WO2017061016A1

WO2017061016A1 - Information display device

Info

Publication number: WO2017061016A1
Application number: PCT/JP2015/078677
Authority: WO
Inventors: 平田　浩二; 谷津　雅彦; 一臣金子
Original assignee: 日立マクセル株式会社; 株式会社日立産業制御ソリューションズ
Priority date: 2015-10-08
Filing date: 2015-10-08
Publication date: 2017-04-13

Abstract

Provided is a compact information display device such that distortion including distortion on the reflection surface of a windshield can be eliminated and a highly visible virtual image can be formed for a driver to view. This information display device, which displays virtual video information on the vehicle windshield, includes: an image formation unit for forming the video information; and a virtual image optical system, including the windshield, for displaying the virtual image at the front of the vehicle by reflecting the light emitted from the image formation unit onto the windshield. The horizontal radius of curvature Rh and the vertical radius of curvature Rv of the windshield are different. The virtual image optical system includes a concave mirror that has a curved reflecting surface for cancelling out at least the difference between the horizontal radius of curvature Rh and vertical radius of curvature Rv of the windshield relative to the vehicle body.

Description

Information display device

The present invention relates to an information display device that projects an image on a windshield of an automobile, train, aircraft, or the like (hereinafter also referred to generally as a “vehicle”), and the image is observed as a virtual image through the windshield. The present invention relates to an information display device.

A so-called head-up display (HUD: Head-) that projects image light onto the windshield of an automobile to form a virtual image and displays traffic information such as route information and traffic jam information and automobile information such as fuel remaining amount and cooling water temperature. An Up-Display device is already known from the following Patent Document 1 (Japanese Patent Laid-Open No. 2009-184406).

In this type of information display device, for the purpose of facilitating recognition of information by the driver, virtual images are formed at a plurality of positions according to the driver's visual recognition position, that is, the distance at which the virtual image is formed is determined by the driver. It is required to be matched with the viewing position. For this reason, for example, as disclosed in the following Patent Document 2 (Japanese Patent Laid-Open No. 2015-34919), there is an apparatus that forms an image at a distance (long distance) and a vicinity (short distance) from the driver. is there.

JP 2009-184406 A JP 2015-34919 A

In a moving body such as an automobile, if the driver's viewpoint movement during driving is large, it becomes a so-called side-view driving state and causes a traffic accident. Therefore, the information display position by the information display device (that is, on the windshield) ) Is limited, and the installation space is also limited by the arrangement of other devices and piping. For this reason, downsizing of the information display device itself has been demanded. However, in the information display device described in Patent Document 1, it is necessary to use two video projection devices in order to form virtual images at different viewpoint positions (distances) from the driver. The problem that it will enlarge will arise.

On the other hand, also in the information display device described in Patent Document 2, the image forming means (12) on which the light projected from the information display means is projected is a screen (specifically, a screen made of at least two translucent members). A first screen 14 and a second screen 16), one of these screens being disposed on the light path from the imaging means to the projection member (6: specifically, the windshield), and The other of these screens is arranged at a different distance from the one screen. This complicates the device. In addition, the video projector for projecting information light has poor feasibility, such as including a focus adjustment means (variable focus lens 35) for individually changing the focal length in accordance with the distance of the imaging means. there were.

Further, the reflection surface of the windshield which is the projection target member (6) in Patent Document 2 has a different vehicle body vertical curvature radius and vehicle body horizontal curvature radius, which causes distortion in the displayed image. Was not considered at all. Further, no consideration has been given to the point at which distortion occurs depending on the viewpoint position of the driver.

Therefore, in the present invention, in consideration of the problems in the prior art described above, the apparatus itself is prevented from being enlarged and complicated, distortion including distortion on the reflection surface of the windshield is eliminated, and visual recognition from the driver. An object of the present invention is to provide an information display device capable of forming a high-quality virtual image.

According to the present invention, in order to achieve the above-described object, for example, an information display device for displaying video information of a virtual image on a windshield of a vehicle, the image forming unit for forming the video information, and the image forming unit A virtual image optical system including the windshield for displaying a virtual image in front of the vehicle by reflecting light emitted from the windshield, and a horizontal curvature radius Rh of the windshield, The curvature radius Rv in the vertical direction is different, and the virtual image optical system has a concave reflecting mirror having a reflection curved surface that cancels at least the difference between the curvature radius Rh in the vehicle body horizontal direction and the curvature radius Rv in the vertical direction of the windshield. Is included.

ADVANTAGE OF THE INVENTION According to this invention, the information display apparatus which can suppress the enlargement and complexity of apparatus itself and can form a virtual image with high visibility from a driver | operator including the distortion of the reflective surface of a windshield is provided. Exhibits an excellent effect.

1 is a schematic configuration diagram showing a schematic configuration of an information display device according to a first embodiment of the present invention and peripheral devices assigned to the information display device. It is a top view of the motor vehicle carrying the said information display apparatus. It is a figure for demonstrating the difference in the curvature radius of the windshield of the motor vehicle carrying the said information display apparatus. It is the schematic which shows the area | region which the driver | operator of the motor vehicle carrying the said information display device observes during a driving | operation. It is a block diagram which shows the optical system of the information display apparatus which concerns on 2nd embodiment of this invention. It is a block diagram which shows the optical system of the information display apparatus which concerns on 3rd embodiment of this invention. It is a block diagram which shows the optical system of the information display apparatus which concerns on 3rd embodiment of this invention. It is a block diagram which shows the optical system of the information display apparatus which concerns on other embodiment of this invention. FIG. 9A is an overall ray diagram of the virtual image optical system according to the first embodiment, and FIG. 9A illustrates a state in which video information on the virtual image plane 7 is viewed with an observer's eye on the YZ plane, and FIG. It is the schematic showing a mode that the image | video information of the virtual image surface 7 is seen with an observer's eyes in XZ plane. It is a principal part perspective enlarged view of the optical system of the information display apparatus which concerns on 1st embodiment. It is a partially expanded perspective view of the lens part of the information display apparatus which concerns on 1st embodiment. It is a figure explaining the relationship between a virtual image surface and the virtual image surface seen from the driver | operator, in order to demonstrate the screen distortion performance of the information display apparatus of 1st embodiment. It is a figure showing the distortion performance of the virtual image optical system of the information display apparatus of 1st embodiment. It is a spot figure of the virtual image optical system of the information display apparatus of 1st embodiment.

