JP7439770B2 - heads up display device - Google Patents

Description

The present disclosure relates to a head-up display device.

Conventional head-up display devices include those in which a motor drives a reflective mirror (e.g., a concave mirror) that reflects display light representing an image toward a light-transmitting member (e.g., a windshield of a vehicle). , is disclosed in Patent Document 1.

Japanese Patent Application Publication No. 2010-230157

In a conventional head-up display device, vibrations caused by a motor for driving a reflecting mirror are propagated to an exterior case and the like and amplified, and the driving sound of the motor may be heard as harsh.

The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a head-up display device that can suppress the driving sound of a motor for driving a reflecting mirror.

In order to achieve the above object, a head-up display device according to the present disclosure includes:
A head-up display device that displays an image represented by the display light as a virtual image by emitting display light reflected by a reflecting mirror toward a transparent member,
a motor for rotationally driving the reflecting mirror;
a drive control unit that controls the rotational drive of the reflecting mirror by controlling the operation of the motor;
a storage unit that stores an initial setting position within a rotation range of the reflecting mirror;
an origin detection unit that detects an origin within a rotation range of the reflecting mirror;
a mass damper having a mass body and suppressing vibrations of the motor;
The drive control unit drives the motor at a first drive frequency to move the reflecting mirror to the initial setting position after the origin is detected by the origin detection unit;
The mass of the mass body is determined so that the amount of reduction in drive sound corresponding to the first drive frequency is maximized .

According to the present disclosure, it is possible to suppress the driving noise of the motor for driving the reflecting mirror.

FIG. 1 is a diagram showing how a head-up display (HUD) device according to an embodiment of the present disclosure is mounted on a vehicle. It is a schematic block diagram of a HUD device. FIG. 3 is a perspective view of a reflector drive device. FIG. 2 is an exploded perspective view of the reflector drive device. FIG. 3 is a schematic diagram for explaining the positional relationship between a concave mirror and a slide portion. FIG. 3 is a graph showing the effect of reducing motor drive noise.

An embodiment of the present disclosure will be described with reference to the drawings.

A head-up display (HUD) device 10 according to the present embodiment is disposed, for example, in a dashboard 2 of a vehicle 1, as shown in FIG. The HUD device 10 emits display light L toward the windshield 3. The display light L reflected by the windshield 3 heads toward the user 4 (mainly the driver of the vehicle 1), and causes the user 4 to visually recognize the image represented by the display light L as a virtual image V. The virtual image V is displayed in front of the vehicle 1 through the windshield 3. Thereby, the user 4 can observe the virtual image V superimposed on the front scenery. The virtual image V displays various information regarding the vehicle 1 (hereinafter referred to as vehicle information). Note that the vehicle information includes not only information about the vehicle 1 itself but also information external to the vehicle 1.

As shown in FIG. 2, the HUD device 10 includes a display 11, a plane mirror 12, a concave mirror 13, a housing 14, a reflector drive device 20, and an operation section 90.

By displaying an image, the display device 11 emits display light L representing the image toward the plane mirror 12. The display device 11 includes, for example, an LCD (Liquid Crystal Display) and a backlight that illuminates the LCD from behind. The LCD is, for example, of a TFT (Thin Film Transistor) type. The backlight includes, for example, an LED (Light Emitting Diode), a light guide member, and the like.

The plane mirror 12 is made of, for example, a cold mirror, and is arranged obliquely to the optical axis of the display light L emitted by the display 11. The plane mirror 12 reflects the display light L from the display 11 toward the concave mirror 13 . The plane mirror 12 is fixed to the housing 14 via a holder (not shown).

The concave mirror 13 is constructed by, for example, depositing a reflective layer on a resin substrate made of polycarbonate and having a concave surface. The concave mirror 13 magnifies the display light L from the plane mirror 12 and reflects it toward the windshield 3. Thereby, the virtual image V visually recognized by the user 4 becomes an enlarged image of the image displayed on the display 11.

