JP2020042154A - Head-up display device - Google Patents

Abstract

To provide a head-up display device that is compact and can project a virtual image at a plurality of distances.SOLUTION: A head-up display device 100 comprises: a display element 11; a projection optical system 15 that enlarges an image formed on the display element 11; an intermediate screen 16m that has a diffusion function and is arranged on a light-emission side of the projection optical system 15; and an enlargement projection optical system 17 that enlarges and projects an intermediate image TI formed on the intermediate screen 16m. The enlargement projection optical system 17 has a first mirror 17a and a second mirror 17b in order from the intermediate screen 16m, and the intermediate screen 16m is arranged substantially parallel to light close to the intermediate screen 16m and on the outermost side of a light beam between the first mirror 17a and second mirror 17b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a head-up display device that displays a virtual image ahead of a line of sight and that changes the projection position of the virtual image.

  Conventional head-up display (HUD) devices generally generate a virtual image at a position separated by a certain distance from the driver, and when the distance from the driver to the virtual image is constant. If the position of the eyes is displaced, the position of the real object (object) and the position of the danger signal (virtual image) are displaced, and the driver may mistakenly recognize the danger signal, or the deviation between the position of the real object and the position of the danger signal If there is, there arises a problem that a sense of incongruity occurs due to a difference in the focal position. In order to solve such a problem, it is desirable to superimpose a virtual image on a real object including the depth direction.

  As a HUD device for changing the position of the virtual image, the position of the virtual image is changed by a scanning type image forming means such as a MEMS (Micro Electro Mechanical Systems) mirror, a screen, a projection means, and a movable means for changing the position of the screen. A method for causing the above to occur is disclosed (for example, see Patent Document 1). However, the main purpose of Patent Literature 1 is to reduce the driver's line of sight by moving the virtual image position closer or farther in accordance with the speed of the vehicle, and display the danger signal and the target object in a superimposed manner. It is not intended. Further, in the device of Patent Document 1, the arrangement of the optical system is limited, and the device may be enlarged.

JP 2009-150947 A

  The present invention has been made in view of the above background art, and has as its object to provide a head-up display device which is small and can project virtual images at a plurality of distances.

  In order to solve the above problems, a head-up display device according to the present invention includes a display element, a projection optical system for enlarging an image formed on the display element, and a diffusion function, which is disposed on a light emission side of the projection optical system. And an enlarged projection optical system for enlarging and projecting an intermediate image formed on the intermediate screen. The enlarged projection optical system has a first mirror and a second mirror in order from the intermediate screen side. The screen is disposed between the first mirror and the second mirror on the intermediate screen side and substantially parallel to the outermost light beam of the light beam. Here, the luminous flux means a bundle of light rays that come out of the intermediate screen and reach the eye box, and when the intermediate screen moves, a light flux that reaches the eye box from all intermediate screen positions.

  According to the above head-up display device, the intermediate screen is disposed between the first mirror and the second mirror on the intermediate screen side and substantially parallel to the outermost light beam of the light beam, so that the intermediate screen is provided. Can be arranged close to the optical path of the next stage in a space-saving manner, and the device can be downsized. Further, when the intermediate screen and the outermost light beam of the light beam are arranged substantially in parallel, the interval at which the intermediate image can be moved can be increased in order to change the virtual image projection distance. That is, the distance over which the virtual image can be superimposed increases. If the intermediate screen and the outermost light beam of the light beam are not substantially parallel, when the intermediate screen is moved in a direction approaching the light beam, the intermediate screen blocks a part of the light beam, and the virtual image projection distance change range becomes smaller. It becomes narrow.

In a specific aspect of the present invention, the head-up display device satisfies the following conditional expression.
−30 <θ <+30 (1)
Here, θ is the angle between the outermost ray of the light beam and the intermediate screen. By setting the value θ within the range of the conditional expression (1), it is necessary to separate the intermediate screen as a whole as compared with the case where the outermost ray of the light beam is completely parallel to the intermediate screen. The distance from the outermost rays can be less than half the size of the intermediate screen. This makes it possible to reduce the size of the device and to increase the range in which the position of the virtual image can be changed.

  In still another aspect of the present invention, the intermediate screen is provided on a moving flat member. With the above configuration, the intermediate screen can be brought closer to the first mirror, and the virtual image distance can be changed while reducing the size of the apparatus.