Hereinafter, an embodiment and various embodiments of the present invention will be described with reference to the drawings. In addition, the following description shows the specific example of the content of this invention, This invention is not limited to these description, The person skilled in the art within the range of the technical idea disclosed by this specification. Various changes and modifications are possible. In all the drawings for explaining the present invention, components having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

<First embodiment>
FIG. 1 is a block diagram and a schematic configuration diagram showing a peripheral device configuration of the information display device 1 according to the first embodiment of the present invention. Here, as an example thereof, an image is projected particularly on a windshield of an automobile. The information display device will be described.

The information display device 1 forms various virtual images V1 to V3 at a plurality of positions in front of the host vehicle in the line of sight 8 of the driver, and thus various types of information reflected by the projection target member 6 (windscreen in the present embodiment). A device (so-called HUD (Headup Display)) that displays information as a virtual image VI (virtual image). The projection target member 6 may be a member on which information is projected, and is not limited to the above-described windshield. That is, in the information device 1 of the present embodiment, a virtual image is formed at each of a plurality of positions in front of the host vehicle in the driver's line of sight 8 and is visually recognized by the driver. As information to be displayed as, for example, vehicle information, a camera such as a surveillance camera or an around viewer (not shown) is used. Including the foreground information.

Further, the information display device 1 includes a video projection device 11 that projects video light for displaying information, an intermediate image imaging unit 4 that forms an image of light from the video display device 11, and the intermediate image imaging unit 4. The optical component 5 that converges or diverges the image information (image light) formed in FIG. 1 and the control device 40 that controls the image projection device 11 are provided. The optical component 5 is a virtual image optical system described below, and includes a concave mirror that reflects light. Further, the light reflected by the optical component 5 is reflected by the projection member 6 and travels toward the driver's line of sight 8 (EyeBox: described in detail later).

The intermediate image formation (or intermediate image display) unit 4 has a function of forming an image of light from the image projection device 11, for example, by a microlens array in which microlenses are arranged two-dimensionally. Composed. In the present embodiment, an optical element 21 and an optical element 22 are disposed between the intermediate image forming unit 4 and the optical component 5 including the concave reflecting mirror forming the eyepiece optical system. The arrangement of the element 21 and the optical element 22 is, for the first purpose, to set the virtual image forming positions at a plurality of positions in front of the host vehicle (three positions in the present embodiment), and further, intermediate image formation. Between the unit 4 and the optical component 5 that forms the eyepiece optical system, each is provided for correcting aberrations at a position where the image light from the intermediate image forming unit 4 is separated. According to the aberration correction by these optical elements, even if virtual images are formed at different positions, a plurality of virtual images can be displayed at different magnifications by using the same virtual image optical system.

More specifically, the aberration of the light beam forming the virtual image V3 located far away is improved by the optical element 21, and at the same time, the aberration correction of the virtual image V2 located in the middle is performed by the optical element 22. In addition, the virtual image V1 formed at the closest position is optimally designed for aberration correction in the original virtual image optical system, so no optical element is provided here, however, it is optimal for further improving the aberration correction capability. Needless to say, the provision of the designed optical element does not depart from the technical idea or scope of the present invention.

Further, in the present embodiment, for convenience of explanation, an example in which the generation position of the virtual image is divided into the far virtual image V3, the intermediate virtual image V2, and the near virtual image V1, and the

optical elements

21 and 22 are individually provided, has been described. However, the present invention is not limited to this. For example, in order to continuously change the display position of the virtual image from a distant place to a close position, the position where the virtual image is continuously generated is changed by changing the spatial optical distance. Needless to say, even if a common optical element is provided in order to sufficiently reduce aberration so as to change, it does not depart from the technical idea or scope of the present invention.

On the other hand, the control device 30 includes a storage device 31 and a microcomputer (hereinafter referred to as “microcomputer”) 32. The storage device 31 is a non-volatile storage device that can rewrite stored contents. The microcomputer 32 includes a ROM 34 that stores processing programs and data that need to retain stored contents even when the power is turned off, a RAM 33 that temporarily stores processing programs and data, and processes stored in the ROM 34 and PAM 33. It is mainly configured by a computer having a CPU 35 that executes various processes according to a program.

Among these, the ROM 34 stores a processing program for the microcomputer 44 to execute information display processing for controlling the video projection device 11 so that various information such as vehicle information and foreground information is projected onto the projection target member 6. ing. The control device 30 is connected with at least a navigation system 41 and a driving support electronic control device (hereinafter referred to as “driving support ECU (Electronic Control Unit))” 42 as an acquisition source of vehicle information and foreground information. Yes.

The navigation system 61 is a device that guides a route to a set destination according to the result of collating the current position detected by the position detection device with the map data stored in the map data storage unit. The map data includes various information such as information on road speed limits, the number of lanes, and intersections.

From such a navigation system 61, the control device 30 obtains information such as the speed limit and number of lanes of the road corresponding to the current position where the host vehicle is traveling, the planned travel route of the host vehicle set in the navigation system 51, and the like. Obtained as foreground information (that is, information displayed in front of the host vehicle by the virtual image).

