Image projection device and image projection method

Abstract

To provide an image projection device and image projection method, which enable effective suppression of an increase in temperature of an image irradiation unit due to external light using a simple configuration.SOLUTION: An image projection device (10) for projecting a virtual image via a display unit is provided, comprising an image irradiation unit (11) for irradiating image display light (GL) for forming a virtual image, and a reflective mirror (12) for guiding the image display light (GL) to a display unit, where the orientation of the reflective mirror (12) is changed so as to prevent light (SL) incident on the reflective mirror (12) from a direction of the display unit from entering the image irradiation unit (11) when a given condition is met.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, an instrument panel that displays various information inside a vehicle has been used, which displays icons by lighting them. However, since the instrument panel is located below the windshield (front glass) of the vehicle, the driver needs to move his / her eyes downward while driving in order to visually confirm the information displayed on the instrument panel, which is undesirable. Therefore, an image projection device such as a head up display (hereinafter referred to as "HUD") has been proposed, which projects an image onto the windshield so that the driver can read the information when he / she looks ahead of the vehicle.

[0003] In the image projection device of the conventional technology described above, an image projection unit such as a liquid crystal display device projects light containing an image (hereinafter referred to as "image display light"), and one or more free-form surface mirrors (hereinafter sometimes referred to as "optical system") reflect the light so that the image (virtual image) reaches the eye box of the driver or the like so as to be formed in space. This allows the driver or the like to recognize that an image is being displayed at the imaging position in the depth direction in front of the vehicle due to the image display light incident on the eye box. Patent Document 1 discloses an example of such a HUD according to the conventional technology. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-156071 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in the HUD according to the above-mentioned conventional technology, it is assumed that sunlight, which is external light concentrated by the optical system, hits the image irradiation unit by tracing the optical path from the image irradiation unit to the driver's eye box in reverse. If sunlight hits the image irradiation unit for a long time, the heat of the sunlight will increase the temperature of the image irradiation unit, and it is assumed that the image irradiation unit will reach a high temperature state exceeding the rated temperature of the image irradiation unit. As a result, there is a concern that the image irradiation unit will break down. Therefore, there has been a demand for an image projection device that can protect the image irradiation unit from irradiation of sunlight as external light. In addition, it is also important that such an image projection device does not depend on the configuration of the optical system and has a simple configuration. The image projection device according to Patent Document 1 has an issue of suppressing the temperature rise of the image irradiation unit due to external light, but the image projection device according to Patent Document 1 solves this issue by devising an image formation in the optical system.

[0006] Therefore, the present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide an image projection device and an image projection method that are simply configured and can effectively suppress the temperature rise of the image irradiation section due to external light. [Means for solving the problem]

[0007] In order to solve the above problems, the image projection device of the present invention is an image projection device that projects a virtual image via a display unit, and is equipped with an image irradiation unit that irradiates image display light to form the virtual image, and a reflection unit that guides the image display light to the display unit, and is characterized in that, when a predetermined condition is satisfied, the orientation of the reflection unit is changed so that light incident on the reflection unit from the direction of the display unit is not incident on the image irradiation unit.

[0008] The image projection device of the present invention includes an image projection unit that projects image display light to form a virtual image, and a reflecting unit that directs the image display light to the display unit, and when a predetermined condition is satisfied, changes the orientation of the reflecting unit so that light incident on the reflecting unit from the direction of the display unit is not incident on the image projection unit. As a result, the temperature rise of the image projection unit due to external light can be effectively suppressed with a simple configuration.

[0009] In one aspect of the present invention, the light incident on the reflecting portion from the direction of the display portion is sunlight.

[0010] In one aspect of the present invention, the reflecting unit has two positions: an operating position where the image display light is guided to the display unit, and a retracted position where light incident on the reflecting unit from the direction of the display unit is not allowed to be incident on the image irradiation unit, and further includes a temperature monitoring unit that monitors the temperature of the image irradiation unit, a drive unit that rotates the reflecting unit in a vertical plane around a rotation axis, and a control unit that controls the drive unit to change the position of the reflecting unit from the operating position to the retracted position when the temperature monitored by the temperature monitoring unit exceeds a predetermined retraction judgment temperature.

