Image projection apparatus

Abstract

To provide an image projection device capable of improving the accuracy of angle adjustment of a mirror part by suppressing the influence of backlash by a gear part.SOLUTION: An image projection device (100) that projects a projection image onto a display unit for displaying a virtual image includes an image emission unit (10) that emits image light L, a mirror part (20) that forms an image of the image light L at a first distance from a viewpoint position via the display unit, and a mirror driving unit (60) that adjusts an angle of the mirror part (20). In the image projector (100), a mirror driving part (60) has a motor part and a gear part, and rotates the motor part more by a backlash angle θ B of the gear part in total of normal rotation and reverse rotation when rotating and driving the mirror part (20) to an instruction angle θ.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image projection device. [Background technology]

[0002] Conventionally, dashboards that illuminate icons have been used to display various types of information inside vehicles. As the amount of information to be displayed increases, it has been proposed to embed an image display device in the dashboard or to configure the entire dashboard with an image display device.

[0003] However, because the instrument panel is located below the vehicle's windshield, passengers such as the driver must undesirably move their eyes downward while driving in order to view the information displayed on the instrument panel. Therefore, image projection devices such as head-up displays (hereinafter referred to as HUDs) have been proposed that project images onto the windshield so that passengers can read information when they view the area ahead of the vehicle (see, for example, Patent Documents 1 and 2).

[0004] In conventional image projection devices, an image projection unit emits light containing an image, and the light is reflected by a free-form mirror or the like, and the light reaches the viewpoint of the occupant so that the image is formed in space via a display unit such as a windshield. This allows the occupant to perceive the image as being displayed at the imaging position in the depth direction due to the light incident at the viewpoint. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-119248 [Patent Document 2] Japanese Patent Application Publication No. 2019-119262 Summary of the Invention [Problem to be solved by the invention]

[0006] Furthermore, some conventional image projection devices have been proposed that are equipped with a function that adjusts the tilt angle of the mirror according to the viewpoint position of the passenger, thereby adjusting the angle of incidence of the image light onto the windshield, so that the virtual image P can be properly viewed even if the viewpoint position changes. However, the gear section (reduction mechanism) used to drive the mirror section has a gap to provide mechanical leeway in the meshing portion of the gear teeth, and the rotation speed of the motor section is not necessarily used directly to change the angle of the mirror section.

[0007] The presence of such a gap causes a problem that when the motor changes from rotating in the forward direction to rotating in the reverse direction, backlash occurs, in which the mirror does not rotate even though the motor is rotating, reducing the accuracy of the desired angle adjustment of the mirror.In an image projection device, the position where the passenger views the virtual image P is an extension of the path of the image light reflected by the windshield, so even a slight deviation in angle may make it impossible to view the virtual image P properly.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide an image projection device that can suppress the effects of backlash caused by the gear section and improve the accuracy of angle adjustment of the mirror section. [Means for solving the problem]

[0009] In order to solve the above problem, the image projection device of the present invention is an image projection device that projects a projection image onto a display unit for displaying a virtual image, and includes an image projection unit that irradiates image light, a mirror unit that forms an image of the image light at a first distance from a viewpoint position via the display unit, and a mirror drive unit that adjusts the angle of the mirror unit, the mirror drive unit having a motor unit and a gear unit, and when rotating the mirror unit to an indicated angle θ, a backlash angle θ of the gear unit is adjusted by a total of forward and reverse rotations. B The motor unit is rotated by an additional amount.

[0010] In the image projection device of the present invention, when the mirror unit is rotated to the designated angle θ, the backlash angle θ of the gear unit is the sum of the forward and reverse rotations. B In order to rotate the motor by an additional amount, the backlash angle θ B This makes it possible to correct the idling equivalent to the above, suppress the effect of backlash caused by the gear portion, and improve the accuracy of angle adjustment of the mirror portion.

[0011] In one aspect of the present invention, a temperature measuring unit for measuring an environmental temperature is provided, and the backlash angle θ B Set.

