JP7280557B2 - Display device and display method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device in which the projection position of a virtual image is variable, and a display method thereof.

Some display devices generate display images as virtual images at a plurality of locations at different distances from the driver (Patent Documents 1 to 6).

For example, in the apparatus disclosed in Patent Document 1, two mirror surfaces having different curvatures are provided as reflecting mirrors in an optical system for forming a virtual image, and the mirrors arranged on the optical path are switched by rotating the two mirror surfaces, thereby adjusting the projection distance of the virtual image. Variable.

Further, in the device of Patent Document 2, the display distance to the virtual image is changed without providing a movable part by forming the virtual image using a plurality of display panels with different arrangements in the optical system for forming the virtual image.

In the device disclosed in Patent Document 3, the optical system for forming a virtual image uses a condenser lens that moves in the optical axis direction to change the magnification of the displayed image. There is a description that the position of the virtual image in the optical axis direction can be adjusted.

In the device of Patent Document 4, a relay optical system is arranged between a display element and an imaging optical system, an intermediate image is formed by the relay optical system, and the positions of the optical elements constituting the relay optical system are changed. By changing the position of the intermediate image, the projection distance of the virtual image is changed.

In the device of Patent Document 5, the display screen of a head-up display (hereinafter also referred to as HUD) device is divided vertically and projected on the near side and the far side. At this time, the projection distance of the virtual image is made variable by moving the intermediate screen for the display on the far side.

In the device of Patent Document 6, laser scanning is used in the optical system for forming a virtual image, an intermediate screen is arranged in the optical path, and the projection distance of the virtual image is made variable by moving the intermediate screen.

However, the device of Patent Document 1 obtains two projection distances using two mirror surfaces, and if the number of projection distance settings is increased, the number of mirrors must be increased, resulting in a larger and more complicated device. .

Further, in the device of Patent Document 2, the position of each display panel and the resulting display distance are fixed, so the projection distance cannot be changed at an arbitrary position within the screen.

Patent Document 3 does not explain the significance of changing the projection distance of the virtual image, nor does it show a specific method for adjusting the position of the virtual image.

The device of Patent Document 4 moves the optical element of the relay optical system, but there is no explanation of the specific driving method of the optical element or the accompanying method of changing the display, and high-brightness images are displayed at a plurality of distance positions. There is no disclosure of a technique for simultaneous projection.

In the devices of Patent Documents 5 and 6, the intermediate screen is moved, but there is no explanation of the method of driving the intermediate screen or the method of changing the display accompanying this, and the method of simultaneously projecting high-brightness images at a plurality of distance positions. is not disclosed.

JP-A-9-185012 JP-A-2004-168230 JP 2007-94394 A JP 2008-180759 A JP 2015-11211 A JP 2009-150947 A

SUMMARY OF THE INVENTION The present invention has been made in view of the above background art, and aims to provide a display device such as a head-up display device capable of simultaneously projecting high-brightness images at a plurality of distance positions, and a display method using the same. aim.

In order to achieve at least one of the above objects, a display device reflecting one aspect of the present invention includes a first projection optical system for projecting image light formed by a display element, and a first projection optical system. An intermediate screen that diffuses light at a projection position; a second projection optical system that enlarges and projects the intermediate image formed on the intermediate screen as a virtual image; and periodically projects the functional area of the intermediate screen as a virtual image in the optical axis direction. A driving unit that moves at a moving speed that makes it appear as if the images are displayed simultaneously at a plurality of projection distances, and a display element that is synchronized with the movement of the intermediate screen that changes the projection distances to display and display the depth. and a control unit for setting a unit of display having a display zone as a display zone , and setting a plurality of display zones corresponding to the plurality of projection distances so that adjacent display zones partially overlap in a depth direction with different projection distances .

In order to achieve at least one of the above objects, a display method reflecting one aspect of the present invention provides an enlarged virtual image of an intermediate image formed on an intermediate screen by projection of image light formed by a display element. In this display method, the functional area of the intermediate screen is moved periodically in the optical axis direction at a moving speed that makes it appear as if the projected images as virtual images are simultaneously displayed at a plurality of projection distances. and displaying on the display element in synchronism with the movement of the intermediate screen that changes the projection distance. The display zone is set to partially overlap in the depth direction with different projection distances.

FIG. 1A is a side cross-sectional view showing a state in which a head-up display device, which is a display device of the first embodiment, is mounted on a vehicle body, and FIG. 1B is a front view from the inside of the vehicle explaining the head-up display device. be. 2 is an enlarged side cross-sectional view for explaining a specific configuration example of a projection optical system and the like that constitute a head-up display device, which is a display device; FIG. 3A and 3B are a partially cutaway plan view and a partially cutaway side view illustrating the structure of the diffusing section incorporating the intermediate screen, and FIG. 3C is a perspective view illustrating a rotating body in the diffusing section. 4A and 4B are side views explaining the setting of the reference axis of the rotating body, and FIG. 4C is a diagram explaining the movement of the functional area accompanying the rotation of the intermediate screen. FIG. 10 is a diagram specifically illustrating changes in the position of an intermediate image; FIG. 4 is a diagram showing the relationship between the position of an intermediate image and the projection distance, and explaining display zones and distance zones; It is a block diagram explaining the whole structure of a head-up display device. It is a perspective view explaining a concrete display state. 9A corresponds to FIG. 5, and FIGS. 9B-9D correspond to the projected images or frames in FIG. 8A and 8B are diagrams for explaining an operation example of the head-up display device shown in FIG. 7; FIG. FIG. 4 is a conceptual diagram illustrating an example of switching of display in a display zone; It is a figure explaining the display of 2nd Embodiment, or a head-up display apparatus. FIG. 10 is a diagram specifically illustrating changes in the position of an intermediate image in the second embodiment;

[First Embodiment]
A head-up display device as a display device according to a first embodiment of the present invention and a display method thereof will be described below with reference to the drawings.

