WO2019130948A1 - Dispositif d'affichage d'informations - Google Patents

Dispositif d'affichage d'informations Download PDF

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Publication number
WO2019130948A1
WO2019130948A1 PCT/JP2018/043544 JP2018043544W WO2019130948A1 WO 2019130948 A1 WO2019130948 A1 WO 2019130948A1 JP 2018043544 W JP2018043544 W JP 2018043544W WO 2019130948 A1 WO2019130948 A1 WO 2019130948A1
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WIPO (PCT)
Prior art keywords
light
image
information display
display unit
concave mirror
Prior art date
Application number
PCT/JP2018/043544
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English (en)
Japanese (ja)
Inventor
平田　浩二
渡辺　敏光
昭央 三沢
公二 吉田
武田　薫
Original Assignee
マクセル株式会社
株式会社ジャパンディスプレイ
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Application filed by マクセル株式会社, 株式会社ジャパンディスプレイ filed Critical マクセル株式会社
Publication of WO2019130948A1 publication Critical patent/WO2019130948A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/16—Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays

Definitions

  • the present invention relates to an information display apparatus that projects video information on a windshield or a combiner of a car, a train, an aircraft, etc. and observes the video information as a virtual image through the windshield.
  • HUD head-up display
  • the device is known.
  • Patent Document 1 proposes a small-sized display device including a device for displaying an image and a projection optical system for projecting (projecting) the displayed image, and having a small screen distortion over the entire viewpoint area of the driver. It is done.
  • a laser beam for pixel display emitted from a light source unit is deflected by a two-dimensional deflecting means (MEMS mirror) and reflected toward a curved screen which is a transmitting member via a concave mirror.
  • MEMS mirror two-dimensional deflecting means
  • An arrangement for forming an intermediate image is disclosed.
  • the intermediate image is then reflected by the concave mirror, and the image light is projected onto the windshield or the combiner of the automobile to form a virtual image.
  • the head-up display device needs a windshield or a combiner as a final reflection surface for providing a virtual image to the driver, and the inventors further improve the visibility to obtain good resolution performance. I realized that it was important.
  • the size of the concave mirror is matched to the observation range, and the magnification of the virtual image is determined in consideration of the image display unit. I had no choice. Therefore, in the prior art, in order to obtain a large virtual image in a desired observation range, the distance from the concave mirror to the virtual image is increased, that is, the distance between the final reflection surface, the windshield or the combiner, and the concave mirror is simultaneously increased. , It was necessary to increase the size of the concave mirror. These requirements are factors that prevent the miniaturization of the device.
  • Patent Document 1 and Patent Document 2 do not disclose a technique for miniaturizing the configuration of the apparatus and obtaining a large virtual image in a desired observation range. Further, as the device is miniaturized, distortion and aberration of a virtual image visually recognized by the driver increase, but a technique for effectively solving this is not disclosed.
  • the object of the present invention is to propose a technical means for obtaining a larger virtual image in a desired observation range while miniaturizing the apparatus.
  • the present invention is an information display apparatus for projecting a video on a projection member, wherein a video display unit for arranging a light source on the back side to generate video light of the video, and the video light generated by the video display unit
  • the curved shape of the display surface of the image display unit is determined so as to reduce the curvature of field generated in the virtual image by the shape of the concave mirror.
  • an information display apparatus for obtaining a larger virtual image in a desired observation range while reducing the size of the apparatus, and reducing distortion and aberration of the virtual image visually recognized by the driver to form a virtual image having high visibility. Can be realized.
  • FIG. 1 It is a schematic block diagram which shows an information display apparatus and its peripheral device. It is a figure explaining the generation
  • FIG. 15 is a ray diagram enlarging a part of the virtual image optical system of FIG. 14. It is an external view of a liquid crystal panel and a back light. It is an enlarged view of a light source unit in a back light. It is a figure which shows the external appearance of a light guide. It is a principal part cross section enlarged view of a light guide. It is a figure which shows the simulation result of the emitted light which passed the liquid crystal panel. It is a figure which shows the luminance distribution of the output surface of a liquid crystal panel.
  • FIG. 1 is a schematic configuration view showing an information display apparatus and its peripheral device according to an embodiment of the present invention.
  • the information display apparatus 100 which projects video information on the windshield of a motor vehicle is demonstrated as the example.
  • this information display device 100 forms a virtual image V1 ahead of the host vehicle at the driver's viewpoint (eye point) 8
  • various information reflected by the projection member 6 Is a device that displays as a virtual image VI (Virtual Image), a so-called head-up display (HUD) device.