[0011] In one aspect of the present invention, the control unit further controls the position of the reflection unit to be changed from the operating position to the retracted position when an instruction to end operation of the image projection device is received.

[0012] In one aspect of the present invention, the control unit stops the emission of image display light by the image emitting unit before changing the position of the reflecting unit from the operating position to the retracted position.

[0013] In addition, in one aspect of the present invention, when the monitoring temperature becomes equal to or lower than a predetermined return judgment temperature after the reflection unit has been temporarily retracted to the retracted position, the control unit changes the position of the reflection unit from the retracted position to the operating position and resumes irradiation of the image display light in the image irradiation unit.

[0014] In addition, in one aspect of the present invention, when the operating position is changed by adjusting the position of an eye box formed by reflection of the image display light on the display unit, the control unit stops irradiating the image display light in the image irradiation unit and waits for the movement time from the retracted position to the changed operating position.

[0015] In order to solve the above problems, the image projection method of the present invention is an image projection method using an image projection device that projects a virtual image via a display unit, the image projection device having an image irradiation unit that irradiates image display light to form the virtual image, and a reflection unit that guides the image display light to the display unit, and is characterized in that, when a predetermined condition is satisfied, the orientation of the reflection unit is changed so that light incident on the reflection unit from the direction of the display unit is not incident on the image irradiation unit. Effect of the Invention

[0016] The present invention can provide an image projection device and an image projection method that can effectively suppress a temperature rise in an image irradiation section caused by external light with a simple configuration. [Brief description of the drawings]

[0017] [Figure 1] 1A is a vertical cross-sectional view showing an example of the configuration of an image projection device according to an embodiment, FIG. 1B is a vertical cross-sectional view showing an operating position of a reflecting mirror, and FIG. 1C is a vertical cross-sectional view showing a retracted position of the reflecting mirror. [Diagram 2] In the image projection device of the embodiment, (a) is a longitudinal cross-sectional view explaining the path of sunlight, (b) is a plan view showing the positional relationship between the sunlight irradiation area and the image irradiation unit when the reflector is in the operating position, and (c) is a plan view showing the positional relationship between the sunlight irradiation area and the image irradiation unit when the reflector is in the retracted position. [Diagram 3] 1 is a block diagram showing an example of a configuration of an image projection device according to an embodiment. [Figure 4] 5 is a flowchart showing a process flow of a main routine of a reflecting mirror driving program executed by the image projection device according to the first embodiment. [Diagram 5] 6 is a flowchart showing a process flow of an abnormal temperature processing subroutine of a reflecting mirror driving program executed by the image projection device according to the first embodiment. [Figure 6] 10 is a flowchart showing a process flow of a reflecting mirror driving program executed by an image projection device according to a second embodiment. [Figure 7]FIG. 11 is a diagram showing a differential angle-operation time comparison table referred to by the image projection device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and duplicated explanations will be omitted as appropriate. In the following explanation, an embodiment in which the image projection device of the present invention is applied to a HUD mounted on a vehicle or the like will be described as an example.

[0019] (First embodiment) An image projection device and an image projection method according to this embodiment will be described with reference to Fig. 1 to Fig. 5. Fig. 1(a) is a vertical cross-sectional view showing an example of the configuration of an image projection device 10 according to this embodiment. The main body of the image projection device 10 is disposed, for example, under the dashboard of a vehicle. As shown in Fig. 1(a), the image projection device 10 includes an image irradiation unit 11, a reflecting mirror 12, a driving unit 13, a temperature monitoring unit 14, a control unit 20, a housing 30, and a light-transmitting unit 31. In Fig. 1(a), the traveling direction of the vehicle is the -Y direction, and the height direction of the vehicle is the Z-axis direction.

[0020] The image projection unit 11 projects image display light for forming a virtual image in front of the vehicle. The image projection unit 11 is, for example, configured with a liquid crystal panel, an organic EL panel, or the like. FIG. 1(b) shows the path of the image display light. That is, the image display light GL projected from the image projection unit 11 passes through a light-transmitting portion 31 provided in a part of a housing 30, which will be described later, and travels toward a windshield (not shown). The "windshield" is an example of a "display unit" according to the present invention.

