JP2017067944A - Display image generation device and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display image generation device which generates a display image that is visually recognized with ease even with a small optical system mounted therein.SOLUTION: An image display device includes a light source part which emits light from a light source element to a scanning optical system, a scanning optical system which generates an intermediate image on an intermediate screen by an optical flux emitted from the light source part, and a reflection optical element which guides the intermediate image to a combination optical element. The reflection optical element has a shape for guiding the intermediate image to the combination optical element except for a part of it.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display image creation device and an image display device.

  An image display device that is mounted on a moving body such as an automobile, an aircraft, or a ship, and that enables a driver (driver) to visually recognize information useful for maneuvering the moving body with a small amount of line-of-sight movement. It has been known. Such an image display device is generally called a head-up display (hereinafter referred to as “HUD”).

  The HUD creates an image including information on a moving object as an intermediate image, and displays the intermediate image as a virtual image so that the driver can recognize the information. The “information about the moving body” includes information related to what is present in the field of view of the driver of the moving body, information related to the operation of the moving body, and the like. For example, an alarm for notifying the operating state of the moving body is also included.

  In the conventional HUD, as a method for creating an intermediate image, for example, a panel method using an imaging device such as a liquid crystal, a laser scanning method in which a laser beam emitted from a laser diode is scanned by a two-dimensional scanning device, and the like are known. . In the panel method, an intermediate image is created by partially blocking light emission on the entire screen. The laser scanning method creates an intermediate image by assigning “light emission” and “non-light emission” to each pixel. In general, the laser scanning method is more suitable for creating a high-contrast intermediate image.

  The HUD is placed in the driver's forward view. If the moving body is an automobile, the main body of the HUD is arranged inside the dashboard. In the case of an automobile, since structures such as air conditioning ducts and meters are housed inside the dashboard, it is necessary to arrange these structures so that they do not interfere with the HUD. Therefore, it is desirable that the HUD is small.

  In order to reduce the size of the HUD, the optical system included in the HUD may be reduced in size. An apparatus that reduces the entire HUD by reducing some optical elements included in the optical system is known (see, for example, Patent Document 1).

  If the optical system is made smaller as in the HUD of Patent Document 1, the intermediate image becomes smaller. If it does so, the virtual image which a driver | operator visually recognizes becomes small and it becomes difficult to visually recognize information. If the virtual image is enlarged even if the optical system is small, the magnification in the optical system may be increased. However, if the magnification of the optical system is increased, the sensitivity becomes sensitive and fine adjustment of the optical element is difficult.

  As another method of reducing the optical system, there is a method of using a decentered optical system in an observation optical system from an intermediate screen for creating an intermediate image to a driver's viewpoint. If the decentering amount of the decentering optical system is increased, the storage space of the observation optical system can be reduced, so that the HUD can be reduced.

  However, when a decentered optical system is used as the observation optical system, a new problem arises if the decentration amount of the decentered optical system is increased. In general, it is advantageous for a scanning optical system that performs two-dimensional deflection scanning to have symmetry in the main scanning direction from the viewpoint of optical design. For this purpose, it is desirable that the light beam incident on the intermediate screen from the scanning optical system is incident perpendicularly to the intermediate screen in the main scanning direction.

  When the HUD is reduced by increasing the amount of eccentricity of the decentering optical system, the folding mirror included in the observation optical system is decentered when considering from the eye point. When the shape of the area where the folding mirror reflects the intermediate image (light-passing area) is rectangular, when the folding mirror is decentered and arranged obliquely, the folding mirror protrudes in the vertical and horizontal directions. Therefore, the HUD may be increased by using a decentered optical system for the observation optical system.

  An object of the present invention is to provide a display image creation device and an image display device that are capable of creating a display image of a virtual image that is small and easy for an observer to recognize.

  The present invention provides a light source unit that emits light from a light source element to a scanning optical system, a scanning optical system that creates an intermediate image on an intermediate screen by a light beam emitted from the light source unit, and the intermediate image as a coupling optical element. A reflective optical element for guiding, the reflective optical element having a shape for guiding to the coupling optical element except for a part of the intermediate image.

  According to the present invention, it is possible to create an image for displaying a virtual image that is small and easily recognized by an observer.

It is a block diagram which shows the example of embodiment of the image display apparatus containing the display image production apparatus which concerns on this invention. It is a block diagram which shows the example of the light source part with which the said display image production apparatus is provided. It is a block diagram which shows the example of the scanning optical system with which the said display image production apparatus is provided. It is a block diagram which shows the example of the hardware constitutions of the said image production apparatus. It is a functional block diagram which shows the example of a function structure of the said display image production apparatus. It is a top view which shows the example of the optical deflector with which the said display image production apparatus is provided. It is a figure which shows the example of a shape and arrangement example of the reflective optical element with which the said display image production apparatus is provided. It is a diagram showing an example of the relationship between a scanned surface element, a reflective optical element, and a coupling optical element provided in the display image creation device It is an optical arrangement | positioning figure which shows the example of the said image display apparatus. It is a figure which shows the example of arrangement | positioning of the intermediate | middle screen which concerns on another embodiment of the said display image production apparatus, and a sensor. It is a figure which shows arrangement | positioning of the intermediate | middle screen and sensor of the said display image production apparatus with a comparative example. It is a figure which shows the example of arrangement | positioning of the intermediate | middle screen and sensor which concern on another embodiment of the said display image production apparatus. It is an optical arrangement | positioning figure which shows the example of the conventional image display apparatus.

  Hereinafter, embodiments of a display image creation device according to the present invention and embodiments of an image display device including the display image creation device will be described with reference to the drawings. First, HUD1 which is embodiment of the image display apparatus based on this invention is demonstrated.

● Outline of image display device ●
As shown in FIG. 1, the HUD 1 is a device mounted on a moving body such as an automobile, an aircraft, or a ship. The HUD 1 displays information useful for maneuvering the mobile object within the field of view of the operator of the mobile object. Note that “information useful for maneuvering a mobile object” includes information related to information existing in the field of view of the operator of the mobile object, information related to the operation of the mobile object, and the like. For example, an alarm for notifying the operating state of the moving body is also included. In this specification, “information useful for maneuvering a moving object” may be simply referred to as “information”.