Concave mirror 13 is held by holder 13a. The holder 13a is made of, for example, a synthetic resin material, and includes a shaft portion 13b and a lever portion 13c. The shaft portion 13b is formed in a substantially cylindrical shape, with the height direction being the direction in which the axis AX extends (the normal direction to the paper surface in FIG. 2). Note that although a pair of shaft portions 13b are provided on the holder 13a, only one shaft portion 13b is shown in FIG. The shaft portion 13b is rotatably supported by a bearing portion (not shown) provided in the housing 14. Thereby, the concave mirror 13 held by the holder 13a is rotatable about the axis AX with respect to the housing 14. The lever portion 13c has a flat plate shape and is formed to protrude toward the reflector drive device 20. The reflecting mirror driving device 20 rotates the concave mirror 13 held by the holder 13a around the axis AX by moving the lever part 13c in parallel in the X-axis direction. The reflecting mirror driving device 20 will be described in detail later.

The casing 14 accommodates the display 11, the plane mirror 12, the concave mirror 13, and the reflecting mirror driving device 20 at appropriate positions to achieve the above-described functions. The housing 14 is made of synthetic resin or metal and has a light-shielding property and is formed into a box shape. Note that the housing 14 may be configured by a combination of a plurality of members. The housing 14 is provided with an injection port 14a that opens toward the windshield 3. A translucent cover 15 is attached to the housing 14 to close the injection port 14a.

The display light L emitted from the display device 11 and reflected by the plane mirror 12 and the concave mirror 13 in this order is emitted from the exit port 14 a to the outside of the HUD device 10 and is directed toward the windshield 3 . When this display light L is reflected by the windshield 3, a virtual image V is displayed in front of the windshield 3 as viewed from the user 4.

The reflector driving device 20 includes a motor 30, a support body 40, a guide shaft G, a slide portion 50, and a circuit board 60, as shown in FIGS. 3 and 4. Further, the reflecting mirror driving device 20 includes a mass body 70, a control section 80, and a storage section 81, which are schematically shown in FIG.

The motor 30 is for rotationally driving the concave mirror 13, and is composed of, for example, a PM (Permanent Magnet) type stepping motor. The motor 30 is driven by a microstep drive method by a drive control means to be described later. The driven motor 30 rotates a rotating shaft 31 extending along the X-axis shown in FIG. 3 . A spiral thread groove is formed on the circumferential surface of the rotating shaft 31.

The support body 40 mainly supports the motor 30, and is integrally formed of, for example, metal. The support body 40 has a flat plate part 40a fixed to the bottom part 14b (see FIG. 2) of the housing 14, and a first wall part 41 and a second wall part 42 that face each other in the X-axis direction. The support body 40 has a flat plate portion 40a fixed to the bottom portion 14b using fixing means such as screws. Note that the support body 40 may be fixed to the bottom portion 14b via a buffer member (not shown). The first wall portion 41 is erected from one end of the flat plate portion 40a, and the second wall portion 42 is erected from the other end of the flat plate portion 40a. The motor 30 is attached to the back side of the first wall 41 facing the second wall 42 . The motor 30 is fixed to the first wall portion 41 using fixing means such as screws. A rotating shaft 31 extending from the motor 30 passes through an insertion hole O1 provided in the first wall 41 and is rotatably supported in a bearing hole O2 provided in the second wall 42. Further, the support body 40 supports the mass body 70.

The guide shaft G guides the moving direction of the slide portion 50, and similarly to the rotating shaft 31, it extends in the X-axis direction. The guide shaft G has one end supported by the first wall 41 and the other end supported by the second wall 42.

The slide portion 50 has a base portion 51 and a sandwiching portion 52 that sandwiches the lever portion 13c of the concave mirror 13. The slide portion 50 is integrally formed from a synthetic resin material such as polyacetal, for example.

A guide hole 51a into which the guide shaft G is inserted is formed in the base 51. Further, the base portion 51 is provided with a nut portion (not shown) that engages with the thread groove of the rotating shaft 31, and the nut portion moves the slide portion 50 in the X-axis direction in accordance with the rotation of the rotating shaft 31. . With such a configuration, the slide portion 50 can slide in the X-axis direction along the guide shaft G according to the rotation of the rotation shaft 31.