[0021] The reflector 12 is an optical system that guides the image display light GL irradiated from the image irradiation unit 11 to the windshield. The shape of the reflector 12 is not particularly limited, but in this embodiment, a concave mirror is used. The image display light irradiated to the windshield is reflected by the windshield to form an eye box for the driver and a virtual image in front of the vehicle. This reduces the amount of line-of-sight movement required for the driver to visually recognize the driving support information. In this embodiment, an optical system using one reflector 12 is described as an example, but the present invention is not limited to this, and other reflecting members such as a free-form mirror may be included. The "reflector 12" is an example of the "reflecting unit" according to the present invention.

[0022] The driving unit 13 includes a motor 13a and has a function of changing the rotation angle of the reflecting mirror 12 in the vertical plane as necessary. That is, the reflecting mirror 12 according to this embodiment is rotatable in the direction of the double-headed arrow D around the rotation axis in the X-axis direction of the rotation mechanism 13b engaged with the motor 13a. Here, the "vertical plane" according to this embodiment refers to a plane perpendicular to the ground, that is, the YZ plane shown in FIG. 1(a). The motor to be used is not particularly limited, but for example, a synchronous motor that operates in synchronization with input pulse power, or a stepping motor, etc. can be used. Note that, in this embodiment, an example using the rotation mechanism 13b engaged with the motor 13a has been described as an example, but the present invention is not limited to this, and the orientation of the reflecting mirror 12 may be changed directly around the rotation axis of the motor 13a.

[0023] Here, in this embodiment, a leveling actuator such as a headlamp is used as the motor 13a. The leveling actuator is a motor used in an auto-leveling system for the headlamp of a vehicle. The auto-leveling system for the headlamp is a system that automatically adjusts the illumination range (vertical direction) of the headlamp according to the longitudinal inclination of the vehicle. This system aims to prevent the headlamp from dazzling the surroundings when the longitudinal inclination of the vehicle changes due to an increase or decrease in the number of occupants in the vehicle, the presence or absence of luggage, acceleration or deceleration during driving, etc., and to ensure the necessary illumination range. Since both are motors that move up and down, it is possible to reuse them including the control software. This allows the components to be shared, which also contributes to cost reduction.

[0024] For the sake of convenience, the position of the reflecting mirror 12 is defined as a rotation angle θ (hereinafter, "position angle θ") of the rotation direction D of the rotation mechanism 13b with respect to the horizontal line h shown in FIG. 1(a) as a reference. However, this is not limited to this, and the reference position may be another position, for example, the irradiation direction of the image display light GL from the image irradiation unit 11. Furthermore, the method of defining the position is not limited to the position angle, and may be, for example, the stroke amount of the motor 13a. Here, the position angle θ in the state in FIG. 1(b) is defined as the "operation angle θ". w The position of the reflecting mirror 12 in this state is called the "operating position."

[0025] The temperature monitoring unit 14 has a function of monitoring the temperature of the image projection unit 11. The form of the temperature monitoring unit 14 is not particularly limited, but for example, it is configured by attaching a thermistor to a part of the image projection unit 11. The monitored temperature monitored by the temperature monitoring unit 14 is sent to the control unit 20 described later.

[0026] The control unit 20 controls the entire image projection device 10 and executes a reflecting mirror driving program described later. The control unit 20 includes a CPU, ROM, RAM, etc., which are not shown. The control unit 20 may be an ECU (Engine Control Unit) of a vehicle in which the image projection device 10 is mounted.

[0027] The housing 30 accommodates the above-mentioned components therein to form one unit. The light-transmitting section 31 is disposed in a part of the housing 30 and has a function of transmitting the image display light GL from the image illuminating section 11. The light-transmitting section 31 is formed of a transparent resin or the like.