1A and 1B are conceptual side sectional views and front views for explaining an image display device 100 of a head-up display device as a display device of an embodiment. This image display device 100 is mounted, for example, in a vehicle body 2 of an automobile, and includes a projection unit 10 and a display screen 20 . The image display device 100 displays a virtual image of image information displayed on a later-described drawing device 11 in the projection unit 10 toward the driver VD via the display screen 20, and is also called a display device.

The projection unit 10 of the image display device 100 is installed in the dashboard 4 of the vehicle body 2 so as to be embedded behind the display 50, and displays display light, which is image light corresponding to an image including driving-related information. DL is projected toward the display screen 20 . The display screen 20, also called a combiner, is a semi-transmissive concave mirror or plane mirror. The display screen 20 is erected on the dashboard 4 by its lower end support, and reflects the display light (image light) DL from the projection unit 10 toward the rear of the vehicle body 2 . That is, in the illustrated case, the display screen 20 is an independent type that is installed separately from the front window 8 . The display light DL reflected by the display screen 20 is guided to an eye box (not shown) corresponding to the pupil PU of the driver VD sitting in the driver's seat 6 and its peripheral position. The driver VD can observe the display light DL reflected by the display screen 20 , that is, the projected image IM as a virtual image in front of the vehicle body 2 . On the other hand, the driver VD can observe the external light transmitted through the display screen 20, that is, the real image of the front scenery, the automobile, or the like. As a result, the driver VD superimposes the image of the external world behind the display screen 20 or the see-through image on the display screen 20, and superimposes it on the display screen 20. The projection image (virtual image) includes relevant information such as driving-related information formed by reflection of the display light DL on the display screen 20. ) IM can be observed.

Here, although the display screen 20 is configured separately from the front window 8, the front window 8 is used as the display screen, and the display range set in the front window 8 is projected so that the driver VD displays the projected image IM. can be observed. At this time, by changing the reflectance of a partial area of the glass of the front window 8 with a coating or the like, a reflective area can be secured. Also, if the angle of reflection on the front window 8 is, for example, about 60 degrees, the reflectance is ensured to be about 15%, and it can be used as a reflecting surface having transparency without providing a coating. Besides these, the display screen can also be provided by sandwiching it in the glass of the front window 8 .

As shown in FIG. 2, the projection unit 10 includes a main body optical system 13 which is a virtual image type enlarging imaging system including a drawing device 11, a display control unit 18 for operating the main body optical system 13, a main body optical system 13, and the like. and a housing 14 for accommodating the. A combination of the main body optical system 13 and the display screen 20 constitutes a display optical system 30 .

In addition to the drawing device 11, the main body optical system 13 includes an imaging optical system 15, which is a first projection optical system that forms an intermediate image TI obtained by enlarging the image formed on the drawing device 11, and a virtual image of the intermediate image TI. It comprises a virtual image forming optical system 17 which is a second projection optical system for conversion, and a diffusion section 16 arranged between both optical systems 15 and 17 for projection.

The drawing device 11 is a display element having a two-dimensional display surface 11a. An image formed on a display surface 11a of a drawing device (display element) 11 is enlarged by an imaging optical system (first projection optical system) 15 and projected onto a spiral intermediate screen 19 provided in a diffusion section 16. be. At this time, by using the drawing device 11 capable of two-dimensional display, the switching of the projection image on the intermediate screen 19, that is, the switching of the projection image IM displayed as a virtual image through the display screen 20 can be performed relatively quickly. The drawing device 11 may be a reflective element such as DMD or LCOS, or a transmissive element such as liquid crystal. In particular, using a DMD or LCOS as the drawing device 11 facilitates high-speed switching of images (including high-speed intermittent display) while maintaining brightness, which is advantageous for display that changes the virtual image distance or projection distance. be. When the display distance or the projection distance is changed, the drawing device 11 operates at a frame rate of 30 fps or higher, preferably 60 fps or higher for each projection distance. This makes it possible to make it appear to the driver VD that a plurality of projected images (virtual images) IM are simultaneously displayed at different projection distances. In particular, DMD and LCOS are candidates for the drawing device 11 when the display is switched at 90 fps or higher.

The diffusion unit 16 is arranged at a projection position or an imaging position (i.e., a planned imaging position of an intermediate image or its vicinity) by an imaging optical system (first projection optical system) 15, and is composed of a rotor 16a and a hollow frame 16b. , and is driven by a rotation drive section (driving section) 64 to rotate around the reference axis SX at a constant speed, for example.

3A is a front view for explaining the diffusion section 16, FIG. 3B is a side sectional view for explaining the diffusion section 16, and FIG. 3C is a perspective view for explaining the rotating body 16a in the diffusion section 16. FIG. be. The diffusing portion 16 has a helical rotating body 16a having an outline similar to that of a disk as a whole, and a cylindrical hollow frame 16b that accommodates the rotating body 16a.

