JP2015059968A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for accurately displaying an image, while achieving miniaturization.SOLUTION: An intermediate image forming part is arranged on a bottom surface facing an upper surface side inside a housing and outputs imaged image display light. A projection mirror 400 is rotatably supported by two side surfaces facing each other inside the housing and reflects the image display light from the intermediate image forming part, to output the image display light from an opening. An angle adjustment part is arranged on the bottom surface inside the housing and changes the angle of the projection mirror 400 by rotating the projection mirror 400. A detection part is arranged on the bottom surface inside the housing and determines an original point with respect to the angle of the projection mirror 400.

Description

  The present invention relates to an image display device.

  A vehicle display device called a head-up display is known. The head-up display is a display that displays information superimposed on the scenery outside the vehicle by transmitting light entering from outside the vehicle and reflecting the image projected from the optical unit arranged inside the vehicle to the windshield of the vehicle. Device. A head-up display has recently been attracting attention as a display device for vehicles because a driver who is viewing the scenery outside the vehicle can recognize information on the image projected from the optical unit with almost no change in line of sight or focus. Collecting.

  In the head-up display, for example, a display emits display light, and a projection mirror in the case reflects the display light and projects it onto a windshield or the like. The projection mirror is held by a holder, and the holder is rotatably supported by the base plate. The stepping motor changes the direction of the projection mirror by rotating the holder holding the reflecting plate (see, for example, Patent Document 1).

JP 2013-125193 A

  Since the mounting position and space for the head-up display are often limited, the device is required to be downsized. On the other hand, even if the device is downsized, it is also required to display an image accurately.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a technique for accurately displaying an image while reducing the size.

  In order to solve the above-described problems, an image display device according to an aspect of the present invention includes a housing having an opening on the upper surface side, a bottom surface facing the upper surface side inside the housing, and a connection. An output unit that outputs the image display light that is imaged, and a projection mirror that is rotatably supported by two opposing side surfaces inside the housing, and that reflects the image display light from the output unit and outputs it from the opening And an angle adjustment unit that is arranged on the bottom surface inside the housing and changes the angle of the projection mirror by rotating the projection mirror, and a reference that is arranged on the bottom surface inside the housing and is relative to the angle of the projection mirror And a detecting unit for determining. The angle adjustment unit and the detection unit are disposed between the output unit and the projection mirror, and are spaced apart on both sides of the two side surfaces that support the projection mirror.

  According to the image display device of the present invention, it is possible to display an image accurately while downsizing.

It is a figure which shows typically the installation aspect of the head-up display which concerns on embodiment of this invention. It is a figure which shows the internal structure of an optical unit. It is a figure which shows typically the internal structure of an image projection part. It is a figure which shows the optical path of the image display light projected on a windshield. It is a figure which shows the structure from the horizontal direction of the optical unit of FIG. It is a perspective view which shows the structure of the projection mirror assembly of FIG. It is a figure which shows the structure from the back direction of the projection mirror assembly of FIG. It is a figure which shows the structure from the downward direction of the projection mirror assembly of FIG. It is a figure which shows the structure from the front direction of the projection mirror assembly of FIG. It is a figure which shows the structure which mounted the housing | casing of FIG. 2 on the dashboard. It is a figure which shows the optical path of the image display light projected by the projection mirror of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. Specific numerical values and the like shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  As an image display device according to an embodiment, a head-up display 10 that is installed and used in a dashboard of a vehicle will be described as an example. FIG. 1 is a diagram schematically showing an installation mode of a head-up display 10 according to an embodiment of the present invention. The head-up display 10 includes an optical unit 100 and a control device 50. FIG. 1 is a diagram showing a case where an optical unit 100 is used in a dashboard on the left side with reference to the traveling direction of the vehicle (left direction in FIG. 1). The following embodiment is a left-hand drive vehicle. The example in which the head-up display 10 is arranged for the driver in FIG. In order to use it for a right-hand drive vehicle, the internal configuration of the optical unit 100 may be reversed horizontally with reference to the traveling direction of the vehicle. Hereinafter, an outline of the head-up display 10 will be described with reference to FIG.