The sandwiching part 52 is provided on the base 51 and has a pair of wall parts facing each other, and the lever part 13c of the concave mirror 13 is sandwiched between the pair of wall parts. As shown in FIG. 3, one of the pair of wall portions is formed with a protrusion 52a that protrudes toward the other, and the other is provided with a leaf spring 52b. The clamping part 52 clamps the lever part 13c in a point contact state by pressing the lever part 13c toward the projection part 52a with the elastic force of the leaf spring 52b.

The circuit board 60 is a printed circuit board on which various circuits are formed, and on which the motor 30, a drive circuit for driving the motor 30, and a switch 61 are mounted. The circuit board 60 is fixed to the upper part of the first wall part 41 of the support body 40, as shown in FIG. The switch 61 is provided at a position facing the slide part 50 in the X-axis direction, and as the slide part 50 moves to the left in FIG. 3, it comes into contact with the slide part 50 and controls a detection signal indicating the contact. 80. The control unit 80 controls the drive of the concave mirror 13 with the position of the slide unit 50 at the time of acquiring the detection signal as the origin.

The mass body 70 is configured to function as a part of a mass damper D, which will be described later, and is provided at an arbitrary location on the support body 40. The mass body 70 is, for example, a weight made of a metal material such as brass. Although the material of the mass body 70 is not limited, it is preferable to select a material with a high specific gravity in order to save space and ensure the functions necessary for the mass damper D.

In the reflector drive device 20, the mass body 70 and the support body 40 function as a mass damper D (also called a tuned mass damper) schematically shown in FIG. The mass damper D suppresses the resonance phenomenon by adding an auxiliary mass body 70 to the motor 30, which is the object of vibration absorption, via a support body 40 that functions as a spring. In this way, mass damper D suppresses vibrations of motor 30. The mass of the mass body 70 is determined based on the drive frequency when driving the motor 30, as described later.

The control unit 80 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the operation of the reflector driving device 20. The storage unit 81 is a nonvolatile memory such as a flash memory, and is controlled by the control unit 80 to store an initial setting position of the concave mirror 13, which will be described later. Note that the initial setting position may be stored in the ROM of the control unit 80. For example, the control unit 80 and the storage unit 81 are mounted on a printed circuit board (a board different from the circuit board 60) provided at a predetermined position of the housing 14. In this embodiment, the control unit 80 controls not only the operation of the reflector drive device 20 but also the overall operation of the HUD device 10 and the display operation of the display 11. For example, the control unit 80 communicates with a system such as an ECU (Electronic Control Unit) that controls each part of the vehicle 1, and causes the display 11 to display an image indicating vehicle information.

Further, the control unit 80 controls the rotational drive of the concave mirror 13 by driving the motor 30 in a microstep drive method via the drive circuit of the circuit board 60. That is, the control unit 80 and the drive circuit function as a drive control unit that controls the rotation of the concave mirror 13. The drive circuit has a transistor bridge connected to the excitation coil of the motor 30, and is configured to be able to adjust the direction and magnitude of the excitation current flowing through the excitation coil. The drive circuit controls the current flowing through the excitation coil of the motor 30 under the control of the control unit 80 . Note that how the drive control section is configured is arbitrary, and it may be mounted on one substrate, or may be realized by cooperation of various sections mounted on a plurality of substrates.

Further, the control unit 80 stores the point where the slide unit 50 contacts the switch 61 as the origin in the RAM of the control unit 80, and counts the number of driving steps of the motor 30 during driving based on the origin stored in the RAM. Specify where the concave mirror 13 is currently located.

The control section 80 drives the motor 30 via the drive circuit to move the slide section 50 in the X-axis direction within the range between the first wall section 41 and the second wall section 42 of the support body 40. , controls the rotational position of the concave mirror 13. In addition, the control unit 80 adjusts the position of the concave mirror 13 within the rotation range of the concave mirror 13 in which the virtual image V can be displayed in response to an input operation by the user 4 from the operation unit 90. The display position of the virtual image V in the vertical direction is adjusted. Then, the control unit 80 sets the position of the concave mirror 13 adjusted by the operation of the user 4 as a new initial setting position, and overwrites (updates) the initial setting position stored in the storage unit 81.