  The HUD 1 displays information as a virtual image 2 in a state that can be recognized by the pilot. The virtual image 2 is an image that appears based on the intermediate image, and the intermediate image is an image for displaying the virtual image 2. The HUD 1 includes an intermediate image creation device (display image creation device). Details of the embodiment of the display image creation device will be described later.

  The HUD 1 projects the intermediate image created in the display image creation device as image light onto the pilot's field of view, and displays this as a virtual image 2 in the pilot's field of view. An optical system that projects image light includes an optical element that reflects image light toward the pilot and transmits reflected light (external light) of the surrounding environment that exists in the driver's field of view. This optical element is an element that combines image light and external light so that the operator can see the combined light. With this combined light, the driver recognizes as if the virtual image 2 is at a position away from the position where the image light is projected.

Configuration of Image Display Device As shown in FIG. 1, the HUD 1 includes a light source unit 10, a scanning optical system 20, and an observation optical system 30. As already described, the HUD 1 is a device that displays the virtual image 2 in the field of view of the observer 3 who is the pilot.

  In the present embodiment, a case where the HUD 1 is mounted on an automobile will be described as an example. An intermediate image that is a source of the virtual image 2 in the HUD 1 is created by the concave mirror 31 that constitutes the light source unit 10, the scanning optical system 20, and the observation optical system 30. Therefore, the image creating apparatus 100 which is an embodiment of the display image creating apparatus according to the present invention includes the light source unit 10, the scanning optical system 20, and the concave mirror 31.

  The intermediate image created by the image creation device 100 is projected onto an optical combiner 32 that forms part of the observation optical system 30. The light combiner 32 is a combined optical element that combines the intermediate image and the external light and makes the viewer 3 visible.

  In the present embodiment, a front windshield 50 (so-called windshield) is used as the optical combiner 32. In addition, a dedicated coupling optical element may be arranged in the field of view of the observer 3 as the optical combiner 32.

Overview of the light source unit 10 The light source unit 10 emits a light beam used to create an intermediate image that is the basis of the virtual image 2. If the virtual image 2 is to be a color image, a light beam corresponding to the three primary colors of light necessary for the color image is emitted from the light source unit 10.

Overview of Scanning Optical System 20 The scanning optical system 20 creates an intermediate image for displaying predetermined information in the virtual image 2 based on the light beam emitted from the light source unit 10. In general, the outer shape of the intermediate image is a rectangle such as a rectangle or a square.

Overview of Observation Optical System 30 The intermediate image created in the scanning optical system 20 is enlarged and projected by a concave mirror 31 that is a reflection optical element of the observation optical system 30. The intermediate image thus magnified and projected is reflected toward the observer 3 by the optical combiner 32.

  When the intermediate image is reflected by the optical combiner 32, the virtual image 2 appears at a position different from the physical position of the optical combiner 32 (a position in a direction away from the observer 3). As already described, the information recognizable in the virtual image 2 is information related to the operation of the automobile, for example, navigation information such as the speed, travel distance, and destination display of the automobile.

  The viewpoint of the observer 3 simply indicates a reference viewpoint position (reference eye point). The viewpoint range of the observer 3 is equal to or less than the driver's eye range (JIS D0021) of the automobile.

  Here, a description will be given of a three-dimensional orthogonal coordinate system commonly used in the description of the embodiments according to the present invention. As shown in FIG. 1, the viewing direction of the observer 3 (the forward direction of the moving body) is taken as the Z axis. In this case, the direction from the virtual image 2 toward the observer 3 (retracting direction of the moving body) is the + Z direction, and the line-of-sight direction of the observer 3 (advancing direction of the moving body) is the −Z direction. The left-right direction of the visual field of the observer 3 is defined as the X direction. In this case, the right direction of the observer 3 (the depth direction on the paper surface) is the + X direction, and the left direction of the observer 3 is the −X direction (the front side of the paper surface). The vertical direction of the visual field of the observer 3 is defined as the Y direction. The upward direction of the observer 3 is defined as + Y direction, and the downward direction of the observer 3 is defined as -Y direction.

  In other words, when the mobile body used for the description of the embodiment according to the present invention is an automobile, the width direction of the automobile is the X direction, the height direction of the automobile is the Y direction, and the longitudinal direction of the automobile is Z. The direction. From the viewpoint of the observer 3, the left hand direction is the -X direction, and the right hand direction is the + X direction. The upward direction when viewed from the observer 3 is the + Y direction. The reverse direction of the automobile is the + Z direction, and the traveling direction is the -Z direction.

Next, a detailed configuration of the light source unit 10 will be described with reference to FIG. The light source unit 10 emits an image creation beam 101 used to form a virtual image 2 that is a color image. The image creation beam 101 is one beam of three colors of red (hereinafter referred to as “R”), green (hereinafter referred to as “G”), and blue (hereinafter referred to as “B”). It is a light beam synthesized into

  The light source unit 10 includes a semiconductor laser element that emits laser light of each color as a light source element. The semiconductor laser elements corresponding to each color are referred to as a first laser element 110, a second laser element 120, and a third laser element 130.

  Further, the light source unit 10 includes a coupling lens that suppresses the divergence of the laser light emitted from each laser element. The coupling lenses corresponding to the laser beams of the respective colors are a first coupling lens 111, a second coupling lens 121, and a third coupling lens 131.

  In addition, the light source unit 10 includes an aperture that regulates and shapes the beam diameter of each laser beam from each coupling lens. The apertures corresponding to the respective laser beams are a first aperture 112, a second aperture 122, and a third aperture 132.

  In addition, the light source unit 10 includes a beam combining prism 140 that combines the shaped laser beams of the respective colors and emits an image forming beam 101, and a lens 150.

  The first laser element 110 is a laser element that emits a laser beam that forms a red image. The second laser element 120 is a laser element that emits laser light that forms a green image. The third laser element 130 is a laser element that emits a laser beam that forms a blue image. As each laser element, a laser diode (LD) called an edge emitting laser can be used. Further, a surface emitting laser (VCSEL) can be used instead of the edge emitting laser.