The driving support ECU 62 is a control device that realizes driving support control by controlling the drive system and the control system in accordance with the obstacle detected as a result of monitoring by the periphery monitoring device 63, and cruise control is used as the driving support control. , Including well-known technologies such as adaptive cruise control, pre-crash safety, lane keeping assistance.

The periphery monitoring device 63 is a device that monitors the situation around the host vehicle. As an example, a camera that detects an object around the host vehicle based on an image obtained by shooting the periphery of the host vehicle, an exploration wave, and the like. An exploration device that detects an object that exists in the vicinity of the host vehicle based on the result of transmitting and receiving the vehicle.

The control device 30 acquires such information from the driving support ECU 62 (for example, the distance to the preceding vehicle, the heading direction of the preceding vehicle, the position where the obstacle or sign is present, etc.) as the foreground information. Further, an ignition (IG) signal and own vehicle state information are input to the control device 30. Among these pieces of information, the own vehicle state information is information acquired as vehicle information, and represents, for example, that a predetermined abnormal state such as the remaining amount of fuel in the internal combustion engine or the temperature of the cooling water has been entered. Contains warning information. Information such as the operation result of the direction indicator, the traveling speed of the host vehicle, and the shift position is also included. The control device 30 described above is activated when an ignition signal is input. The above is the description of the entire information display apparatus system of the present invention.

<Details of virtual image optical system>
Next, further details of the virtual image optical system and the video display device of the present embodiment will be described below.

FIG. 2 is a top view of an automobile equipped with the information display device of the present embodiment, and a windshield as the projection member 6 exists in the front part of the driver's seat of the automobile body 101. The windshield has a different inclination angle with respect to the vehicle body depending on the type of automobile. Furthermore, the inventors investigated the radius of curvature in order to realize an optimal virtual image optical system. As a result, as shown in FIG. 3, the windshield has a horizontal radius of curvature Rh parallel to the ground contact surface of the automobile and a vertical radius of curvature Rv perpendicular to the horizontal axis. It was found that Rv generally has the following relationship.
Rh> Rv

It was also found that the difference in radius of curvature, that is, Rh relative to Rv is often in the range of 1.5 to 2.5 times.

Next, the inventors investigated a commercial product for the inclination angle of the windshield. As a result, although it differs depending on the body type, it was 20 to 30 degrees for light cars and 1 Box type, 30 to 40 degrees for sedan type, and 40 degrees or more for sports type. Therefore, in the present invention, considering the difference between the curvature radius Rh in the horizontal direction parallel to the ground contact surface of the windshield and the curvature radius Rv in the vertical direction perpendicular to the horizontal axis and the inclination angle of the windshield, A virtual image optical system was designed.

More specifically, since the horizontal curvature radius Rh and the vertical curvature radius Rv of the windshield which is the projection member are greatly different, the horizontal axis of the windshield and the axis perpendicular to this axis with respect to the optical axis (Z axis). Aberrant aberration correction was achieved by providing an axially asymmetric optical element in the virtual image optical system. Furthermore, a favorable aberration correction was realized by tilting the reflecting surface using a windshield as a projection member in the virtual image optical system as an optical component. The lens data of the obtained virtual image optical system are shown in Tables 1 to 3 below.

These Tables 1 to 3 are diagrams showing lens data according to an embodiment of the virtual image optical system that realizes the information display device of the present invention. In the lens data shown in Table 1, the radius of curvature is represented by a positive sign when the center position of the radius of curvature is in the traveling direction, and the inter-surface distance is the light from the vertex position of each surface to the vertex position of the next surface. Expressed as a distance on the axis.

Eccentricity is a value in the Y-axis direction, tilting is rotation about the X axis in the YZ plane, and eccentricity / falling acts in the order of eccentricity and tilting on the corresponding surface. The next surface is placed at the position of the inter-surface distance on the new coordinate system on which. The decentration and return eccentricity and collapse will only affect one aspect and not the next. Further, the glass material name PMMA is a plastic acrylic (Polymethyl methacrylate).

The windshield, which is the projection target, is defined as an anamorphic aspherical surface with different radii of curvature on the X and Y axes, the horizontal radius of curvature is 9686 mm, the vertical radius of curvature is 5531 mm, and each center of curvature is the X axis. The angle was defined as -340 mm in the direction, -1959 mm in the Y-axis direction, and inclined by 43.7 degrees.

Table 2 is a table of free-form surface coefficients of the virtual image optical system according to the embodiment. The free-form surface coefficient in Table 2 is obtained by the following equation (1).

Free-form surface coefficient C _j is a rotationally asymmetric shape with respect to each of the optical axis (Z axis), a shape defined by the component sections of the component and the XY polynomial conical section. For example, when X is second order (m = 2) and Y is third order (n = 3), the coefficient of C ₁₉ corresponding to j = {(2 + 3) ² + 2 + 3 × 3} / 2 + 1 = 19 corresponds. The position of each optical axis of the free-form surface is determined by the amount of decentering / falling in the lens data in Table 1.

Table 3 is a table showing odd-order aspheric coefficients of the virtual image optical system according to the embodiment of the present application. The free-form surface coefficient in Table 3 is obtained by the following equation (2).

Further, the anamorphic aspheric coefficient of the virtual image optical system corresponding to the windshield 6 according to the embodiment of the present invention is obtained by the following expression (3). Note that cuy (= 1 / rdy) and cux (= 1 / rdx) in the following expression (3) are rdy = 9666 mm and rdx = 5531 mm described in Table 1 above, and other coefficients are all 0. did.

In order to optically cancel the anamorphic property of the windshield 6 described above, the reflecting mirror provided in the virtual image optical system was formed into a cylinder shape.

Further, the values of the monitoring range (eye box size) and the viewing angle obtained by the virtual image optical system according to the embodiment of the present invention are shown in the horizontal direction and the vertical direction as follows.