The operation unit 90 receives input operations by the user 4, and is composed of a known input device such as a push button or a touch panel, and supplies a signal indicating the operation content to the control unit 80 in response to the input operation. do. As the operation unit 90, for example, a steering switch provided in the vehicle 1 can be used.

Here, the positional relationship between the concave mirror 13 and the slide portion 50 will be explained with reference to FIG. 5. FIG. 5 schematically shows the relationship between the rotational position of the concave mirror 13 and the sliding position of the sliding part 50, and in reality, the axis AX, which is the rotation center of the concave mirror 13, does not move in the X-axis direction. Needless to say. The rotation range of the concave mirror 13 in which the display light L reflected by the concave mirror 13 does not reach the windshield 3 and the virtual image V cannot be displayed is defined as a non-display range R1. Further, the rotation range of the concave mirror 13 in which the display light L reflected by the concave mirror 13 reaches the windshield 3 and the virtual image V can be displayed is defined as a display range R2. In the non-display range R1, the rotational position of the concave mirror 13 at the position X1 where the slide portion 50 contacts the switch 61 is defined as a first position P1. Further, the initial setting position of the concave mirror 13 in the display range R2 (the position set by adjustment by the user 4) is defined as a second position P2. Further, the position closest to the non-display range R1 within the display range R2, that is, the position of the concave mirror 13 when the virtual image V switches from the non-display state to the display state, is defined as a specific position Ps. In such a case, in the sliding range of the sliding portion 50, in order of proximity to the switch 61, position X1, position Xs of the sliding portion 50 with the concave mirror 13 as the specific position Ps, position The position becomes X2.

When the ignition of the vehicle 1 is turned on and operating power is supplied to the HUD device 10, the control section 80 drives the motor 30 via the drive circuit, brings the slide section 50 into contact with the switch 61, and detects the contact point. Store it as the starting point. In this way, the control section 80 functions as an origin detection section that detects the origin. After storing the origin, the control unit 80 moves the slide unit 50 from position X1 to position X2, thereby moving the concave mirror 13 from position P1, which is the origin of non-display range R1, to an initial setting position within display range R2. Rotationally move to position P2 stored as . When the control unit 80 positions the concave mirror 13 at the position P2, the control unit 80 controls the operation of the display 11 and controls the display of the virtual image V.

In this embodiment, when rotating the concave mirror 13 from position P1 (origin) to position P2 (initial setting position), the control unit 80 changes the rotation speed of the concave mirror 13 in the non-display range R1 to the rotation speed of the concave mirror 13 in the display range R2. 13 to shorten the time until the virtual image V starts to be displayed. Specifically, the control unit 80 drives the motor 30 at the first drive frequency when moving the concave mirror 13 from the position P1 (origin) in the non-display range R1 to the position P2 (initial setting position) in the display range R2. do. Further, after moving the concave mirror 13 to the position P2 (initial setting position), the control unit 80 controls the first The motor 30 is driven at a second drive frequency lower than the drive frequency. At this time, the control unit 80 drives the motor 30 at a drive frequency of about 2500 pps (pulse per second) (for example, 2496 pps) as the first drive frequency in order to achieve the rotational speed of the concave mirror 13 in the non-display range R1. do. In this case, if no measures are taken, a drive sound in the 2.5 kHz band may be generated corresponding to the drive frequency, which may be harsh to the user 4.

Therefore, in this embodiment, in order to suppress the drive noise generated as described above, the mass of the mass body 70 in the mass damper D is determined based on the drive frequency of the motor 30 of 2500 pps. The mass of the mass body 70 can be determined theoretically, for example, by solving the equation of motion in a linear spring-mass system. Since there are complex factors such as the configuration of the HUD device 10 and the manner in which the HUD device 10 is mounted on the vehicle 1, it is actually determined by experiment or a combination of theory and experiment. For the same reason, it is preferable to determine the location of the mass body 70 on the support body 40 in order to effectively suppress drive noise by experiment or a combination of theory and experiment.