  The wavelength λR of the light beam (laser light) emitted from the first laser element 110 is, for example, 640 nm. The wavelength λG of the light beam (laser light) emitted from the second laser element 120 is, for example, 530 nm. The wavelength λB of the light beam (laser light) emitted from the third laser element 130 is, for example, 445 nm.

  The beam synthesis prism 140 includes a first dichroic film 141 that transmits red laser light and reflects green laser light, and a second dichroic film 142 that transmits red and green laser light and reflects blue laser light. And having.

  The red laser light emitted from the first laser element 110 enters the beam combining prism 140 through the first coupling lens 111 and the first aperture 112. The red laser light incident on the beam combining prism 140 passes straight through the first dichroic film 141.

  The green laser light emitted from the second laser element 120 enters the beam combining prism 140 via the second coupling lens 121 and the second aperture 122. The green laser light incident on the beam combining prism 140 is reflected by the first dichroic film 141 and guided in the same direction as the red laser light (direction of the second dichroic film 142).

  The blue laser light emitted from the third laser element 130 is incident on the beam combining prism 140 via the third coupling lens 131 and the third aperture 132. The blue laser light incident on the beam combining prism 140 is reflected by the second dichroic film 142 in the same direction as the red laser light and the green laser light.

  Each aperture may have various shapes such as a circle, an ellipse, a rectangle, and a square according to the divergence angle of the light beam.

  As described above, the red laser light and the green laser light that have passed through the second dichroic film 142 and the blue laser light reflected by the second dichroic film 142 are emitted from the beam combining prism 140. Therefore, the laser light emitted from the beam combining prism 140 is a combination of red laser light, green laser light, and blue laser light as one laser beam.

  The laser light emitted from the beam combining prism 140 is converted into a “parallel beam” having a predetermined beam diameter by the lens 150. This “parallel beam” is the image forming beam 101. The lens 150 is a meniscus lens having a concave surface toward the optical deflector 21 described later.

  The R (red), G (green), and B (blue) laser beams constituting the image creation beam 101 are either in accordance with an image signal related to a “two-dimensional color image” to be displayed, or Intensity modulation is performed according to image data indicating image information. The intensity modulation of the laser beam may be a method of directly modulating the semiconductor laser of each color (direct modulation method) or a method of modulating the laser beam emitted from the semiconductor laser of each color (external modulation method). That is, each semiconductor laser element emits a laser beam of each color whose emission intensity is modulated by an image signal of each color component of R, G, and B by a driving unit that drives each semiconductor laser element.

  An LED element may be used instead of the semiconductor laser element as described above.

Configuration of Scanning Optical System 20 As shown in FIG. 3, the scanning optical system 20 includes an optical deflector 21 that is a two-dimensional deflection element, a scanning mirror 22, and an intermediate screen 23.

Overview of Optical Deflector 21 The optical deflector 21 is an image forming element that deflects and scans the image forming beam 101 emitted from the light source unit 10 and performs two-dimensional deflection scanning on the intermediate screen 23. The optical deflector 21 is a MEMS (Micro Electro Mechanical Systems) manufactured as a micro oscillating mirror element by a semiconductor process or the like. For example, the optical deflector 21 is composed of a collection of minute mirrors, and each minute mirror is configured to be swung using two axes perpendicular to each other. The minute oscillating mirror element (DMD: Digital Micromirror Device, Texas Instruments).

  The image forming element that can be used as the optical deflector 21 is not limited to the above example. In the same micro-oscillation mirror element as described above, two micro mirrors may be disposed on one axis, and the two micro mirrors may swing in directions orthogonal to each other around the one axis. . Further, as the image forming element used as the optical deflector 21, a transmissive liquid crystal element including a transmissive liquid crystal panel, a reflective liquid crystal element that is a liquid crystal device including a reflective liquid crystal panel, or the like may be used.

Configuration of Optical Deflector 21 Here, the detailed structure of the optical deflector 21 will be described with reference to FIG. As already described, the optical deflector 21 is a MEMS mirror manufactured by a semiconductor process and includes a micromirror 210. In FIG. 6, the longitudinal axis of the optical deflector 21 is the x axis, the short axis of the optical deflector 21 orthogonal to the x axis is the y axis, and the optical deflector 21 is orthogonal to the x axis and the y axis. The direction in which the light reflected by the light travels is taken as the z-axis. The x-axis, y-axis, and z-axis in FIG. 6 are axes having different directions from the axes already shown in FIG. 1 (X-axis, Y-axis, and Z-axis).

  On both sides of the micromirror 210, a pair of meandering beam portions 152 formed by meandering by a plurality of folded portions are disposed. The meandering beam portion 152 is folded and divided into adjacent beams as a first beam portion 152a and a second beam portion 152b, and each includes a piezoelectric member 156. The piezoelectric member 156 used here is, for example, PZT.

  The voltages applied to the first beam portion 152a and the second beam portion 152b are independently applied to those adjacent to each other. These independently applied voltages have different voltage values. When different voltages are applied to the first beam portion 152a and the second beam portion 152b, warpage occurs. Since the direction of warping is determined by the applied voltage, the adjacent first beam portion 152a and second beam portion 152b bend in different directions. By accumulating this bending, the micromirror 210 rotates at a large angle around the x axis. The meandering beam portion 152 is supported by the frame member 154.

Effect of optical deflector 21 By using the optical deflector 21 having the above configuration, optical scanning in the vertical direction centering on the x axis can be performed with a low voltage. On the other hand, in the horizontal direction around the y-axis, optical scanning by resonance using a torsion bar or the like connected to the micromirror 210 can be performed.

● Operation of Optical Deflector 21 Returning to FIG. When the image forming beam 101 is deflected two-dimensionally in the optical deflector 21, the deflected beam is incident on the scanning mirror 22 as a scanning beam 102. The scanning mirror 22 is, for example, a concave mirror, and has an effect of correcting the bending of the scanning line (scanning locus) generated on the intermediate screen 23. The scanning beam 102 reflected by the scanning mirror 22 enters the intermediate screen 23 while moving in parallel with the deflection by the optical deflector 21.