Eye box size 100 × 50mm
Effective size of image light on screen plate 40.30 × 18.86mm
Virtual image size on the tangent plane 1603 × 534mm
Viewing angle (full angle of view) 5.4 x 1.8 degrees

Next, the optical performance of this embodiment will be described with reference to FIGS. FIG. 12 is a diagram for explaining the relationship between the virtual image plane 7 and the virtual image plane 7 viewed from the driver 8 in order to explain the screen distortion performance, and FIG. 13 is a virtual image optical system according to the embodiment of the present invention. FIG. 14 is a spot diagram of the virtual image optical system.

The screen distortion performance on the curved virtual image surface 7 shown in FIG. 12 is a large amount of distortion as shown in FIG. 13B, but the virtual image surface 7 itself has a curved surface shape. It differs from the apparent distortion performance when seen by a certain driver. For this reason, the distortion performance on the projection virtual image plane 70 on the tangential plane in contact with the virtual image plane 7 was calculated based on the position of the eyes of the driver who actually drives the car. The result is shown in FIG. The distortion seen from the driver's eyes is a level with no problem in practice, which is a sufficiently rectangular shape.

13A and 13B show how an object point is arranged on the virtual image plane 7 and how the rectangular frame on the intermediate image imaging unit 4 is distorted on the virtual image plane 7. Further, the size of the virtual image in FIGS. 13A and 13B is 1020 mm in the horizontal direction and 155.6 mm in the vertical direction on the cross line including the optical axis, and therefore the distance from the driver's eye 8 to the virtual image plane 7. Calculated at 5000 mm, the horizontal viewing angle is 11.6 degrees (= atan (1020/2/5000)) and the vertical viewing angle is 1.8 degrees (= atan (155.6 / 2/5000)), which is large. It can be seen that the viewing angle is realized.

FIG. 14 is a spot diagram showing the result of calculating the spot (light ray condensing degree) at the intermediate image forming unit 4 by placing an object point on the virtual image plane 7 and realizing good optical performance. Yes. In this spot diagram, the spot is formed by the total luminous flux that passes when the range (eye box) 9 in which the observer can monitor the virtual image is 110 mm horizontal × 50 mm vertical. On the other hand, in the case of a virtual image viewed by an actual supervisor (driver), the spot obtained by filtering even by the size of the iris of the human eye (which is said to be φ7 mm at the maximum) is much larger than that in FIG. Get better.

Subsequently, the configuration of the above-described virtual image optical system will be described with reference to FIG. FIG. 9 is an overall ray diagram of the virtual image optical system 5 according to the first embodiment of the present invention. In particular, FIG. 9A shows the image information of the virtual image plane 7 on the YZ plane as viewed by the observer's eyes. FIG. 9B shows a state in which the video information on the virtual image plane 7 is viewed with an observer's eyes on the XZ plane. The right eye and the left eye overlap on the YZ plane (see reference numeral 8), and the right eye and the left eye appear separately on the XZ plane.

Further, FIG. 10 is an enlarged view of a main part of the virtual image optical system 5 of the first embodiment, and FIG. 11 is an enlarged perspective view of a lens part constituting the eyepiece optical system 5a constituting the virtual image optical system in FIG. FIG. As shown in FIGS. 10 and 11, each of the free-form surface lens 54 and the free-form surface mirror 56 is configured in a rotationally asymmetric shape. The convex lens 51 and the concave lens 52 have a large amount of eccentricity (no eccentricity on the front and rear surfaces).

As shown in FIG. 11, the virtual image optical system 5 includes a convex lens 51 having a positive refractive power, a concave lens 52 having a negative refractive power, and a convex lens 53 having a positive refractive power in order from the intermediate image display unit 4 side. A rotationally asymmetric free-form surface lens 54, a cylinder mirror 55, and a rotationally asymmetric free-form surface mirror 56 are arranged side by side with the windshield 6. And the difference of the curvature radius of the horizontal direction and the vertical direction of the windshield 6 mentioned above is set as the structure canceled by adding the cylinder mirror 55. FIG. Furthermore, the rotationally asymmetric free-form surface mirror 56 of the reflecting surface has a trapezoidal distortion correcting action.

<Image projection device>
In the embodiment described in detail above, the image projection device 11 modulates the intensity of light in accordance with the image signal by using an image display element such as a small liquid crystal panel or DMD (Digital Mirror Device). The light is enlarged and projected onto the intermediate image display unit 4 by the projection means. Alternatively, image information similar to that described above may be obtained by scanning light source light with a micro mirror of MEMS (Micro Electro Mechanical Systems). Furthermore, a flat display such as a single plate LCOS (Liquid Crystal On Silicon) or an OLED (Organic Light Emitting Diode) provided with a TFT color liquid crystal panel or a color filter may be used. The (video display unit) becomes the intermediate image display unit 4. In this case, when the image display unit itself is the image source of the virtual image optical system and the display surface is a flat surface, the design freedom is inclined with respect to the optical axis of the virtual image optical system and the inclination of the windshield is taken into consideration. Thus, there is a degree of freedom such as correction of trapezoidal distortion.

That is, for the video representing the display information, the video light from the video projection device 11 is displayed on the same surface of the intermediate image display (imaging) unit 4 and the information is displayed as a virtual image. For this purpose, the virtual image optical system 5 is optimally designed including the automobile windshield 6 which is the final reflecting surface. For this reason, the best image plane of the projection means and the image plane obtained by scanning are made to substantially coincide with the planar shape of the intermediate image display unit 4, and other than the planar shape, for example, a spherical surface, an aspherical surface, and a free curved surface. Accordingly, the degree of freedom in designing the virtual image optical system 5 can be increased.