FIG. 6 shows the effect of reducing the drive noise of the motor 30 by the mass damper D. Graph 5 with a solid line shows the measurement results of drive sound when the mass of the mass body 70 of the mass damper D is determined based on a drive frequency of 2496 pps in the reflector drive device 20 described above. On the other hand, the broken line graph 6 is the measurement result of the drive sound of the reflector drive device without the mass damper D. Referring to FIG. 6, it can be seen that when the mass damper D is provided, the drive noise in the 2.5 kHz band is significantly reduced compared to the case where it is not provided.

(1) The HUD device 10 described above emits the display light L reflected by the concave mirror 13 (an example of a reflecting mirror) toward the windshield 3 (an example of a transparent member), thereby producing an image represented by the display light L. is displayed as a virtual image V. The HUD device 10 includes a motor 30 for rotationally driving the concave mirror 13, a drive control section and an origin detection section realized as functions of the control section 80, a storage section 81, and a mass damper D. The drive control unit controls the rotation of the concave mirror 13 by controlling the operation of the motor 30 . The storage unit 81 stores an initial setting position (position P2) within the rotation range of the concave mirror 13. The origin detection section detects the origin (position P1) within the rotation range of the concave mirror 13. The mass damper D has a mass body 70 and suppresses vibrations of the motor 30.
With this configuration, as described above, the driving sound of the motor 30 for driving the reflecting mirror can be suppressed.

(2) Specifically, the origin (position P1) is within the rotation range (non-display range R1) of the concave mirror 13 in which the virtual image V cannot be displayed. Further, the initial setting position (position P2) is within the rotation range (display range R2) of the concave mirror 13 where the virtual image V can be displayed.
With this configuration, it is possible to suppress the driving noise of the motor 30 when rotating the reflecting mirror from the origin located within the non-display range R1 to the initial setting position within the display range R2.

(3) The HUD device 10 also includes an operation section 90. After moving the concave mirror 13 to the initial setting position, the drive control unit drives the motor 30 at a second drive frequency lower than the first drive frequency in response to an input from the operation unit 90 to display the virtual image V. The position of the reflecting mirror is moved within the rotation range of the concave mirror 13 (indication range R2) that allows the rotation of the concave mirror 13.
With this configuration, it is possible to more effectively reduce the drive sound generated at the first drive frequency, which occurs more significantly than the drive sound at the second drive frequency, which corresponds to the adjustment operation by the user 4. As a result, for example, the period from when the HUD device 10 starts up to when the concave mirror 13 is moved to the initial setting position (that is, when the vehicle 1 has not yet started running, there is no road noise, and the driving noise is bothersome) It is possible to effectively reduce driving noise during the expected period.

Note that the present disclosure is not limited to the above embodiments and drawings. It is possible to make changes (including deletion of components) as appropriate without changing the gist of the present disclosure.

In the optical path of the display light L connecting the plane mirror 12 and the concave mirror 13, a plane mirror other than the plane mirror 12 may be provided. Furthermore, a free-form mirror may be provided instead of the plane mirror 12. In the HUD device 10, the number of mirrors used and how the optical path of the display light L is folded can be changed as appropriate depending on the design.

In the above, an example in which the reflecting mirror driving device 20 rotates and moves the concave mirror 13 has been described, but the reflecting mirror driving device 20 may also rotate a plane mirror or a free-form mirror (another example of a reflecting mirror). good. The configuration of the reflecting mirror driving device 20 is arbitrary as long as it rotates the reflecting mirror using the power of the motor 30.

Although an example in which the mass body 70 is provided on the support body 40 has been described above, a configuration in which the mass body 70 is attached to the motor 30 or the support body 40 via an elastic member may also be adopted.