  When an optical element of a transmissive liquid crystal element is used for the optical deflector 21, the scanning beam 102 deflected two-dimensionally in the transmissive liquid crystal element is incident on the intermediate screen 23 without passing through the scanning mirror 22. To do.

  The scanning beam 102 incident on the intermediate screen 23 is scanned in the main scanning direction and the sub-scanning direction. That is, the optical deflector 21 deflects the scanning beam 102 biaxially, and sinusoidal vibration is performed in the main scanning direction and sawtooth vibration is performed in the sub-scanning direction. Perform deflection scanning.

Outline of Intermediate Screen 23 An intermediate image is created by two-dimensional deflection scanning of the intermediate screen 23 by the scanning beam 102. The intermediate image created here is a color two-dimensional image. In this embodiment, a color image is assumed. However, a monochrome intermediate image may be created on the intermediate screen 23.

  Note that the intermediate image displayed at each moment on the intermediate screen 23 is created by “only the pixels that the scanning beam 102 irradiates at that moment”. Therefore, the above-described “color two-dimensional image” is created as “a set of pixels displayed at each moment” by two-dimensional scanning of the scanning beam 102.

Configuration of Intermediate Screen 23 The intermediate screen 23 is a microlens array in which fine convex lenses are two-dimensionally arranged, and the scanning beam 102 incident on the fine convex lenses is diffused and emitted from the emission surface. . The scanning of the intermediate screen 23 is, for example, a raster scan in which the main scanning direction is scanned at a high speed and the sub scanning direction is scanned at a low speed. An intermediate image is created by the diffused light emitted from the scanned intermediate screen 23. That is, the intermediate image appears on the exit surface side (observation optical system 30 side) of the intermediate screen 23.

  The optical element used as the intermediate screen 23 is not limited to the above example, and a diffusion plate, a transmission screen, a reflection screen, or the like may be adopted. A plurality of microlenses arranged one-dimensionally or three-dimensionally arranged can also be used.

Configuration of Observation Optical System 30 The observation optical system 30 includes a concave mirror 31 and an optical combiner 32. The concave mirror 31 magnifies and reflects the intermediate image created in the scanning optical system 20. In the present embodiment, a front windshield 50 is used as the optical combiner 32.

Operation of Observation Optical System 30 As already described, an intermediate image appears on the exit surface side of the intermediate screen 23, that is, on the concave mirror 31 side. The image light related to the intermediate image is reflected toward the optical combiner 32 by the reflecting surface of the concave mirror 31.

  Generally, the front windshield 50 as the optical combiner 32 on which an intermediate image is projected is not a plane. Accordingly, the image light related to the projected intermediate image is projected onto a surface that is not a flat surface. The virtual image 2 that appears thereby is distorted in accordance with the shape of the front windshield 50. Therefore, in order to correct this distortion, the shape of the single concave mirror 31 is devised. For example, the concave mirror 31 has a reflecting surface that corrects an optical distortion element in which the horizontal line of the intermediate image is convex upward or downward, and is arranged at a position where the distortion of the virtual image 2 is corrected by this effect. The

Effect of Observation Optical System 30 By the concave mirror 31 and the optical combiner 32, the intermediate image is displayed as a virtual image 2 in a wide area within the field of view of the observer 3. Thereby, even if the observer 3 moves his head a little (moving the viewpoint), the virtual image 2 can be surely visually recognized.

Configuration of Control System of Image Display Device Here, the configuration of the control system that controls the operation of the image creation device 100 included in the HUD 1 will be described. As illustrated in FIG. 4, the HUD 1 includes an FPGA 600, a CPU 602, a ROM 604, a RAM 606, an I / F 608, a bus line 610, an LD driver 6111, and a MEMS controller 615.

  The FPGA 600 operates the light source unit 10 including LA and the optical deflector 21 that is a MEMS by an LD driver 6111 and a MEMS controller 615. The CPU 602 is a processor that controls the operation of each piece of hardware included in the HUD 1. The ROM 604 is a semiconductor memory that stores an image processing program executed by the CPU 602 to control each function of the HUD 1. The RAM 606 is a semiconductor memory used as a work area when the CPU 602 executes control processing of each hardware.

  The I / F 608 is a contact that connects the HUD 1 to an external controller or the like. For example, the HUD 1 is connected to a CAN (Controller Area Network) or the like via the I / F 608. As a result, the HUD 1 can operate while communicating with other external controllers connected via the CAN.

Functional configuration of image creating apparatus 100 Next, a functional configuration of the image creating apparatus 100 included in the HUD 1 will be described. As illustrated in FIG. 5, the image creation apparatus 100 includes a vehicle information input unit 800, an external information input unit 802, an image information generation unit 804, and an image creation unit 806.

  The vehicle information input unit 800 acquires information (for example, a traveling speed or a traveling distance of the vehicle) from another external controller or the like connected via the I / F 608.

  The external information input unit 802 acquires other external controllers connected via the I / F 608 (for example, position information by GPS, traffic information from the navigation device, etc.).

  The image information generation unit 804 generates a process for generating information for creating an intermediate image that is a source of the virtual image 2 (see FIG. 1) based on the division inputted from the vehicle information input unit 800 and the external information input unit 802. Run.

  The image creation unit 806 includes a control unit 8060. The control unit 8060 controls operations of the light source unit 10 and the scanning optical system 20 based on information generated by the image information generation unit 804. With this control function, an intermediate image projected on the front windshield 50 is generated. By the operation of the functional blocks described above, it is possible to create a state where the virtual image 2 is visually recognized from the viewpoint of the observer 3.

First Embodiment Next, features of the image creating apparatus 100 will be described in more detail. As already described, the intermediate image created by the image creating apparatus 100 is created by two-dimensionally scanning the intermediate screen 23 with the scanning beam 102. In other words, the intermediate image is created on the intermediate screen 23 by scanning the scanning beam 102 in two directions, the main scanning direction and the sub-scanning direction. In general, a scanning range for the intermediate screen 23 is defined, and this scanning range is defined as an effective image area. Since the effective image area is an area that is two-dimensionally deflected and scanned in the main scanning direction and the sub-scanning direction, the shape of the boundary is rectangular. Since the shape of the intermediate image is determined following the shape of the effective image area, the outer shape of the intermediate image is rectangular.