  The control device 50 includes a CPU (Central Processing Unit) (not shown), and generates an image signal to be displayed on the optical unit 100. The control device 50 also includes an external input interface (not shown), which receives an image signal output from an external device such as a navigation device or a media playback device, and performs a predetermined process on the input signal. Thereafter, it can be output to the optical unit 100.

  The optical unit 100 generates image display light to be displayed as a virtual image 450 on the windshield 610 based on the image signal generated by the control device 50. Therefore, the optical unit 100 includes an image projection unit 210, an intermediate mirror 350, an intermediate image formation unit 360, and a projection mirror 400 inside the housing 110.

  The image projection unit 210 houses a light source, an image display element, various optical lenses, and the like. The image projection unit 210 generates and projects image display light based on the image signal output from the control device 50. In this embodiment, a case where LCOS (Liquid crystal on silicon) which is a reflective liquid crystal display panel is used as an image display element is illustrated, but a DMD (Digital Micromirror Device) may be used as an image display element. In that case, the optical system and the driving circuit according to the display element to be applied are used.

  The image display light projected by the image projection unit 210 is reflected by the intermediate mirror 350. The image display light reflected by the intermediate mirror 350 forms an image on the intermediate image forming unit 360. The image display light related to the real image formed by the intermediate image forming unit 360 is transmitted through the intermediate image forming unit 360 and projected onto the projection mirror 400. The image projection unit 210, the intermediate mirror 350, and the intermediate image forming unit 360 function as an output unit that outputs image display light.

  The projection mirror 400 is a concave mirror, and the image display light transmitted through the intermediate image forming unit 360 is enlarged by the projection mirror 400 and projected onto the windshield 610. The image display light projected on the windshield 610 is changed to an optical path toward the user by the windshield 610. The user E who is a driver recognizes the image display light reflected by the windshield 610 as a virtual image 450 ahead of the windshield 610 in the line-of-sight direction.

  FIG. 2 is a diagram showing an internal configuration of the optical unit 100 according to the embodiment of the present invention. Hereinafter, the internal configuration of the optical unit 100 will be described with reference to FIG.

  As described above, the optical unit 100 includes the image projection unit 210, the intermediate mirror 350, the intermediate image formation unit 360, and the projection mirror 400 inside the housing 110. Although details will be described later, the image projection unit 210 includes three different light sources that respectively generate red, green, or blue light. The light source can be realized by using an LED (Light Emitting Diode) or a semiconductor laser light source. In the present embodiment, a case where an LED is used as the light source will be described.

  The light source generates heat during use. For this reason, the optical unit 100 includes a heat sink for cooling the light source. Since there are three types of light sources, in order to cool the light sources, a heat sink 120a connected to the red light source, a heat sink 120b (not shown) connected to the green light source, and the outside of the housing 110 of the optical unit 100, A heat sink 120c connected to the blue light source is provided.

  The case 110 is aluminum die-cast. Here, both the heat sink 120b and the heat sink 120c for cooling the blue light source and the green light source are configured integrally with the housing 110, respectively. On the other hand, the heat sink 120a for cooling the red light source is installed at a location spatially separated from the heat sink 120b and the heat sink 120c, and is externally attached separately from the housing 110. For this reason, the heat generated by the red light source is carried to the heat sink 120a via the heat pipe 25.

  Next, the optical system of the head-up display 10 will be described with reference to FIGS. FIG. 3 is a diagram schematically showing the internal configuration of the image projection unit 210 together with the optical path of the image display light. FIG. 4 is a diagram illustrating an optical path of image display light projected onto the windshield 610 via the intermediate mirror 350, the intermediate image forming unit 360, and the projection mirror 400.

  First, the internal configuration of the image projection unit 210 will be described with reference to FIG. The image projection unit 210 includes illumination units 230a, 230b, and 230c (hereinafter also collectively referred to as illumination units 230), a dichroic cross prism 244, a reflector 236, a field lens 237, a polarization beam splitter 238, a phase difference plate 239, and an analyzer. 241 and a projection lens group 242. In FIG. 3, the description of the internal configurations of the first illumination unit 230a and the third illumination unit 230c is omitted, and only the internal configuration of the second illumination unit 230b is shown, but each illumination unit 230 has the same configuration. .