Here, the above-described virtual image optical system will be described again. That is, the virtual image optical system performs an optimal design including the difference between the curvature radius in the vehicle horizontal direction and the curvature radius in the vertical direction of the windshield 6 that has been the projection target member, and the windshield 6 and the image display unit or A concave mirror 56 with a concave surface facing the windshield exists between the intermediate image display unit 4 and the image projected on the video display unit or the intermediate image display unit 4 is enlarged and reflected on the windshield 6. . A plurality of optical elements are arranged between the concave mirror 56 and the video display unit or intermediate image display unit 4. As a result, the image light beam forming the enlarged image (virtual image) of the image formed corresponding to the viewpoint position of the driver passes through the optical element disposed between the image display device or the intermediate image display unit. Are arranged so as to pass through positions separated from each other, and by performing optimum aberration correction obtained by dividing the optical element corresponding to each light beam, visibility corresponding to a plurality of viewpoint positions of the driver It is possible to obtain a high virtual image.

More specifically, in the first embodiment, the virtual image obtained by being reflected by the upper part of the windshield 6 (the upper part in the vehicle body vertical direction) needs to be formed farther away. For this reason, in order to favorably image the image light flux emitted from the upper part of the image display unit or the intermediate image display unit 4 on which the corresponding image is displayed, the above-described concave mirror 56 and the image display unit or intermediate The composite focal length f1 of the plurality of optical elements arranged between the image display units 4 is short. On the contrary, the virtual image obtained by being reflected by the lower part of the windshield 6 (the lower part in the vehicle body vertical direction) is closer to the vicinity. It is necessary to form an image. For this reason, in order to favorably form the image light flux diverged from the lower part of the image display unit and the intermediate image display unit 4 on which an image corresponding to this is displayed, the above-described concave mirror 56 and the image display unit or intermediate The combined focal length f2 of the plurality of optical elements arranged between the image display units 4 is preferably set long. In other words, the relationship between the two is preferably set so that f1 <f2. In order to realize the above-described object of the present invention, as described above, the video display unit and the intermediate image display unit 4 may be divided into some pieces to display necessary information. Alternatively, it may be configured to display information continuously.

Furthermore, in the embodiment shown in FIG. 1, the virtual image V3 obtained by being reflected on the upper part of the windshield 6 (upper part in the vehicle body direction) needs to be formed further away. For this reason, in order to form an image light beam diverging from the upper part of the intermediate image display unit 4 on which an image corresponding to this is displayed, it is disposed between the concave mirror 56 and the intermediate image display unit 4 described above. The combined focal length f1 of the plurality of optical elements is short, and on the contrary, the virtual image V1 obtained by being reflected by the lower part of the windshield 6 (lower part in the vehicle body vertical direction) needs to be formed closer to the image. For this reason, in order to form an image light beam diverging from the lower part of the intermediate image display unit 4 on which an image corresponding to this is displayed, it is disposed between the concave mirror 56 and the intermediate image display unit 4 described above. The combined focal length f2 of the plurality of optical elements is set to be relatively long.

In addition, in the present embodiment, the screen of the virtual image that the driver sees because the curvature radius of the windshield 6 in the horizontal direction (parallel to the ground) and the curvature radius in the vertical direction (direction perpendicular to the windshield horizontal direction) are different. In order to correct the distortion, optical elements having different axial symmetry with respect to the optical axis are arranged in the virtual image optical system 5 described above, thereby realizing the correction of the distortion described above.

Furthermore, the distortion of the displayed characters and figures caused by the shape of the reflection surface of the windshield 6 described above is caused by changing the aspect ratio of the characters and the figures according to the position of the display image, so that the virtual image that the driver sees is changed. The shape can be expressed more naturally (with a more correct aspect ratio).

<Second Embodiment>
Next, the basic structure of the optical system of the information display apparatus according to the second embodiment of the present invention will be described with reference to FIG. The optical system shown in FIG. 5 includes an image forming unit 10 and an eyepiece optical system 5a constituting the virtual image optical system 5. Thus, the image light emitted from the projection optical system 20 is reflected on the windshield 6 of an automobile (not shown) and is incident on the driver's eyes 8.

More specifically, the light beam emitted from the backlight 1 to the liquid crystal display panel 2 is incident on the relay optical system 3 as an image light beam including video information displayed on the liquid crystal display panel 2. The image information on the liquid crystal display panel 2 is enlarged by the imaging action in the relay optical system 3 and then enlarged and projected onto the intermediate image imaging unit 4. The points P1, P2, and P3 on the liquid crystal display panel 2 correspond to the points Q1, Q2, and Q3 of the intermediate image forming unit 4, respectively. By using the relay optical system 3, a liquid crystal display panel having a small display size can be used. Since the backlight 1, the liquid crystal display panel 2, the relay optical system 3, and the intermediate image forming unit 4 form image information (video information) on the intermediate image forming unit 4, they are collectively referred to as an image forming unit. Say ten.

Next, the image information on the intermediate image forming unit 4 is projected onto the windshield 6 by the virtual image optical system 5, and the light beam reflected by the windshield 6 reaches the position of the eye 8 of the observer. When this is viewed from the eyes of the observer, a relationship is established as if viewing image information of the virtual image plane 7 in front of the host vehicle. Points Q1, Q2, and Q3 on the intermediate image forming unit 4 correspond to points V1, V2, and V3 on the virtual image plane 7, respectively. The range in which the points V1, V2, and V3 on the virtual image plane 7 can be seen even if the observer moves the position of the eye 8 is a so-called eye box 9. As described above, the virtual image optical system 5 is an optical system that displays an object (aerial image) and an image (virtual image) in front of an observer's eyes, like an eyepiece lens of a camera finder or an eyepiece lens of a microscope. is there.

Further, the intermediate image forming unit 4 is configured by a microlens array in which microlenses are two-dimensionally arranged. As a result, a diffusing action occurs, the spread angle of the light beam emitted from the intermediate image forming unit 4 is increased, and the size of the eyebock 9 is set to a predetermined size. The diffusing action of the intermediate image forming unit 4 can also be realized by incorporating diffusing particles.

