JP2020064235A - Display device - Google Patents

Abstract

To provide a display device with which it is possible to expand the spread range of virtual image projection distance while suppressing an increase in intermediate screen movement amount.SOLUTION: The display device comprises: a display element 11 for displaying an image to be projected; a projection optical system 15 for enlarging the image formed in the display element 11; an intermediate screen 16 having a diffusion function and arranged on the light projection side of the projection optical system 15; an enlargement optical system 17 for enlarging an intermediate image formed on the intermediate screen 16; and a rotation drive unit 64 for moving the position of the intermediate screen 16 in the direction of an optical axis AX of the projection optical system 15 while arranging the intermediate screen 16 aslant in relation to the optical axis AX in a transverse plane, and causing the virtual image projection position to change. The intermediate screen 16 is inclined so that the lower part of an intermediate image TI is arranged on the enlargement optical system 17 side and the upper part of the intermediate image TI is arranged on the projection optical system 15 side in the transverse plane.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a display device in which a virtual image is displayed in front of the line of sight and the projection position of the virtual image is variable.

  As a display device, there is a head-up display (HUD) device including a projection system for projecting an image displayed on a display element as a virtual image and a display screen such as a windshield or a combiner for displaying the virtual image. The HUD device allows the driver to check the display without significantly moving the line of sight or viewpoint, and has the advantage of reducing the risk compared to the conventional device that displays information on the instrument panel such as a speedometer. is there. In the future, it is expected that the HUD device will be actively used as a device for displaying a display to support the driver's safe driving. At that time, it is necessary to surely inform the driver of dangerous information and cautionary information to be transmitted. is there. In order to convey the information to the driver more reliably, for example, by looking at the target (target) that the driver should pay attention to while driving, without looking far away from the target, you can feel more natural and comfortable. In addition, it is necessary to recognize information such as danger faster and faster. In order to achieve such a function, the HUD device is required to display the projection distance of the virtual image to be displayed at the distance at which the target exists and also the ordinate and abscissa in the distance plane. Therefore, the HUD device requires an optical system in which the virtual image projection distance is variable. At that time, if the projection distance of the virtual image can be changed from the near side to the far side (or vice versa) within 1/60 sec, for example, the projected images of all distances from the driver can be converted into a 3D image. It is possible to observe and display images projected at a plurality of distances at the same time.

  As a means for changing the projection distance of the virtual image in the HUD device, there is a method of projecting a display element such as DMD or LCOS on the intermediate screen and moving the intermediate screen to change the virtual image distance. However, when moving the intermediate screen, it is necessary to make the optical magnification of the optical system relatively low in order to secure the optical performance for virtual image display from the near side to the far side. Will increase. In particular, when the position on the optical axis of the intermediate screen is moved to change the virtual image distance, the intermediate screen is used as a fixed focus without changing the focus position of the projection optical system that projects an image on the intermediate screen. When it is configured to move within the depth of focus, if the amount of movement of the intermediate screen is large, it is necessary to set the F value of the projection optical system to a large value in order to deepen the depth, which makes it difficult to secure the display brightness. Become.

  Patent Document 1 discloses an optical system for a HUD device that scans an image using a MEMS mirror to display a virtual image, and reciprocates a movable screen in a posture inclined with respect to the moving direction of the movable screen. The display distance of is variable. The optical system of Patent Document 1 does not form a projected image of a two-dimensional display image, and it is not easy to increase the display speed.

  Patent Document 2 discloses a virtual image display device in which the inclination angle of the virtual image can be displaced along with the distance from the driver to the virtual image. Although a configuration in which the virtual image length is changed by using two mirrors to change the optical path length is shown, a means for changing the inclination of the virtual image is not disclosed.

  Patent Document 3 discloses a HUD device that has a projector for displaying two virtual images and can display at two virtual image distances, and an assumed inclination of the virtual image on the far side is arranged on an intermediate screen or an optical path. It is changed by rotating the mirror. In this case, the relative angles of the virtual images by the two projectors can be adjusted, but the three-dimensional display is not performed by a single projector.

JP 2017-15954 JP JP 2016-102966 JP JP 2016-212338 JP

  The present invention has been made in view of the background art described above, and an object of the present invention is to provide a display device capable of widening the spread range of the projection distance of a virtual image while suppressing an increase in the movement amount of the intermediate screen.

  In order to solve the above problems, a display device according to the present invention includes a display element that displays an image to be projected, a projection optical system that magnifies an image formed on the display element, and a light of the projection optical system that has a diffusion function. The intermediate screen located on the exit side, the magnifying optical system that magnifies the intermediate image formed on the intermediate screen, and the intermediate screen that is inclined with respect to the optical axis in the cross section while projecting the position of the intermediate screen And an arrangement changing device for changing the virtual image projection position by moving in the optical axis direction of the optical system.In the intermediate screen, the lower part of the intermediate image is on the magnifying optical system side and the upper part of the intermediate image is on the projection optical system side in the cross section. Tilt to be placed in.