  The illumination unit 230 includes a light source 231, a collimator lens 232, a UV-IR (UltraViolet-Infrared Ray) cut filter 233, a polarizer 234, and a fly-eye lens 235. The light source 231 includes a light emitting diode that emits light of any one of red, green, and blue. The 1st illumination part 230a has a light emitting diode which emits red light as a light source. The 2nd illumination part 230b has a light emitting diode which emits green light as the light source 231. The 3rd illumination part 230c has a light emitting diode which emits blue light as a light source.

  The light source 231 is attached to the light source attachment portion 243. The light source mounting portion 243 is thermally coupled to a heat sink (not shown), and cools the heat generated when the light source 231 emits light. The light emitted from the light source 231 is converted into parallel light by the collimating lens 232. The UV-IR cut filter 233 absorbs and removes ultraviolet light and infrared light from the parallel light that has passed through the collimating lens 232. The polarizer 234 changes the light that has passed through the UV-IR cut filter 233 into unpolarized P-polarized light. The fly-eye lens 235 uniformly adjusts the brightness of the light that has passed through the polarizer 234.

  Light transmitted through the fly-eye lens 235 of each illumination unit 230 is incident on the dichroic cross prism 244 from different directions. The red, green, and blue light incident on the dichroic cross prism 244 becomes white light that is a combination of the three colors and travels toward the reflecting mirror 236. The reflecting mirror 236 changes the optical path of the white light synthesized by the dichroic cross prism 244 by 90 degrees. The light reflected by the reflecting mirror 236 is collected by the field lens 237. The light collected by the field lens 237 is irradiated to the image display element 240 via the polarization beam splitter 238 and the phase difference plate 239 that transmit the P-polarized light.

  The image display element 240 includes red, green, and blue color filters for each pixel. The light emitted to the image display element 240 has a color corresponding to each pixel, is modulated by the liquid crystal composition included in the image display element 240, and becomes S-polarized image display light toward the polarization beam splitter 238. Emitted. The emitted S-polarized light is reflected by the polarization beam splitter 238, changes its optical path, passes through the analyzer 241, and then enters the projection lens group 242. The image display light transmitted through the projection lens group 242 exits the image projection unit 210 and enters the intermediate mirror 350.

  Next, the optical path of the image display light projected from the intermediate mirror 350 onto the windshield 610 via the intermediate image forming unit 360 and the projection mirror 400 will be described with reference to FIG. The optical path of the image display light emitted from the projection lens group 242 of the image projection unit 210 is changed to an optical path toward the projection mirror 400 by the intermediate mirror 350. On the way, a real image based on the image display light reflected by the intermediate mirror 350 is formed by the intermediate image forming unit 360.

  The intermediate image forming unit 360 includes a diffusion screen 362 and a concave lens 364. The diffusion screen 362 forms a real image based on the image display light transmitted through the intermediate image forming unit 360 and controls the orientation angle ψ of the image display light toward the projection mirror 400. The concave lens 364 controls the principal ray direction of the image display light traveling toward the projection mirror 400 and adjusts the angle θ formed by the image display light before and after passing through the intermediate image forming unit 360.

  The image display light transmitted through the intermediate image forming unit 360 is reflected by the projection mirror 400 and projected onto the windshield 610. The image display light projected on the windshield 610 is changed to an optical path toward the user by the windshield 610. Thereby, the user can visually recognize the virtual image based on the image display light forward through the windshield 610 as described above.

  With the above configuration, the user can visually recognize the virtual image based on the image signal output from the control device 50 by superimposing it on the actual landscape via the windshield 610.