  • the projection member 6 should just be a member by which imaging
  • the video information to be displayed as the virtual image VI includes, for example, vehicle information such as a vehicle speed and foreground information captured by an on-vehicle camera.
  • the configuration of the information display device 100 includes an image display unit 4 such as a liquid crystal display (LCD) that generates image light of image information to be displayed, and a backlight 5 disposed on the back side of the image display unit 4 and serving as a light source of image light.
  • an image display unit 4 such as a liquid crystal display (LCD) that generates image light of image information to be displayed
  • a backlight 5 disposed on the back side of the image display unit 4 and serving as a light source of image light.
  • the optical element 2 is for correcting distortion or aberration which occurs when projecting a video light to form a virtual image.
  • the image light reflected by the concave mirror 1 is reflected by the projection member 6 and travels to the viewpoint 8 of the driver to display a virtual image VI.
  • the video display unit 4 and the backlight 5 are controlled by the control unit 40.
  • the control unit 40 uses the navigation system 61 to set various information such as the speed limit and the number of lanes of the road corresponding to the current position where the host vehicle is traveling, the planned travel route of the host vehicle set in the navigation system 61, etc. It is acquired as foreground information (that is, information to be displayed in front of the host vehicle by the virtual image).
  • the driving support ECU 62 is a control device that realizes driving support control by controlling a drive system and a control system in accordance with an obstacle detected as a result of monitoring by the periphery monitoring device 63.
  • the driver assistance control includes, for example, known techniques such as cruise control, adaptive cruise control, pre-crash safety, and lane keeping assist.
  • the periphery monitoring device 63 is a device that monitors the situation around the host vehicle, and as an example, a camera that detects an object present around the host vehicle based on an image obtained by photographing the periphery of the host vehicle, a survey wave
  • the search device or the like detects an object present around the host vehicle based on the result of transmitting and receiving
  • the control unit 40 acquires such information from the driving support ECU 62 (for example, the distance to the preceding vehicle and the heading of the preceding vehicle, the position where an obstacle or a sign is present, etc.) as foreground information. Furthermore, an ignition (IG) signal and the vehicle state information detected by the various sensors 64 are input to the control unit 40. Among these pieces of information, the vehicle state information is information acquired as vehicle information, and for example, a predetermined abnormal state such as the remaining amount of fuel of the internal combustion engine or the temperature of the cooling water Contains warning information to represent. In addition, the operation result of the turn indicator, the traveling speed of the host vehicle, and the shift position information are also included. The control unit 40 described above is activated when an ignition signal is input.
  • optical components such as the image display unit 4, the backlight 5 and the concave mirror 1 form a virtual image optical system described below.
  • FIG. 2 is a diagram for explaining the generation principle of a virtual image.
  • an object (image source) AB is disposed inside the focal point F of the concave mirror 1 'which is a reflection surface (position a on the reflection surface side in the figure)
  • a virtual image is formed at position b with size A'B'. Be done.
  • the reflective surface is a lens surface
  • a virtual image is formed at a relative position (not shown) to the reflective surface.
  • the shape of the concave mirror 1 for reducing distortion of a displayed virtual image will be described with reference to FIG.
  • a light beam is incident below the windshield 6, and the distance (L1 + L2) to the driver's viewpoint 8 is relatively short, so the radius of curvature is reduced to increase the magnification.
  • the radius of curvature is increased so as to decrease the magnification.
  • the distortion itself can be reduced by inclining the image display unit 4 with respect to the optical axis of the concave mirror 1 to correct the difference in the virtual image magnification.
  • FIG. 3 is a top view of a car equipped with the information display device
  • FIG. 4 is a view showing a curved shape of the windshield 6.
  • the radius of curvature Rh in the horizontal direction is different from the radius of curvature Rv in the vertical direction with respect to the vehicle body 101, and generally, there is a relationship of Rh> Rv. Therefore, when the windshield 6 is regarded as a reflection surface, it becomes a toroidal concave mirror. For this reason, the shape of the concave mirror 1 in the information display device 100 is such that the virtual image magnification due to the shape of the windshield 6 is corrected. That is, in order to correct the difference between the curvature radiuses Rh and Rv of the windshield 6 in the horizontal direction and the vertical direction, the average curvature radius is different in the horizontal direction and the vertical direction.
  • the shape of the concave mirror 1 is preferably corrected as a function of the coordinates (x, y) of the surface from the optical axis of the mirror surface as the shape of a free-form surface shown by the following [Equation 1].
  • a spherical or non-spherical shape shown by [Equation 2] below
  • [Equation 2] a spherical or non-spherical shape symmetrical to the optical axis is a function of the distance r from the optical axis and can not control the horizontal and vertical cross-sectional shapes separately. It is from.