  According to the above display device, the arrangement changing device changes the virtual image projection position by moving the position of the intermediate screen in the optical axis direction of the projection optical system while arranging the intermediate screen in a cross-section inclined with respect to the optical axis. Therefore, it is possible to spatially expand the display, and it is possible to expand the overall distance width or expansion range of the virtual image projection distance while reducing the amount of movement of the intermediate screen in the optical axis direction. Also, by tilting the intermediate screen so that the lower part of the intermediate image is located on the magnifying optical system side and the upper part of the intermediate image is located on the projection optical system side, the upper side of the displayed image is displayed while being projected relatively far. The lower side of the image can be projected relatively to the near side, and the display along a horizontal plane such as a road surface becomes possible.

  In one specific aspect of the present invention, in the display device, the display element has an inclination angle adjusted according to the inclination angle of the intermediate screen. In this case, the focus state of the intermediate image on the intermediate screen can be easily made uniform, and the image quality of the virtual image can be improved.

  In another aspect of the invention, the repositioning device moves the intermediate screen at a constant tilt angle. In this case, the moving mechanism of the intermediate screen can be simplified, and it becomes easy to maintain the state of the virtual image regardless of the movement of the intermediate screen.

  In still another aspect of the present invention, the arrangement changing device moves the intermediate screen by inclining the intermediate screen with the lower part of the intermediate image of the intermediate screen as a fulcrum in the cross section.

  In still another aspect of the present invention, the intermediate screen is provided on the rotating body that rotates about the rotation axis. In this case, the movement of the intermediate screen in the optical axis direction is stabilized, the virtual image distance can be changed at high speed, and the reliability of the apparatus is increased.

  In still another aspect of the present invention, a display control unit that displays an image on a display element so that projection distances partially overlap in adjacent display zones among a plurality of display zones that change projection distances is provided. In this case, the spatial display density can be increased.

  In yet another aspect of the present invention, the plurality of display zones have a wider distance range to be displayed from a short distance to a long distance.

  In still another aspect of the present invention, the projection optical system has a design optimized for the tilt angle of the intermediate screen tilted with respect to the optical axis. At that time, the projection optical system having a design optimized for the tilt angle of the intermediate screen is configured by tilting the display element with respect to the optical axis. Alternatively, in the projection optical system designed to optimize the tilt angle of the intermediate screen, the display element is arranged so that the center position of the display element is a position shifted from the optical axis in a plane perpendicular to the optical axis. Alternatively, the projection optical system having a design optimized for the tilt angle of the intermediate screen is configured by shifting or tilting at least one of the lenses forming the projection optical system with respect to the optical axis. With these configurations, the projection optical system can be optimally focused on the inclination of the intermediate screen, and it is possible to prevent the image quality from being deteriorated due to the defocus on the intermediate screen. If the projection optical system is not provided with the focusing function and the intermediate screen is moved within the depth of the projection optical system, the F of the projection optical system is reduced by the amount of movement of the intermediate screen. The value can be set small, and it is easy to ensure the brightness of the virtual image to be displayed, which is a desirable configuration.

  In still another aspect of the present invention, the magnifying optical system has a design optimized for the tilt angle of the intermediate screen tilted with respect to the optical axis. Here, optimization means designing aberration correction with the intermediate screen surface as the object plane so that the inclined intermediate screen is in focus. For example, when a magnifying optical system optimized for a normal intermediate screen having no tilt is used in an apparatus having a tilted intermediate screen, aberrations such as image distortion and field curvature become large, which is a performance problem. . To prevent this problem, a magnifying optical system optimized for the tilted intermediate screen is required.

(A) is a side sectional view showing a state in which the display device of the first embodiment is mounted on a vehicle body as a head-up display device, and (B) is a front view from the inside of the vehicle for explaining the head-up display device. Is. It is an expanded side sectional view explaining a concrete example of composition, such as a virtual image display optical system. (A) And (B) is a top view and a side sectional view explaining the structure of the diffusion part which incorporated the intermediate screen, and (C) is a figure explaining movement etc. of a functional area accompanying rotation of an intermediate screen. Is. It is a figure which illustrates the change of the position of an intermediate screen and an intermediate image concretely. It is a figure which illustrates the change of the position of an intermediate image concretely. It is a conceptual diagram explaining the projection state of a display image. It is a figure explaining the concrete projection distance of a display image. It is a block diagram explaining the display system for mobiles including a head-up display device. 3 is a cross-sectional view illustrating a projection optical system, a display element, and the like in Example 1. FIG. It is a figure explaining the display apparatus of 2nd Embodiment. It is a figure explaining the display of 3rd Embodiment. It is a figure explaining the display of 4th Embodiment.

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

  Referring to FIGS. 1A and 1B, the head-up display device 100 of the present embodiment is a display device mounted in the vehicle body 2 and includes a drawing unit 10 and a display screen 20. A head-up display (HUD) device 100 displays 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 toward the DR.