  In still another aspect of the present invention, the intermediate screen is provided on a disk, and a rotation axis of the intermediate screen is disposed between the first mirror and the second mirror and includes an optical axis before and after reflection of the first mirror. It extends substantially parallel to the plane. With the above-described configuration, the outer end of the intermediate screen can be disposed below the inside of the first mirror, and the virtual image distance can be changed while reducing the size of the apparatus.

  According to yet another aspect of the present invention, a display screen for projecting a virtual image formed by the magnifying projection optical system is provided, and the display screen is a combiner.

(A) is a side sectional view showing a state in which the head-up display device of the first embodiment is mounted on a vehicle body, and (B) is a front view from the inside of the vehicle for explaining the head-up display device. FIG. 3 is an enlarged side sectional view illustrating a specific configuration example of a head-up display device. FIG. 4 is a cross-sectional view illustrating an arrangement of an intermediate screen in the head-up display device. (A) and (B) are a side perspective view and a back side perspective view for explaining a specific optical system of the head-up display device. FIG. 3 is a conceptual block diagram illustrating a mobile display system including the head-up display device shown in FIG. 2. It is a perspective view explaining the specific display state by the display system for mobile bodies. It is an expanded side sectional view explaining the example of a specific structure of the head-up display device of a 2nd embodiment. (A) and (B) are a partially cutaway plan view and a partially cutaway cross-sectional view illustrating an intermediate screen of the head-up display device of FIG. 7, and (C) is a functional area associated with rotation of the intermediate screen. It is a figure explaining movement of.

[First Embodiment]
Hereinafter, a first embodiment of a head-up display device according to the present invention will be described with reference to the drawings.

  Referring to FIGS. 1A and 1B, a head-up display device 100 of the present embodiment is a display device mounted in a vehicle body 2, and includes a drawing unit 10 and a display screen 20. A head-up display (HUD) device 100 transmits image information displayed on a display element 11 (see FIG. 2) described later in the drawing unit 10 via a display screen 20 to a driver (observer). ) A virtual image is displayed for UN.

  The drawing unit 10 of the HUD device 100 is installed so as to be embedded in the dashboard 4 of the vehicle body 2, and emits display light HK corresponding to an image including driving-related information and a danger signal toward the display screen 20. I do. The display screen 20 is a half mirror, also called a combiner, and is a semi-transparent concave mirror or a plane mirror. The display screen 20 is erected on the dashboard 4 by supporting the lower end, and reflects the display light HK from the drawing unit 10 toward the rear of the vehicle body 2. In the illustrated case, the display screen 20 is a stand-alone type that is installed separately from the windshield (windshield) 8, but the display screen 20 may be the windshield itself.

  As shown in FIGS. 1A and 2, the display light HK reflected on the display screen 20 which is a half mirror is an eye box corresponding to the pupil HT of the driver UN sitting on the driver's seat 6 and its peripheral position. Guided to EB. The driver UN can observe the display light HK reflected on the display screen 20, that is, the display image IM as a virtual image in front of the vehicle body 2. On the other hand, the driver UN can observe the external light transmitted through the display screen 20 which is a half mirror, that is, the front view, the real image of the automobile, and the like. As a result, the driver UN superimposes a display image (virtual image) IM including driving-related information, a danger signal, and the like formed by reflection of the display light HK on the display screen 20 over the external image behind the display screen 20. Can be observed.

  As shown in FIG. 2, the drawing unit 10 includes a main body optical system 13, a display control unit 18 that operates the main body optical system 13, and a housing 14 that houses the main body optical system 13 and the like. Of these, a combination of the main body optical system 13 and the display screen (combiner) 20 constitutes a virtual image display optical system 30. In FIG. 2 and the like, the origin of the coordinate axis XYZ is the center of the eye box EB corresponding to the position between the pupils HT of the general driver UN, but the origin is shifted for convenience.