  • a lens element is disposed as an optical element 2 between the image display unit 4 and the concave mirror 1 to control the emission direction of the light beam to the concave mirror 1.
  • the distortion aberration of the virtual image is corrected together with the correction function of the concave mirror 1.
  • the optical element 2 realizes aberration correction of a virtual image including astigmatism which is caused by the difference between the curvature radii Rh and Rv in the horizontal and vertical directions of the windshield 6 described above.
  • an optical element optimally designed may be provided between the concave mirror 1 and the image display unit 4.
  • the optical distance between the concave mirror 1 and the image display unit 4 is changed to change the display position of the virtual image by changing the thickness in the optical axis direction of the optical element 2 described above. It is also possible to change continuously from a distance to a close position. Further, by arranging the image display unit 4 to be inclined with respect to the optical axis normal of the concave mirror 1, it is possible to correct the difference in the magnification of the virtual image in the vertical direction.
  • the image light emitted toward the concave mirror 1 from the image display unit 4 is reflected on the surface of the optical element 2 disposed halfway and is displayed on the image display unit 4.
  • the light may be reflected back and superimposed on the original image light to degrade the image quality.
  • an antireflection film is formed on the surface of the optical element 2 to suppress reflection, but also the lens surface shape of at least one of the image light incident surface and the output surface of the optical element 2 is The concave surface is directed to 4 so that the above-described reflected light is not condensed on a part of the image display unit 4.
  • the image display unit 4 (hereinafter, also referred to as a liquid crystal panel), in order to absorb the reflected light from the optical element 2 described above, in addition to the first polarizing plate disposed close to the liquid crystal panel 4 If the second polarizing plate is disposed separately from the liquid crystal panel 4, the deterioration of the image quality can be reduced. Further, the backlight 5 of the liquid crystal panel 4 is controlled so that the incident direction of light incident on the liquid crystal panel 4 is efficiently incident on the incident pupil of the concave mirror 1. At this time, if the divergence angle of the light beam incident on the liquid crystal panel 4 is made small, not only the video light can be efficiently directed to the driver's viewpoint 8 but also a video with high contrast and high visibility is obtained. Is possible.
  • FIG. 5 is a diagram showing the angle characteristics of the backlight luminance of the liquid crystal panel in the vertical direction.
  • FIG. 6 is a diagram showing the angle characteristics of the contrast of the liquid crystal panel in the vertical direction.
  • the contrast performance with respect to the divergence angle of the image is within ⁇ 20 degrees in the vertical direction, and excellent characteristics are obtained.
  • a solid light source having a long product life in particular, an LED (Light Emitting Diode) having a small change in light output with respect to fluctuation of ambient temperature is preferable.
  • PBS Polarizing Beam Splitter
  • polarizing plates are disposed on the light incident surface side and the light emitting surface side, thereby enhancing the contrast ratio of the image light.
  • a high contrast ratio can be obtained by adopting an iodine-based polarizing plate having a high degree of polarization as the polarizing plate provided on the light incident surface side.
  • a dye-based polarizing plate on the light emitting surface side high reliability can be obtained even when external light is incident or when the environmental temperature is high.
  • a ⁇ / 4 plate may be disposed on the optical element 2 side of the polarizing plate disposed on the exit surface side of the liquid crystal panel 4 to convert image light aligned in a specific polarization direction into circularly polarized light. preferable.
  • the windshield 6 as a projection member is present on the front part of the driver's seat of the car body 101.
  • the windshield 6 has different inclination angles with respect to the vehicle body depending on the type of automobile.
  • the inventors investigated the radius of curvature of the windshield 6 in order to realize an optimum virtual image optical system.
  • the windshield 6 is different in the horizontal curvature radius Rh parallel to the contact surface of the automobile and the vertical curvature radius Rv orthogonal to the horizontal axis. It is found that there is a general relationship of Rh> Rv between and Rv. Specifically, it was also found that the ratio of radius of curvature Rh / Rv was often in the range of 1.5 times to 2.5 times.
  • the commercial product was investigated also about the inclination angle of the windshield 6.
  • FIG. As a result, depending on the vehicle type, it was 20 degrees to 30 degrees for the minicar and 1 Box type, 30 degrees to 40 degrees for the sedan type, and 40 degrees or more for the sport type. Therefore, in the present embodiment, the virtual image optical system is designed in consideration of the difference between the horizontal curvature radius Rh of the windshield and the curvature radius Rv in the vertical direction, and the inclination angle of the windshield.