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 an intermediate screen 19 is formed over the entire surface 16f. A surface 16 f of the rotating body 16 a functions as a three-dimensional portion 116 . The intermediate screen 19 is a diffusion plate that controls the light distribution angle to a desired angle. The intermediate screen 19 can be a sheet attached to the rotating body 16a, but it may also be a fine concavo-convex pattern formed on the surface of the rotating body 16a. Furthermore, the intermediate screen 19 may be formed so as to be embedded inside the rotor 16a. The intermediate screen 19 forms an intermediate image TI by diffusing the incident display light DL (see FIG. 2). 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 light-transmitting spiral member, and the pair of surfaces 16f and 16s are spiral surfaces having the reference axis SX as the spiral axis. As a result, the intermediate screen 19 formed on one surface 16f is also formed along a continuous spiral surface. The intermediate screen 19 is formed in a range corresponding to one cycle of the spiral. That is, the intermediate screen 19 is formed in a range of one pitch of the spiral. As a result, a stepped portion 16j is formed at one location along the circumference of the diffusion portion 16, and this stepped portion 16j divides the position of the intermediate screen in the direction of the optical axis AX or the direction of the reference axis SX at a position corresponding to the end of the spiral. It is something to give. That is, since the three-dimensional shape portion 116 includes the spiral shape portion, the function area FA of the intermediate screen 19, which will be described later, can be moved in the optical axis AX direction by the rotation of the intermediate screen 19. FIG. This makes it easy to display the projection images IM whose display positions are different including the depth direction while changing them at high speed. The step amount of the stepped portion 16 j is set according to the specifications of the near side and the far side of the distance for projecting the virtual image and the magnification of the virtual image forming optical system (second projection optical system) 17 . At this time, if the stepped portions 16j are given a distance difference or pitch of 30 mm or less, the thickness of the diffusing portion 16 in the direction of the optical axis AX can be made relatively small. It is possible to design a virtual image forming optical system (second projection optical system) 17, which will be described later, with a narrower gap between mirrors, which is effective in reducing the size of the apparatus. The stepped portion 16j has a connection surface 16k that connects the steps between the spiral ends and is inclined with respect to a plane that includes the reference axis SX for rotating the diffusion portion 16 . As described above, since the pair of surfaces 16f and 16s of the rotating body 16a are spiral surfaces having the reference axis SX as the spiral axis, the rotating body 16a has a thickness t that is substantially equal in the direction of the reference axis SX or the optical axis AX. have.

In the rotating body 16a, one point 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 is formed by the intermediate screen 19 in the functional area FA. This functional area FA moves at a constant speed on the rotating body 16a as the rotating body 16a rotates. That is, by causing the display light (image light) DL to enter the functional area FA, which is a part of the rotating body 16a, while rotating the rotating body 16a, the position of the functional area FA or the intermediate image TI reciprocates along the optical axis AX. (If the display of the drawing device 11 is not operating, the intermediate image is not necessarily formed as a display, but the position where the intermediate image will be formed is also called the position of the intermediate image). In the illustrated example, the intermediate screen 19 is formed in a range corresponding to one cycle of the spiral. One round trip is made for a distance corresponding to . The imaging optical system (first projection optical system) 15 has a predetermined depth of focus that is greater than or equal to the movement range of the functional area FA so that the position of the intermediate screen 19 does not cause defocusing. Alternatively, by providing the imaging optical system (first projection optical system) 15 with a focusing function, it is possible to obtain an image without blurring.

The hollow frame 16b has a columnar outline and is composed of a side surface 16e and a pair of end surfaces 16g and 16h. The side surface portion 16e and the pair of end surface portions 16g and 16h are made of the same light transmissive material. However, the side portion 16e does not have to be optically transparent. Principal surfaces 63a and 63b of one end surface portion 16g are smooth surfaces or optical surfaces parallel to each other, and principal surfaces 64a and 64b of the other end surface portion 16h are also smooth surfaces or optical surfaces parallel to each other. there is Here, the main surfaces 63a and 63b or the main surfaces 64a and 64b do not necessarily have to be parallel planes, and if at least the range corresponding to the functional area FA is formed into a free curved surface shape or an aspherical shape, it is difficult to ensure performance, for example. Even in a high-magnification optical system, image performance such as distortion and image plane property required for the optical system can be ensured, so a desired surface shape may be selected as necessary. The rotating body 16a in the hollow frame 16b is fixed to the hollow frame 16b via a pair of central shafts 65, and the hollow frame 16b and the rotating body 16a integrally rotate around the reference axis SX. do. By disposing the rotating body 16a provided with the intermediate screen 19 in the hollow frame body 16b in this way, it is possible to suppress the adhesion of dust and the like to the rotating body 16a, and to suppress the generation of noise accompanying the rotation of the rotating body 16a. This makes it easier to stabilize the rotation of the rotating body 16a at high speed. In addition, the rotor 16a may be fixed to the hollow frame 16b at its outer peripheral portion. In this case, it becomes easy to reduce the thickness t of the rotor 16a.

The setting of the reference axis SX of the rotating body 16a (or the three-dimensional shape portion 116) will be described with reference to FIGS. 4A and 4B. The reference axis SX of the rotating body 16a is arranged in a non-parallel and slightly inclined manner with respect to the optical axis AX of the main body optical system 13. As shown in FIG. Here, the intermediate screen 19 on the rotating body 16a is arranged so that its local functional area FA is substantially orthogonal to the optical axis AX direction of the main body optical system 13 . That is, as shown in FIG. 4A, when the rotating body 16a is observed from a viewpoint away from the optical axis AX in the lateral direction where the functional area FA is located, the reference axis SX is inclined by a predetermined angle α with respect to the optical axis AX. As shown in FIG. 4B, the reference axis SX is positioned at a predetermined distance d from the optical axis AX when the rotating body 16a is used as a reference and viewed from a viewpoint away from the direction perpendicular to the case shown in FIG. 4A. are separated from each other. In FIG. 4A, a first position PO1 indicated by a dashed-dotted line indicates the case where the functional area FA or the intermediate image TI is positioned on the most upstream side of the optical path. This shows the case where the intermediate image TI is located on the most downstream side of the optical path. The distance D between these positions PO1 and PO2 corresponds to the amount of displacement of the functional area FA or the intermediate image TI in the direction of the optical axis AX.

Returning to FIG. 2, by rotating the diffusion section 16 around the reference axis SX at a constant speed by the rotary drive section 64, the intermediate screen 19 (or the three-dimensional shape section 116) of the rotating body 16a intersects the optical axis AX. The position (that is, functional area FA) also moves in the optical axis AX direction. That is, as shown in FIG. 4C, as the rotating body 16a rotates, the functional area FA on the intermediate screen 19 is sequentially shifted to adjacent functional areas FA′ set at equiangularly shifted positions. Move 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. Although the details will be described later, for example, by moving the position of the intermediate image TI toward the virtual image forming optical system 17, the projection distance or the virtual image distance to the projection image IM can be reduced. Further, by moving the position of the intermediate image TI toward the drawing device (display element) 11 side, the projection distance or the virtual image distance to the projection image IM can be increased.