  The main body optical system 13 includes a display element (display device) 11, a projection optical system 15 capable of forming an intermediate image TI obtained by enlarging an image formed on the display element 11, and an imaging position of the intermediate image TI. The image forming apparatus includes a diffusion member 16 disposed downstream of the optical path, and an enlarged projection optical system 17 that converts the intermediate image TI into a virtual image. Although details will be described later, the virtual image projection distance of the display image IM is variable by the main body optical system 13. The projection optical system 15, the diffusion member 16, and the enlarged projection optical system 17 of the main optical system 13 constitute an imaging optical system 30a. In addition, a combination of the enlarged projection optical system 17 and the display screen 20 disposed above the main body optical system 13 in the main body optical system 13 constitutes an emission-side combined optical system 30b.

  In the main optical system 13, the display element 11 is a drawing device (display unit) having a two-dimensional display surface 11a. The image formed on the display surface 11a of the display element 11 is enlarged by the projection optical system 15 of the main optical system 13, forms an intermediate image TI on the diffusion member 16, and is guided to the enlarged projection optical system 17 and the like. At this time, by using the display element 11 capable of two-dimensional display, switching between the intermediate image TI and the display image (virtual image) IM can be made relatively fast. As the display element 11, a digital mirror device (DMD: Digital Mirror Device) or a reflection type liquid crystal device (LCOS: Liquid crystal on silicon) can be used. When DMD or LCOS is used as the display element 11, it is easy to switch images at high speed (including high-speed intermittent display) while maintaining brightness, which is advantageous for display in which a virtual image distance or a projection distance is changed. As an application example, when simultaneously projecting a virtual image at a plurality of distances, the display element 11 displays at a frame rate of, for example, 30 fps or more, preferably 60 fps or more per virtual image distance. Thereby, when a plurality of display images (virtual images) IM are displayed at different projection distances as if they are simultaneously displayed to the driver UN, the flicker of the virtual images can be improved.

  The projection optical system 15 has a main body lens 15a. The main body lens 15a is a fixed-focus lens system, and has a plurality of lens elements (not shown). The F value of the projection optical system 15 is 1.8 or more. The projection optical system 15 enlarges and projects an image formed on the display surface 11a of the display element 11 at an appropriate magnification, and places the intermediate image TI (or the intermediate screen TI) at a position close to the intermediate screen 16m provided on the surface of the diffusion member 16. A forced intermediate image TI ′) is formed at a position of 16 m. The forced intermediate image TI ′ includes an intermediate image TI itself and an image that is slightly out of focus due to a positional shift from the intermediate image TI, and is sometimes referred to in a broad sense as the intermediate image TI.

  The diffusion member 16 is a flat transmission type diffusion member having an intermediate screen 16m provided on the surface. The intermediate screen 16m has a diffusion property. The intermediate screen 16m forms a forced intermediate image TI 'at an image forming position (i.e., at or near the planned image forming position of the intermediate image TI). The intermediate screen 16m can control the diffusion angle to a desired angle. By moving the diffusing member 16 or the intermediate screen 16m in the optical axis AX direction as described later, the position of the forced intermediate image TI 'can also be moved in the optical axis AX direction. Since the forced intermediate image TI 'is formed on the intermediate screen 16m, this serves as a new secondary light source and diffuses light. Therefore, it is necessary to secure a wide eye box EB even if the enlarged projection optical system 17 performs enlarged projection. Can be. As the diffusion member 16 or the intermediate screen 16m, for example, a diffusion plate, a diffusion screen, a microlens array, or the like can be used.

  The diffusing member 16 is driven along the optical axis AX by a driving device 62 for changing the arrangement, for example, at a constant speed or a periodic motion. In the case of this example, the optical axis AX is an image point corresponding to the center of the display element 11 that is a display device (drawing device), the center of the eye box EB, and the center of the display element 11 created by the HUD device 100 ( Virtual image). By moving the diffusion member 16 or the intermediate screen 16m along the optical axis AX by the driving device 62, the display image IM as a virtual image formed behind the display screen (combiner) 20 by the magnifying projection optical system 17 and the viewer Can be made longer or shorter with the driver UN. That is, the driving device 62 changes the configuration and arrangement of the main body optical system 13 to change the projection distance. In this way, by changing the position of the projected display image IM back and forth, and by making the display content correspond to the position, the display image IM can be changed while changing the virtual image distance or the projection distance to the display image IM. Is changed, and the display image IM as a series of projection images can be made three-dimensional.