  • the horizontal curvature radius Rh and the vertical curvature radius Rv of the windshield 6 are largely different, they are in a plane perpendicular to the optical axis (Z axis), that is, perpendicular to the horizontal direction (X axis) of the windshield 6
  • Z axis optical axis
  • X axis horizontal direction
  • Y axis vertical curvature radius
  • the viewing angle (FOV) is 7 degrees in the horizontal direction and 2.6 degrees in the vertical direction, and the virtual image distance is 2 m, as a condition for the miniaturization study.
  • one optical path turning mirror was disposed between the video display unit 4 and the concave mirror 1 with the concave mirror 1 for generating a virtual image, the video display unit 4 and the backlight 5 as basic configurations.
  • simulations were performed using the arrangement of each member and the distance from the image display unit 4 to the concave mirror 1 as parameters.
  • the volume of the information display device 100 became 3.6 liters.
  • the optical path turning mirror a flat mirror provided to increase the optical path length or reduce the volume.
  • FIG. 7 is an entire configuration diagram of the virtual image optical system in FIG. 1 and is shown together with the information display device 100 including the windshield 6 and the viewpoint 8 of the driver.
  • FIG. 8 is a diagram showing the basic configuration of the virtual image optical system, and the miniaturization will be described based on this.
  • the concave mirror 1 is drawn as a plane mirror for the sake of simplicity.
  • the optical element 2 for aberration correction is omitted for simplification of the description.
  • a liquid crystal panel is assumed for the image display unit 4, and a configuration in which the backlight 5 is disposed behind is basically used.
  • the image display unit 4 arranges the displayed image so that a virtual image can be obtained by the concave mirror 1.
  • the restriction condition is that when the image light R1 from the upper end of the screen of the image display unit 4, the image light R2 from the center, and the image light R3 from the lower end are reflected by the concave mirror 1 in the light beam shown in FIG. It is to arrange so that light may not be blocked by interfering with the image display unit 4.
  • the distance between the concave mirror 1 and the image display unit (liquid crystal panel) 4 so as to satisfy the above-mentioned constraint conditions and the above-mentioned study conditions (FOV horizontal: 7 degrees, vertical: 2.6 degrees, virtual image distance 2 m)
  • the volume of the information display apparatus 100 was determined using Z as a parameter.
  • the distance Z is a distance along the image light R 2 and is a horizontal distance between the center of the concave mirror 1 and the center of the image display unit 4.
  • FIG. 9 is a diagram showing the positional relationship between the concave mirror 1 and the image display unit 4, and shows the distance Z as a parameter.
  • the distance Z is 100 mm
  • the configuration is as shown in (c), and in this case, the vertical dimension of the concave mirror 1 can be made the smallest.
  • the distance Z is 75 mm, as shown in (b), the angle ⁇ 2 between the horizontal plane and the concave mirror 1 increases, and the vertical dimension of the concave mirror 1 also increases.
  • the distance Z is further shortened to 50 mm or less, as shown in (a), the angle ⁇ 3 between the horizontal plane and the concave mirror 1 becomes larger, and the vertical dimension of the concave mirror 1 also becomes larger.
  • the set height is increased.
  • FIG. 10 is a diagram showing the relationship between the distance Z and the volume of the information display device 100.
  • the relationship between the distance Z and the set volume is steeper in the set volume (including the LCD drive circuit, the light source drive circuit, the backlight volume, etc.) compared to the change in the spatial volume from the image display unit 4 to the concave mirror 1 .
  • the distance between the image display unit 4 and the upper end of the concave mirror 1 (corresponding to the light beam R1) is long, and the distance between the image display unit 4 and the lower end of the concave mirror 1 (corresponding to the light beam R3) is short. Therefore, it is preferable to dispose the video display unit 4 so that the distance between the video display unit 4 and the concave mirror 1 is as uniform as possible. Then, the optimum value of the distance Z is determined so as to satisfy the condition that the distance between the image display unit 4 and the concave mirror 1 becomes uniform.
  • the display surface (hereinafter, panel surface) of the liquid crystal panel which is the image display unit 4 is characterized in that it has a curved shape.
  • the optical element 2 is disposed to reduce distortion and aberration generated by the concave mirror 1.
  • the optical element 2 is a transmission type optical lens, and has the following configuration in order to reduce the change of the refractive power of the lens due to the change of the refractive index and the shape due to the change of the ambient temperature.
  • the distortion of the locally generated distortion is corrected by diverging the image light from the image display unit 4 by the optical element 2 and refracting the position where the image light is incident on the concave mirror 1 from the optical axis can do. At this time, since the lens action of the optical element 2 has negative refractive power on the optical axis, it is necessary to increase the relative positive refractive power of the concave mirror 1.