The virtual image forming optical system (second projection optical system) 17 cooperates with the display screen 20 to enlarge the intermediate image TI formed by the imaging optical system (first projection optical system) 15, and projects it in front of the driver VD. A projection image IM is formed as a virtual image. The virtual image forming optical system 17 is composed of at least one mirror, and includes two mirrors 17a and 17b in the illustrated example. The virtual image forming optical system (second projection optical system) 17 can have optical characteristics that correct the curvature of the intermediate screen 19 (that is, the field curvature of the intermediate image TI) in the functional area FA of the rotating body 16a.

In the image display device 100 shown in FIG. 2 and the like, by operating the rotation drive unit 64 under the control of the display control unit 18, the diffusion unit 16 rotates around the reference axis SX and the position of the intermediate image TI is aligned with the optical axis. It is possible to increase or decrease the distance between the projected image IM as a virtual image formed behind the display screen 20 by the virtual image forming optical system 17 and the driver VD who is an observer by repeatedly and periodically moving in the AX direction. . In this way, the position of the projection image IM to be projected is changed back and forth, and the content displayed by the drawing device (display element) 11 under the control of the display control unit 18 is made to correspond to the position. By changing the display content of the projection image IM while changing the projection distance or the virtual image distance to the image IM, the projection image IM as a series of projection images can be made three-dimensional. Even if the functional area FA moves in the direction of the optical axis AX, the curved state of the intermediate screen 19 in the functional area FA is maintained. ) 17 is maintained.

The rotation speed of the diffusing part 16 or the rotating body 16a or the movement speed of the functional area FA should be a speed that makes it appear as if the projected image IM as a virtual image is displayed at a plurality of locations or at a plurality of projection distances at the same time. desirable. Here, if the projection image IM of each distance zone (sub-zone described later) is switched at 30 fps or more, preferably at 60 fps or more, a plurality of displayed images are recognized as continuous images. For example, assuming that the projection image IM is sequentially projected in five stages from short distance to long distance as the diffusion unit 16 operates, if the drawing device 11 is caused to display at 200 fps, each distance (for example, short distance) , the display of the projected image IM is switched at 40 fps, and the projected images IM at each distance are performed in parallel and the switching is recognized as substantially continuous.

5A and 5B are diagrams specifically illustrating changes in the position of the intermediate image TI due to the rotation of the diffusing section 16. FIG. The functional area FA of the diffusing portion 16 is repeatedly and periodically moved in a saw-tooth temporal pattern PA along the optical axis AX direction. In this case, as shown in the figure, it moves repeatedly and periodically along the direction of the optical axis AX in a sawtooth-like time-lapse pattern PA. In other words, the position of the intermediate image TI changes continuously and periodically as the diffusing section 16 rotates, although it is discontinuous at the location corresponding to the stepped section 16j. As a result, although illustration is omitted, the position of the projected image (virtual image) IM also moves repeatedly and periodically along the optical axis AX direction in the same manner as the position of the intermediate image TI, although the scale is different. can change dramatically. Here, since the drawing device 11 does not perform continuous display, but performs intermittent display while switching the display contents, the display positions of the intermediate images TI are also discrete positions on the sawtooth temporal pattern. becomes. In the temporal pattern PA, the closest display position Pn and the furthest display position Pf are set at positions away from both ends of the temporal pattern PA with a margin secured. A discontinuity PD of the temporal pattern PA corresponds to a stepped portion 16 j provided on the rotating body 16 a of the diffusing portion 16 . Here, in the example shown in FIG. 5, the position of the intermediate image TI is changed in a sawtooth pattern with a constant inclination with respect to time. It is desirable to change the position so that the display timing can be controlled, and depending on the specification of the display distance, the change may not be constant.

Here, when an image of a certain distance zone is displayed, the displayed distance changes as the position of the intermediate image TI changes within the displayed time as shown in FIG. At this time, the display distance seen by the observer (driver VD) for the display zone in which the distance changes in this way is approximately the average position of the distance that changes within the display time.

FIG. 6 is a diagram for explaining the relationship between the position of the intermediate image TI and the projection distance or the relationship between the position of the intermediate image TI and the display zone. When the intermediate image TI is moved at the same speed in the direction of the optical axis AX according to the characteristic C1 indicated by the dashed line, if the increment δ of the switching time of each distance zone is set to a constant value, the increment width of the projection distance is short, longer at longer distances. The interval Δ of movement of the intermediate image TI corresponds to the switching time of the distance zone to be displayed.

Assuming that the time required to move between the positions of the intermediate image TI shown in FIG. If the time is shorter than the product of the number n, the display zone will span multiple distance zones, and at least adjacent display zones will overlap in projected distance ranges (see display zones DZ1 to DZn in FIG. 6). By performing overlapping display in this manner, the same projected image (virtual image) IM can be displayed with a spread in the depth direction. It can be lengthened, and the brightness of the projection image (virtual image) IM is improved.