[0028] Here, the retreat position of the reflecting mirror 12 will be described with reference to FIG. 1(c). As described above, the image projection device 10 according to this embodiment aims to effectively suppress the temperature rise of the image projection unit 11 due to external light. FIG. 2(a) shows the path of sunlight SL, which is external light irradiated from the direction of the windshield, entering the image projection unit 11 when the reflecting mirror 12 is in the operating position. As shown in FIG. 2(a), the sunlight SL, whose traveling direction is along the irradiation path of the image display light GL, enters the image projection unit 11 by tracing the irradiation path in reverse. This causes a temperature rise of the image projection unit 11. In order to avoid this, in the image projection device 10, when the temperature monitoring unit 14 detects an abnormal monitored temperature, the reflecting mirror 12 is controlled so that the sunlight SL does not directly hit the image projection unit 11, as shown in FIG. 1(c). That is, the reflecting mirror 12 is rotated in the rotation direction indicated by LD to divert the sunlight SL from the image projection unit 11. The area of ​​the housing 30 on which the sunlight SL hits after the control is called the "retreat area LA". The position of the reflecting mirror 12 shown in FIG. 1(c) is called the “retracted position”, and the position angle of the reflecting mirror 12 is called the “retracted angle θ e The operation of retracting reflector 12 to the retracted position is referred to as an "evacuation operation." Note that the retraction area LA of housing 30 may be provided with a light absorber that absorbs sunlight SL, a light shield against sunlight SL, or the like, so that the sunlight SL is not scattered to other areas within the housing.

[0029] Here, it is considered that the intensity of sunlight SL shown in FIG. 2(a) changes depending on the position of the sun in a day. In order to deal with this, the retraction angle θ is set to be more efficient by taking into account the position of the sun in a day. e Alternatively, the retraction angle θ may be set according to the time of day. e may be changed.

[0030] FIG. 2(b) is a plan view showing the positional relationship between the irradiation area SA1 of the sunlight SL and the image projection unit 11 when the reflector 12 is in the operating position, and FIG. 2(c) is a plan view showing the positional relationship between the irradiation area SA2 of the sunlight SL and the image projection unit 11 when the reflector 12 is in the retracted position. In the normal display operation, as shown in FIG. 2(b), the irradiation area SA1 of the sunlight SL overlaps with the image projection unit 11, but when the retraction operation is performed, the irradiation area SA2 of the sunlight SL shifts above the image projection unit 11, and the sunlight SL does not directly hit the image projection unit 11. In this embodiment, an example in which the irradiation area of ​​the sunlight SL is shifted above the image projection unit 11 is described, but this is not limiting and the irradiation area may be shifted to another part of the housing 30, for example, downward. When the irradiation area SA1 is retracted in the horizontal direction in FIG. 2(b), the drive unit 13 may be changed so that it can rotate in that direction.

[0031] Next, referring to FIG. 3, the electrical configuration of the image projection device 10 according to this embodiment will be described. As shown in FIG. 3, the image projection device 10 includes an image irradiation unit 11, a motor 13a, a temperature monitoring unit 14, a storage unit 24, and a control unit 20. The control unit 20 is connected to an HCU 40. The HCU (Human Machine Interface Control Unit) 40 is one of the vehicle-mounted ECUs and has a function of controlling a Human Machine Interface (HMI) system. The HMI has an input interface function for accepting operations by the driver of the vehicle and an output interface function for presenting information to the driver. The HCU 40 sends instructions corresponding to the operation contents input by the driver to the control unit 20. The HCU 40 also acquires information such as the position angle of the reflecting mirror 12 from the control unit 20.

[0032] The control unit 20 includes a processing unit 21, a drive signal generating unit 22, and an image signal generating unit 23. The processing unit 21 mainly controls the motor 13a and the image projection unit 11 based on monitored temperature information from the temperature monitoring unit 14, each judgment temperature (described later) from the storage unit 24, and the like. The processing unit 21 acquires instructions corresponding to the operation contents input by the driver from the HCU 40. The processing unit 21 also sends information such as the position angle of the reflecting mirror 12 to the HCU 40. The drive signal generating unit 22 generates a signal to control the motor 13a of the driving unit 13, and the image signal generating unit 23 generates a signal to control the display image in the image projection unit 11.

[0033] The storage unit 24 stores the respective determination temperatures and the operating angle θ in the reflecting mirror driving process (described later) executed by the image projection device 10. w , Retract angle θ e , a reflecting mirror driving program, etc. The form of the storage unit 24 is not particularly limited, but for example, a ROM, a HDD (Hard Disk Drive), etc. can be used.