  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 the display light HK corresponding to the image including the driving-related information and the danger signal toward the display screen 20. To 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 being supported at its 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 an independent type 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 by the display screen 20 which is a half mirror is an eye box corresponding to the pupil HT of the driver DR sitting in the driver's seat 6 and the peripheral position thereof. Guided by EB. The driver DR can observe the display light HK reflected by 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 DR can observe external light transmitted through the display screen 20 that is a half mirror, that is, a front view, a real image of an automobile or the like. As a result, the driver DR superimposes on the external image behind the display screen 20, and a display image (virtual image) IM including driving-related information, a danger signal, and the like formed by the reflection of the display light HK on 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 controller 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. Note that, in FIG. 2 and the like, the coordinate axes XYZ have the center of the eye box EB corresponding to the position between the pupils HT of the general driver DR as the origin, but are displayed with the origin shifted for convenience.

  The main body optical system 13 is arranged in the latter stage of the optical path corresponding to the display element 11, the projection optical system 15 capable of forming the intermediate image TI in which the image formed on the display element 11 is enlarged, and the image formation position of the intermediate image TI. And a magnifying optical system 17 for converting the intermediate image TI into a virtual image. As will be described later in detail, the main body optical system 13 can change the projection distance by projecting the display image IM which is a virtual image in a state of being inclined with respect to the optical axis AX. The projection optical system 15, the diffusing unit 19, and the magnifying optical system 17 of the main body optical system 13 constitute an imaging optical system 30a. A combination of the magnifying optical system 17 of the main body optical system 13 and the display screen 20 arranged above the main body optical system 13 constitutes an exit side combining optical system 30b.

  In the main body optical system 13, the display element 11 is a drawing device (display unit) having a two-dimensional display surface 11a. Here, the display surface 11a is inclined at an angle θ2 with respect to the optical axis AX, corresponding to the inclination of the diffusion surface 16m of the intermediate screen 16. The image formed on the display surface 11a of the display element 11 is magnified by the projection optical system 15 of the main body optical system 13 to form an intermediate image TI on the diffusing member 16k provided in the diffusing section 19, and the magnifying optical system 17 is formed. Be led to At this time, by appropriately tilting the display surface 11a, it becomes easy to make the focus state of the intermediate image TI on the diffusion surface 16m uniform. By using a drawing device capable of two-dimensional display as the display element 11, the intermediate image TI or the display image (virtual image) IM can be switched at a relatively high speed. For the display element 11, a digital mirror device (DMD: Digital Mirror Device) or a reflective liquid crystal device (LCOS: Liquid crystal on silicon) can be used. When DMD or LCOS is used as the display element 11, it becomes easy to switch images at high speed (including high-speed intermittent display) while maintaining brightness, which is advantageous for display in which the virtual image distance or the projection distance is changed. As an application example, when the virtual image is simultaneously projected on 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. Accordingly, the flicker of the virtual image can be improved when a plurality of display images (virtual images) IM are displayed at different projection distances to the driver DR as if they are being displayed at the same time.

  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, although not shown. The F value of the projection optical system 15 is 1.8 or more. The projection optical system 15 magnifies and projects the image formed on the display surface 11a of the display element 11 to an appropriate magnification, and places the intermediate image TI at a position close to the intermediate screen 16 provided on the surface of the diffusion member 16k of the diffusion unit 19. (Or, a forced intermediate image TI ′ is formed at the position of the intermediate screen 16. The compulsory intermediate image TI 'includes, in addition to the intermediate image TI itself, an image that is displaced from the intermediate image TI and is slightly out of focus, and may be referred to as an intermediate image TI in a broad sense.

  The diffusing unit 19 is a member arranged at the projection position or the image forming position of the projection optical system 15 (that is, the planned image forming position of the intermediate image TI or in the vicinity thereof), and is driven by the rotation driving unit 64 which is the arrangement changing device. Then, for example, it rotates around the rotation axis SX at a constant speed. That is, the rotation drive unit 64 causes the diffusion unit 19 (specifically, the intermediate screen 16 of the rotating body 19a described later) to perform periodic motion within the movable range along the optical axis AX direction. Further, the rotation drive unit 64 operates under the control of the display control unit 18, and adjusts the rotation position and the rotation speed of the intermediate screen 16 according to the projection timing of the display element 11.

  As shown in FIGS. 3 (A) and 3 (B), the diffusing portion 19 is composed of a spiral rotating body 19a having a contour close to a disc as a whole, and a cylindrical hollow frame housing the rotating body 19a. It has a certain screen cover 19b.