  The intermediate screen 16m is provided on the flat diffusion member 16, and the intermediate screen 16m is moved along the optical axis AX to move the intermediate screen 16m to the first mirror 17a of the later-described enlarged projection optical system 17 (that is, the intermediate mirror 16a). The mirror can be closer to the screen 16m), and the virtual image distance can be changed while the apparatus is downsized.

  The moving range of the diffusion member 16 or the intermediate screen 16m along the optical axis AX is equivalent to or near the planned imaging position of the intermediate image TI, but the depth of focus of the projection optical system 15 on the diffusion member 16 side is reduced. It is desirable to be within the range. Thereby, both the state of the forced intermediate image TI 'and the image forming state of the display image IM as a virtual image can be set to a good state in which both are almost in focus. The moving amount of the diffusion member 16 in the optical axis AX direction is, for example, 20 mm or less. Thereby, the movement of the diffusion member 16 can be performed efficiently, and the responsiveness of the diffusion member 16 can be improved. The moving speed of the diffusion member 16 is desirably a speed that allows the display image IM as a virtual image to appear as if displayed simultaneously at a plurality of locations or a plurality of virtual image distances. The driving device 62 moves the diffusion member 16 at a speed of, for example, 15 Hz or more. In this case, since the speed exceeds the perception of the observer (driver UN), the observer can recognize virtual images having different projection distances almost simultaneously.

  The diffusion member 16 is movably attached to the driving device 62 within a predetermined range along the optical axis AX direction. At the timing when the diffusion member 16 or the intermediate screen 16m is disposed on the most upstream side of the moving range (that is, on the upper side closest to the magnifying projection optical system 17), the image displayed on the intermediate screen 16m at this time is a half mirror. Is displayed as a virtual image closest to the back of the display screen (combiner) 20. In addition, at the timing when the diffusion member 16 or the intermediate screen 16m is disposed on the most downstream side of the moving range (that is, on the lowermost side farthest from the enlarged projection optical system 17), the image displayed on the intermediate screen 16m at this point in time. Is displayed as a virtual image farthest behind the display screen (combiner) 20, which is a half mirror.

  The enlargement projection optical system 17 is an enlargement optical system that enlarges the forced intermediate image TI ′ formed on the intermediate screen 16m of the diffusion member 16 in cooperation with the display screen 20, and displays a virtual image in front of the driver UN. An image IM is formed. The enlarged projection optical system 17 includes a first mirror 17a and a second mirror 17b. The first and second mirrors 17a and 17b are free-form mirrors having a concave shape as a whole, and have optical power. Here, the free-form surface shape includes an aspheric surface.

  Here, as shown in FIG. 3 in an enlarged manner, the intermediate screen 16m extends in a plane, and between the first mirror 17a and the second mirror 17b, the outermost light beam L1 on the intermediate screen 16m side. They are arranged substantially in parallel. Since the outermost light beam L1 of the light beam and the intermediate screen 16m are arranged substantially in parallel, even if the intermediate screen 16m is brought closer to the magnifying projection optical system 17, it does not interfere with the outermost light beam L1 of the light beam. In addition, since the intermediate screen 16m can be arranged closer to the enlarged projection optical system 17, the magnification of the enlarged projection optical system 17 can be increased, and the amount of movement of the intermediate screen 16m can be reduced.

The outermost light beam L1 and the intermediate screen 16m satisfy the following conditional expression.
−30 <θ <30 (1)
Here, θ is an angle (unit: °) between the outermost light ray L1 of the light beam and the intermediate screen 16m. By setting the value θ within the range of the conditional expression (1), the intermediate screen 16m needs to be separated as a whole as compared with the case where the outermost ray L1 of the light beam is completely parallel to the intermediate screen 16m. The distance between 16 m and the outermost light beam L1 of the light beam can be made half or less of the intermediate screen size. This makes it possible to reduce the size of the device and to increase the range in which the position of the virtual image can be changed.

  FIG. 4A is a side perspective view for explaining the optical system of the specific embodiment, and shows optical surfaces and light rays from the intermediate screen 16m to the exit-side combined optical system 30b. FIG. 4B is a front view illustrating an optical system according to a specific embodiment, showing optical surfaces and light rays from the intermediate screen 16m to the exit-side combining optical system 30b.