[0034] A method of controlling the reflecting mirror 12 in the image projector 10 will be described with reference to Figs. 4 and 5. Fig. 4 is a flowchart showing the flow of processing of a reflecting mirror drive program, which describes the reflecting mirror drive processing executed in the image projector 10. This reflecting mirror drive program is stored in a storage means such as a ROM (not shown), and is read out by the CPU, expanded in a RAM or the like, and executed. In the flowchart shown in Fig. 4, it is assumed that an instruction to start operation has already been sent from the HCU 40 to the control unit 20. Also, the reflecting mirror 12 is in a retracted position, and the position angle θ is the retraction angle θ e It is as follows.

[0035] In step S10, the control unit 20 performs an initial process as necessary. For example, the control unit 20 checks the position angle of the reflecting mirror 12. The reflecting mirror 12 is usually in a retracted position. After checking the position, the control unit 20 moves the reflecting mirror 12 from the retracted position to an operating position. In other words, the position angle θ is set to the retracted angle θ e From the operating angle θ wThe initial process also includes clearing the monitored temperature data stored in the storage unit 24.

[0036] In step S11, the control unit 20 acquires the monitored temperature from the temperature monitoring unit .

[0037] In step S12, the control unit 20 determines whether the monitoring temperature acquired in step S11 exceeds an evacuation determination temperature, which is a threshold for determining a temperature abnormality. The evacuation determination temperature is set based on the upper limit of the temperature at which the image projection unit 11 can operate normally. Specifically, the evacuation determination temperature may be appropriately determined according to the specifications of the image projection unit 11 to be used, and may be, for example, the rated upper limit temperature of the image projection unit 11, for example, 105°C. The evacuation determination temperature may be determined with a margin with respect to the rated upper limit temperature, and may be, for example, 95°C. If the determination is negative, the process proceeds to step S13, and if the determination is positive, the process proceeds to a temperature abnormality processing subroutine.

[0038] In step S13, the control unit 20 determines whether or not an end instruction to the image projection device 10 has been received from the HCU 40. If the determination is affirmative, the process proceeds to step S16, and if the determination is negative, the process proceeds to step S14.

[0039] In step S14, the control unit 20 acquires an operation instruction for the image projection device 10 (HUD) from the HCU 40. The operation instruction for the image projection device 10 is, for example, an instruction on the display contents of the image projection device 10 by the driver.

[0040] In step S15, the control unit 20 controls the image projection unit 11 so that the image display light GL is projected onto the driver's eyebox.

[0041] In step S16, the control unit 20 controls the image projection unit 11 to stop projection of the image display light GL.

[0042] In step S17, the control unit 20 controls the drive unit 13 (motor 13a) to move the reflecting mirror 12 to the retracted position. By retracting the reflecting mirror 12 to the retracted position, it is possible to prevent sunlight SL from being irradiated onto the image projection unit 11 when the image projection device 10 is not in operation. Thereafter, the reflecting mirror drive program is terminated.

[0043] The temperature abnormality processing subroutine will be described with reference to Fig. 5. This subroutine is a program that mainly performs processing to wait until the temperature of the image projection unit 11, which has once become abnormally high, drops to a normal temperature.

[0044] In step S20, the control unit 20 controls the image projection unit 11 to stop projection of the image display light GL.

[0045] In step S21, the control unit 20 controls the drive unit 13 (motor 13a) so that the reflecting mirror 12 moves to the retracted position.

[0046] In step S22, the control unit 20 determines whether or not an end instruction for the image projection device 10 has been received from the HCU 40. If the determination is negative, the process proceeds to step S23, and if the determination is positive, the reflecting mirror driving program is terminated.

[0047] In step S23, the control unit 20 acquires the monitored temperature from the temperature monitoring unit 14.

[0048] In step S24, the control unit 20 determines whether the monitoring temperature acquired in step S23 is equal to or lower than a return judgment temperature for judging a return to the main routine. If the judgment is negative, the process returns to step S22, and if the judgment is positive, the process proceeds to step S25. There is no particular limit to the value of the return judgment temperature, but it is preferable to set it to a temperature sufficiently lower than the evacuation judgment temperature, for example, room temperature, in order to confirm that the temperature of the image projection unit 11 has sufficiently dropped.

[0049] In step S25, the control unit 20 changes the position of the reflecting mirror 12 from the retreat position to the operating position. That is, the position angle θ is changed to the retreat angle θ eFrom the operating angle θ w Then, the process returns to the main routine, because the temperature of the image projection unit 11 has returned to the normal range, and the image projection device 10 is then operated normally.