  The rotating body 19 a is a conical member that functions as the intermediate screen 16. One surface 19f formed on the rotating body 19a is formed as a smooth surface or an optical surface, and a diffusion surface 16m is formed over the entire surface of the surface 19f. That is, the intermediate screen 16 is a diffusion screen. The diffusion surface 16m is a portion that controls the light distribution angle to a desired angle. The diffusion surface 16m can be a sheet attached to the rotating body 19a, but may be a fine concavo-convex pattern formed on the surface of the rotating body 19a. Further, the diffusion surface 16m may be formed so as to be embedded inside the rotating body 19a. The diffusion surface 16m forms the intermediate image TI or the forced intermediate image TI 'by diffusing the incident display light HK. The other surface 19s formed on the rotating body 19a is formed as a smooth surface or an optical surface. The rotating body 19a is a light-transmitting spiral member, and the pair of surfaces 19f and 19s are formed by deforming the conical side surfaces and are spiral displacement surfaces having the rotation axis SX as the spiral axis. . As a result, the diffusion surface 16m formed on the one surface 19f is also formed along the spiral displacement surface obtained by deforming the conical side surface. The rotator 19a or the intermediate screen 16 has a substantially equal thickness t in the direction of the rotation axis SX or the optical axis AX. The diffusion surface 16m is formed in a range corresponding to one cycle of the spiral, and a step portion 19j is formed as a cut of the diffusion surface 16m at one location along the circumference of the diffusion portion 19. By forming the rotating body 19a, that is, the intermediate screen 16 in such a shape, the diffusing surface 16m of the intermediate screen 16 can be inclined at a desired angle with respect to the optical axis AX, and the diffusing surface 16m in the optical axis AX direction. It is possible to continuously change the position of, and it is possible to perform projection in which the display image IM is inclined with respect to the optical axis AX and the projection distance is changed.

  In the rotating body 19a, one position along the circumferential direction is a functional area FA through which the optical axis AX of the projection optical system 15 or the virtual image display optical system 30 passes, and an intermediate image is formed by the diffusion surface 16m in the functional area FA. TI is formed. This functional area FA moves on the rotating body 19a at a constant speed as the rotating body 19a rotates. That is, while rotating the rotating body 19a, the display light (image light) HK is incident on the functional area FA which is a part of the rotating body 19a, so that the functional area FA or the intermediate image TI is maintained in an inclined posture and the functional area FA is maintained. Alternatively, the position of the intermediate image TI reciprocates along the optical axis AX (see FIG. 4). That is, the intermediate screen 16 is moved at a constant inclination angle. In the illustrated example, since the diffusion surface 16m is formed in the range corresponding to one cycle of the spiral, the functional area FA of the diffusion surface 16m or the intermediate image TI is stepped in the optical axis AX direction by one rotation of the rotating body 19a. It will make one round trip for a distance equivalent to.

  In the transverse section parallel to the YZ plane shown in the drawing, the diffusing surface 16m of the intermediate screen 16 or the intermediate image TI is inclined by an angle θ1 so as to rotate clockwise in the drawing with reference to the plane perpendicular to the optical axis AX. Thus, in the case of the magnifying optical system 17 shown in the figure, the upper side of the display image IM can be projected relatively far, while the lower side of the display image IM can be projected relatively near, and the display image IM can be projected upward. You can make it fall into the back. Correspondingly, the intermediate screen 16 is inclined so that the lower part of the intermediate image TI is arranged on the magnifying optical system 17 side and the upper part of the intermediate image TI is arranged on the projection optical system 15 side.

  Here, the projection optical system 15 is designed to be optimized for the tilt angle θ1 of the intermediate screen 16 tilted with respect to the optical axis AX. At that time, the projection optical system 15 having a design optimized for the tilt angle θ1 of the intermediate screen 16 can be configured by tilting the display element 11 with respect to the optical axis AX. Alternatively, the projection optical system 15 designed to be optimized for the tilt angle θ1 of the intermediate screen 16 has the display element 11 at a position where the center position of the display element 11 is shifted from the optical axis AX in a plane perpendicular to the optical axis AX. Can be arranged so that Alternatively, the projection optical system 15 designed to be optimized for the tilt angle θ1 of the intermediate screen 16 is configured by shifting or tilting at least one lens of the projection optical system 15 with respect to the optical axis AX. Can be With these configurations, the projection optical system 15 can be optimally focused on the inclination of the intermediate screen 16 (specifically, for example, the functional area FA of the intermediate screen 16 or a part thereof is approximated or The fitted flat surface or curved surface and the flat surface or curved surface approximated or fitted to the focus surface of the projection optical system 15 can be made to substantially coincide with each other without a relative angular difference or displacement in the optical axis AX direction), and the intermediate screen 16 It is possible to prevent the image quality from being deteriorated due to the out-of-focus condition. When the projection optical system 15 does not have the focusing function and the intermediate screen 16 is moved within the depth of the projection optical system 15, the projection is performed by the amount of movement of the intermediate screen 16 that is small. The F value of the optical system 15 can be set small, and the brightness of the virtual image to be displayed can be easily secured, which is a desirable configuration. The magnifying optical system 17 is also designed to be optimized for the tilt angle θ1 of the intermediate screen 16 tilted with respect to the optical axis AX.

