JP2007108429A - Display device and headup display device for vehicle equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the luminance unevenness of illumination light passing through a display unit while suppressing the degradation in the luminance in a display device equipped with the display unit, a light source for transmissively illuminating the same, and a diffusion plate for transmissively illuminating the display unit by uniformizing the light from the light source. <P>SOLUTION: The display device 2 is equipped with the display unit 21 which displays desired information by being transmissively illuminated, the light source 22 which is arranged behind the display unit 21 and transmissively illuminates the display unit 21, the diffusion plate 24 which uniformizes the light emitted from the light source 22, and a first condensing lens 23 which condenses the light uniformized by the diffusion plate 24 to the display unit 21 to transmissively illuminate the display unit 21. As a result, the luminance unevenness of the transmissive illumination light can be reduced by the diffusion plate 24 while the degradation in the luminance of the transmissive illumination light is suppressed by the first condensing lens 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device and a vehicle head-up display device including the display device.

  The vehicle head-up display device (HUD) includes a display device, a reflecting mirror, and a half mirror formed on the inner surface of the windshield.

  The display device emits display light representing information, the reflecting mirror reflects display light from the display device toward the half mirror (wind shield), and the half mirror is reflected from the reflecting mirror. The reflected light is reflected toward the driver side. The HUD causes the driver to recognize the information on the display device as a virtual image when the half mirror reflects the reflected light from the reflecting mirror toward the driver.

  The display device includes a display such as a liquid crystal panel that displays desired information by being transmissively illuminated, and a light source that illuminates the display.

A general display device including a liquid crystal panel and a light source that transmits and illuminates the liquid crystal panel is disclosed in which a plurality of light emitting diodes are arranged as a light source and a diffusion plate is provided between the light emitting diodes and the liquid crystal panel. (See Patent Document 1).
JP-A-1-179913

  Although not described in Patent Document 1, the diffuser plate is intended to reduce unevenness in luminance of illumination light transmitted through the liquid crystal panel by uniformizing light emitted from a plurality of light emitting diodes. However, since the light source of the light emitting diode is almost a point light source, there is a possibility that the luminance unevenness of the illumination light transmitted through the liquid crystal panel cannot be sufficiently reduced.

  On the other hand, in order to reduce this luminance unevenness, it is conceivable that the diffuser plate enhances the function of making the light uniform (the function of diffusing light). However, in this case, since the illumination light transmitted through the liquid crystal panel is further diffused by the diffusion plate, there arises a problem that the luminance of the transmitted illumination light is lowered.

  If such a display device is used for the HUD, if the luminance unevenness of the transmitted illumination light cannot be reduced, there is a problem that the display unevenness occurs in the display of the HUD. If the brightness of the transmitted illumination light is low, the display of the HUD is weakened. The problem arises.

  This problem is not limited to liquid crystal panels, but is a problem common to displays that display desired information by being transmitted and illuminated, and is a problem common to light sources such as lamps as well as light-emitting diodes. Not limited to a display device that includes a display that displays desired information by being transmissively illuminated, a light source that transmissively illuminates the display, and a diffuser that illuminates the display by uniformizing light from the light source. It is a problem to do.

  The present invention has been made in view of the above points, and in a display device including a display, a light source that transmits and illuminates the display, and a diffusion plate that uniformizes light from the light source and transmits and illuminates the display. An object of the present invention is to reduce luminance unevenness while suppressing a decrease in luminance of illumination light transmitted through a display.

  In order to achieve the above object, the present invention employs the following technical means.

  The display device according to claim 1, wherein a display that displays desired information by being transmitted and illuminated, a light source that is disposed behind the display and that illuminates the display, and light emitted from the light source is made uniform And a first condensing lens that condenses the light uniformized by the diffusing plate onto the display and illuminates the display.

  In this configuration, the light emitted from the light source is made uniform by the diffuser plate, and the light that has been made uniform and diffused and spread is condensed by the first condenser lens to transmit the display to the display. Thereby, the brightness | luminance nonuniformity of transmitted illumination light can be reduced with a diffuser plate, suppressing the fall of the brightness of transmitted illumination light with the 1st condensing lens.

  The display device according to claim 2 includes a second condenser lens that is disposed between the light source and the diffusion plate and collects the light emitted from the light source onto the diffusion plate.

  In this configuration, since the light emitted from the light source is condensed on the diffusion plate by the second condenser lens, it is possible to further suppress the decrease in the luminance of the transmitted illumination light while obtaining the above-described effect.

  The display device according to claim 3 includes a plurality of light sources and a plurality of second condenser lenses corresponding to each of the plurality of light sources.

  In this configuration, a plurality of light sources are provided, and the same plurality of second condenser lenses are provided in correspondence with each of the plurality of light sources. Thereby, the above-described effects can be obtained in a display device including a display device having a large area.