  FIG. 5 shows a configuration of the optical unit 100 from the lateral direction. The optical unit 100 includes a housing 110, a heat sink 120b, and a heat sink 120c. The housing 110 includes an opening 540 and a bottom surface 542, and includes an intermediate image forming unit 360 and a projection mirror 400 therein. FIG. 5 corresponds to the case where the optical unit 100 shown in FIG. 2 is viewed from the same direction as FIG. When the optical unit 100 is viewed from this direction, the intermediate image forming unit 360 and the projection mirror 400 are disposed inside the housing 110, and thus cannot be seen. Here, the correspondence with FIG. These are shown as dotted lines for clarity.

  An opening 540 is provided on the upper surface side of the housing 110. In particular, as shown in FIG. 2, the opening 540 is provided on the entire upper surface side. Note that an opening 540 may be provided in part of the upper surface side. Further, a portion corresponding to the upper surface side of the housing 110 is a bottom surface 542. The intermediate image forming unit 360 described above is disposed on the bottom surface 542 inside the housing 110. The intermediate image forming unit 360 outputs the image display light that has been formed.

  FIG. 6 is a perspective view showing the configuration of the projection mirror assembly 550. The projection mirror assembly 550 includes a projection mirror 400, an upper holder 500, a lower holder 502, a left holder 504, a right holder 506, a left angle adjustment shaft 508, a right angle adjustment shaft 510, a left upper clip 512, and a left lower clip 514. , An upper right side fastener 516, a lower right side fastener 518, an angle adjustment motor 520, a lead screw 522, a photo interrupter 524, and a power transmission member 526. Projection mirror assembly 550 is shown as projection mirror 400 in FIG. In FIG. 5, the projection mirror 400 is assembled on one side of the casing 110, that is, on the windshield 610 side. On the other hand, the intermediate image forming unit 360 is assembled on the other side of the housing 110, that is, on the driver's seat side. Returning to FIG.

  The projection mirror 400 is a concave mirror, and the concave side is a reflecting surface, and the opposite side is a back surface. The upper holder 500, the lower holder 502, the left holder 504, and the right holder 506 are joined to form a frame-shaped holder. The projection mirror 400 is held by a holder. Specifically, the projection mirror 400 is pressed against the lower holder 502 and the right holder 506, and is fitted into the holder so as to be pushed from the reflecting surface toward the back surface.

  FIG. 7 shows the configuration of the projection mirror assembly 550 from the back side. A projection mirror 400 is shown in the center portion, which corresponds to the back surface. The right back plate 530 is joined to the upper holder 500, the right holder 506, and the lower holder 502 on the back side. Further, the left back plate 532 is joined to the upper holder 500, the left holder 504, and the lower holder 502 on the back surface side. The projection mirror 400 fitted from the reflecting surface toward the back surface is supported by four pedestal pins provided so as to protrude from the right back plate 530 and the left back plate 532 in the front surface direction. Returning to FIG. The projection mirror 400 is fixed from the reflective surface side by a left upper clip 512, a lower left clip 514, an upper right clip 516, and a lower right clip 518.

  The left angle adjustment shaft 508 is provided so as to protrude outward from the left holder 504, and the right angle adjustment shaft 510 is provided so as to protrude outward from the right holder 506. A hole through which the left angle adjustment shaft 508 and the right angle adjustment shaft 510 can be inserted is provided on the side surface of the housing 110 (not shown). By inserting the left angle adjustment shaft 508 and the right angle adjustment shaft 510 into these holes, the holder holding the projection mirror 400 is rotatably supported on two opposite side surfaces inside the housing 110. The The direction of rotation is a direction centered on a horizontal axis as indicated by an arrow in the figure. By such rotation, the direction of the reflecting surface of the projection mirror 400 is changed. Image display light from an intermediate image forming unit 360 (not shown) is guided to the projection mirror 400. The projection mirror 400 magnifies and reflects the image display light upward. The image display light magnified and reflected by the projection mirror 400 is emitted through the opening 540 of FIG. 5, reflected by the windshield 610, and guided to the driver's eye range.