  • the above is the correction of distortion in the vicinity of the optical axis of the concave mirror 1, but by making the shape of the optical element 2 an aspheric shape, a decentered aspheric shape away from the optical axis, or a free curved surface shape
  • the optical element 2 has local positive or negative refractive power, and distortion can be corrected at a higher degree.
  • the degree of freedom of aberration correction is increased, and the above-described distortion is also corrected.
  • a plurality of transmissive optical elements may be used.
  • FIG. 11 is a view for explaining a typical state of field curvature (distortion).
  • (A) is an image pattern without distortion
  • (b) shows a state in which pincushion distortion occurs
  • (c) shows a state in which barrel distortion occurs. Therefore, the virtual image optical system of the present embodiment is characterized in that the liquid crystal panel surface which is the image display unit 4 has a curved shape.
  • FIG. 12 is a view schematically showing a configuration in which the liquid crystal panel surface has a curved shape.
  • a panel surface 4 a shown by a solid line
  • curvature of field generated is reduced.
  • An optical system using such a concave panel will be referred to as a "first virtual image optical system”.
  • the panel surface may be reversely directed as indicated by a reference numeral 4b (indicated by a broken line), and may be curved so as to be convex with respect to the concave mirror 1 (indicated by a broken line).
  • An optical system using such a convex panel is called a "second virtual image optical system".
  • the curvature of field generated is increased, and the image plane position is further moved away from the driver.
  • the size of the virtual image that can be obtained as the virtual image formation position is further increased.
  • the aberration correction capability can be compensated by providing a plurality of the optical elements 2 described above, and a good virtual image with high visibility can be obtained.
  • the curvature of the image plane of the image from the image display unit 4 can also be reduced by curving it in conformity with the curved surface of the windshield 6 as well. Specifically, since the curvature radius Rv in the vertical direction of the windshield 6 is smaller than the curvature radius Rh in the horizontal direction, optical power in the vertical direction is large when the windshield 6 is replaced with a concave mirror. For this reason, the curvature of curvature in the vertical direction of the panel surface 4a is reduced relative to the horizontal direction to reduce the curvature of field. This can be realized by making the panel surface 4 a convexly curved with respect to the light source 5 (first virtual image optical system). In addition, as described above, since the windshield 6 has different radii of curvature in the vertical direction and the horizontal direction, the curved shape of the panel surface 4 a is also set corresponding to the different radius of curvature of the windshield 6. Is preferred.
  • the miniaturization of the device is realized, and the curvature of field by the optical element 2 which is indispensable for the miniaturization of the device is reduced. Then, the reflection at the concave mirror 1 can display a highly visible virtual image at high resolution.
  • FIG. 13 is a diagram showing a configuration in which the light emitting surface of the light source 5 is curved together with the liquid crystal panel surface.
  • the radius of curvature of the light emitting surface of the light source 5a (shown by a solid line) is made to substantially coincide with the radius of curvature of the panel surface 4a so as to be concave with respect to the concave mirror 1.
  • the reflection at the concave mirror 1 can display a highly visible virtual image with higher luminance and resolution.
  • the radius of curvature of the light emitting surface of the light source 5b (shown by a broken line) is made to substantially coincide with the radius of curvature of the panel surface 4b and configured to be convex with respect to the concave mirror 1. .
  • the effect in this case is the same as that of the first virtual image optical system.
  • FIG. 14 shows a ray diagram of the entire virtual image optical system of this embodiment, where (a) is a cross-sectional view in the vertical direction (Y-axis direction) and (b) is a cross-sectional view in the horizontal direction (X-axis direction).
  • AB represents an image light source
  • A'B ' represents the position of a virtual image, and indicates the positional relationship between the concave mirror 1 and the windshield 6.
  • FIG. 15 is a ray diagram in which a part of the virtual image optical system of FIG. 14 is enlarged, and the vicinity of the optical element 2, the concave mirror 1, and the windshield 6 is enlarged.
  • the optical element 2 is composed of two lens elements.
  • a method of bending a liquid crystal panel as an image display unit according to an embodiment of the present invention will be described below.
  • the cover glass As a base material into a necessary curved shape.
  • the desired shape is obtained by heating the flat glass substrate to a thermal deformation temperature, pressing it with a mold having a desired curved surface shape, deforming it, and precooling it.
  • a liquid crystal panel is bonded to the obtained curved glass substrate in accordance with the curved surface.
  • the device may be large and the manufacturing tact may be long and productivity may be low.
  • a method of bonding a liquid crystal panel or the like to a member curved in the air for example, described in JP-A-2016-179600.
  • JP-A-2016-179600 There is a technology of
  • FIG. 16 is an external view of an image display unit (liquid crystal panel) 4 and a light source (backlight) 5.