  The projection optical system 15 has a predetermined depth of focus equal to or larger than the moving range of the functional area FA so that defocusing does not occur due to the position of the intermediate screen 16 or the diffusion surface 16m provided in the diffusion unit 19.

  The screen cover 19b has a cylindrical outer contour and is composed of a cylindrical side surface portion 19e and a pair of disc-shaped end surface portions 19g and 19h. The side surface portion 19e does not have to be light transmissive and can be formed of a light shield. The pair of end face portions 19g and 19h are made of a material having high transparency in the visible wavelength range and allow the display light HK which is a visible light to pass therethrough. The pair of end surface portions 19g and 19h are parallel flat plates, but may have a free-form surface shape or an aspherical surface shape. The rotating body 19a in the screen cover 19b is fixed to the screen cover 19b via a pair of central shaft portions 65, and the screen cover 19b and the rotating body 19a rotate integrally around the rotation axis SX. As described above, by disposing the rotating body 19a provided with the diffusion surface 16m in the screen cover 19b, it is possible to suppress dust and the like from adhering to the rotating body 19a, and suppress the generation of sound accompanying the rotation of the rotating body 19a. It is possible to stabilize the rotation of the rotating body 19a at high speed. The rotating body 19a may be fixed to the screen cover 19b at the outer peripheral portion thereof.

  Returning to FIG. 2, the magnifying optical system 17 magnifies the intermediate image TI formed on the diffusing unit 19 in cooperation with the display screen 20, and displays a virtual image through the display screen 20 in front of the driver DR. Form IM. The magnifying optical system 17 includes at least one mirror, but includes two mirrors 17a and 17b in the illustrated example. Further, the two mirrors 17a and 17b forming the magnifying optical system 17 have a free-form surface shape and are designed to be optimized for the tilt angle of the intermediate screen 16.

  In the head-up display device 100 shown in FIG. 2 and the like, by rotating the diffusing unit 19 around the rotation axis SX at a constant speed by the rotation driving unit 64, the diffusing surface 16m of the rotating body 19a or the intermediate screen 16 is made to be the optical axis AX. The position intersecting with (specifically, the functional area FA shown in FIG. 3A and the like) also moves in the optical axis AX direction. That is, as shown in FIG. 3C, the functional area FA on the intermediate screen 16 is adjacent to the original functional area FA1 at a position offset by an equal angle with the rotation of the rotating body 19a. The functional areas FA2 and FA3 are sequentially shifted and moved in the optical axis AX direction. By moving the functional area FA in the optical axis AX direction, the position of the intermediate image TI can also be moved in the optical axis AX direction. By rotating the diffusion unit 19 around the rotation axis SX, the position of the intermediate image TI corresponding to the functional area FA repeatedly and cyclically moves in the optical axis AX direction, and the magnifying optical system 17 moves the position behind the display screen 20. It is possible to increase or decrease the distance between the display image IM as a virtual image formed and the driver DR who is the observer. That is, the virtual image projection position of the display image IM is changed. In this way, under the control of the display control unit 18, the virtual image projection position of the projected display image IM is changed back and forth, and the display content by the display element 11 is adapted to the position, so that The display content of the display image IM is changed while changing the projection distance or the virtual image distance to the intersection point of the display image IM with the optical axis AX while displaying the display image IM that has fallen in the back. The display image IM of can be three-dimensional.

  FIG. 5 is a diagram specifically exemplifying a change in the center position of the intermediate image TI (intersection point of the intermediate image TI with the optical axis AX) due to the rotation of the diffusion unit 19. The center of the functional area FA of the intermediate screen 16 shown in FIG. 2 is repeatedly moved cyclically along the optical axis AX in a sawtooth pattern with time PA, and the center position of the intermediate image TI is also displayed by the display element 11. In the case where the display is continuously performed, as shown in the drawing, the sawtooth-shaped aging pattern PA is repeatedly moved cyclically along the optical axis AX direction. That is, the center position of the intermediate image TI is discontinuous at the location corresponding to the boundary 16j, but continuously and periodically changes as the diffusion unit 19 rotates. As a result, although not shown, the center position of the display image (virtual image) IM (intersection point with the optical axis AX of the display image IM) has a different scale, but is similar to the center position of the intermediate image TI in the optical axis AX direction. The projection distance can be continuously changed by repeatedly moving along with. Strictly speaking, the display element 11 does not perform continuous display, but performs intermittent display while switching the display content. Therefore, the center position of the intermediate image TI is also discrete on the sawtooth temporal pattern PA. The position. In the temporal pattern PA, the display position Pn closest to the closest distance side or the enlarging optical system 17 and the display position Pf closest to the far distance side or the projection optical system 15 are set at both ends of the temporal pattern PA. Further, the discontinuity PD of the temporal pattern PA corresponds to the boundary portion 16j provided on the rotating body 19a of the diffusion unit 19. Further, the center positions of the functional areas FA1, FA2, FA3 shown in FIG. 3C correspond to the discrete display positions P1, P2, P3 on the temporal pattern PA.