  According to a fourth aspect of the present invention, the light source is composed of a light emitting diode and the display is composed of a liquid crystal panel.

  Even with this configuration, the above-described effects can be obtained.

  A vehicle head-up display device according to claim 5 is a vehicle head-up display device comprising the display device according to any one of claims 1 to 4, wherein the vehicle head-up display device transmits a display. The display light representing the desired information is configured to include a reflecting mirror that reflects toward the windshield of the host vehicle and a reflector that is provided on the windshield side and reflects the reflected light from the reflecting mirror.

  In this configuration, the vehicle head-up display device includes the display device according to any one of claims 1 to 4. Thereby, in the head-up display device for a vehicle, the display unevenness can be reduced while suppressing the display from being weakened.

  Hereinafter, a case where the display device according to the present invention is applied to a head-up display device for a vehicle will be described with reference to the drawings.

(Constitution)
FIG. 1 is a schematic diagram showing an overall configuration of a vehicle head-up display device 1 according to an embodiment of the present invention.

  FIG. 2 is a schematic view showing the instrument panel 7, the windshield 8, and the periphery thereof in front of the vehicle interior.

  FIG. 3 is a schematic perspective view showing the internal configuration of the vehicle head-up display device 1 shown in FIG.

  4 is a view taken along arrow VI in FIG. 3 showing the internal configuration of the display device 2 shown in FIG.

  5 is a cross-sectional view taken along line VV in FIG.

  FIG. 6 is a circuit configuration diagram illustrating an electrical circuit configuration of the vehicle head-up display device 1 (display device 2) according to the embodiment of the present invention.

  As shown in FIG. 1, a vehicle head-up display device (HUD) 1 includes a display device 2, a plane mirror 3 and a concave mirror 4 that are reflecting mirrors, and an inner surface of a windshield 8 (a vehicle interior side surface in FIG. 1). And a half mirror 6 that is a reflector formed on the right side surface). A casing 5 disposed inside the instrument panel 7 (on the lower side in FIG. 1) contains the display device 2, the plane mirror 3, and the concave mirror 4.

  As shown in FIG. 2, the half mirror 6 is formed on the windshield 8 on the driver's seat side (right side in FIG. 2). The casing 5 containing the display device 2 and the like is arranged below the half mirror 6 in FIG. 2, that is, behind the combination meter 11 and below the instrument panel 7 in FIG.

  The display device 2 emits display light representing, for example, travel speed information, and the plane mirror 3 and the concave mirror 4 reflect the display light from the display device 2 toward the half mirror 6 (wind shield 8). The half mirror 6 reflects the reflected light from the concave mirror 4 toward the driver M.

  The HUD 1 causes the driver M to recognize the real image 2A of the information represented by the display light emitted from the display device 2 as the virtual image 2B when the half mirror 6 reflects the reflected light from the concave mirror 4 to the driver M. is there.

  In the casing 5, the display device 2, the plane mirror 3, and the concave mirror 4 are arranged as shown in FIG. That is, the plane mirror 3 is arranged at a position where the display light emitted from the display device 2 can be reflected to the concave mirror 4, and the concave mirror 4 is arranged at a position where the reflected light from the plane mirror 3 can be reflected to the half mirror 6. The concave mirror 4 enlarges and displays the virtual image 2B with respect to the real image 2A.

  As shown in FIGS. 4 and 5, the display device 2 includes a liquid crystal panel 21 that is a display, a light-emitting diode 22 that is a light source, a first condenser lens 23, a diffusion plate 24, and a second condenser lens. 25 and a printed circuit board 26 on which the light emitting diode 22 is mounted. These are built in the casing part 27.

  The liquid crystal panel 21 displays desired information (for example, traveling speed) by being transmissively illuminated, and the light emitting diode 22 is disposed behind the liquid crystal panel 21 to illuminate the liquid crystal panel 21. . The second condenser lens 25 is a convex lens that condenses the light emitted from the light emitting diode 22 onto a predetermined region, that is, the diffuser plate 24, and the diffuser plate 24 is condensed by the second condenser lens 25. The light is made uniform. The first condenser lens 23 is a convex lens that condenses and spreads the light spread and diffused by the diffusion plate 24 onto a predetermined region, that is, the liquid crystal panel 21. .

  Here, the liquid crystal panel 21 has, for example, a shape that is long in the horizontal direction (vertical direction in FIG. 4), and five light emitting diodes 22 are arranged in one row in the horizontal direction. The second condenser lenses 25 are arranged in correspondence with each of the five light emitting diodes 22, that is, five in a row in the lateral direction. The five second condenser lenses 25 are integrally formed from a transparent resin such as an acrylic resin.