  • the liquid crystal panel 4 includes a panel display surface 11, a frame 12, and a flexible substrate 10, and the backlight 5 includes an exterior member 16 that houses a light source unit, a diffusion member 14, a frame 15, and heat dissipating fins 13.
  • the liquid crystal panel 4 displays an image on the panel display surface 11 by modulating the light from the backlight 5 with the image signal input from the flexible substrate 10.
  • the displayed image is converted into a virtual image by the virtual image optical system, and is transmitted to the driver as image information.
  • the output surfaces of the liquid crystal panel 4 and the backlight 5 are shown as a plane for simplicity, but as shown in FIG. 12 and FIG. 13, they have a curved shape as needed.
  • a relatively inexpensive and reliable LED light source is used as a light emitting element of the backlight 5 as a solid state light emitting element. Since the LED uses a surface emitting type to achieve high output, the light utilization efficiency is improved using the technical device described later.
  • the luminous efficiency with respect to the input power of the LED varies depending on the luminous color, but is about 20 to 30%, and most of the remaining is converted to heat.
  • the frame 15 to which the LED is attached is provided with fins 13 for heat dissipation made of a member with high thermal conductivity (for example, a metal member such as aluminum) to dissipate the heat to the outside, thereby the luminous efficiency of the LED itself Improve.
  • the red light emitting LEDs currently on the market are greatly reduced in luminous efficiency as the junction temperature increases, and at the same time the chromaticity of the image is changed, so the temperature reduction priority of the LEDs is increased. It is preferable to enlarge the area of the corresponding radiation fin 13 to increase the cooling efficiency.
  • a light guide symbol 18 in FIG. 17
  • FIG. 17 is an enlarged view of the light source unit 9 in the backlight 5.
  • the light source unit 9 has a light funnel unit 20 including a plurality of LED light sources, a light guide 18 and a diffusion member 14.
  • the light funnel unit 20 takes in diverging rays from the plurality of LEDs 21 at the openings 23 of the corresponding plurality of light funnels 22.
  • the opening 23 is a flat surface, and a medium is inserted between the LED 21 and optically connected, or a convex light shape is provided to have a condensing action, so that diverging source light is parallel light as much as possible.
  • the incident angle of light incident on the interface of the light funnel 22 is reduced.
  • the divergence angle can be further reduced after passing through the light funnel 22, control of light source light directed to the liquid crystal panel 4 after being reflected by the light guide 18 becomes easy.
  • polarization conversion is performed using a polarization conversion element (PBS) at the junction 25 of the light funnel 22 and the light guide 18 to convert it into a desired polarization direction.
  • PBS polarization conversion element
  • a light flux from the LED 21 whose divergence angle is reduced is controlled by the light guide 18, and is reflected by the total reflection surface provided on the slope of the light guide 18, and a diffusion member disposed between the facing surface and the liquid crystal panel 4 After being diffused by the light source 14, the light enters the liquid crystal panel 4.
  • the diffusion member 14 is disposed between the light guide 18 and the liquid crystal panel 4 in the present embodiment, a structure in which the end face of the light guide 18 has a diffusion effect, for example, a structure in which a minute uneven shape is provided The same effect is obtained.
  • FIG. 18 is a view showing the appearance of the light guide 18.
  • the luminous flux whose divergence angle is reduced by the light funnel 22 shown in FIG. 17 enters the incident surface 18a of the light guide 18 and exits from the emission surface 18c.
  • the divergence angle in the vertical direction (vertical direction in FIG. 19) is controlled by the shape effect (the cross-sectional shape is shown in FIG. 19) of the incident surface 18a, and the light is efficiently propagated in the light guide 18.
  • FIG. 19 is an enlarged sectional view of an essential part of the light guide 18.
  • the light source light whose divergence angle is reduced by the light funnel 22 is incident from the incident surface 18a via the joint portion 25 as shown in (a), totally reflected by the prism 18b provided on the opposite surface, and then emitted. Head to face 18c.
  • the total reflection prism 18b is in the vicinity of the incident surface 18a ((b), B part enlargement) and at the end ((c) figure, A part enlargement), the shape is the divergence angle of the light beam incident on each surface Accordingly, it is divided into steps and formed, thereby controlling the angle of the total reflection surface.
  • the division size of the reflection surface of the total reflection prism 18b is taken as a variable so that the light quantity distribution in the light exit surface of the liquid crystal panel 4 becomes uniform after the light flux incident on the liquid crystal panel 4 is reflected. Control the arrival position and the amount of energy.
  • FIG. 20 is a view showing a simulation result in a state where the light emitted from the backlight 5 has passed through the liquid crystal panel 4.