That is, in the second embodiment, the aberration correction optical system corresponds to the virtual image generation position between the intermediate image forming unit 4 side of FIG. 5 and the eyepiece optical system 5a constituting the virtual image optical system 5. Arrange the elements. More specifically, by disposing the correction optical element 21 at the position where the light beam corresponding to V3 located farthest passes, the virtual image generation position of the virtual image optical system 5 is moved far away to increase the magnification. At the same time, distortion and aberration generated in the virtual image are reduced. Next, a correction optical element 22 is disposed at a position where the light beam corresponding to the virtual image V2 established at the intermediate position passes, thereby establishing the virtual image generation position of the virtual image optical system 5 at the intermediate position and increasing the medium magnification. At the same time, distortion and aberration generated in the virtual image are reduced. In other words, the eyepiece optical system that constitutes the virtual image optical system 5 so that the correcting optical element does not have to be disposed at the position where the light beam corresponding to the virtual image V1 formed closest to the observer passes. 5a is optimally designed.

More specifically, the eyepiece optical system 5a is optimally designed for the virtual image V1 that is formed closest to the reference. On the other hand, the correction is made for V2 that is established at an intermediate distance and V3 that is established at a far distance.

Optical elements

21 and 22 are disposed. As described above, the arrangement of the correction

optical elements

21 and 22 shortens the optical distance between the intermediate image forming unit 4 and the eyepiece optical system 5a, so that the magnification of the virtual image is increased. Not only is it advantageous, it is optimal for correcting distortion and aberration of the virtual image established at each image position.

That is, in the present embodiment, the light beam corresponding to the virtual image V3 formed in the distance, the light beam corresponding to the virtual image V2 formed in the middle, and the light beam corresponding to the virtual image V1 formed in the vicinity are separated, and the virtual image optics By disposing an optical system for correction corresponding to each virtual image at a position incident on the system 5, distortion and aberration correction of the virtual image is performed. Even if the virtual image formation position is continuous from a distance to the vicinity, the optical distance between the virtual image optical system 5 and the intermediate image forming unit 4 is changed corresponding to each virtual image formation position, and the correction optical element is arranged. It should be obvious to those skilled in the art that the present invention is not deviated from the technical idea or scope of the present invention.

<Third embodiment>
Next, the optical system of the information display apparatus according to the third embodiment of the present invention will be described in detail below with reference to the attached FIG. 6 and FIG.

6 uses a flat display (for example, a liquid crystal display panel) 4a as an image source. The light beam emitted from the backlight 1 enters the eyepiece optical system 5a constituting the virtual image optical system 5 as a video light beam including video information displayed on the liquid crystal display panel 4a. In this embodiment, similarly to the second embodiment, an aberration correcting optical device is provided between the liquid crystal display panel 4a and the eyepiece optical system 5a constituting the virtual image optical system 5, corresponding to the virtual image generation position. Arrange the elements. Specifically, a correction optical element 24 is disposed at a position where a light beam corresponding to V3 located at the farthest position passes, thereby increasing the magnification by moving the virtual image generation position of the virtual image optical system 5 far away. At the same time, distortion and aberration generated in a virtual image are reduced.

Next, an optical element 23 for correction is disposed at a position where the light beam corresponding to the virtual image V2 established at the intermediate position passes, and thereby, the virtual image generation position of the virtual image optical system 5 is established at the intermediate position to increase the medium magnification. At the same time, distortion and aberration generated in a virtual image are reduced. Finally, no correction optical element is disposed at a position where a light beam corresponding to the virtual image V1 formed closest to the observer passes. That is, the eyepiece optical system 5a constituting the virtual image optical system 5 is optimally designed so that the correcting optical element does not have to be disposed at the position where the light beam corresponding to the virtual image V1 passes.

As described above, the virtual image optical system 5 is optimally designed with respect to the virtual image V1 that is formed closest to the observer so as to be the design reference of the virtual image optical system 5, and the virtual image optical system 5 is formed at V2 that is established at an intermediate distance and far away. For V3, arranging the correction optical elements respectively shortens the optical distance between the intermediate image forming unit 4 and the virtual image optical system 5 as in the second embodiment. This is advantageous not only for increasing the magnification of a virtual image but also for correcting distortion and aberration of the virtual image established at each image position.

In the present embodiment, the image plane corresponding to the intermediate image forming unit 4 described above is configured as a flat panel display. Specifically, a single plate provided with a TFT color liquid crystal panel and a color filter is provided. It is composed of a flat display such as LCOS (Liquid Crystal On Silicon) and OLED (Organic Light Emitting Diode). According to such a configuration, it is possible to realize an information display device that is excellent in use efficiency of light from the light source. Note that the display screen size may be, for example, about 1 inch to 5 inches, and preferably about 3 inches in consideration of effective use of image light.

Next, in the information display apparatus shown in FIG. 7, a plurality of flat displays (for example, liquid crystal display panels) 4b and 4c are used as video sources. The light beams emitted from the

backlights

1b and 1c enter the virtual image optical system 5 as video light beams including video information displayed on the liquid

crystal display panels

4b and 4c. The operations of the virtual image optical system 5 and the correction optical elements corresponding to the virtual images V3, V2, and V1 are the same as those shown in FIG. 6, and description thereof is omitted here.

As described above, by using a plurality of liquid crystal display panels as video sources, the following specific effects can be obtained.

First, the composition resolution can be increased by using a plurality of liquid crystal display panels as video sources. As a result, since the amount of information of the entire virtual image can be increased, it is possible to establish a virtual image over almost the entire area of the windshield 6 as shown in FIG.