[0050] As described above in detail, the image projection device and image projection method according to the present embodiment can provide an image projection device and an image projection method that are capable of effectively suppressing the temperature rise of the image irradiation section due to external light with a simple configuration.

[0051] Second embodiment An image projection device and an image projection method according to this embodiment will be described with reference to FIG. 6. This embodiment is a form in which the position adjustment of the eye box is considered in comparison with the above embodiment. In order for the driver to normally view the projected image (virtual image) in the image projection device 10, it is necessary that the driver's viewpoint (eye point) is present within the eye box. The eye box is a visible range in which the driver can view the virtual image of the projected image in a certain two-dimensional space, and the eye box is determined by the characteristics of the optical system of the image projection device 10 (the reflector 12 in this embodiment). In other words, in order for the driver to view the virtual image of the projected image, the image display light GL must be irradiated onto the windshield in the driver's line of sight, and the irradiation position and irradiation angle of the image irradiation light GL onto the windshield are mainly determined by the characteristics of the optical system of the image projection device 10. In other words, the range in which the driver can view the virtual image of the projected image is determined by the reflector 12 of the image projection device 10.

[0052] On the other hand, since the position of the viewpoint changes depending on the driver's height, etc., it may be necessary to adjust the position of the eye box depending on the driver. As described above, the eye box position adjustment is performed by adjusting the operating angle θ w In this embodiment, the position adjustment of the eye box, that is, the operating angle θ wThis is a form that takes into consideration the adjustment of the image projection light GL. After receiving a notification from the control unit 20 that the reflecting mirror 12 has been set to the operating position, the HCU 40 sends an instruction to the control unit 20 to start emitting the image projection light GL from the image projection unit 11. If the movement time from the retreat position to the operating position is unknown, the HCU 40 needs to wait until the image projection unit 11 starts operating, with a margin of time for the expected movement time. In other words, the main purpose of this embodiment is to reduce the unnecessary waiting time caused by the HCU 40. Note that the configuration of the image projection device according to this embodiment is the same as the configuration of the image projection device 10 of the above embodiment, so that FIG. 1 will be referred to if necessary, and detailed description will be omitted.

[0053] Referring to FIG. 6, the operation position adjustment performed in the image projection device 10 according to the present embodiment The process will be described. FIG. 6 is a flowchart showing the process flow of the operation position adjustment program describing the operation position adjustment process. The operation position adjustment program is stored in a storage means such as a ROM (not shown), and is read out by the CPU, expanded into a RAM, etc., and executed. In the flowchart shown in FIG. 6, it is assumed that an instruction to start operation has already been sent from the HCU 40 to the control unit 20. The operation position adjustment process is executed, for example, when an instruction to adjust the position of the projected image is input by the driver via a UI (User Interface) of the HCU 40. The operation position adjustment program may be executed as an initial process of the reflecting mirror drive program shown in FIG. 4. In that case, the operation position adjustment program may be incorporated into the initial process of step S10. Before the execution of the flowchart shown in FIG. 6, the reflecting mirror 12 is in the retracted position, and the position angle θ is the retracted angle θ e It is as follows.

[0054] In step S30, the control unit 20 acquires position information of the eyebox from the HCU 40. For example, the driver sets this position information of the eyebox via the UI of the HCU 40 while checking the image projected by the image projection device 10. Alternatively, the driver's viewpoint (eye point) may be detected using an imaging device or the like and set automatically.

[0055] In step S31, the control unit 20 calculates the operating angle θ based on the position information of the eye box acquired in step S30. w Calculate.

[0056] In step S32, the control unit 20 determines the retraction angle θ e and operating angle θ w The difference angle θ d =(θ e -θ w In this embodiment, the avoidance area LA is set above the image projection unit 11. d 0, but when the avoidance area LA is set below the image projection unit 11, θ d <0.