  The image creating apparatus 100 has a configuration in which a part of the intermediate image is blocked by the observation optical system 30. When the intermediate image created by the image creation device 100 is displayed as the virtual image 2, information that the observer 3 wants to recognize is difficult to be placed at the edge of the display range of the virtual image 2. This is because the movement of the line of sight increases as the display range is expanded.

  Therefore, information to be displayed in the virtual image 2 is difficult to be placed in the portion corresponding to the edge of the outer shape of the intermediate image, and even if a part of the edge portion of the intermediate image created on the intermediate screen 23 is deleted, it is effective. There will be no hindrance.

Overview of Concave Mirror 31 The virtual image 2 displayed on the HUD 1 is visually recognized in a state of being superimposed on the surrounding scenery existing in the field of view of the observer 3. Therefore, when an intermediate image is created in which all of the effective image area of the intermediate screen 23 is filled with information, the entire display area of the virtual image 2 displayed based on the intermediate image is filled with information. . When such a large amount of information appears as the virtual image 2, the amount of information that the observer 3 should recognize becomes too large, and the observer 3 is stressed.

  When the moving body is an automobile, information convenient for the observer 3 to recognize by the virtual image 2 is the traveling speed of the automobile, navigation information for guiding the traveling direction of the automobile, and the like. With such information, it is sufficient to create an intermediate image using only a part of the effective image area on the intermediate screen 23.

  Therefore, the image creating apparatus 100 has a configuration in which not all of the intermediate image based on the effective image area of the intermediate screen 23 is used, but an intermediate image that uses only a necessary portion for the virtual image 2 is created. Specifically, the intermediate image is created so that a part such as the central portion of the intermediate image, the lower end or the central portion of the upper end is used for the virtual image 2. As a result, it is possible to prevent missing information that is convenient to be recognized, and to reduce the size of the image creating apparatus 100.

  In consideration of the above, the shape of the concave mirror 31 provided in the image creating apparatus 100 is a shape in which a part of the reflecting surface is omitted so as to block the light flux related to a part of the effective image area in the intermediate screen 23. And

Next, an example of the concave mirror 31 will be described in detail. As shown in FIG. 7, the concave mirror 31 has a structure for guiding, to the optical combiner 32, a light beam excluding the light beams corresponding to the four corners of the concave mirror 31 among the light beams related to the intermediate image. In other words, a part of the light flux related to the intermediate image is kicked by the concave mirror 31.

  Of the light beams related to the intermediate image, the light beams corresponding to the four corners of the concave mirror 31 are not guided to the optical combiner 32.

  Furthermore, in other words, the shape of the concave mirror 31 is a shape that lacks corner portions that constitute a part of the contour of the reflecting surface. Generally, the shape of the folding mirror that reflects the intermediate image to the optical combiner 32 is rectangular. In this respect, the concave mirror 31 is such that the shape of the reflecting surface lacks rectangular corners.

  The solid line shown in FIG. 7 shows the outer shape (contour) of the concave mirror 31. The dotted line indicates the range in which the light beam related to the intermediate image reaches the concave mirror 31 (the range in which the light beam corresponding to the entire effective image area reaches).

  In other words, the concave mirror 31 has a structure that does not reflect a light beam (light beam related to a part of the intermediate image) at a position corresponding to a corner of the rectangle, assuming a rectangle with a minimum area that circumscribes the intermediate image. doing.

  In other words, the concave mirror 31 acts so that a part of the intermediate image (a rectangular corner portion with the smallest area circumscribing the intermediate image) does not represent the virtual image 2 in the optical combiner 32. . That is, the light beam corresponding to the corner portion of the rectangle with the smallest area circumscribing the intermediate image is transmitted so as not to be reflected toward the optical combiner 32.

  Further, the concave mirror 31 is disposed in an inclined state with respect to the XZ plane inside the housing of the HUD 1. In other words, the concave mirror 31 is arranged in a state of being rotated by a predetermined amount with a virtual axis parallel to the Z axis as a rotation axis. In other words, the concave mirror 31 is inclined and arranged in a state of being rotated around the axis in the traveling direction of the light beam (the light beam coming toward the light beam) guided from the intermediate screen 23 to the reflection surface of the concave mirror 31. Yes.

  The shape of the concave mirror 31 may be a shape lacking all four corners as shown in FIG. 7A, or a shape lacking only the opposite corners as shown in FIG. 7B. . The concave mirror 31 has a structure that blocks the light flux corresponding to some corners of the rectangle having the smallest area out of the rectangle formed by the entire area that is two-dimensionally scanned as an intermediate image so as not to be viewed by the observer 3. have.

  Next, the relationship between the concave mirror 31, the intermediate screen 23, and the optical combiner 32 will be described. FIG. 8A is the same as the example of the concave mirror 31 shown in FIG. As shown in FIG. 8B, the outer shape of the intermediate screen 23 is rectangular, and the shape of the effective image area 231 indicated by the solid line is the same as the outer shape of the intermediate screen 23. A light beam traveling from the intermediate screen 23 toward the concave mirror 31 is a light beam emitted from the entire region 231. This is because the intermediate screen 23 performs main scanning and sub-scanning on the entire area 231.

  On the other hand, the display area 321 in the optical combiner 32 has the same shape as the image creation area 232 as shown in FIG. Of the area 231 of the intermediate screen 23, an area where the virtual image 2 is displayed via the optical combiner 32 is indicated by a dotted line. The display area 321 has a shape with corners imitating the shape of the concave mirror 31.

● Effect of concave mirror 31 Returning to FIG. By making the shape of the concave mirror 31 different from the shape of the effective image area on the intermediate screen 23, that is, the shape of the intermediate image to be created, the image creating apparatus 100 can be made smaller. Moreover, HUD1 provided with the image production apparatus 100 can be made small. The reason will be described below.

  As shown in FIG. 7, the concave mirror 31 is disposed in an inclined state inside the housing of the HUD 1. As already described, the inclination of the concave mirror 31 is such that, for example, the longitudinal side of the concave mirror 31 is inclined with respect to the XY plane. The reason for inclining the concave mirror 31 is to reduce the size in the Z direction in the HUD 1 including the image creating apparatus 100.