  FIG. 6 is a conceptual diagram illustrating the projection state of the display image IM. The display image IM spreads from a direction of 0 ° near the horizontal direction to a direction of a dip angle of about 4 °, and an angle of view in the vertical direction is about 4 °. The spatial display SI realized by the display image IM is composed of a plurality of display zones IM1 to IM5 that move over time, and 3D display is possible by sequentially displaying the display zones IM1 to IM5 at high speed. Here, the display image IM or the spatial display SI is composed of five display zones IM1 to IM5, but the number of divisions of the display zone is not limited to five, and can be, for example, three, four, or six or more. . As is clear from the figure, by tilting the display image IM or the display zones IM1 to IM5, the horizontal plane HP passing through the pupil HT from the road surface RS while suppressing the movement amount of the center position of the intermediate image TI at a relatively narrow angle of view α. It is possible to cover the space up to, and if traveling on the road is premised, it is possible to display efficiently with a small angle of view. In the display zones IM1 to IM5, the distance width to be displayed is widened from the short distance to the long distance.

  In the case of FIG. 6, the display image IM or the display zones IM1 to IM5 is formed on a curved surface that is convex upward in the vertical YZ cross section, but the diffusion surface 16m is curved or the magnifying optical system 17 has an image surface. By causing the curvature, it can be formed on a curved surface which is convex downward as shown by a chain double-dashed line, and although not shown, it can also be formed on a linear surface. In the case of FIG. 6, the adjacent display zones, for example, the display zones IM2 and IM3 have the area AR1 which partially overlaps with respect to the projection distance, but the projection distance between the adjacent display zones (for example, the display zones IM2 and IM3). Does not have to overlap. However, the larger the number of overlapping display zones or the higher the density of the display zones, the higher the spatial display density of the display image IM, and the higher the degree of freedom of display in the vertical direction perpendicular to the optical axis AX. Regarding the area AR2 in the depth direction, different display is performed in corresponding areas AP1 to AP5 of the display zones IM1 to IM5 along the optical axis AX, for example. This allows different displays in the depth direction for each projection distance. However, common display can be performed in all or part of the corresponding areas AP1 to AP5. For example, when a common display (for example, a frame surrounding a moving object in front) is performed in the corresponding areas AP1 to AP3, if the display is switched at high speed and the overlapping of images is accurate, the visual recognition is near the central corresponding area AP2. It is perceived that the display was made on. Similarly, when a common display is performed in the corresponding areas AP2 to AP4 (for example, a frame surrounding a moving object in front), if the display is switched at high speed and the overlapping of images is accurate, the corresponding area in the center is visually recognized. It is perceived that the display was performed near AP3. In this way, when performing overlapping display in the depth direction, it is desirable to cause the display element 11 to perform the display operation in substantially the same display time for each of the display zones IM1 to IM5 from the viewpoint of maintaining the luminance balance.

FIG. 7 is a diagram illustrating a specific projection distance of the display image IM. The vertical axis represents the position of the diffusing surface 16m of the intermediate screen 16 or the intermediate image TI in the vertical direction or the Z'direction, and the horizontal axis represents the projection distance. Here, the magnifying power of the magnifying optical system 17 is 11 times when the virtual image distance is 4 m and 77 times when the virtual image distance is 24 m. The width of the diffusion surface 16m or the functional area FA in the vertical direction or the Z ′ direction is 26 mm, and the maximum positional difference Δ of the intermediate image TI in the optical axis AX direction is 4.6 mm. Table 1 below explains specific numerical values corresponding to FIG. 7. In Table 1, arrangement examples 1 to 6 corresponding to the curves in the graph of FIG. 7 are listed vertically, and in each of the arrangement examples 1 to 6, the left side indicates the short-distance projection and the right side indicates the long-distance projection. The position in the optical axis direction in Table 1 indicates the amount of movement of the intermediate screen 16 in the optical axis AX direction at each position above and below the intermediate image TI.
[Table 1]

  FIG. 8 is a block diagram illustrating the display system 200 for a mobile body, and the display system 200 for a mobile body 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 will not be described here. The moving body display system 200 is incorporated in a moving body such as an automobile.

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

  The environment monitoring unit 72 is a unit that identifies a vehicle, a bicycle, a pedestrian, etc., which are in the vicinity of the front, and includes an external camera 72a, an external image processing unit 72b, and a determination unit 72c. The external camera 72a is installed in a proper place inside and outside the vehicle body 2 and captures an external image of the front side or the side of the driver DR or the front window 8. The external image processing unit 72b facilitates the processing in the determination unit 72c by performing various image processing such as brightness correction on the image captured by the external camera 72a. The determination unit 72c detects the presence or absence of an object such as a car, a bicycle, or a pedestrian by extracting or cutting out an object from the external image that has passed through the external image processing unit 72b, and determines from the depth information that accompanies the external image. The spatial position of the object in front of the vehicle body 2 is calculated.