[0012] In one aspect of the present invention, the temperature measurement unit measures the temperature in the vicinity of the image projection unit as the environmental temperature.

[0013] In one aspect of the present invention, the mirror driving unit executes an initial setting step of setting the mirror unit to an initial angle θ0, and a rotation step of rotating the mirror unit to the designated angle θ after the initial setting step. When rotating the mirror unit to the initial angle θ0 in the initial setting step, the motor unit is rotated an additional amount by a first adjustment angle θ1. In the rotation step, the motor unit is rotated an additional amount by the first adjustment angle θ1 when rotating in the same direction as in the initial setting step, and is rotated an additional amount by a second adjustment angle θ2 when rotating in the opposite direction to the initial setting step, so that θ1+θ2=θ B is.

[0014] In one aspect of the present invention, the first adjustment angle θ1 and the second adjustment angle θ2 are θ1=θ2.

[0015] In one aspect of the present invention, the gear portion is a multi-stage gear formed by combining a plurality of gears. [Effects of the Invention]

[0016] The present invention can provide an image projection device that can reduce the influence of backlash caused by the gear portion and improve the accuracy of angle adjustment of the mirror portion. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing projection of a virtual image P using the image projection device 100 according to the first embodiment. [Figure 2] FIG. 1 is a schematic cross-sectional view illustrating an overview of an image projection device 100 according to a first embodiment. [Figure 3] 10 is a schematic diagram illustrating the driving of the mirror section 20 by the mirror driving section 60 and the projection angle of the image light. FIG. [Figure 4] 2 is a schematic diagram showing an example of the configuration of a motor unit 61 and a gear unit of a mirror driving unit 60. FIG. [Figure 5] 10 is a flowchart showing an example of the operation of the mirror driver 60. DETAILED DESCRIPTION OF THE INVENTION

[0018] (First embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be assigned the same reference numerals, and redundant explanations will be omitted where appropriate. Figure 1 is a schematic diagram showing the projection of a virtual image P using an image projection device 100 according to this embodiment.

[0019] As shown in FIG. 1, image light L projected from image projection device 100 is irradiated toward windshield (display unit) WS, reflected by the windshield WS, and irradiated at the driver's viewpoint E. The driver visually recognizes a virtual image P formed on an extension of the optical path of the incident image light L. The solid and dashed lines shown in FIG. 1 schematically represent the luminous flux of image light L irradiated from image projection device 100, the optical path of image light L reflected by the windshield WS and reaching viewpoint E, and its extension. The actual image light L is displayed with a predetermined area in image projection unit 10, and has a predetermined area in the direction perpendicular to the traveling direction.

[0020] The windshield WS is a part of the vehicle that is provided in front of the driver's seat and transmits visible light. The windshield WS corresponds to the display unit of the present invention because the windshield WS, on the inside surface of the vehicle, reflects the image light L incident from the image projection device 100 toward the viewpoint and transmits light from outside the vehicle toward the viewpoint. While an example in which the windshield WS is used as the display unit is shown here, a combiner may be provided as a display unit separate from the windshield WS and reflect the image light L toward the viewpoint. Furthermore, the display unit is not limited to being located at the front of the vehicle, and may be located to the side or rear as long as it projects an image toward the viewpoint of the passenger.

[0021] The virtual image P is an image that appears as if it were formed in space when the image light L reflected by the windshield WS reaches the viewpoint E (eyebox) of the driver or the like. The position at which the virtual image P is formed is determined by the spread angle of the image light L irradiated from the image projection device 100 as it travels toward the viewpoint after being reflected by the projection optical unit (not shown in FIG. 1) and the windshield WS. The display content of the image projected as the virtual image P may include auxiliary information related to driving such as a warning image or emergency information, a volume indicator, a driving direction guide, etc.

[0022] 2 is a schematic cross-sectional view illustrating an overview of an image projection device 100 according to this embodiment. As shown in FIG. 2, the image projection device 100 includes an image irradiation unit 10, a mirror unit 20, a cover unit 30, a housing unit 40, a control unit 50, and a mirror driving unit 60.