  The angle adjustment motor 520 is disposed between the intermediate image forming unit 360 and the projection mirror 400 on the bottom surface inside the housing 110. Furthermore, the angle adjustment motor 520 is disposed on the left holder 504 side of the holder. An example of the angle adjustment motor 520 is a step motor. The angle adjustment motor 520 functions as an angle adjustment unit that adjusts the angle of the projection mirror 400, and may be a drive unit other than the step motor. A lead screw 522 is attached to the drive shaft of the angle adjustment motor 520. The lead screw 522 is connected to the power transmission member 526, and the power transmission member 526 is fixed to the bottom surface side of the lower holder 502 as shown in FIG. FIG. 8 shows the configuration of the projection mirror assembly 550 from below. The upper side of the drawing corresponds to the reflection surface side of the projection mirror 400, and the lower side of the drawing corresponds to the back side of the projection mirror 400. As illustrated, the power transmission member 526 is fixed to the lower holder 502 with screws. Returning to FIG.

  When the angle adjustment motor 520 is driven and the lead screw 522 is rotated, the rotational force is transmitted to the power transmission member 526. Then, the power transmission member 526 pushes the lower holder 502 from the reflection surface side to the back surface side of the projection mirror 400 or pulls the lower holder 502 from the back surface side of the projection mirror 400 to the reflection surface side. As a result, the holder is rotated about the horizontal axis that is the axis of the left angle adjustment shaft 508 and the right angle adjustment shaft 510. Thereby, the direction of the projection mirror 400 is changed, and the projection angle of the image display light reflected by the projection mirror 400 and emitted through the opening 540 is adjusted. That is, the angle adjustment motor 520 changes the angle of the projection mirror 400 by rotating the projection mirror 400.

  The photo interrupter 524 is disposed between the intermediate image forming unit 360 and the projection mirror 400 on the bottom surface inside the housing 110. Further, the photo interrupter 524 is arranged on the right holder 506 side of the holder. In other words, the photo interrupter 524 and the angle adjustment motor 520 are arranged separately on both sides of the two side surfaces that support the holder. The photo interrupter 524 is a sensor that includes a light emitting unit and a light receiving unit that face each other, and detects the presence and position of an object by detecting that the object blocks light from the light emitting unit. Here, it is used to specify the origin with respect to the angle of the holder rotated by the angle adjusting motor 520. The photo interrupter 524 is called a transmissive photosensor, and a light emitting unit and a light receiving unit are disposed side by side, and light emitted from the light emitting unit is transmitted through a slit linked to the lower holder 502 or the projection mirror 400. To detect. Since a known technique may be used for such a photo interrupter 524, description thereof is omitted here. The height from the bottom surface of the angle adjustment motor 520 is higher than the height from the bottom surface of the photo interrupter 524. The photo interrupter 524 functions as a detection unit that determines a reference for the angle of the projection mirror, and may be a detection unit other than the transmissive sensor.

  FIG. 9 shows a configuration of the projection mirror assembly 550 from the front direction. Since the configuration is the same as that of FIG. 6, the description thereof is omitted here. FIG. 10 shows a configuration in which the housing 110 is mounted on the dashboard 612. As described above, the case 110 is intended for the left handle, and the housing 110 is provided under the dashboard 612 disposed between the handle (not shown) and the windshield 610. Here, the right side of the figure corresponds to the central portion of the vehicle, and the left side of the figure corresponds to the outside of the vehicle. Similarly to FIG. 5, a heat sink 120 b and a heat sink 120 c are provided on the handle side, that is, on the driver side of the housing 110.

  FIG. 11 shows an optical path of image display light projected by the projection mirror 400. Here, the intermediate image forming unit 360 is disposed on the front side of the drawing, and the projection mirror 400 is disposed on the far side of the intermediate image forming unit 360. As described above, the image display light output from the intermediate image forming unit 360 is reflected by the projection mirror 400 and projected onto the windshield 610 (not shown). Here, only the optical paths of the image display light output from the four corners of the intermediate image forming unit 360 are shown for the sake of clarity. For example, image display light output from the upper right corner of the intermediate image forming unit 360 is reflected near the upper right corner of the projection mirror 400. The same applies to image display light output from other corners.