As shown in FIG. 6, n display zones can be set along the characteristic C1. Here, for convenience of explanation, the closest display zone is called the first display zone DZ1, and the farthest display zone is called the n-th display zone DZn (n is a natural number). In the plurality of display zones DZ1 to DZn, the display distance width widens as the distance increases from short distance to long distance. In this case, the depth of the object to be displayed or the composite projected image IM is expanded on the long distance side, but since the parallax becomes smaller as the distance increases, there is almost no effect on the display state. Adjacent display zones among the plurality of display zones DZ1 to DZn have partially overlapping projection distances, and each display zone includes zones that should originally have different projection distances. That is, the k-th display zone DZk (k is a natural number smaller than n) and the k+1-th display zone DZk+1 partially overlap in projection distance. are partially duplicated. The k-th display zone DZk also displays an image displayed in a display zone set before, after, or both before and after the original display image of the projection distance of the display object to be displayed there. It is a composite projected image. The display zone includes sub-zones with progressively varying distances to be projected. In the illustrated example, the images corresponding to the distance zones or sub-zones LZk-2 to LZk+1 for four sections are displayed in a state in which they are superimposed on each other during the display of the k-th display zone DZk. It is In this case, the display time of the image displayed in each of the display zones DZ1 to DZn differs between the adjacent display zones DZ1 to DZn at the pitch of the display time increment δ. The distance between both ends of the near side and the far side varies, and the average distance also varies. Since the human eye or brain perceives the display image at the average distance of the display zones DZ1 to DZn, even when the display is visually performed simultaneously, the display distances of the respective display zones DZ1 to DZn are displayed as different positions. can be in a state of being

When the k-th display zone DZk is divided at the timing when the overlapping distance zones are switched and considered as a series of sub-zones LZk-2 to LZk+1 with different projection distances including the reference sub-zone LZk, the drawing device (display element) 11 By performing the display operation, the same projected image (virtual image) IM is displayed in each subzone. In other words, the display zone DZk is configured by a combination of a series of sub-zones LZk-2 to LZk+1 whose distances change stepwise. From a different point of view, a local image to be projected onto a distance zone corresponding to one reference subzone LZk of interest is displayed repeatedly in, for example, four display zones. The image will have a uniform increase in brightness. At this time, considering the change in the projection distance, the common local projection image (virtual image) IM projected on the distance zone (corresponding to the sub-zones LZk-2 to LZk+1) common to the adjacent display zones is positioned and angle Overlap to match size. As a result, the projected image (virtual image) IM whose projection distance changes can be displayed without any deviation or blurring. Also, the display distance at this time is the distance corresponding to the reference subzone LZk. In FIG. 6, the display zones DZ1 to DZn are shown extending in the horizontal direction for convenience of display. It extends along C1.

The display times in the first display zone DZ1 to the n-th display zone DZn are all equal. By equalizing the display time in each of the display zones DZ1 to DZn constituting the plurality of display zones, it is possible to match the display brightness of the composite projection image IM by each of the display zones DZ1 to DZn, and the observer can It is possible to prevent the driver VD from unintentionally focusing his/her attention on an image at a specific distance. It should be noted that, depending on the application, it is possible to give a difference in the display brightness in each of the display zones DZ1 to DZn. For example, a display zone corresponding to long-distance projection can be processed to increase display brightness.

The first to third pre-interpolation zones CZ1 to CZ3 added to the projection at the short distance end are added from the viewpoint of making the display distance in the first distance zone LZ1 a desired distance, but they are not essential. . Similarly, the first to third post-interpolation zones CZ4 to CZ6 added to the far end projection are added from the viewpoint of making the display distance in the nth distance zone LZn a desired distance. not a thing

When different objects are displayed in a specific depth direction on the screen, display objects with different distances overlap or almost overlap in a two-dimensional plane other than the depth direction, and interference between the displays is caused. This may occur and should be avoided. For example, when a display object existing at a different display distance DZk′ is positioned close to the display object in the display zone DZk in the two-dimensional plane and interference occurs in the display of each object, in the interference area It is conceivable to perform a display that synthesizes the Specifically, in the common area or the intersection area where the pair of display objects overlap, an image in which the pair of display objects are superimposed and translucent is displayed, and in the difference area or the independent area where the pair of display objects do not overlap, each part is sufficient for standard display. Alternatively, a method of displaying different colors, sizes (including thickness in the case of lines), brightness, blinking, etc. may be considered, and it may be devised so as to be conveyed to the driver VD.

FIG. 7 is a conceptual block diagram illustrating the overall structure of head-up display device 200. Head-up display device 200 includes image display device 100 as a part thereof. The image display device 100 has the structure shown in FIG. 2, and the description thereof is omitted here.

The head-up display device 200 includes an environment monitoring section 72 and a main control section 90 in addition to the image display device 100 .

The environment monitoring unit 72 is an object detection unit that detects objects that exist within the detection area, and identifies moving objects and people that exist close to the front (specifically, automobiles, bicycles, pedestrians, etc.) as objects. , has a three-dimensional measuring instrument for extracting three-dimensional position information of an object. The environment monitoring unit (object detection unit) 72 includes an external camera 72a, an external image processing unit 72b, and a determination unit 72c as a three-dimensional measuring device. The external camera 72a enables capturing of an external image in the visible or infrared range. The exterior camera 72a is installed at an appropriate location inside and outside the vehicle body 2, and captures the driver VD or the detection area VF in front of the front window 8 (see FIG. 8, which will be described later) as an exterior image. The external image processing unit 72b performs various image processing such as brightness correction on the external image captured by the external camera 72a to facilitate processing in the determination unit 72c. The determination unit 72c extracts or cuts out an object image from the external image that has passed through the external image processing unit 72b, thereby determining objects such as automobiles, bicycles, and pedestrians (specifically, objects OB1 and OB1 in FIG. 8 to be described later). OB2 and OB3) is detected, and the spatial position of the object in front of the vehicle body 2 is calculated from the depth information attached to the external image and stored as three-dimensional position information in the storage unit 72m. The storage unit 72m of the determination unit 72c stores software that enables extraction of an object image from an external image. Data is read. The determination unit 72c can detect what element corresponds to the object element from, for example, the shape, size, color, etc. of each object element in the obtained image. As a judgment criterion at that time, there is a method of performing pattern matching with information registered in advance and detecting what the object is from the degree of matching. In addition, from the viewpoint of increasing the processing speed, it is also possible to detect a lane from an image and detect an object based on the shape, size, color, etc. of a target or object element in the lane.