  In the exit-side combining optical system 30b, the intermediate screen 16m of the diffusion member 16 has a rectangular contour corresponding to the angle of view. The short side direction and the long side direction of the intermediate screen 16m are defined from the shape of the intermediate image TI on the intermediate screen 16m. For example, considering a case where a horizontally long virtual image is displayed, the short side direction is the vertical direction or the vertical direction of the virtual image. Direction (Y direction), and the long side direction corresponds to the horizontal direction (X direction) of the virtual image.

  Returning to FIG. 2, the housing 14 has an opening 14a for passing the display light HK, and a film or thin plate-shaped light transmitting member 14b can be disposed in the opening 14a.

  FIG. 5 is a block diagram illustrating the display system 200 for a mobile object. The display system 200 for a mobile object includes the head-up display device 100 as a part thereof. The head-up display device 100 has the structure shown in FIG. 2, and the description is omitted here. The moving object display system 200 shown in FIG. 5 is incorporated in a moving object such as an automobile.

  The mobile display system 200 includes a driver detection unit 71, an environment monitoring unit 72, and a main control device 90, in addition to the head-up display device 100.

  The driver detection unit 71 is a unit that detects the presence or the viewpoint position of the driver UN, and includes a driver seat camera 71a, a driver seat image processing unit 71b, and a driver seat image determination unit 71c. The driver's seat camera 71a is installed in front of the driver's seat of the dashboard 4 in the vehicle body 2 (see FIG. 1B), and captures images of the head of the driver UN and its surroundings. The driver's seat image processing unit 71b performs various image processing such as brightness correction on an image captured by the driver's seat camera 71a, and facilitates the processing by the driver's seat image determination unit 71c. The driver's seat image determination unit 71c detects the head and eyes of the driver UN by extracting or cutting out objects from the driver's seat image that has passed through the driver's seat image processing unit 71b, and also detects the depth accompanying the driver's seat image. From the information, the spatial position of the eyes of the driver UN (and consequently the direction of the line of sight) is calculated together with the presence or absence of the head of the driver UN in the vehicle body 2.

  The environment monitoring unit 72 is a unit that identifies an automobile, a bicycle, a pedestrian, and the like approaching forward, and includes an external camera 72a, an external image processing unit 72b, and an external image determination unit 72c. The external camera 72a is installed at an appropriate position inside or outside the vehicle body 2, and captures an external image of the driver UN or the front or side of the windshield 8 or the like. The external image processing unit 72b performs various types of image processing such as brightness correction on an image captured by the external camera 72a to facilitate the processing by the external image determination unit 72c. The external image determining unit 72c extracts or cuts out an object from the external image that has passed through the external image processing unit 72b to determine whether or not there is a target object such as a car, a bicycle, and a pedestrian (for example, see the object OB shown in FIG. 6). At the same time, the spatial position of the target object in front of the vehicle body 2 is calculated from the depth information attached to the external image.

  The driver's seat camera 71a and the external camera 72a, particularly the external camera 72a, are not shown, but are, for example, compound eye three-dimensional cameras. That is, each of the cameras 71a and 72a is configured by arranging, in a matrix, camera elements each having a pair of an imaging lens and a CMOS or other imaging element, and has a driving circuit for the imaging element. The plurality of camera elements constituting each of the cameras 71a and 72a are adapted to focus on, for example, different positions in the depth direction, or to detect relative parallax, and are obtained from each camera element. By analyzing the state of the image (the focus state, the position of the object, and the like), it is possible to determine the distance to each area or object in the image.

  Also, instead of using the compound-eye cameras 71a and 72a as described above, a combination of a two-dimensional camera and an infrared distance sensor may be used. Distance information can be obtained. Also, instead of the compound-eye cameras 71a and 72a, a stereo camera in which two two-dimensional cameras are separately arranged can obtain distance information in the depth direction with respect to each part (region or object) in the captured screen. In addition, distance information in the depth direction can be obtained for each part in the captured screen by performing imaging while changing the focal length at a high speed with a single two-dimensional camera.

  The display control unit 18 operates the virtual image display optical system 30 under the control of the main controller 90 to display a three-dimensional display image IM in which the virtual image distance or the projection distance changes behind the display screen 20. The display control unit 18 generates a display image IM to be displayed on the virtual image display optical system 30 from the display information including the display shape and the display distance received from the environment monitoring unit 72 via the main control device 90. The display image IM may be, for example, a sign such as a display frame positioned around the vehicle, bicycle, pedestrian, or other object behind the display screen 20 in the depth direction.