  Although not shown, the external camera 72a is, for example, a compound-eye type three-dimensional camera. In other words, the external camera 72a is an array of camera elements each including a lens for image formation and a CMOS or other image pickup element arranged in a matrix, and each has a drive circuit for the image pickup element. The plurality of camera elements that form the external camera 72a are configured to focus at different positions in the depth direction, or to detect relative parallax, for example. By analyzing the state (focus state, object position, etc.), the distance to each region or object in the image can be determined.

  Even when a combination of a two-dimensional camera and an infrared distance sensor is used instead of the compound-eye type external camera 72a as described above, each part (area or object) in the captured screen is displayed in the depth direction. Distance information can be obtained. Further, instead of the compound-eye type external camera 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 (area or object) in the captured image. In addition, by using a single two-dimensional camera to perform imaging while changing the focal length at high speed, it is possible to obtain distance information in the depth direction with respect to each part (region or object) in the captured screen.

  The display control unit 18 operates the virtual image display optical system 30 under the control of the main controller 90 to display the three-dimensional display image IM in which the virtual image distance changes behind the display screen 20. The display image IM can be, for example, a sign such as a frame frame located around the automobile, bicycle, pedestrian, or other object behind the display screen 20 in the depth direction.

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

  According to the head-up display device (display device) 100 of the first embodiment described above, the rotation drive unit 64, which is the arrangement changing device, arranges the intermediate screen 16 in a cross section with an inclination with respect to the optical axis AX. At the same time, the position of the intermediate screen 16 is moved in the optical axis AX direction of the projection optical system 15 to change the virtual image projection position, so that a spatially wide display is possible, and the intermediate screen 16 is moved in the optical axis AX direction. The overall distance width or spread range of the projection distance of the virtual image can be expanded while reducing the amount. Further, by tilting the intermediate screen 16 so that the lower part of the intermediate image TI is arranged on the magnifying optical system 17 side and the upper part of the intermediate image TI is arranged on the projection optical system 15 side, the upper side of the display image IM is relatively far away. The lower side of the display image IM can be projected relatively to the near side while projecting to the side, and display along a horizontal plane such as a road surface becomes possible.

[Example 1]
Examples of the projection optical system, the display element, etc. of the display device of the present invention will be shown below. The projection optical system is designed to be optimized for the tilt angle of the intermediate screen tilted with respect to the optical axis. The overall specifications of the projection optical system, the display element, etc. of Example 1 are shown below.
Effective focal length: 27.342 (mm)
F number: 4.000
Magnification: 6.046
Display device (DMD) tilt: 2.400 (°)
Tilt of object (intermediate image): 15.000 (°)

The data of the lens surfaces of the projection optical system, the display element and the like of Example 1 are shown in Table 1 below. In Table 1 below, the surface number is represented by "Surf. N", the object is represented by "OBJ", the aperture stop is represented by "ST", infinity is represented by "INF", and the total reflection prism is represented by " It is represented by "TIR" and the display element is represented by "DMD". Further, the radius of curvature is represented by “R”, the axial upper surface distance is represented by “D”, and the lens material is represented by “N”.
[Table 1]
Surf. NR (mm) D (mm) N
OBJ INF 142.97
1 110.00 2.62 SLAL18_OHARA
2 -110.00 8.86
3 9.63 4.00 SNPH3_OHARA
4 5.56 3.92
5 (ST) INF 5.80
6 -16.00 4.72 SLAL18_OHARA
7 -10.00 13.22
8 25.00 2.00 SNPH3_OHARA
9 16.00 1.96
10 19.00 4.61 SLAL18_OHARA
11 -70.00 8.02
12 (TIR) INF 15.00 BSC7_HOYA
13 (TIR) INF 2.00
14 (DMD) INF 0.65 B270_SCHOTT
15 (DMD) INF 0.30

  FIG. 9 is a sectional view of the projection optical system 15 and the like of the first example. The projection optical system 15 includes, in order from the object side, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, and a fifth lens L5. An aperture stop ST is arranged between the second lens L2 and the third lens L3. It should be noted that the present embodiment is designed to be optimized with the display element 11 tilted without shifting or tilting the lenses L1 to L5 that form the projection optical system 15. However, in the projection optical system 15, A configuration may be adopted in which at least one of the lenses L1 to L5 is shifted or tilted to minimize the lens.

[Second Embodiment]
The display device according to the second embodiment will be described below. The display device of the second embodiment is a modification of the display device of the first embodiment, and matters not particularly described are the same as those of the first embodiment.

  Referring to FIG. 10, in head-up display device 100, which is a display device, diffusion unit 19 has a flat intermediate screen 216, and is driven by reciprocating drive unit 264, which is an arrangement changing device, in the optical axis AX direction. Move to. However, by tilting the diffusion surface 16m of the intermediate screen 216 or the intermediate image TI so as to rotate clockwise in the drawing with reference to the plane perpendicular to the optical axis AX, the display image IM may be tilted backward at the upper side. It can be in a state.