  The concave mirror 31 is arranged in a state of being rotated in the traveling direction of the light beam related to the intermediate image with respect to the reflection surface. Since the concave mirror 31 lacks a part of the outer shape, interference with the housing of the HUD 1 in the Y direction does not occur even if it is rotated as described above. That is, by using the concave mirror 31, the dimension of the HUD 1 in the Y direction can be reduced.

  Next, the effect obtained by tilting the concave mirror 31 with respect to the XY plane will be described in detail. FIG. 9 is an optical layout diagram in which a part of the optical elements constituting the HUD 1 is omitted, and is a diagram when the one shown in FIG. 1 is viewed from the + Y direction. In order to shorten the dimension of the HUD 1 in the traveling direction (Z direction) of the vehicle and reduce the dimension in the depth direction, the concave mirror 31 is inclined greatly in the left-right direction (X direction) of the vehicle body.

  As shown in FIG. 9, in the HUD 1, the light beam incident on the intermediate screen 23 is incident only from one side in the sub-scanning direction with respect to the perpendicular of the intermediate screen 23. In this way, by making the light flux incident on the intermediate screen 23 by making it asymmetric (tilted) in the sub-scanning direction, the deflection angle in the sub-scanning direction can be narrowed. Thereby, the image scanning period rate can be increased in the sub-scanning direction, and the luminance can be improved.

  Here, the inclination of the concave mirror 31 in the X direction is θ2, the inclination of the intermediate screen 23 in the X direction is θ3, and the inclination of the optical combiner 32 in the X direction is θ1. In HUD 1, inclination θ 2 of concave mirror 31 is larger than inclination θ 1 of optical combiner 32. That is, in the HUD 1, the optical elements are arranged so that θ2> θ1.

  The inclination θ2 of the concave mirror 31 is larger than the inclination θ3 of the intermediate screen 23. That is, in the HUD 1, the optical elements are arranged so that θ2> θ3.

  When the concave mirror 31 is greatly inclined in the X direction, the inclination of the image light beam 103 directed from the intermediate screen 23 toward the concave mirror 31 with respect to the vehicle body traveling direction (Z direction) of the image light beam 103 is the image light beam 103 at both ends of the intermediate screen 23 in the X direction. Is very different.

  In other words, when the concave mirror 31 is greatly tilted with respect to the XY plane, the inclination of the light beam related to the intermediate image emitted from the intermediate screen 23 with respect to the Z direction is the image light beam 103 at both ends of the intermediate screen 23 in the X direction. Is very different.

  Here, a comparative example when the concave mirror 31 is tilted with respect to the XY plane using a conventional optical element will be described with reference to FIG. When the optical element is arranged as shown in FIG. 13, the incident angle to the intermediate screen 23 in the main scanning section becomes symmetric. However, in this case, the scanning optical system 20 including the intermediate screen 23 must be tilted more greatly with respect to the XY plane. The “main scanning section” refers to a section parallel to the XZ plane in the three-dimensional orthogonal coordinate system shown in FIG.

  Then, the relationship between the inclination θ1 of the optical combiner 32 in the X direction, the inclination θ2 of the concave mirror 31, and the inclination θ3 of the intermediate screen 23 is θ3> θ2> θ1. The reason why the arrangement needs to satisfy such a relationship is due to the influence on the luminance of the virtual image 2.

  In order to increase the brightness of the virtual image 2, the direction of the light ray that travels to the outermost periphery among the light rays (scanning beam 102) incident on the intermediate screen 23 and the marginal ray of the light ray (image light beam 103) emitted from the intermediate screen 23. It is desirable that the directions match as much as possible.

  However, in order to widen the display area 321 (virtual image observable area) of the virtual image 2, it is necessary to give diffusion characteristics to the intermediate screen 23. When the diffusion characteristics are given to the intermediate screen 23, the deviation between the direction of the light incident on the outermost periphery of the intermediate screen 23 and the direction of the light emitted from the intermediate screen 23 toward the concave mirror 31 increases.

  That is, when the display area 321 of the virtual image 2 is expanded, as a result, the brightness of the virtual image 2 decreases. In order to prevent this, conventionally, as shown in FIG. 13, it is necessary to project the scanning optical system 20 largely in the left-right direction (X direction) of the HUD 1. As a result, the horizontal dimension of the HUD 1 is increased.

  Therefore, in order to reduce the horizontal dimension of the HUD 1, the scanning optical system 20 according to the present embodiment first tilts the arrangement relationship between the intermediate screen 23 and the concave mirror 31 as described above. Thereby, the dimension in the X direction of HUD1 becomes small.

  Further, a part of the four corners of the concave mirror 31 is omitted and the concave mirror 31 is rotated about the direction in which the light beam to be reflected enters. As a result, the dimension in the Y direction can also be reduced.

  Further, the image creating apparatus 100 according to the present embodiment can also reduce the dimension in the Z direction (depth direction) by arranging the concave mirror 31 in a state of being largely inclined with respect to the XY plane.

  The HUD 1 has a configuration in which the effective range of the optical element disposed after the intermediate screen 23 is not a rectangle having four corners, but at least a part of the corners of the rectangle is limited to a shape. The shape of the concave mirror 31 is determined in accordance with this effective range.

  In other words, the HUD 1 is configured such that, among the light beams related to the intermediate image, the light beams corresponding to the four corners of the rectangular with the smallest area of the intermediate image are kicked by the optical element at the stage subsequent to the optical element that creates the intermediate image. Has been. According to the HUD 1 having the above-described configuration, the vertical direction (Y direction) of the effective range can be particularly narrow as compared with the conventional case where the effective range of the virtual image 2 is rectangular. As a result, the HUD 1 can be reduced in the vertical direction (Y direction).

  The scanning optical system 20 scans in the X direction and the Y direction. That is, the scanning in the scanning optical system 20 is two-dimensional. Therefore, if the four corners of the intermediate image are not used as the effective range as in the present embodiment, the virtual image 2 approaches a circle. Thereby, the image height of the scanning optical system 20 can be reduced. If the image height can be reduced, the optical characteristics (distortion, field curvature, etc.) will be further improved.