  The display control unit 18 receives a detection output regarding the presence of the driver UN and the position of the eyes from the driver detection unit 71 via the main control device 90. Thereby, it becomes possible to automatically start and stop the projection of the display image IM by the virtual image display optical system 30. Further, the display image IM can be projected only in the direction of the line of sight of the driver UN. Further, it is also possible to perform projection in which only the display image IM in the direction of the line of sight of the driver UN is brightened or blinked.

  The main controller 90 has a role of coordinating the operations of the head-up display device 100, the environment monitoring unit 72, and the like, and virtual image display optics so as to correspond to the spatial position of the object detected by the environment monitoring unit 72. The spatial arrangement of the display frame projected by the system 30 is adjusted.

  FIG. 6 is a perspective view illustrating a specific display state. The front of the driver UN, which is the observer, is a detection area VF corresponding to the observation visual field. It is assumed that there are objects OB1 and OB3 of a person such as a pedestrian and an object OB2 of a moving object such as a car in the detection area VF, that is, on the road and its periphery. In this case, main controller 90 causes head-up display device 100 to project a three-dimensional display image (virtual image) IM, and displays display frames HW1, HW2 as related information images for objects OB1, OB2, and OB3. HW3 is added. At this time, since the distance from the driver UN to each object OB1, OB2, OB3 is different, the projection distance from the driver UN to each of the objects IM1, IM2, IM3 for displaying the display frames HW1, HW2, HW3 is different from that of the driver UN. It is equivalent to the distance to OB1, OB2, and OB3. Note that the projection distances of the display images IM1, IM2, and IM3 are discrete, and cannot exactly match the actual distances to the objects OB1, OB2, and OB3. However, if the difference between the projection distance of the display images IM1, IM2, and IM3 and the actual distance to the objects OB1, OB2, and OB3 is not large, parallax is unlikely to occur even if the viewpoint of the driver UN moves. The arrangement relationship between OB2, OB3 and display frames HW1, HW2, HW3 can be substantially maintained.

  According to the head-up display device 100 described above, the intermediate screen 16m is substantially parallel to the outermost light ray L1 of the light beam on the intermediate screen 16m side between the first mirror 17a and the second mirror 17b. , The intermediate screen 16m can be arranged close to the optical path of the next stage in a space-saving manner, and the apparatus can be downsized. Further, when the intermediate screen 16m and the outermost light beam L1 of the light beam are arranged substantially in parallel, the interval at which the intermediate image TI can be moved can be increased in order to change the virtual image projection distance. That is, the distance over which the display image (virtual image) IM can be superimposed increases. When the intermediate screen 16m and the outermost light beam L1 of the light beam are not substantially parallel, when the intermediate screen 16m is moved in a direction approaching the light beam, the intermediate screen 16m blocks a part of the light beam, and the virtual image is projected. The distance change range becomes narrow.

[Second embodiment]
Hereinafter, a head-up display device according to the second embodiment will be described. Note that the head-up display device of the second embodiment is a modification of the head-up display device of the first embodiment, and items that are not particularly described are the same as those of the first embodiment. In the case of the present embodiment, a diffusing section including a rotary intermediate screen is arranged instead of the reciprocating intermediate screen 16m or the like shown in FIG.

  As shown in FIGS. 7, 8A and 8B, the diffusion member 16 has a spiral rotating body (rotating disk) 16a having an overall shape close to a disk. The diffusing member 16 is disposed at a projection position or an image forming position by the projection optical system 15 shown in FIG. It rotates around a rotation axis SX parallel to AX. 8A to 8C, for convenience of explanation, the diffusing member 16 is shown based on local xyz rectangular coordinates, and the diffusing member 16 has an enlarged projection optical system as described later. 17 is disposed between the first mirror 17a and the second mirror 17b on the intermediate screen 16m side so as to be substantially parallel to the outermost light ray L1 of the light beam.