[Third Embodiment]
The display device according to the third embodiment will be described below. The display device of the third embodiment is a modification of the display device of the second embodiment, and matters not particularly described are the same as those of the second embodiment.

  As shown in FIG. 11, the intermediate screen 216 of the diffusion unit 19 is rotatable about a reference axis TX perpendicular to the paper surface. By rotating the intermediate screen 216 around the reference axis TX by the rotation driving unit 364 which is a layout changing device, the intermediate screen 216 can be moved as a whole in the optical axis AX direction. However, when the intermediate screen 216 moves in the optical axis AX direction, the angle with respect to the optical axis AX changes, and the tilted state of the display image IM also changes.

  Note that the diffusion unit 19 of the first embodiment may be used in the third embodiment. In this case, in the diffusion unit 19, for example, the inclination angle of the conical side surface of the rotating body 19a is changed according to the rotation angle.

[Fourth Embodiment]
The display device according to the fourth embodiment will be described below. The display device of the fourth embodiment is a modification of the display device of the first embodiment, and matters not particularly described are the same as those of the first embodiment.

  Referring to FIG. 12, in head-up display device 100, which is a display device, display element 11 has element displacement portion 464. The element displacement unit 464, which is a layout changing device, moves the display element 11 in the optical axis AX direction in synchronization with the displacement of the intermediate screen 16. Thereby, the intermediate image TI can be accurately focused on the intermediate screen 16 or the diffusion surface 16m, and the F value of the projection optical system 15 can be increased.

  Although the display device as a specific embodiment has been described above, the display device according to the present invention is not limited to the above. For example, the head-up display device 100 can be mounted on a device other than the vehicle body 2.

DESCRIPTION OF SYMBOLS 10 ... Drawing unit, 11 ... Display element, 13 ... Main body optical system, 15 ... Projection optical system, 16,216 ... Intermediate screen, 17 ... Enlargement optical system, 18 ... Display control part, 19 ... Diffusion part, 19a ... Rotating body , 19b ... Screen cover, 20 ... Display screen, 30 ... Virtual image display optical system, 64 ... Rotation drive unit, 72 ... Environment monitoring unit, 90 ... Main control device, 100 ... Head-up display device, 200 ... Mobile display system , 264 ... Reciprocating drive section, 364 ... Rotation drive section, 464 ... Element displacement section, AX ... Optical axis, DR ... Driver, EB ... Eye box, FA, FA1, FA2, FA3 ... Functional area, HK ... Display light, HT ... pupil, IM ... display image, IM1-IM5 ... display zone, SX ... rotation axis, TI ... intermediate image

Claims (12)

A display element for displaying an image to be projected,
A projection optical system for enlarging the image formed on the display element,
An intermediate screen having a diffusing function and arranged on the light exit side of the projection optical system;
A magnifying optical system for magnifying the intermediate image formed on the intermediate screen,
An arrangement changing device for changing the virtual image projection position by moving the position of the intermediate screen in the optical axis direction of the projection optical system while arranging the intermediate screen in a cross-section with an inclination with respect to the optical axis. Prepare,
The display device characterized in that the intermediate screen is inclined so that a lower portion of the intermediate image is arranged on a side of the magnifying optical system and an upper portion of the intermediate image is arranged on a side of the projection optical system in a cross section.   The display device according to claim 1, wherein an inclination angle of the display element is adjusted according to an inclination angle of the intermediate screen.   The display device according to claim 1, wherein the arrangement changing device moves the intermediate screen at a constant inclination angle.   The display device according to claim 1, wherein the arrangement changing device moves the intermediate screen by inclining the intermediate screen with a lower portion of the intermediate screen as a fulcrum in a cross section. .   The display device according to any one of claims 1 to 4, wherein the intermediate screen is provided on a rotating body that rotates about a rotation axis.   A display control unit that displays the image on the display element so that the projection distances partially overlap in adjacent display zones among a plurality of display zones that change the projection distance. 5. The display device according to any one of 5.   7. The display device according to claim 6, wherein the plurality of display zones have a wider distance range to be displayed from a short distance to a long distance.   The display device according to claim 1, wherein the projection optical system has a design optimized for a tilt angle of the intermediate screen tilted with respect to the optical axis.   9. The display device according to claim 8, wherein the projection optical system having a design optimized for the tilt angle of the intermediate screen is configured by tilting the display element with respect to the optical axis.   The projection optical system designed to be optimized for the inclination angle of the intermediate screen is such that the center position of the display element is a position shifted from the optical axis in a plane perpendicular to the optical axis. The display device according to claim 8, wherein the display device is arranged.   The projection optical system having a design optimized for the tilt angle of the intermediate screen is configured by shifting or tilting at least one lens of the projection optical system with respect to the optical axis. The display device according to claim 8.   The display device according to any one of claims 1 to 11, wherein the magnifying optical system has a design optimized for a tilt angle of the intermediate screen tilted with respect to the optical axis.

Images