  • (A) shows the emission state of light as viewed from the longitudinal direction of the liquid crystal panel 4, and
  • (b) shows the emission state of light as viewed from the lateral direction of the liquid crystal panel 4.
  • the horizontal diffusion angle is increased relative to the vertical direction, and even when the driver shakes his head or the eye position moves, It is designed so that the brightness of the virtual image visually recognized by the left and right eyes does not change extremely. Further, by reducing the divergence angle in the vertical direction of the backlight 5, the divergence angle in the screen vertical direction of the image displayed on the liquid crystal panel 4 is reduced, thereby suppressing the occurrence of double images.
  • FIG. 21 is a diagram showing the luminance distribution of the exit surface of the liquid crystal panel 4.
  • the light guide 18 is used for the backlight 5 to control the light emission direction and intensity.
  • the inclination of the luminance reduction can be reduced outside the effective range in the screen horizontal direction (X-axis direction) with respect to the luminance distribution in the screen vertical direction (Y-axis direction).
  • the angle of the total reflection surface of the light guide 18 and the light source light from the LED 21 by the light funnel 22 are obtained so that the emitted light from the liquid crystal panel 4 taken into the virtual image optical system can be obtained as light perpendicular to the screen.
  • the divergence angle of to narrow the viewing angle characteristics of the backlight 5 to a small range high luminance is obtained.
  • light with a range of ⁇ 30 ° at the left and right viewing angles is used, and in consideration of contrast performance, focusing on ⁇ 20 ° or less simultaneously achieves good image quality. I could get a virtual image using video.
  • the contrast performance that affects the image quality of the video display unit is determined by how much the luminance (black luminance) in black display, which is the basis for determining the image quality, can be reduced. Therefore, it is preferable to use an iodine-based polarizing plate having a high degree of polarization between the liquid crystal panel 4 and the backlight 5. On the other hand, by using a dye-based polarizing plate as the polarizing plate provided on the light emitting surface side of the liquid crystal panel 4, high reliability can be obtained even when external light is incident or when the environmental temperature is high.
  • color filters corresponding to the respective pixels are provided. Therefore, when the light source color of the backlight 5 is white, the light absorption by the color filter is large and the loss is large. Therefore, as shown in FIG. 17 above, using a plurality of LEDs 21, (1) A green LED having a large contribution to brightness is added as compared to the case where a plurality of white LEDs are used. (2) Add red or blue LED to white LED to enhance the glossiness of the image. (3) If the red, blue, and green LEDs are individually arranged, and the green LEDs that have a large contribution to the brightness are added to drive the LEDs individually, the color reproduction range is expanded and the glossiness is enhanced. The brightness also improves at the same time.
  • the transmittance of each color filter with respect to the peak luminance of the red, blue, and green LEDs is increased to improve the overall brightness.
  • PBS is placed between the light funnel and the light guide and aligned to a specific polarization, thereby reducing damage to the polarizing plate on the liquid crystal panel incident side Do.
  • the polarization direction of the polarizing plate disposed on the liquid crystal panel incident side may be a direction through which polarized light aligned in a specific direction passes through the PBS.
  • the image display unit 4 it is also possible to provide a ⁇ / 4 plate on the exit surface of the liquid crystal panel to make the exit light circularly polarized. As a result, the driver can observe a good virtual image even when wearing polarized sunglasses.
  • the liquid crystal panel is assumed to have a structure in which liquid crystal is sealed between transparent glass substrates, but is not limited to this.
  • the backlight is not limited to the side light type using a light guide, but may be a direct type.
  • the curved shape of the liquid crystal panel may be a curved one axis or a curved one having two or more axes. In that case, the curvature of the curvature at the center of the liquid crystal panel may be different from the curvature at the periphery.
  • shafts you may make curvature different for every axis
  • the reflection film of the reflection mirror used in the virtual image optical system is formed of a metal multilayer film, the angle dependency of the reflectance is small, and the reflectance changes depending on the polarization direction (P wave or S wave) Therefore, the chromaticity and brightness of the screen can be kept uniform.
  • the liquid crystal can be obtained even when external light (sunlight) is incident. Since the panel and the polarizing plate can be reduced from the temperature rise and damage, the reliability of the information display device is not impaired.
  • the virtual image optical system of this embodiment performs optimum design including the difference between the curvature radius in the vehicle horizontal direction and the curvature radius in the vertical direction of the windshield as the projection member, and the windshield 5 and the image display unit 4 (or an intermediate image A concave mirror 1 having a concave surface facing the front glass 6 is disposed between the display sections), whereby the image of the video display section 4 is enlarged and reflected on the front glass 6.