  The rotating body 16a has a central portion 16c and an outer peripheral optical portion 16p. One surface 16f formed on the outer peripheral optical portion 16p of the rotating body 16a is formed as a smooth surface or an optical surface, and on the surface 16f, an intermediate screen 16m serving as a diffusion surface is provided over the entire area. I have. The intermediate screen 16m is a part that controls the light distribution angle to a desired angle. The intermediate screen 16m can be a sheet to be attached to the rotating body 16a, but may be a fine uneven pattern formed on the surface of the rotating body 16a. Further, the intermediate screen 16m may be formed so as to be embedded inside the rotating body 16a. In the diffusion member 16, a cover may be provided around the rotating body 16a.

  The intermediate screen 16m forms an intermediate image TI or a forced intermediate image TI 'by diffusing the incident display light HK. The other surface 16s formed on the outer peripheral optical portion 16p of the rotating body 16a is formed as a smooth surface or an optical surface. The rotating body 16a is a spiral member having optical transparency, and the pair of surfaces 16f and 16s are spiral surfaces having the rotating axis SX as a spiral axis. As a result, the intermediate screen 16m formed on one surface 16f is also formed along the spiral surface. The rotating body 16a has substantially the same thickness t in the direction of the rotation axis SX or the optical axis AX. The intermediate screen 16m is formed in a range corresponding to one cycle of the spiral. That is, the intermediate screen 16m is formed in a range of one spiral pitch. As a result, a step 16j is formed at one location along the circumference of the diffusion member 16. By setting the rotating body 16a in such a shape, the position of the intermediate screen 16m provided on the rotating body 16a in the optical axis AX direction can be continuously changed, and the projection that changes the virtual image projection distance can be performed. Become.

  One portion of the rotating body 16a along the circumferential direction is a functional area FA through which the optical axis AX of the main body optical system 13 passes, and an intermediate image TI (more precisely, a part of the intermediate screen 16m in the functional area FA). A forced intermediate image TI ′) is formed. The functional area FA moves at a constant speed on the rotating body 16a as the rotating body 16a rotates. That is, by rotating the rotating body 16a and causing the display light (video light) HK to enter the function area FA which is a part thereof, the position of the function area FA or the intermediate image TI reciprocates along the optical axis AX. (If the display of the display element 11 is not operating, an intermediate image as a display is not necessarily formed, but a position where an intermediate image will be formed is also called an intermediate image position). In the illustrated example, since the intermediate screen 16m is formed in a range corresponding to one cycle of the spiral, the function area FA or the intermediate image TI of the intermediate screen 16m is shifted in the optical axis AX direction by one rotation of the rotating body 16a. Makes one reciprocation by the distance corresponding to.

  Note that the projection optical system 15 has a predetermined depth of focus equal to or larger than the movement range of the functional area FA so that the focus is not caused by the position of the rotating body 16a of the diffusing member 16 or the position of the intermediate screen 16m.

  By rotating the diffusion member 16 around the rotation axis SX at a constant speed by the driving device 162, the position where the intermediate screen 16m of the rotating body 16a intersects the optical axis AX (that is, the functional area FA) also moves in the optical axis AX direction. I do. In other words, as shown in FIG. 8C, for example, with the rotation of the rotating body 16a, the functional area FA on the intermediate screen 16m is, for example, adjacent to the functional area FA ′ set at a position shifted at an equal angle. The light sequentially shifts and moves in the direction of the optical axis AX. By moving the functional area FA in the direction of the optical axis AX, the position of the intermediate image TI can also be moved in the direction of the optical axis AX. The diffusion member 16 rotates around the rotation axis SX, and the position of the intermediate image TI corresponding to the functional area FA repeatedly and periodically moves in the optical axis AX direction, and is formed behind the display screen 20 by the enlarged projection optical system 17. It is possible to increase or decrease the distance between the displayed image IM as the virtual image and the driver UN who is the observer.

  The intermediate screen 16m is disposed between the first mirror 17a and the second mirror 17b on the intermediate screen 16m side and substantially parallel to the outermost light ray L1 of the light beam (see FIG. 3). As shown in FIG. 7, the rotation axis SX of the rotating body 16a or the intermediate screen 16m is disposed between the first mirror 17a and the second mirror 17b of the magnifying projection optical system 17, and the reflection of the first mirror 17a is performed. It extends substantially parallel to a plane including the front and rear optical axes AX. Since the rotation axis SX of the intermediate screen 16m is arranged between the two mirrors 17a and 17b of the enlarged projection optical system 17, the outer end of the intermediate screen 16m can be arranged below the first mirror 17a. It is possible to change the distance while reducing the size of the device.