Normally, a virtual image is formed in the image display area 1 (a) or both of the image display areas 1 (c), 1 (a), and 1 (c) without forming a virtual image on the entire surface of the windshield 6. Let As a result, as shown in FIG. 4, the video information and alert information from the periphery monitoring apparatus shown in FIG. Information from the system can be displayed and virtual reality can be realized. In addition, information on pedestrians that may cause problems in driving safety when attempting to make a right turn is recognized by the perimeter monitoring device, and then alert information is displayed on the captured video information to assist safe driving. It becomes.

Further, for a car 102 traveling from the left in the direction of travel, if there is a safety problem, the driver's safety may be displayed, for example, by intermittently displaying a warning image in the image display area 2 of FIG. It can be used to enhance awareness.

Second, the virtual image formation position and the magnification obtained can be controlled by arranging them at desired positions within the object plane range of the virtual image optical system.

Third, by tilting the direction of each liquid crystal display panel toward the entrance pupil direction of the eyepiece optical system 5a, the use efficiency of image light can be improved and a bright virtual image can be obtained. Similarly, the degree of freedom of design can be improved by tilting the liquid crystal display panel so as to be advantageous in correcting aberrations and distortions of virtual images that are formed depending on the position of the liquid crystal display panel.

As a result, compared to the example shown in FIG. 6, the degree of freedom of design in the virtual image optical system is increased, and further, the resolution performance and the degree of freedom of aberration correction and distortion correction can be improved. The formation position of the virtual image when viewed from the viewpoint can be established at a desired position.

In the example shown in FIG. 7, an example in which two liquid

crystal display panels

4 b and 4 c are arranged in parallel is described. However, the present invention is not limited to this, and these are not included in the virtual image optical system 5. Needless to say, the correction optical element described above may be inserted in the space between the optical axis and moved in the optical axis direction. It is also effective to improve the degree of freedom of distortion correction and aberration correction by tilting each liquid crystal display panel with respect to the optical axis of the virtual image optical system.

As described above, in this embodiment, a high-resolution information display device can be realized at low cost by arranging a plurality of small video display elements to form a video display device. Furthermore, the generation position and magnification of the virtual image when viewed from the driver can be appropriately controlled by appropriately selecting the arrangement location of the plurality of video display elements with respect to the virtual image optical system described above. . It is also possible to obtain a desired resolution by combining a plurality of small flat displays. Furthermore, in the information display apparatus using a plurality of small flat displays, the above-described virtual image generation position and magnification can be controlled by changing the location where the small flat display is disposed with respect to the virtual image optical system.

<Other embodiments>
FIG. 8 is a cross-sectional view showing an outline of the entire configuration including the liquid crystal display panel 4a and the backlight 1 as a video light source as still another embodiment of the present invention. The light emitted from the white LED 46, which is a solid light source, has its divergence angle suppressed by the action of the light funnel 44, and the intensity distribution is made uniform. Then, the light is substantially parallel light on the optical element 43, and is further aligned with a single polarization in the PBS 45 for polarization conversion. Thereafter, the light is reflected by the reflecting surface 41 and is incident on the liquid crystal display panel 4a. At this time, an optical element 17 for controlling the incident angle of the light beam to the liquid crystal display panel 4a is provided so that the image light beam obtained by the liquid crystal display panel 4a has excellent contrast performance.

That is, in an image display device using only a specific polarization such as a single-plate LCOS (Liquid Crystal On Silicon) provided with a TFT color liquid crystal panel or a color filter, or an OLED (Organic Light Emitting Diode), the light source light is converted into polarized light. By providing an optical element for extracting only a desired polarization component between the light source and the video display device, the light source light can be effectively used. Further, by controlling the divergence angle of the light source light and using only the angle component having high contrast performance from the output light from the above-mentioned image display device, it is possible to improve the contrast performance of the image.

Furthermore, polarizing plates (not shown) are respectively provided on the light incident surface and the light exit surface of the liquid crystal display element 4a, thereby obtaining an image light beam with excellent contrast performance. Further, a λ / 4 plate 46 is provided on the exit surface of the liquid crystal display panel 4a, thereby making the emitted light circularly polarized. As a result, a good virtual image can be monitored even if the driver wears polarized sunglasses.

In addition, by providing the ultraviolet reflection film or the optical member 47 in which the ultraviolet reflection film and the infrared reflection film are combined at a position closest to the virtual image optical system 5, liquid crystal can be used even when external light (sunlight) is incident. An information display device can be realized in which the display panel and the polarizing plate can be reduced from damage due to the temperature rise, and the reliability is not impaired.

Finally, the reflection surface of the windshield 6 has a different viewpoint position of the driver, such as when the driver is replaced, and therefore there are cases where a plurality of viewpoint positions must be taken into consideration. In such a case, since the center position of the vehicle body vertical direction radius of curvature and the vehicle body horizontal direction radius of curvature of the windshield and the position of the driver's eyes are different, the distortion of the image obtained by the virtual image is different. In order to solve such a problem, for example, it is conceivable to provide a camera or the like (not shown) that can measure the viewpoint position of the driver in a car. In this case, the distortion generated in the virtual image is calculated in advance by measuring the position of the driver's pupil measured by the camera, and the display image on the video display device may be distorted so as to correct the distortion. In addition, what is necessary is just to perform these processes by the control apparatus 30 shown in the said FIG.

As described in detail above, according to the information display device of the present invention, a highly visible virtual image can be formed at a plurality of viewpoint positions (different distances) of the driver. Furthermore, according to the information display device of the present invention, it can be realized with a simple configuration as compared with the techniques disclosed in Patent Document 1 and Patent Document 2 described above, and the apparatus structure can be increased in size and complexity as much as possible. Can be suppressed. Further, in the information display device of the present invention, it is not necessary to adjust the focal length of the projection means at a high speed according to the individual image forming means, especially compared to the technique described in Patent Document 2 described above, and it is inexpensive and simple. With such a configuration, a virtual image can be formed at a position suitable for the driver's line of sight such as a short distance (corresponding to the lower part of the windshield) or a long distance (corresponding to the upper part of the windshield) according to the viewpoint of the driver. As a result, it is possible for a user to provide an information display device that is relatively inexpensive and easy to use.