  • the optical element 2 is disposed between the concave mirror 1 and the image display unit 4 described above, and on the other hand, an enlarged image (virtual image) of the image formed corresponding to the viewpoint position 8 of the driver.
  • the image light beam forming the light passes through the optical element 2 disposed between the image display units 4 and corrects distortion and aberration generated in the concave mirror 1. Therefore, it is possible to obtain a virtual image in which distortion and aberration are greatly reduced as compared with the conventional virtual image optical system of only the concave mirror 1.
  • the virtual image VI obtained by being reflected by the upper portion (upper portion in the vehicle body vertical direction) of the windshield 6 needs to be imaged farther.
  • the above-described optical element disposed between the concave mirror 1 and the image display unit 4 The focal length f1 of the element 2 is set short.
  • the virtual image obtained by being reflected by the lower part (lower part in the vehicle body vertical direction) of the windshield 6 needs to be imaged closer.
  • the combined focal length f2 of the element 2 may be set relatively long.
  • the information display device of the present embodiment is mounted on a car and observed as a virtual image through a windshield, the present invention is not limited to this.
  • the information display device is mounted on a "vehicle" such as a train or an aircraft. The same applies to the case where the
  • the present invention is not limited to the embodiments described above, but includes various modifications.
  • the above-described embodiment describes the entire apparatus in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to one having all the described configurations.
  • part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Instrument Panels (AREA)
  • Lenses (AREA)

Abstract

La présente invention concerne un dispositif d'affichage d'informations susceptible d'obtenir une image virtuelle plus grande ayant une visibilité élevée tout en réduisant la taille du dispositif. Un dispositif d'affichage d'informations (100) pour projeter une vidéo sur un élément d'écran (6) comprend : une unité d'affichage vidéo (4) pour générer une lumière vidéo avec une source de lumière (5) disposée derrière celle-ci; et un système optique qui réfléchit la lumière vidéo générée par l'unité d'affichage vidéo (4) avec un miroir concave (1) pour projeter la lumière vidéo sur l'élément d'écran (6), affichant ainsi une image virtuelle (VI) devant l'élément d'écran. La surface d'affichage de l'unité d'affichage vidéo (4) est configurée pour avoir une surface incurvée faisant face au miroir concave (1). Ici, la forme incurvée de la surface d'affichage de l'unité d'affichage vidéo (4) est définie pour réduire la distorsion de surface d'image générée dans l'image virtuelle (VI) provoquée par la forme du miroir concave (1).
PCT/JP2018/043544 2017-12-27 2018-11-27 Dispositif d'affichage d'informations WO2019130948A1 (fr)

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JP2017-250869 2017-12-27
JP2017250869A JP7021939B2 (ja) 2017-12-27 2017-12-27 情報表示装置

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CN115113394A (zh) * 2021-03-23 2022-09-27 群创光电股份有限公司 抬头显示***
EP4261594A4 (fr) * 2020-12-14 2024-05-29 Jvckenwood Corp Dispositif d'affichage
JP7493149B2 (ja) 2020-10-28 2024-05-31 パナソニックＩｐマネジメント株式会社 光屈折部材、光学システム、照明システム、表示システム、移動体及び金型

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WO2017072841A1 (fr) * 2015-10-27 2017-05-04 日立マクセル株式会社 Dispositif d'affichage d'informations
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JP2018112628A (ja) * 2017-01-10 2018-07-19 株式会社デンソー ヘッドアップディスプレイ装置

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US6402321B1 (en) * 1999-10-29 2002-06-11 Delphi Technologies, Inc. Head up display with modular projection system
WO2015186488A1 (fr) * 2014-06-03 2015-12-10 矢崎総業株式会社 Dispositif d'affichage par projection pour véhicule
JP2016136222A (ja) * 2014-10-24 2016-07-28 株式会社リコー 画像表示装置及び物体装置
JP2017072668A (ja) * 2015-10-06 2017-04-13 株式会社ジャパンディスプレイ 表示装置及び表示システム
WO2017072841A1 (fr) * 2015-10-27 2017-05-04 日立マクセル株式会社 Dispositif d'affichage d'informations
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JP2018112628A (ja) * 2017-01-10 2018-07-19 株式会社デンソー ヘッドアップディスプレイ装置

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7493149B2 (ja) 2020-10-28 2024-05-31 パナソニックＩｐマネジメント株式会社 光屈折部材、光学システム、照明システム、表示システム、移動体及び金型
EP4261594A4 (fr) * 2020-12-14 2024-05-29 Jvckenwood Corp Dispositif d'affichage
CN115113394A (zh) * 2021-03-23 2022-09-27 群创光电股份有限公司 抬头显示***

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