[0023] The image projection unit 10 is a part that projects image light L containing an image based on image information from the control unit 50. The specific configuration of the image projection unit 10 is not limited, but as an example, a PGU (Picture Generation Unit) equipped with a backlight, a liquid crystal display device, and optical elements can be used.

[0024] The mirror unit 20 is an optical element that projects the image light L emitted from the image projection unit 10 onto the driver's viewpoint E via the windshield WS, forming an image at a first distance from the viewpoint E. The optical characteristics of the mirror unit 20 are not limited, but a free-form concave mirror with a predetermined focal length can be used. As will be described later, the mirror unit 20 is held rotatable about a central axis in the left-right direction of the vehicle (a direction perpendicular to the paper surface in the figure), and the tilt angle (vertical direction in the figure) relative to the windshield WS can be changed by a mirror driver 60.

[0025] The reflective surface of the mirror unit 20 is designed to expand the light diameter in the driver's line of sight in order to project the image light L as a virtual image P through the windshield WS. Here, "expanding the light diameter in the line of sight" includes not only the case where the light diameter consistently expands after reflection, but also the case where the light diameter shrinks and expands after forming an image at an intermediate point. While FIG. 1 shows an example in which the image light L from the image projection unit 10 is directly incident on the mirror unit 20, the image light L from the image projection unit 10 may be reflected by another mirror and then reach the mirror unit 20.

[0026] The cover unit 30 is made of a material that transmits the image light L, and is a member disposed to cover the opening of the housing unit 40. Although not shown in FIG. 1, the cover unit 30 is fixed to the housing unit 40 in a structure that leaves no gap between them, thereby preventing dust and dirt from entering the interior of the housing unit 40. There are no limitations on the material that makes up the cover unit 30, and known resin materials or glass that transmit the image light L can be used.

[0027] The housing unit 40 is a component that forms the outer shape of the image projection device 100 and accommodates the image irradiation unit 10, the mirror unit 20, the control unit 50, and the mirror drive unit 60 inside. An opening is provided at the top of the housing unit 40, and a cover unit 30 is provided to cover the opening and seal the interior. The shape and material of the housing unit 40 are not limited, and a resin material or metal material that blocks light can be used.

[0028] The control unit 50 is a part that is connected to each part so as to be able to communicate information with them and controls each part according to a predetermined program. The configuration of the control unit 50 is not limited, but an example includes a CPU (Central Processing Unit) for performing information processing, a memory device, a recording medium, an information communication device, etc. As an example, the control unit 50 may be an ECU (Engine Control Unit) of a vehicle equipped with the image projection device 100. Furthermore, the control unit 50 sends information including an image (image information) to the image projection unit 10 according to a predetermined program, and causes the image projection unit 10 to irradiate image light L.

[0029] The mirror driver 60 is a component that operates based on a control signal from the controller 50 and changes the tilt angle of the mirror unit 20. The specific configuration of the mirror driver 60 is not limited, but it at least includes a structure that rotatably supports the mirror unit 20 and a power source that rotates the mirror unit 20. Examples of the direction in which the mirror driver 60 rotates the mirror unit 20 include a tilt direction relative to the horizontal direction of the vehicle and a swing direction within a horizontal plane. The rotational driving of the mirror unit 20 and the change in the projection angle of the image light L by the mirror driver 60 will be described in detail below.

[0030] FIG. 3 is a schematic diagram illustrating the driving of the mirror unit 20 by the mirror driver 60 and the projection angle of the image light L. The mirror unit 20 is held by the mirror driver 60 so that the tilt angle can be changed around the rotation axis. As indicated by the solid and dashed lines in the figure, the tilt angle of the mirror unit 20 relative to the windshield WS is changed by the operation of the mirror driver 60, and the direction in which the incident image light L is reflected is accordingly changed from L1 to L2. The incident position and incident angle of the image light L reflected by the mirror unit 20 relative to the windshield WS are changed by changing the tilt angle of the mirror unit 20, and the optical path until it reaches the viewpoint E is changed. Therefore, the height of the viewpoint E and the depression angle for viewing the virtual image P from the viewpoint E can be adjusted by control by the mirror driver 60.