In the above, the mass of the mass body 70 was determined based on the drive frequency of the motor 30 when rotating the concave mirror 13 in the non-display range R1, but when driving the motor 30 when rotating the concave mirror 13 in the display range R2. The mass of the mass body 70 may be determined based on the frequency. Moreover, the frequency band to be suppressed among the drive sounds is also arbitrary, and may be higher or lower than the 2.5 kHz band. For example, the frequency band that the user 4 finds harsh may be any frequency band within the range of 1 kHz to 5 kHz. If the mass body is made lighter than the mass body 70 of the mass damper D that suppresses the 2.5 kHz band of drive sound, any frequency band higher than the 2.5 kHz band can be reduced; if the mass body is made heavier, , any frequency band lower than the 2.5kHz band can be reduced.

Although the example in which the support body 40 is fixed to the bottom portion 14b of the housing 14 has been described above, the present invention is not limited to this. As long as the reflecting mirror can be rotated, the support body 40 of the reflecting mirror driving device 20 can be fixed to the housing 14 in any manner.

Further, the display device 11 is not limited to one using an LCD, but may also use one using an OLED (Organic Light-Emitting Diode). Further, the display 11 may use a reflective display device such as a DMD (Digital Micro mirror Device) or an LCOS (Liquid Crystal On Silicon), for example.

Further, the light-transmitting member on which the display light L is projected is not limited to the windshield 3 of the vehicle 1, but may be a combiner formed of a plate-shaped half mirror, a hologram element, or the like.

Further, the type of vehicle 1 in which the HUD device 10 is mounted is not limited, and the present invention is applicable to various vehicles such as four-wheeled motor vehicles and motorcycles. Further, the HUD device 10 may be mounted on a vehicle other than the vehicle 1, such as an aircraft, a ship, or a snowmobile.

In the above description, descriptions of known technical matters have been omitted as appropriate in order to facilitate understanding of the present disclosure.

DESCRIPTION OF SYMBOLS 1...Vehicle, 2...Dashboard, 3...Windshield, 4...User L...Display light, V...Virtual image 10...Head-up display (HUD) device 11...Display device 12...Plane mirror 13...Concave mirror (an example of a reflecting mirror)
R1... Hidden range, R2... Display range P1... First position, P2... Second position, Ps... Specific position 13a... Holder, 13b... Shaft part, 13c... Lever part, AX... Axis line 14... Housing, 14a... Injection port, 14b... Bottom part 20... Reflector drive device 30... Motor, 31... Rotating shaft 40... Support body, 40a... Flat plate part, 41... First wall part, 42... Second wall part G... Guide shaft 50 ...Slide part, 51...Base, 52...Pinch part 60...Circuit board, 61...Switch 70...Mass body, D...Mass damper 80...Control part, 81...Storage part 90...Operation part

Claims (3)

A head-up display device that displays an image represented by the display light as a virtual image by emitting display light reflected by a reflecting mirror toward a transparent member,
a motor for rotationally driving the reflecting mirror;
a drive control unit that controls the rotational drive of the reflecting mirror by controlling the operation of the motor;
a storage unit that stores an initial setting position within a rotation range of the reflecting mirror;
an origin detection unit that detects an origin within a rotation range of the reflecting mirror;
a mass damper having a mass body and suppressing vibrations of the motor;
The drive control unit drives the motor at a first drive frequency to move the reflecting mirror to the initial setting position after the origin is detected by the origin detection unit;
The mass of the mass body is determined so that the amount of reduction in drive sound corresponding to the first drive frequency is maximized. The head-up display device. The origin is within a rotation range of the reflecting mirror in which the virtual image cannot be displayed;
The initial setting position is within a rotation range of the reflecting mirror that allows display of the virtual image.
The head-up display device according to claim 1. Equipped with an operation section,
After moving the reflecting mirror to the initial setting position, the drive control unit drives the motor at a second drive frequency lower than the first drive frequency in response to an input from the operation unit to generate the virtual image. moving the position of the reflecting mirror within a rotation range of the reflecting mirror that enables display of
The head-up display device according to claim 2.

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