  The display light HK from the projection optical system 15 shown in FIG. 7 passes through the intermediate screen 16m of the rotating body 16a shown in FIG. Is reflected.

  In the above, the head-up display device as a specific embodiment has been described, but the head-up display device according to the present invention is not limited to the above. For example, in the above-described embodiment, the arrangement of the head-up display device 100 may be inverted upside down, and the display screen 20 may be arranged above the windshield 8 or at the position of the sun visor. In this case, the display screen 20 is disposed obliquely downward and forward of the drawing unit 10. In the above embodiment, the display screen 20 is a flat surface or a concave surface, but may be a free-form surface having no symmetry.

  In the above-described embodiment, the outline of the display screen 20 is not limited to a rectangle, but may be various shapes.

  The main body optical system 13 shown in FIG. 2 and the like is merely an example, and the optical configuration of the main body optical system 13 can be appropriately changed. For example, one or more mirrors having no optical power may be arranged in the optical path of the enlarged projection optical system 17 or the projection optical system 15.

  Further, in the above embodiment, DMD, LCOS, or the like is used as the display element 11 which is a drawing device. However, a liquid crystal display (LCD: liquid crystal display) or another type of display device, for example, an organic EL may be used. Good. Further, as the display element 11, a scanning type video device using MEMS may be used instead of the reflection type element.

  In the above embodiment, the display screen 20 may be provided on the windshield (windshield) 8 shown in FIG. 1A without providing a combiner (see FIG. 2). Specifically, for example, the display screen 20 may be attached to the inside of a rectangular reflection area provided in front of the driver's seat of a windshield (windshield) 8 forming a front window. Note that the display screen 20 can be embedded in the windshield 8.

  In the above embodiment, the projection optical system 15 is a fixed focus optical system, but may be a variable focus optical system.

  Further, in the above embodiment, the configuration of the intermediate screen 16m can be appropriately changed according to the specifications of the HUD device 100. For example, the intermediate screen 16m may be configured to have a deflection characteristic or a diffusion characteristic in a short side direction or a long side direction.

  The head-up display device 100 described above is not limited to a projection device mounted on an automobile or other moving object, but can be incorporated in, for example, digital signage, but can be applied to other uses.

Reference numeral 2 denotes a vehicle body, 8 denotes a windshield, 10 denotes a drawing unit, 11 denotes a display element, 13 denotes a main body optical system, 15 denotes a projection optical system, 16 denotes a diffusion member, 16 m denotes an intermediate screen, and 17 denotes an enlarged projection optical system. 17b: mirror, 18: display control unit, 20: display screen, 30: virtual image display optical system, 62: drive unit, 71: driver detection unit, 72: environment monitoring unit, 90: main control unit, 100: head up Display device, 162: Drive device, 200: Display system for moving body, AX: Optical axis, EB: Eye box, HK: Display light, HW1, HW2, HW3: Display frame, IM, IM1, IM2, IM3: Display image , OB, OB1, OB2, OB3 ... object, SX ... rotation axis, TI ... intermediate image, UN ... driver

Claims (5)

A display element, a projection optical system for enlarging an image formed on the display element, an intermediate screen having a diffusion function and arranged on the light exit side of the projection optical system, and an intermediate image formed on the intermediate screen And an expansion projection optical system for enlarging and projecting
The enlarged projection optical system has a first mirror and a second mirror in order from the intermediate screen side,
The head-up display device, wherein the intermediate screen is disposed between the first mirror and the second mirror on the intermediate screen side and substantially parallel to an outermost light beam of a light beam. The head-up display device according to claim 1, wherein the following conditional expression is satisfied.
−30 <θ <+30 (1)
here,
θ: the angle between the outermost ray of the light beam and the intermediate screen   3. The head-up display device according to claim 1, wherein the intermediate screen is provided on a moving flat member. 4.   The intermediate screen is provided on a disk, and a rotation axis of the intermediate screen is disposed between the first mirror and the second mirror, and is substantially parallel to a plane including an optical axis before and after reflection of the first mirror. The head-up display device according to claim 1, wherein the head-up display device extends. A display screen that projects a virtual image formed by the enlarged projection optical system,
The head-up display device according to any one of claims 1 to 4, wherein the display screen is a combiner.

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