Although not shown, the external camera 72a is, for example, a compound-eye three-dimensional camera. In other words, the external camera 72a is a matrix array of camera elements each composed of an imaging lens and a CMOS or other imaging element, and each has a driving circuit for the imaging element. A plurality of camera elements constituting the external camera 72a can detect, for example, relative parallax. A target distance to each region or object in the image corresponding to the detection region can be determined.

It should be noted that even if a combination of a two-dimensional camera and an infrared distance sensor is used in place of the compound eye type external camera 72a as described above, the depth direction of each part (region or object) within the photographed screen can be measured. A target distance, which is distance information, can be obtained. Also, instead of the compound-eye type external camera 72a, a stereo camera in which two two-dimensional cameras are separately arranged can be used to obtain a target distance, which is distance information in the depth direction, for each part (region or object) in the photographed screen. can be done. In addition, it is also possible to obtain a target distance, which is distance information in the depth direction, for each part (region or object) in the photographed screen by performing imaging while changing the focal length at high speed with a single two-dimensional camera. can.

Further, distance information in the depth direction can be obtained for each part (area or object) within the detection area by using LIDAR technology instead of the compound-eye external camera 72a. Using LIDAR technology, it is possible to measure scattered light from pulsed laser irradiation, measure the distance and spread to an object at a long distance, and acquire distance information to objects within the field of view and information on the spread of the object. . Furthermore, for example, by combining radar sensing technology such as LIDAR technology and technology for detecting the distance of an object from image information, a composite method, that is, a method that fuses multiple sensors, will increase the accuracy of object detection. can be done.

The operating speed of the external camera 72a for detecting objects must be equal to or higher than the operating speed of the drawing device (display element) 11 from the viewpoint of speeding up input. If the display period for one cycle of DZ1 to DZn is, for example, 30 fps or more, it is desirable to make it faster. The external camera 72a is desirably capable of high-speed object detection by high-speed operation such as 480 fps or 1000 fps, for example, higher than 120 fps. Also, when multiple sensors are fused, not all the sensors need to be high speed, and at least one of the multiple sensors must be high speed, but the other sensors do not have to be high speed. In this case, it is possible to use the data detected by the high-speed sensor as the basis and complement it with the data of the low-speed sensor to improve the sensing accuracy.

The display control unit 18 operates the display optical system 30 under the control of the main control unit 90 to display a three-dimensional projection image IM in which the virtual image distance or projection distance changes behind the display screen 20 .

The main control unit 90 has a role of harmonizing the operations of the image display device 100, the environment monitoring unit 72, and the like. The main control unit 90 periodically changes the projection distance of the virtual image, which is the projected image IM, by the display optical system 30 by operating the rotation driving unit 64 via the display control unit 18, for example. That is, the main control unit 90 and the like periodically change the projection position of the virtual image, which is the projected image IM, in the depth direction. In addition, the main control unit 90 adjusts the spatial arrangement of the frame HW (see FIG. 8) projected by the display optical system 30 so as to correspond to the spatial position of the object detected by the environment monitoring unit 72. do. That is, the main control unit 90 generates the projection image IM to be displayed on the display optical system 30 from the display information including the display shape and the display distance received from the environment monitoring unit 72 . The display content of the projected image IM is synchronized with the operation of the rotation drive unit 64, that is, synchronized with the movement of the intermediate image TI. The projected image IM may be, for example, a marker such as a frame HW (see FIG. 8) positioned peripherally with respect to the depth position direction of objects such as automobiles, bicycles, and pedestrians existing behind the display screen 20. can be done. Although the frame HW is shown without depth for convenience of explanation, it actually has a constant depth width corresponding to the depth width of the display zones DZ1 to DZn. As described above, the main control unit 90 functions as an image addition unit in cooperation with the display control unit 18, and at the timing when the target distance to the detected object substantially matches the projection distance, On the other hand, the display optical system 30 adds a related information image as a virtual image.

The main control unit 90 allocates a single display target to at least a single display zone and causes the drawing device (display element) 11 to perform display. In this case, in principle, a single display target is displayed in a single display zone including a specific projection distance, but a single display target may be displayed in a plurality of display zones.

The main control unit 90 sets images corresponding to a series of adjacent distance zones among the plurality of distance zones whose projection distances are changed by moving the intermediate screen 19 as a plurality of sub-zones constituting the display zones DZ1 to DZn, and selects a specific sub-zone. The same projected image IM is repeatedly displayed as a plurality of subzones corresponding to the distance zone. In this case, the distance zone corresponds to the minimum unit of distance resolution, and by repeatedly displaying the same projection image IM in distance zones with different projection distances, the distance range is widened, but the display of the projection image IM This will increase the brightness.

FIG. 8 is a perspective view for explaining a specific display state. In front of the driver VD who is the observer, there is a detection area VF corresponding to the observation field of view. It is assumed that human objects OB1 and OB3 such as pedestrians and a mobile object OB2 such as a car are present in the detection area VF, that is, on the road and its surroundings. In this case, the main control unit 90 causes the image display device 100 to project a three-dimensional projection image (virtual image) IM, and displays frame frames HW1, HW2, and HW3 as related information images for each of the objects OB1, OB2, and OB3. Add At this time, since the distances from the driver VD to the objects OB1, OB2, and OB3 are different, the projection distances from the driver VD to the projection images IM1, IM2, and IM3 that display the frame frames HW1, HW2, and HW3 are It corresponds to the distance to OB2 and OB3.

The projection distances of the projection images IM1, IM2 and IM3 are formed in the display zones DZa to DZc corresponding to some of the display zones DZ1 to DZn shown in FIG. have width. The center of each projection distance, ie the projection distance of the projection images IM1, IM2, IM3, is discrete and cannot always be exactly matched to the actual distance to the objects OB1, OB2, OB3. However, if the difference between the projection distances of the projected images IM1, IM2, and IM3 and the actual distances to the objects OB1, OB2, and OB3 is not large, parallax is unlikely to occur even if the viewpoint of the driver VD moves, and the objects OB1, OB2 , OB3 and the frame frames HW1, HW2, and HW3 can be substantially maintained.