Note that the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Back light, 2 ... Liquid crystal display panel, 3 ... Relay optical system, 4 ... Intermediate image formation (display) part, 5a ... Eyepiece optical system (optical component), 5 ... Virtual image optical system, 6 ... Projection member ( Windshield), 7 ... virtual image plane, 8 ... eye box, 9 ... observer's eye, 10 ... image forming unit, 11 ... video projection device, 17 ... optical element, 20 ... projection optical system, 21 ... optical element, 22 ... Optical element, 23 ... Optical element, 30 ... Control device, 31 ... Storage device, 32 ... Microcomputer, 33 ... RAM, 34 ... ROM, 35 ... CPU, 41 ... Reflecting surface, 42 ... λ / 2 plate, 43 ... Optical Element: 44 ... Light funnel, 45 ... PBS, 46 ... Solid light source, 47 ... Ultraviolet and infrared reflecting sheet, 48 ... λ / 4 plate, 51 ... Convex lens (first optical element), 52 ... Concave lens (second optical) Element), 53 ... convex lens, 54 ... free Curved lens, 55 ... Cylinder mirror (reflection mirror), 56 ... Free-form curved mirror (reflection mirror), 61 ... Navigation system, 62 ... Driving assistance ECU, 63 ... Perimeter monitoring device, V1, V2, V3 ... Virtual image.

Claims

An information display device for displaying virtual image image information on a windshield of a vehicle,
An image forming unit for forming the video information;
A virtual image optical system including the windshield for displaying a virtual image in front of the vehicle by reflecting light emitted from the image forming unit on the windshield,
The horizontal curvature radius Rh and the vertical curvature radius Rv of the windshield are different, and
The virtual image optical system includes at least a concave reflecting mirror having a reflection curved surface that cancels out a difference between a curvature radius Rh in the vehicle body horizontal direction and a curvature radius Rv in the vertical direction of the windshield.
The information display device according to claim 1,
An information display device in which a relationship between a curvature radius Rh in the vehicle body horizontal direction and a curvature radius Rv in the vertical direction of the windshield satisfies the following expression.
Rh> Rv
The information display device according to claim 1,
An information display device comprising a projection optical system in which a relationship between a curvature radius Rh in the vehicle body horizontal direction of the windshield and a curvature radius Rv in the vertical direction satisfies the following expression.
1.5Rv <Rh <2.5Rv
The information display device according to claim 1,
The virtual image optical system further includes an aberration correction optical element disposed at a position where a light beam forming the virtual image is separated.
The information display device according to claim 1,
The virtual image optical system further includes a first optical element having a positive refractive power and a second optical element having a negative refractive power,
An information display device, wherein the first optical element having a positive refractive power, the second optical element having a negative refractive power, and the concave reflecting mirror are arranged in this order from the image forming unit side.
The information display device according to claim 5,
An information display device using a liquid crystal display panel which is a flat display as the image forming unit.
The information display device according to claim 6,
An information display device using a plurality of liquid crystal display panels as the flat display as the image forming unit.
The information display device according to claim 6,
An information display device, wherein a polarizing plate is provided on a liquid crystal display panel which is the flat display as the image forming unit.
The information display device according to claim 8,
An information display device comprising a light funnel in addition to a liquid crystal display panel which is the flat display as the image forming unit.
The information display device according to claim 1,
The image forming unit receives a light source, a transmissive liquid crystal display panel that displays the video information displayed as the virtual image, and a light beam including the image information that is emitted from the light source and transmitted through the liquid crystal panel. An information display device comprising a relay optical system and a screen plate having a diffusion function.
The information display device according to claim 1,
The information display device further comprises means for detecting a position of a pupil of the vehicle driver.
An information display device that displays video information of a plurality of virtual images at different distances on a windshield of a vehicle,
An image forming unit for forming a plurality of the video information;
A virtual image optical system including the windshield for displaying a virtual image in front of the vehicle by reflecting the light emitted from the image forming unit on the windshield,
The virtual image optical system includes an intermediate image forming unit that forms an intermediate image obtained by magnifying and projecting light from the image forming unit, and the magnifying image obtained by magnifying and projecting on the intermediate image forming unit An intermediate image is an optical system that allows a driver to create a plurality of virtual images at different distances and magnifications.
An information display apparatus comprising: an aberration correcting optical element disposed at a position where a light beam forming each of the plurality of virtual images is separated between the windshield and the intermediate image forming unit.
The information display device according to claim 12, wherein
The aberration correcting optical element disposed at a position where the light beams forming the plurality of virtual images are separated between the windshield and the intermediate image forming unit is for correcting the aberration of the virtual image formed at a distant position. An optical display device in which the optical length of the optical element is different from that of the virtual image aberration correcting optical element formed at a position nearer than the far distance.
An information display device for displaying virtual image image information on a windshield of a vehicle,
A flat display for displaying the video information;
A virtual image optical system including the windshield for displaying a virtual image in front of the vehicle by reflecting light emitted from the flat display by the windshield, and
The horizontal curvature radius Rh and the vertical curvature radius Rv of the windshield are different from each other, and
The virtual image optical system includes a canceling optical element that cancels a difference between a curvature radius Rh in the vehicle body horizontal direction and a curvature radius Rv in the vertical direction of the windshield,
In order from the flat display side, a first optical element having a positive refractive power, a second optical element having a negative refractive power, and a projection optical system configured by arranging concave reflecting mirrors side by side, An information display device.