  Further, since the intermediate screen 23 is inclined in the sub-scanning direction (Y direction) with respect to the light beam from the optical deflector 21, the apparent angle in the sub-scanning corresponding direction viewed from the optical deflector 21 can be narrowed. As a result, the image height in the sub-scanning direction of the scanning optical system 20 can be reduced, so that the optical characteristics in the sub-scanning direction are further improved.

  As described above, the HUD 1 according to the present embodiment has an optical element rotated in at least one traveling direction (Z direction) in the observation optical system 30, particularly in the vertical direction (Y direction). A small HUD 1 can be obtained.

  As described above, the image creating apparatus 100 according to the present embodiment can be made small overall by devising the scanning optical system 20 and the concave mirror 31. In addition, the HUD 1 provided with the image creating apparatus 100 has an optical element rotated in at least one traveling direction (Z direction) in the observation optical system 30, and particularly reduces the size in the vertical direction (Y direction). be able to. Moreover, even if the HUD 1 is small, the necessary information can be displayed as the virtual image 2 without missing information that the observer 3 should visually recognize.

  Further, the HUD 1 according to the present embodiment uses a decentered optical system for the purpose of reducing the overall size. Further, in the decentered optical system, the light beam corresponding to the portion (rectangular corner circumscribing the intermediate image) that contributes to the determination of the size of the HUD 1 out of the rectangle with the smallest area circumscribing the intermediate image is transmitted to the observation optical system 30. It is configured to kick with an optical element. As a result, the scanning range (image circle) can be reduced, which is advantageous in terms of optical performance and can be expected to improve optical performance.

Second Embodiment Next, another embodiment of the image creating apparatus 100 will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The image creating apparatus 100 according to the second embodiment is different from the first embodiment in the outer shape of the intermediate screen 23a. Further, a synchronization detection sensor 24 is arranged in accordance with the outer shape of the intermediate screen 23a.

  As already described, the luminous fluxes associated with the four corners of the intermediate image created by the image creation device 100 are not used when the HUD 1 displays the virtual image 2. Therefore, the image creating apparatus 100 according to the present embodiment includes the intermediate screen 23 a having a shape that does not form an intermediate image at a position related to a light beam that is not used for displaying the virtual image 2. As shown in FIG. 10, the outer shape of the intermediate screen 23 a has a shape lacking a portion corresponding to an intermediate image corresponding to a light beam not used for the virtual image 2.

  The outer shape of the intermediate screen 23a is not rectangular as a whole, one corner in the sub-scanning direction is missing obliquely, and the other corner in the sub-scanning direction is missing in a rectangular shape. In other words, in the intermediate screen 23a, the effective image area at one corner in the sub-scanning direction is narrowed obliquely, and the effective image area at the other corner in the sub-scanning direction is narrowed in a rectangular shape.

  The intermediate screen 23a is scanned in the main scanning direction and the sub-scanning direction. Therefore, in order to perform stable deflection scanning, a synchronization detection sensor 24 that detects scanning timing is disposed at a predetermined position. The synchronization detection sensor 24 is a sensor for detecting a range in which two-dimensional scanning is performed using the scanning beam 102 from the optical deflector 21 (see FIG. 3), and includes, for example, a PD (photodiode).

  The synchronization detection sensor 24 is disposed inside a rectangle with the smallest area that circumscribes the intermediate image. The synchronization detection sensor 24 is disposed at substantially the same position as the intermediate screen 23a in the light beam traveling direction. The synchronization detection sensor 24 is disposed at a portion of the corner of the intermediate screen 23a that is missing in a rectangular shape. Since the shape of the intermediate screen 23a is a shape that follows the shape of the intermediate image, interference between the synchronization detection sensor 24 and the intermediate screen 23a can be avoided even when arranged as described above.

  Here, the relationship between the arrangement of the synchronization detection sensor 24 and the intermediate screen 23a will be described. When the time from when the light beam deflected by the optical deflector 21 is detected by one synchronization detection sensor 24 until it is not detected by the other synchronization detection sensor 24 is measured, the scanning period 241 and image scanning shown in FIG. A period 242 is identified.

  FIG. 11B is used as a comparative example of the present embodiment. First, a comparative example will be described. In the comparative example shown in FIG. 11B, the arrangement of the synchronization detection sensor 24 is outside the end portion of the intermediate screen 23 in the main scanning direction.

  Next, the present embodiment will be described with reference to FIG. The arrangement of the synchronization detection sensor 24 with respect to the intermediate screen 23a is inside the rectangle with the smallest area circumscribing the intermediate screen 23a. The reason why it can be arranged in this way is that the outer shape of the intermediate screen 23a is lacking in a rectangular shape at the end where the synchronization detection sensor 24 is arranged.

  As is clear when FIG. 11A is compared with FIG. 11B, this embodiment can narrow the scanning period 241 compared to the comparative example. If the scanning period 241 can be narrowed, the ratio of the image scanning period 242 to the scanning period 241 in the main scanning direction increases, and the brightness of the intermediate image created in the scanning optical system 20 can be further increased.

  In other words, since the intermediate screen 23a can narrow the scanning range in the main scanning direction as compared with the comparative example, the ratio of the image scanning period 242 in the amplitude of the optical deflector 21 in the main scanning direction becomes high. Thereby, the brightness of the intermediate image created in the scanning optical system 20 can be further increased.

  In particular, since the main scanning direction is sinusoidal vibration, the scanning speed becomes slower at the end of the amplitude. For this reason, the brightness of the portion corresponding to the end of the amplitude is increased. Therefore, it is required to increase the image scanning period rate. According to the embodiment described above, the amplitude of the intermediate screen 23a in the main scanning direction can be narrowed, and the luminance of the HUD 1 is improved.

  In other words, by arranging the synchronization detection sensor 24 so as to cut off a part of the edge portion of the intermediate image that does not reach the region (eye box) that can be viewed by the observer 3, the optical deflector 21 in the maximum main scanning direction can be obtained. The amplitude can be reduced. As a result, the image scanning period rate can be increased in the main scanning direction, so that the brightness of the HUD can be improved.