[0057] In step S33, the control unit 20 calculates the difference angle θ d Based on the operating time t w Obtain the operation time t w The reflecting mirror 12 is retracted at an angle θ e From the set operating angle θ w The time required to rotate the motor to the position t w The acquisition of the angle difference θ d and operating time t w This is based on the relationship data. d and operating time t w 1 shows a differential angle-operation time comparison table, which is an example of the relationship data. This differential angle-operation time comparison table may be stored in advance in the storage unit 24. Note that the retraction angle θ e If you want to set it to a fixed value, the operating angle θ w and operating time t w From the relationship between the operating time t w Here, in the present embodiment, the operation time is acquired by referring to the difference angle-operation time comparison table. However, the present invention is not limited to this. For example, the difference angle θ d may be calculated from the rotation speed of the motor 13a.

[0058] In step S34, the control unit 20 counts the operation time t wCount the number.

[0059] In step S35, the control unit 20 determines the operation time t w If the determination is negative, the process returns to step S34 to continue counting the counter, and if the determination is positive, the process proceeds to step S36.

[0060] In step S36, the control unit 20 notifies the HCU 40 that the setting of the reflecting mirror 12 to the operational position has been completed, and then ends the actual operational position adjustment program.

[0061] As described above in detail, the image projection device and the image projection method according to the present embodiment can provide an image projection device and an image projection method capable of effectively suppressing the temperature rise of the image irradiation unit due to external light with a simple configuration. According to the image projection device and the image projection method according to the present embodiment, the HCU 40 can obtain information that the position of the reflecting mirror 12 has been set to the operating position in the initial processing, for example, so that there is an effect that the wasteful waiting time until the image projection by the image projection device 10 can be reduced. [Explanation of symbols]

[0062] 10...Image projection device 11...Image irradiation unit 12...Reflector 13...Drive unit 13a…Motor 13b...Rotation mechanism 14…Temperature monitoring section 20...Control section 21... Processing section 22...Drive signal generating unit 23...Image signal generating unit 24...Storage section 30…Housing 31...Transparent part 40…HCU D, LD...Rotation direction h…Horizontal line LA…Evacuation area GL: Image display light SL…Solar light SA1, SA2…Irradiation area θ…Position angle θ w …cropping angle θ e …retreat angle

Claims

1. An image projection device that projects a virtual image through a display unit, an image irradiating unit that irradiates an image display light for forming the virtual image; a reflecting section that guides the image display light to the display section, 11. An image projection device, comprising: a reflector that changes a direction of said reflector when a predetermined condition is satisfied, so that light incident on said reflector from the direction of said display unit does not enter said image projection unit.

2. 2. The image projection device according to claim 1, 3. An image projection device, wherein light incident on said reflecting portion from the direction of said display portion is sunlight.

3. 3. The image projection device according to claim 2, The reflecting section has two positions: an operating position where the image display light is guided to the display section; and a retreated position where the light incident on the reflecting section from the direction of the display section is not incident on the image irradiating section. a temperature monitoring unit that monitors the temperature of the image irradiation unit; A drive unit that rotates the reflecting unit in a vertical plane around a rotation axis; a control unit that controls the drive unit so as to change the position of the reflection unit from the operating position to the evacuation position when the temperature monitored by the temperature monitoring unit exceeds a predetermined evacuation judgment temperature.

4. 4. The image projection device according to claim 3, The image projection device, wherein the control unit further controls, when receiving an instruction to end operation of the image projection device, to change a position of the reflection unit from the operating position to the retracted position.

5. 4. The image projection device according to claim 3, The image projection device, wherein the control unit stops the emission of image display light from the image emission unit before changing the position of the reflection unit from the operating position to the retracted position.

6. 4. The image projection device according to claim 3, The control unit changes the position of the reflection unit from the evacuation position to the operating position and resumes irradiation of the image display light by the image irradiation unit when the monitoring temperature falls below a predetermined return judgment temperature after the reflection unit has been temporarily evacuated to the evacuation position.

7. 4. The image projection device according to claim 3, An image projection device characterized in that, when the operating position is changed by adjusting the position of an eye box formed by reflection of the image display light on the display unit, the control unit stops irradiating the image display light in the image irradiation unit and waits for the time it takes to move from the retracted position to the changed operating position.

8. An image projection method using an image projection device that projects a virtual image via a display unit, the image projection device including: an image projection unit that projects image display light for forming the virtual image; and a reflection unit that guides the image display light to the display unit, An image projection method, comprising: changing a direction of the reflecting section when a predetermined condition is satisfied, so that light incident on the reflecting section from the direction of the display section does not enter the image projection section.

Images