information having a high degree of attention. The scanning pattern related to the specific image signal may be the same as or different from either the upper scanning pattern or the lower scanning pattern described above. For example, in FIG. 10, the scanning pattern related to a specific image signal is a pattern that passes through the center O of the microlens 41 in the Y direction. In this case, since the display image VI related to the specific image signal is visible from a viewpoint different from the viewpoints for the display images VI1 and VI2, a situation different from the usual situation (a situation with a high degree of attention) is given to the driver or the like. It becomes easy to recognize intuitively. Further, in this case, since the display image VI related to a specific image signal can be output by using the necessary two frames for outputting the display images VI1 and VI2, compared with the case of outputting the display images VI1 and VI2. Therefore, the brightness when the display image VI is output can be doubled. As a result, the visibility can be improved, and it becomes easy for the driver or the like to intuitively recognize the high degree of attention.

Although the specific embodiment has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the claims. It is also possible to combine all or a plurality of the components of the above-described embodiment.

For example, in the above-described embodiment, the display images VI1 and VI2 are generated by utilizing all the microlenses 41 forming the screen 40, respectively. Therefore, in this embodiment, the display images VI1 and VI2 having a relatively large size can be generated (or the display images VI2) as compared with the case where a part of the microlenses 41 forming the screen 40 is used. If the sizes of the display images VI1 and VI2 are the same, the resolution of the display images VI1 and VI2 can be improved), which is advantageous. However, in the modified example, the display image VI1 and / or the display image VI2 may be generated by utilizing a part of the microlens 41 forming the screen 40. For example, the upper scanning pattern and the lower scanning pattern may both be patterns that scan only a part of the rows of the microlens 41 in the Y direction. Similarly, both the upper scanning pattern and / or the lower scanning pattern may be a pattern that scans only a part of the row in the X direction of the microlens 41.

Further, in the above-described embodiment, the display images VI1 and VI2, which are different from each other, can be visually recognized from the two viewpoints offset in the vertical direction, but the present invention is not limited to this. For example, a configuration may be realized in which different display images can be visually recognized from three or more different viewpoints along the vertical direction.

Further, in the above-described embodiment, the feedback control is not executed for the projection position of the laser beam on the screen 40, but the configuration is not limited to this. For example, as disclosed in Patent Document 1, a scanning position detection plate in which light receiving elements are arranged may be provided, and feedback control may be performed on the projection position of the laser beam on the screen 40.

Further, in the above-described embodiment, the viewer of the display image is the driver of the vehicle, but the display image is formed so that the other occupants (for example, the occupants in the passenger seat and the rear seat are the viewers). You may.

Further, in the above-described embodiment, the display images VI1 and VI2 are generated so that the display images VI1 and VI2 can be seen from different viewpoints in the vertical direction, but the present invention is not limited to this. For example, as schematically shown in FIG. 11, the display images VI1 and VI2 may be generated so that the display images VI1 and VI2 can be seen from different viewpoints in the horizontal direction. In this case, the display images VI1 and VI2 may be formed so as to be stereoscopic using parallax.

Further, in the above-described embodiment, as shown in FIGS. 9A and 9B, the scanning pattern has scanning portions related to reciprocating paths that substantially overlap each other within a predetermined scanning range portion 700. That is, the scanning pattern has a scanning portion related to a round-trip path having a spacing in the Y direction of approximately 0. Here, approximately 0 means, for example, twice or less the spot diameter, and significantly smaller than the predetermined amount α and the predetermined amount β described above. However, in the modified example, the scanning pattern may have a scanning portion related to a round-trip path in which the interval in the Y direction is significantly larger than 0.

1 Head-up display 10 Laser unit 11 Laser irradiation device 12 Laser irradiation device 13 Laser irradiation device 20 Dycroic mirror unit 21 Dycroic mirror 22 Dycroic mirror 23 Dycroic mirror 28 Condensing lens 30 MEMS scanner 40 Screen 41 Microlens 50 Control device 51 Laser control Unit 52 Laser control unit

Claims (7)

A head-up display that displays a visible display image.
An emission means that emits laser light according to the image,
A plurality of optical elements that are regularly arranged in the array plane in the first direction and the second direction that are orthogonal to each other and diffuse the laser beam.
A scanning means for scanning a laser beam with a spot diameter smaller than the size of each of the plurality of optical elements is provided.
The scanning means generates a control signal so that the laser beam emitted from the emitting means reciprocates between one end and the other end of the scanning range in the first direction while shifting in the second direction. ,
The emitting means emits a laser beam so that the entire display image is formed based on a predetermined scanning range portion within the scanning range of the control signal.
A head-up display in which the predetermined scanning range portion is a portion of the scanning range biased to one side in the first direction. The scanning means includes a MEMS mirror having two orthogonal axes of rotation.
The control signal includes a first signal of a sinusoidal component having a predetermined frequency corresponding to the reciprocating period in the first direction.
In the MEMS mirror, when vibration of the predetermined frequency is generated around the rotation axis of the two rotation axes that causes the reciprocation in the first direction, vibration is generated around the other rotation axis. The head-up display according to claim 1, which has characteristics. The head-up display according to claim 2, wherein the control signal includes the first signal and a second signal that vibrates at a cycle corresponding to the frame cycle of the image. The scanning locus of the laser beam in the scanning range when the laser beam is emitted from the emitting means within the scanning range by the control signal is more related to the outward path on the one side in the first direction than on the other side. The head-up display according to claim 2 or 3, wherein the distance between the scanning portion and the scanning portion related to the return path in the second direction is narrow. The head-up display according to claim 4, wherein the scanning locus has a spacing of substantially 0 within the predetermined scanning range portion. The emitting means corresponds to the first laser beam corresponding to the image for the first viewpoint and the image for the second viewpoint separated in the vertical direction from the first viewpoint in accordance with the control signal. The head-up display according to any one of claims 1 to 5, which continuously emits a second laser beam. The head-up display according to any one of claims 1 to 6, wherein the predetermined scanning range portion is a portion within the scanning range in which the laser beam is scanned over the entire array surface. ..

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