[0031] 4 is a schematic diagram showing an example of the configuration of the motor unit 61 and gear unit of the mirror driver 60. Fig. 4(a) is a side view with the rotation axis of the motor unit 61 oriented left-right, and Fig. 4(b) is a front view seen from a direction perpendicular to the rotation axis of the motor unit 61. In the example shown in Fig. 4, the mirror driver 60 includes the motor unit 61 and gears 62 and 63.

[0032] The motor unit 61 is a part that converts electric power into rotational motion, and is rotationally driven by electric power and a control signal supplied from the control unit 50. The gear 62 is a gear attached to the rotating shaft of the motor unit 61, and transmits the rotational motion generated by the motor unit 61 to the gear 63. The gear 63 is a gear attached to the mirror unit 20, and transmits the rotational motion of the gear 62 to the mirror unit 20 by reducing the rotational motion according to a gear ratio. Therefore, the combination of the gears 62 and 63 constitutes a speed reduction mechanism, and corresponds to the gear unit in the present invention. While Fig. 4 shows an example in which the combination of two gears 62 and 63 is used as the gear unit, the gear unit may also be constituted by a multi-stage gear that combines more gears.

[0033] As shown in FIG. 4(b), gears 62 and 63 constituting the gear unit transmit rotational motion by rotating while meshing with each other. Here, the clockwise rotation direction of gear 62 is defined as the forward rotation direction, and the counterclockwise rotation direction is defined as the reverse rotation direction. When gear 62 rotates in the forward rotation direction, gear 63 rotates counterclockwise, and when gear 62 rotates in the reverse rotation direction, gear 63 rotates clockwise. Typically, a gap is provided at the meshing portion of gears to provide mechanical margin. For this reason, when motor unit 61 changes its rotation direction between the forward and reverse directions, gear 62 rotates idly by the distance corresponding to the gap before rotating gear 63. In other words, when the rotation direction of motor unit 61 is changed, backlash corresponding to the gap occurs.

[0034] The idling of the motor unit 61 due to this backlash is defined as a backlash angle θ B The backlash angle is θ BThe minute rotation is the rotation of the motor unit 61 from when the motor unit 61 starts to reverse its rotation direction until the mirror unit 20 starts to reverse its rotation direction when the rotation direction of the motor unit 61 is reversed and changed. In other words, it is the rotation of the motor unit 61 from when the gear 62 changes its rotation direction by the motor unit 61 until the gear 63 attached to the mirror unit 20 starts to reverse its rotation direction. In the case where the gear unit is configured with a multi-stage gear, the rotation of the motor unit 61 from when the input side gear attached to the rotation shaft of the motor unit 61 starts to reverse its rotation until the output side gear attached to the mirror unit 20 starts to rotate is the backlash angle θ B This results in a rotation of 1 / 10th of a minute.

[0035] As an example, consider a case where the motor unit 61 rotates by a rotation number n in order for the mirror unit 20 to rotate by one degree in the forward or reverse direction. B If the number of rotations of the motor unit 61 per minute is m, the backlash angle θ B can be expressed as m / n (degrees).

[0036] As described above, when the mirror driving unit 60 rotates the mirror unit 20, if the mirror driving unit 60 is operated by switching between the forward rotation direction and the reverse rotation direction, the backlash angle θ B Therefore, in the image projection device 100 of this embodiment, when the mirror unit 20 is rotated to the designated angle θ, the backlash angle θ of the gear unit is the sum of the forward and reverse rotations. B The motor unit 61 is rotated by an additional amount, and the backlash angle θ B Compensates for slippage.