9A corresponds to FIG. 5, FIG. 9B corresponds to the projected image IM3 or frame frame HW3 in FIG. 8, FIG. 9C corresponds to the projected image IM2 or frame frame HW2 in FIG. 8, and FIG. 9D corresponds to the projected image IM1 or frame frame HW1 in FIG. As is clear from FIGS. 9A to 9D, the projected image IM1 is specifically Specifically, at the display timing of the predetermined display zone determined based on the characteristic C1 shown in FIG. corresponds to the display image of Similarly, the projected image IM2 is a series of displays formed on the display surface 11a of the drawing device 11 when the functional area FA of the rotating body 16a (or the three-dimensional shape portion 116) is within the distance range centered on the display position P2. Corresponding to the image, the projected image IM3 is formed on the display surface 11a of the drawing device 11 when the functional area FA of the rotating body 16a (or the three-dimensional shape portion 116) is within a predetermined distance range centered on the display position P3. corresponds to a series of displayed images. When viewed in one cycle based on the movement of the intermediate image TI, the projected image IM1 or the frame frame HW1 corresponding to the display position P1 is displayed first, and then the projected image IM2 or the frame frame HW2 corresponding to the display position P2 is displayed. After that, the projected image IM3 or frame frame HW3 corresponding to the display position P3 is displayed. If the above one period is visually short, the switching of the projection images IM1, IM2, and IM3 becomes very fast, and the driver VD who is the observer observes the frame frames HW1, HW2, and HW3 simultaneously as images with depth. recognize that In this embodiment, for example, when at least two display positions among these display positions P1 to P3 are designated as adjacent display zones or close display zones, for example, the projection images of FIGS. 9B and 9C, FIGS. There is a period of time in which the projection image of FIG. 9D or all of the projection images of FIGS. 9B, 9C, and 9D are simultaneously displayed overlaid in the overlapping time range within the display time.

FIG. 10 is a conceptual diagram explaining the operation of the main control section 90. As shown in FIG. First, when detecting objects OB1, OB2, and OB3 using the environment monitoring section 72, the main control section 90 generates display data corresponding to frame frames HW1, HW2, and HW3 corresponding to the objects OB1, OB2, and OB3. and stored in a storage unit (not shown) (step S11). After that, the main control unit 90 converts the display data obtained in step S11 so as to distribute the data to the corresponding display zones DZ1 to DZn (step S12). Specifically, according to the positions of the objects OB1, OB2, and OB3, the corresponding frame frames HW1, HW2, and HW3 are set to any one of the display zones DZ1 to DZn (the display zones DZa to DZc in the example of FIG. 8). assign. Next, the main control unit 90 processes the display data corresponding to the frame frames HW1, HW2, HW3 so as to match the allocated display zones DZ1 to DZn, and stores them in a storage unit (not shown) (step S13). This adaptation includes image processing such as correcting the outline and placement of the frame image for each distance zone or subzone LZk-2 to LZk+1. After that, the main control unit 90 synthesizes the display data adapted in step S13 with the existing data (step S14). The display by the display zones DZ1 to DZn are performed in parallel although there is a time lag. This is because it is necessary to rearrange the display contents so that the old object and the new object coexist. Finally, the main control unit 90 outputs the display data obtained in step S14 to the display control unit 18 in synchronization with the operation of the rotation driving unit 64, and outputs the functional area of the rotating body 16a to the drawing device (display element) 11. A display operation corresponding to FA is performed (step S15).

11A and 11B are diagrams for explaining the operation of the drawing device (display element) 11. FIG. In this case, the first to n-th display areas arranged in the vertical direction correspond to the first to n-th display zones DZ1 to DZn shown in FIG. 6 and the like. In one cycle corresponding to one rotation of the rotating body 16a (or the three-dimensional shape section 116), the first The display in the display area to the n-th display area is repeated. In each display area, the signals F1-F4 mean that the same display image is repeated in four sub-zones, and each of the signals F1-F4 includes R, G, and B signal components for color display. ing.

According to the head-up display device 200 or the image display device 100 of the first embodiment described above, the drawing device ( Since the display element 11 performs display, virtual images whose display positions are different including the depth direction can be displayed while being changed at high speed, and various images can be simultaneously projected at a plurality of distance positions. At this time, the main control unit 90 and the display control unit 18 set the projection distances so that the adjacent display zones DZk and DZk+1 of the plurality of display zones DZ1 to DZn whose projection distances are changed partially overlap. It is considered to display in the display zones DZ1 to DZn with the number of distance divisions set within one cycle in which the display distance is changed from the near end to the far end or from the far end to the near end. In this case, compared to a display in which the projection distances do not overlap in the adjacent display zones DZk and DZk+1, even if the number of divisions is the same, the display zones DZ1 to DZn can have an overlapping projection time or display time. Simultaneous projection of high-brightness images is facilitated.

[Second embodiment]
A display device and the like according to the second embodiment will be described below. Note that the display device and the like of the second embodiment are obtained by modifying the display device and the like of the first embodiment, and items that are not particularly described are the same as those of the first embodiment.

As shown in FIG. 12, an intermediate screen 19, which is an optical element that moves in the optical axis AX direction, is arranged at the projection position or imaging position of the imaging optical system 15. As shown in FIG. The intermediate screen 19 is a diffusion plate that controls the light distribution angle to a desired angle, and is made of, for example, frosted glass, a lens diffusion plate, a microlens array, or the like. In this case, the effective area of intermediate screen 19 becomes the functional area of intermediate screen 19 .