Third Embodiment Next, still another embodiment of the image creating apparatus 100 will be described. The same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The image creating apparatus 100 according to the third embodiment is different from the second embodiment in the arrangement of the synchronization detection sensor 24 provided in the scanning optical system 20.

  As already described in the first embodiment, the image creating apparatus 100 and the HUD 1 are configured not to use the image areas at the four corners of the intermediate image created in the scanning optical system 20 for displaying the virtual image 2.

  In order to perform stable deflection scanning, it is necessary to detect the position corresponding to the square of the intermediate image and control the scanning timing. For this purpose, the synchronization detection sensor 24 is arranged at a predetermined position. The position of the synchronization detection sensor 24 may be inside the rectangle with the smallest area that circumscribes at least a part of the intermediate image.

  In this embodiment, as shown in FIGS. 12C and 12D, the image creating apparatus 100 shifts the arrangement of the synchronization detection sensor 24 in the direction in which the light beam is incident on the scanning surface of the intermediate screen 23. . In other words, the synchronization detection sensor 24 is disposed closer to the light deflector 21 than the intermediate screen 23.

  Similarly to the shape of the intermediate image according to the second embodiment, the shape of the intermediate image in the third embodiment is also obliquely cut at one corner in the sub-scanning direction, and the other two in the sub-scanning direction. The corners are cut into rectangles. The synchronization detection sensor 24 is arranged on the side cut into a rectangle.

  The intermediate screen 23 has a rectangular shape unlike the intermediate screen 23a according to the second embodiment. Even if the shape of the intermediate screen 23 remains rectangular, the synchronization detection sensor 24 is closer to the light deflector 21 than the intermediate screen 23 in the light traveling direction, and therefore does not interfere with the intermediate image.

  By making the shape of the intermediate screen 23 rectangular, the structure of the scanning optical system 20 can be simplified and the image creating apparatus 100 according to the third embodiment can be manufactured at a lower cost than the second embodiment.

  By disposing the synchronization detection sensor 24 inside a rectangle with the smallest area circumscribing the intermediate image, the scanning range can be narrowed when the same synchronization detection sensor 24 is used (see FIG. 1). reference). Thereby, the ratio of the image scanning period is increased in the amplitude of the deflector, and the luminance of the scanning optical system can be further increased.

  In particular, since the main scanning direction vibrates sinusoidally, the scanning speed becomes slower and the luminance becomes higher at the end of the amplitude. Therefore, it is required to increase the image scanning period rate. The embodiment described above is desirable because the amplitude of the intermediate screen 23 in the main scanning direction can be reduced and the luminance of the HUD is improved.

1 HUD
DESCRIPTION OF SYMBOLS 2 Virtual image 3 User 10 Light source part 20 Scanning optical system 21 Optical deflector 22 Scanning mirror 23 Intermediate screen 30 Observation optical system 31 Concave mirror 32 Combiner 50 Front glass 101 Image display beam 102 Scanning beam

JP 2004-101829 A

The HUD 1 displays information as a virtual image 2 in a state that can be recognized by the pilot. The virtual image 2 is a Ru image appears on the basis of the intermediate image, the intermediate image is an image for displaying a virtual image 2. The HUD 1 includes an intermediate image creation device (display image creation device). Details of the embodiment of the display image creation device will be described later.

Claims (10)

A light source unit for emitting light from the light source element to the scanning optical system;
A scanning optical system for creating an intermediate image on an intermediate screen by the light beam emitted from the light source unit;
A reflective optical element for guiding the intermediate image to a coupling optical element;
With
The reflective optical element has a shape that guides to the coupling optical element except a part of the intermediate image,
A display image creating apparatus characterized by that. A light source unit for emitting light from the light source element to the scanning optical system;
A scanning optical system for creating an intermediate image on an intermediate screen by the light beam emitted from the light source unit;
A reflective optical element for guiding the intermediate image to a coupling optical element;
With
The reflective optical element guides the intermediate image to the coupling optical element excluding a portion corresponding to a rectangular corner having a minimum area circumscribing the intermediate image;
A display image creating apparatus characterized by that. A light source unit for emitting light from the light source element to the scanning optical system;
A scanning optical system for creating an intermediate image on an intermediate screen by the light beam emitted from the light source unit;
A reflective optical element for guiding the intermediate image to a coupling optical element;
With
The reflective optical element kicks the luminous flux corresponding to a rectangular corner with a minimum area circumscribing the intermediate image;
A display image creating apparatus characterized by that. A light source unit for emitting light from the light source element to the scanning optical system;
A scanning optical system for creating an intermediate image on an intermediate screen by the light beam emitted from the light source unit;
A reflective optical element for guiding the intermediate image to a coupling optical element;
With
The reflective optical element transmits the light beam corresponding to the rectangular corner with the smallest area circumscribing the intermediate image and does not reflect the light to the coupling optical element;
A display image creating apparatus characterized by that. The reflective optical element has a rectangular outer shape, and at least one corner of four corners is cut away.
The display image creation apparatus according to claim 1. The reflective optical element rotates in the traveling direction of the light beam from the intermediate screen of the scanning optical system,
The display image creation apparatus according to claim 1. The scanning optical system has a sensor that detects a scanning range of the intermediate screen by the light flux,
At least a part of the sensor is disposed inside a rectangle having a minimum area that circumscribes the intermediate image.
The display image creation apparatus according to claim 1. At least one of the sensors is shifted in a direction in which the light beam is incident on the intermediate screen with respect to the scanning surface of the intermediate screen.
The display image creation apparatus according to claim 7. The luminous flux incident on the intermediate screen is incident only from one side in the sub-scanning direction with respect to the normal of the intermediate screen.
The display image creation apparatus according to claim 1. An image display device that is mounted on a moving body and forms information about the moving body as a virtual image that can be recognized by a driver of the moving body,
A light source unit for emitting light from the light source element to the scanning optical system;
A scanning optical system for creating an intermediate image on an intermediate screen by the light beam emitted from the light source unit;
An observation optical system comprising: a reflective optical element that guides the intermediate image to a coupling optical element; and a coupling optical element that represents the intermediate image as the virtual image;
With
The reflective optical element has a shape that guides to the coupling optical element except a part of the intermediate image,
An image display device characterized by that.