[0037] More specifically, when rotating in the forward direction, the motor unit 61 is rotated by an additional amount equal to the first adjustment angle θ1, and when rotating in the reverse direction, the motor unit 61 is rotated by an additional amount equal to the second adjustment angle θ2. At this time, the sum of the first adjustment angle θ1 and the second adjustment angle θ2 is the backlash angle θ B and θ1+θ2=θ B The range of the first adjustment angle θ1 and the second adjustment angle θ2 is 0≦θ1≦θ B , 0≦θ2≦θB The ratio x:y of θ1 to θ2 is not limited, but it is preferable to set θ1=θ2, which compensates by the same angle in the forward and reverse directions.

[0038] Fig. 5 is a flowchart showing an example of the operation of the mirror driving unit 60. In this embodiment, when the driver opens the door, sits in the seat, starts the vehicle, or the like, the image projection device 100 starts and the control shown in Fig. 5 begins. The control shown in Fig. 5 is executed by the control unit 50 controlling the image projection unit 10 and the mirror driving unit 60 in accordance with a program recorded in the control unit 50.

[0039] First, in step S1, the motor unit 61 is rotated so that the mirror unit 20 is at an initial angle θ0, which is a reference position. Here, the initial angle θ0 is an angle that is set in advance in the image projection device 100 regardless of the driver or settings, and the initial angle θ0 may be a specific angle from the horizontal direction, or may be an angle relative to a specific portion of the housing unit 40. In this embodiment, the rotation direction of the motor unit 61 up to the initial angle θ0 is described as the forward direction. The initial angle θ0 may be detected by detecting, for example, that a specific portion of the mirror unit 20 has reached a specific position. After the mirror unit 20 is set to the initial angle θ0, the process proceeds to step S2.

[0040] Next, in step S2, with the mirror unit 20 at the initial angle θ0, which is the reference position, the angle of the motor unit 61 is set to θ ini At this time, the control unit 50 and the motor driving unit 60 initialize the position of the motor unit 61 to the initial position θ ini The backlash angle θ B The initial position θ is adjusted by the first adjustment angle θ1 or the second adjustment angle θ2 to compensate for ini More specifically, when the mirror unit 20 is rotated to the initial angle θ0, the motor unit 61 is rotated in the normal direction, and the motor unit 61 rotates in the normal direction until the mirror unit 20 reaches the initial angle θ0. iniThe angle of the motor unit 61 is initialized and then the process proceeds to step S3. Steps S1 and S2 set the mirror unit 20 to the initial angle θ0 and initialize the angle of the motor unit 61, and therefore correspond to the initial setting process of the present invention.

[0041] Next, in step S3, the mirror unit 20 is rotated to a predetermined command angle θ. The command angle θ here can be an angle corresponding to the height of the viewpoint position E recorded in the control unit 50 for each driver. At this time, the control unit 50 and the mirror driving unit 60 set the rotation target of the motor unit 61 to the backlash angle θ in addition to the rotation to the command angle θ. B In order to compensate for this, the motor unit 61 is rotated by an additional first adjustment angle θ1 or second adjustment angle θ2. More specifically, when rotating the motor unit 61 in the forward direction, the control unit 50 sends a control signal to rotate the motor unit 61 to an angle θ-θ1. When rotating the motor unit 61 in the reverse direction, the control unit 50 sends a control signal to rotate the motor unit 61 to an angle θ+θ2. After rotating the mirror unit 20 to the designated angle θ, the process proceeds to step S4.

[0042] Next, in step S4, it is determined whether the driver or the like has made an input to adjust the projection position of the virtual image P. If there is a position adjustment input, the process proceeds to step S5; if there is no position adjustment input, the process proceeds to step S6. Here, the position adjustment input may be an input in which the driver operates a button or an operation panel provided on the image projection device 100 to move the projection position of the virtual image P upward or downward. Alternatively, the position adjustment input may be an input in which the height of the viewpoint position E is detected by image recognition or the like, and the projection position of the virtual image P is moved upward or downward depending on the detected height of the viewpoint position E.