Of the reflecting surface of the projection mirror, the region used to reflect the image display light is determined by the size of the image to be displayed and the expected viewpoint position variation range of the driver. The region used for the projection mirror to reflect the image display light is inside the reflection surface of the projection mirror. Here, because the projection mirror has a curvature, and the windshield that reflects the image display light after that also has a curvature and an inclination, the area used to reflect the image display light is not rectangular, but symmetrical vertically and horizontally not.
The light hits the entire surface of the projection mirror and is reflected, but the driver sees an area of it. If the driver's head is fixed and the viewpoint position is one point, the driver sees an area of a rectangular area at the center of the projection mirror. The range of the viewpoint is assumed so that the image can be seen even if the driver moves his / her head left / right / up / down, and the size of the projection mirror is determined so that the image is not cut within that range. Therefore, the range is not a simple rectangle on the projection mirror. On the other hand, since the projection mirror is rectangular for manufacturing reasons, the areas not used for projection differ vertically and horizontally.

  Here, in the lower left part of the projection mirror 400, the height of the area not used for reflecting the image display light is indicated as “L”, and in the lower right part of the projection mirror 400, it is used for reflecting the image display light. The height of the non-existing region is indicated as “R”. As illustrated, “L” is larger than “R”. The area that is not used for reflecting the image display light is a space that can avoid the formation of a shadow with respect to the image display light.

  As shown in FIG. 10, the bottom surface of the housing 110 is higher when it is closer to the center of the vehicle than when it is closer to the outer portion of the vehicle. This is because the vehicle structure protrudes at the center of the vehicle. In order to avoid this structure, a difference in height of the bottom surface of the housing 110 is provided. As described above, the height of the angle adjustment motor 520 is higher than the height of the photo interrupter 524. For this reason, the angle adjustment motor 520 is disposed at a large “L” in a portion where the image display light does not strike, on both sides of the two side surfaces. That is, the angle adjustment motor 520 is disposed on the outer portion of the vehicle.

  According to the embodiment of the present invention, since the angle adjustment motor and the photo interrupter are arranged separately between the intermediate image forming unit and the projection mirror and on both sides of the projection mirror, the projection mirror and intermediate image formation are performed. The installation area of the section, angle adjustment motor, and photo interrupter can be reduced. In addition, the installation area of the projection mirror, the intermediate image forming unit, the angle adjustment motor, and the photo interrupter is reduced, so that the optical unit can be reduced in size. In addition, since the angle adjustment motor is arranged on the wider side where both sides of the two side surfaces can avoid the formation of a shadow with respect to the image display light, the image can be displayed accurately while downsizing.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of the respective components, and such modifications are within the scope of the present invention.

  400 Projection mirror, 500 Upper holder, 502 Lower holder, 504 Left holder, 506 Right holder, 508 Left angle adjustment shaft, 510 Right angle adjustment shaft, 512 Left upper fastener, 514 Left lower fastener, 516 Upper right fastener 518 Lower right side fastener, 520 Angle adjustment motor, 522 Lead screw, 524 Photo interrupter, 526 Power transmission member, 550 Projection mirror assembly.

Claims (2)

A housing provided with an opening on the upper surface side;
An output unit that is disposed on the bottom surface facing the upper surface side inside the housing and outputs the imaged image display light,
A projection mirror that is rotatably supported by two opposing side surfaces inside the housing, and that reflects the image display light from the output unit and outputs it from the opening, and
An angle adjusting unit that is disposed on the bottom surface inside the housing and changes the angle of the projection mirror by rotating the projection mirror;
A detector that is disposed on the bottom surface inside the housing and that determines a reference for the angle of the projection mirror;
The angle adjustment unit and the detection unit are disposed between the output unit and the projection mirror, and are spaced apart on both sides of two side surfaces that support the projection mirror. Display device. The height from the bottom surface in the angle adjustment unit is higher than the height from the bottom surface in the detection unit,
The image display apparatus according to claim 1, wherein the angle adjusting unit is disposed on a wider side of both sides of the two side surfaces so as to avoid formation of a shadow with respect to image display light.

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