The main control unit 90 and the display control unit 18 as control units cyclically shift the position of the intermediate screen 19 via the reciprocating drive unit 264 so that the position of the intermediate image TI is cyclically shifted as shown in FIG. While the projection distance is periodically changed by reciprocating, the image formed on the drawing device 11 is made to correspond to the projection distance. Specifically, the intermediate screen 19 is reciprocated in the optical axis AX direction by the guide portion 264a and the actuator 264b that constitute the reciprocating drive portion 264, thereby periodically changing the projection distance.

When the position of the intermediate image TI is set to the triangular waveform over time pattern PA shown in FIG. After the display zones DZ1 to Zn are sequentially switched from the long distance to the short distance, the same cycle is repeated.

〔others〕
Although the head-up display device 200 as a specific embodiment has been described above, the display device according to the present invention is not limited to the above. For example, in the first embodiment, the image display device 100 can be arranged upside down and the display screen 20 can be arranged above the front window 8 or at the sun visor position. A display screen 20 is arranged at . The display screen 20 may also be placed in a position corresponding to a conventional mirror on a motor vehicle.

In the above, the intermediate screen 19 or the functional area FA is arranged so as to be substantially orthogonal to the optical axis AX direction of the main body optical system 13, but the functional area FA can be forcibly tilted with respect to the optical axis AX. . In this case, by combining with the virtual image forming optical system 17, it is possible to project the projection image IM with no tilt or with a predetermined tilt.

The first to n-th display zones DZ1 to DZn described above do not need to be continuous over the entire range of the projection distance, and are discontinuous separated at portions corresponding to the boundaries of the subzones LZ1 to LZn. may be Moreover, the display zones DZ1 to DZn are not limited to including the same number of subzones, and may include different subzones for each of the display zones DZ1 to DZn.

Although one intermediate screen 19 is provided in the diffusion section 16 in the first embodiment, two or more intermediate screens 19 may be provided. In this case, the intermediate screen 19 is divided into ranges corresponding to 1/2 pitch, 1/3 pitch, etc. of the spiral.

The three-dimensional portion 116 of the intermediate screen 19 does not need to have a helical shape over the entire circumference. is also conceivable.

In the diffusion part 16, the hollow frame body 16b is not essential, and only the rotating body 16a can be used. In this case as well, since the inclined connection surface 16k is formed on the stepped portion 16j, it is possible to suppress the generation of noise accompanying the rotation of the rotating body 16a, thereby stabilizing the rotation of the rotating body 16a.

In the above embodiments, the contour of the display screen 20 is not limited to a rectangle, and can have various shapes.

The imaging optical system 15 and virtual image forming optical system 17 shown in FIG. 2 are merely examples, and the optical configurations of these imaging optical system 15 and virtual image forming optical system 17 can be changed as appropriate.

In the above description, an object OB existing in front of the vehicle body 2 is detected by the environment monitoring unit 72, and related information images such as frame frames HW1, HW2, and HW3 corresponding to the arrangement of the object OB are displayed on the image display device 100. , irrespective of the presence or absence of the object OB, it is possible to obtain incidental driving-related information using a communication network, and display such driving-related information on the image display device 100 . For example, it is possible to display warnings of vehicles, obstacles, etc. in the blind spot.

The display device of the present invention can be applied not only to a head-up display (HUD) device mounted on a vehicle or other moving body, but also to a head-mounted device, a wearable display device, or the like that performs three-dimensional display.

Claims (11)

a first projection optical system that projects image light formed by the display element;
an intermediate screen that diffuses light at the projection position of the first projection optical system;
a second projection optical system that enlarges and projects the intermediate image formed on the intermediate screen as a virtual image;
a driving unit that periodically moves the functional area of the intermediate screen in the optical axis direction at a moving speed that makes it appear as if projection images as virtual images are simultaneously displayed at a plurality of projection distances;
Display is performed on the display element in synchronism with the movement of the intermediate screen that changes the projection distance, and a unit of display having depth is defined as a display zone , and adjacent display zones corresponding to the plurality of projection distances are displayed. and a control unit that sets display zones so that they partially overlap in depth directions with different projection distances . 2. The display device according to claim 1, wherein said control unit sets the display time for each display zone constituting said plurality of display zones to be substantially the same. The display device according to any one of claims 1 and 2, wherein the control unit allocates a single display target to at least a single display zone and causes the display element to perform display. 4. The display device according to any one of claims 1 to 3, wherein said plurality of display zones widen in display distance width from a short distance to a long distance. The control unit sets images corresponding to a series of adjacent distance zones among a plurality of distance zones whose projection distances are changed by moving the intermediate screen as a plurality of sub-zones constituting the display zone, 5. The display device according to claim 1, wherein the same projection image is repeatedly displayed as a plurality of corresponding subzones. 6. The head-up display device according to claim 5, wherein the same projected image is repeatedly displayed as a series of subzones with different projection distances including the reference subzone. 7. The display device according to any one of claims 5 and 6, wherein the control unit causes the same projection images to be superimposed and displayed in the distance zones having different projection distances so that the positions and angular sizes match. 3. The intermediate screen has a three-dimensional shape portion that continuously changes the position of the functional area in the optical axis direction of the intermediate screen, and the drive unit rotates the intermediate screen around a reference axis. 8. The display device according to any one of 7. 9. The display device according to claim 8, wherein the three-dimensional shape portion includes a spiral shape portion. 8. The display device according to any one of claims 1 to 7, wherein the driving section periodically moves the intermediate screen in the optical axis direction. A display method using a display device for enlarging and projecting an intermediate image formed on an intermediate screen by projecting image light formed by a display element as a virtual image, wherein the functional area of the intermediate screen is periodically projected in the optical axis direction to form a virtual image. is moved at a moving speed that makes it appear as if the projected images are simultaneously displayed at a plurality of projection distances, and the display element performs display in synchronization with the movement of the intermediate screen that changes the projection distance; 3. A display method in which a unit of display having depth is set as a display zone , and neighboring display zones among the plurality of display zones corresponding to the plurality of projection distances are set so as to partially overlap in the depth direction with different projection distances .

Images