[0043] Next, in step S5, the angle of the mirror unit 20 as the target value is set to a new command angle θ in accordance with the position adjustment input input in step S4, and the control unit 50 and the mirror driving unit 60 drive and rotate the mirror unit 20. At this time, the control unit 50 and the mirror driving unit 60 set the backlash angle θ as the rotation target of the motor unit 61 in addition to the rotation up to the command angle θ. B In order to compensate for this, the motor unit 61 is rotated by an additional first adjustment angle θ1 or a second adjustment angle θ2. More specifically, when rotating the motor unit 61 in the forward direction, the control unit 50 sends a control signal to rotate the motor unit 61 to an angle θ-θ1. When rotating the motor unit 61 in the reverse direction, the control unit 50 sends a control signal to rotate the motor unit 61 to an angle θ+θ2. After rotating the mirror unit 20 to the specified angle θ, the process proceeds to step S6. Here, steps S3 and S5 correspond to the rotation process in the present invention, since they control the rotation of the motor unit 61 so as to rotate the mirror unit 20 to the specified angle θ.

[0044] Next, in step S6, it is determined whether a power-off input has been made to stop the operation of the image projection device 100. Examples of power-off input include when a button or operation panel provided on the image projection device 100 is used to select to turn off the power of the image projection device 100, or when the driver stops driving the vehicle. If a power-off input has been made, the control ends; if not, the control proceeds to step S4 and continues.

[0045] A more specific example of control of the motor unit 61 will be described below using specific numerical values. In the initial setting process, the motor unit 61 is rotated in the normal direction, and the backlash angle θ of the gear unit is set to 0. B is 1 degree. The ratio of the first adjustment angle θ1 to the second adjustment angle θ2 is 1:1, with θ1=0.5 degrees and θ2=0.5 degrees. The initial angle θ0, which is the reference position of the mirror unit 20, is set to 0 degrees, and the angle of the motor unit 61 at this time is set to θ ini =0 degrees.

[0046] Furthermore, when rotating the motor unit 61 in the initial setting process and the rotation process, the target angle of the motor unit 61 is set to be different in the forward rotation direction and the reverse rotation direction. Specifically, when the command angle of the mirror unit 20 is θ, the target angle of the motor unit 61 is set to θ-θ1=θ-0.5 in the forward rotation direction, and θ+θ2=θ+0.5 in the reverse rotation direction. Examples of the command angle of the mirror and the target angle of the motor unit 61 are shown in Table 1. As an example, if the command angle of the mirror unit 20 is 5 degrees, when the current angle is 7 degrees, a control signal is sent to rotate the motor unit 61 to 4.5 degrees, and when the current angle is 3 degrees, a control signal is sent to rotate the motor unit 61 to 5.5 degrees.

[0047] [Table 1]

[0048] In the image projection device 100, when changing the height of the viewpoint E at which the virtual image P can be viewed, even if the mirror driving unit 60 repeatedly adjusts the angle of the mirror unit 20, the rotation speed of the motor unit 61 in the forward and reverse directions does not change by the backlash angle θ B As a result, even if the rotation direction of the motor unit 61 is repeatedly reversed, the backlash angle θ B The minute idling can be corrected by adjusting the first adjustment angle θ1 and the second adjustment angle θ2 of the motor unit 61, so that the angle of the mirror unit 20 can always be set accurately.

[0049] As described above, in the image projection device 100 of this embodiment, when the mirror unit 20 is rotated to the designated angle θ, the backlash angle θ of the gear unit is the sum of the forward and reverse rotation directions. B In order to rotate the motor unit 61 by an additional amount, the backlash angle θ B This makes it possible to correct the idling equivalent to the above, suppress the influence of backlash caused by the gear portion, and improve the accuracy of angle adjustment of the mirror portion 20.

[0050] (Second embodiment) Next, a second embodiment of the present invention will be described. Descriptions of content that overlaps with the first embodiment will be omitted. This embodiment differs from the first embodiment in that the control unit 50 includes a temperature measurement unit (not shown) that measures the environmental temperature of the image projection device 100.

[0051] The temperature measurement unit can be any of various sensors capable of measuring temperature, examples of which include a thermistor, a thermocouple, an infrared thermometer, etc. The location where the temperature measurement unit is provided is not limited, but it is preferable to measure the temperature in the vicinity of the image irradiation unit 10 as the environmental temperature.

[0052] The volume of each gear constituting the gear portion of the mirror driving unit 60 increases or decreases slightly depending on the temperature, so the backlash angle θ B In the image projection device 100, even a slight difference in the rotation angle of the mirror unit 20 changes the angle of incidence of the image light L onto the windshield WS. In addition, since the distance from the image light L reflected by the windshield WS to the viewpoint E is long, the height of the viewpoint E at which the virtual image P can be clearly recognized also changes. Therefore, the backlash angle θ B It is also necessary to consider that varies with the environmental temperature.

[0053] Therefore, in the image projection device 100 of this embodiment, the control unit 50 receives the environmental temperature and the backlash angle θ B The relationship between the backlash angle θ and the temperature is recorded in advance, and the backlash angle θ is calculated based on the environmental temperature measured by the temperature measurement unit. B Also, set the backlash angle θ B In this case, the first adjustment angle θ1 and the second adjustment angle θ2 are determined in the range of 0≦θ1≦θ B , 0≦θ2≦θ B and θ1+θ2=θ B The ratio of θ1:θ2=x:y is set. Here, the ambient temperature and backlash angle θ B A predetermined formula may be used as the relationship between the environmental temperature and the backlash angle θ BThe relationship may be stored as a table.

[0054] In the image projection device 100 of this embodiment, when the mirror unit 20 is rotated to the designated angle θ, the backlash angle θ of the gear unit is the sum of the forward and reverse rotation directions. B In order to rotate the motor unit 61 by an additional amount, the backlash angle θ B This makes it possible to correct the idling equivalent to the above, suppress the influence of backlash caused by the gear portion, and improve the accuracy of angle adjustment of the mirror portion 20.

[0055] In addition, the backlash angle θ B By setting the backlash angle θ B By reflecting the change in the angle, the influence of backlash caused by the gear portion can be suppressed, and the accuracy of angle adjustment of the mirror portion 20 can be further improved.

[0056] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0057] 100...Image projection device 10...Image irradiation unit 20...Mirror section 30...Cover part 40...Housing section 50...Control unit 60...Mirror drive unit 61...Motor section 62,63...Gear

Claims

1. An image projection device that projects a projection image onto a display unit for displaying a virtual image, an image irradiating unit that irradiates image light; a mirror unit that forms an image of the image light at a first distance from a viewpoint position via the display unit; a mirror driver for adjusting the angle of the mirror; The mirror driving unit has a motor unit and a gear unit, and when the mirror unit is rotated to the designated angle θ, the backlash angle θ of the gear unit is the sum of the forward and reverse rotations. Ｂ The image projection device is characterized in that the motor unit is rotated by an additional minute.

2. 2. The image projection device according to claim 1, A temperature measuring unit is provided to measure the environmental temperature, The backlash angle θ is determined based on the environmental temperature. Ｂ An image projection device characterized by setting

3. 3. The image projection device according to claim 2, The image projection device, wherein the temperature measurement unit measures the temperature in the vicinity of the image projection unit as the environmental temperature.

4. 2. The image projection device according to claim 1, The mirror driving unit rotates the mirror unit at an initial angle θ ０ and a rotation step of rotating the mirror unit to the designated angle θ after the initial setting step, In the initial setting step, the initial angle θ ０ When the mirror portion is rotated to the first adjustment angle θ １ the motor unit rotates by a further minute, In the rotation step, when the rotation is in the same direction as in the initial setting step, the first adjustment angle θ １ When the motor unit is rotated in the direction opposite to the initial setting step, the second adjustment angle θ ２ the motor unit rotates by a further minute, θ １ +θ ２ = θ Ｂ An image projection device characterized by:

5. 5. The image projection device according to claim 4, The first adjustment angle θ １ and the second adjustment angle θ ２ is θ １ = θ ２ An image projection device characterized by:

6. 6. The image projection device according to claim 1, The image projection device is characterized in that the gear portion is a multi-stage gear formed by combining a plurality of gears.

Images