  Similarly, the diffusion plate 24 and the first condenser lens 23 are formed of a transparent resin such as an acrylic resin. However, the diffusion plate 24 is subjected to a light diffusion process in order to make the incident light uniform (diffuse).

  Light emitted from the light emitting diode 22 illuminates and transmits the liquid crystal panel 21 through the second condenser lens 25, the diffusion plate 24, and the first condenser lens 23. Thereby, the liquid crystal panel 21 displays the traveling speed, and the display device 2 emits display light representing the traveling speed.

  For easy understanding of FIGS. 1 and 3, the casing 5 is illustrated by a one-dot chain line, and for easy understanding of FIGS. 4 and 5, the casing portion 27 is illustrated by a one-dot chain line. .

  The electric circuit configuration of the HUD 1 (display device 2) according to the present embodiment described above will be described with reference to FIG.

Power is always supplied from the battery 13 to the control device 9 constituted by a microcomputer or the like. The ignition switch 12 is connected so as to be able to detect its operating state (ON or OFF), and a speed sensor 10 for detecting the traveling speed of the automobile is connected so that a detection signal can be inputted. Further, the liquid crystal panel 21, the light emitting diode 22, and the combination meter 11 are also connected to the control device 27.
(Operation)
The operation of the HUD 1 according to this embodiment in the above configuration will be described.

  When the ignition switch 12 is turned on by the driver, the control device 9 detects it and starts operation. That is, in FIG. 6, the vehicle speed of the vehicle is calculated based on the output signal from the speed sensor 10, the vehicle speed is displayed on the liquid crystal panel 21, and the light emitting diode 22 is turned on.

  As shown in FIG. 5, the light from the light emitting diode 22 enters the second condenser lens 25 along the optical path P <b> 1, is condensed by the second condenser lens 25, and enters the diffusion plate 24. The incident light is made uniform (diffused) by the diffusion plate 24 along the optical path P <b> 2 and enters the first condenser lens 23. This incident light is condensed by the first condenser lens 23 along the optical path P3 and illuminates the liquid crystal panel 21.

  That is, most of the light from the light emitting diode 22 which is a point light source is efficiently condensed by the second condenser lens 25 and the first condenser lens 23 and is made uniform by the diffusion plate 24 disposed therebetween. The liquid crystal panel 21 is transmitted and illuminated. As a result, the illumination light of the liquid crystal panel 21 can be transmitted and illuminated through the liquid crystal panel 21 with the luminance unevenness reduced while suppressing the decrease in luminance. As a result, it is possible to reduce display unevenness while suppressing the display of the liquid crystal panel 21 from being weakened.

  Here, it can be said that the diffusing plate 24 functions as a surface light emitting portion whose luminance is uniform.

  The liquid crystal panel 21 displays the traveling speed by being transmitted and illuminated, and the display device 2 emits display light representing the vehicle speed.

  The display light emitted from the display device 2 (real image 2A of the vehicle speed display) is incident on the plane mirror 3 along the optical path P4 as shown in FIGS. 1 and 3, and is reflected by the plane mirror 3 toward the concave mirror 4 along the optical path P5. The display light (vehicle speed display real image 2A) is magnified by the concave mirror 4 and reflected toward the half mirror 6 along the optical path P6. The enlarged display light (real image 2A) is incident on the driver's eyes M along the optical path P7 by the half mirror 6 as shown in FIG.

  Thus, the driver recognizes the enlarged virtual image 2B of the vehicle speed display in front of the half mirror 6 (leftward in FIG. 1). At this time, since the driver can also recognize the scenery through the half mirror 6, the driver can recognize the virtual image 2B of the vehicle speed display superimposed on the scenery on the half mirror 6.

  Here, since it is possible to reduce the display unevenness while suppressing the display of the liquid crystal panel 21 from being weakened, the virtual image 2B of the vehicle speed display can also reduce the display unevenness while suppressing the display from being weakened. it can.

  Further, as a general effect of the vehicle head-up display device, the driver can shorten the eye movement time and reduce the focus adjustment load.

  As described above, the display device 2 according to the present embodiment has the liquid crystal panel 21 that is a display that displays desired information by being transmitted and the liquid crystal panel 21 that is disposed behind the liquid crystal panel 21 and transmits the light. A light emitting diode 22 that is a light source that emits light, a diffusion plate 24 that uniformizes light emitted from the light emitting diode 22, and a light that is uniformized by the diffusion plate 24 is condensed on the liquid crystal panel 21 to transmit and illuminate the liquid crystal panel 21. 1 condenser lens 23.

  In this configuration, the light emitted from the light emitting diode 22 is made uniform by the diffusion plate 24, and the light that has been made uniform and diffused and spread is condensed by the first condenser lens 23 and transmitted through the liquid crystal panel 21. Illuminate. As a result, the luminance unevenness of the transmitted illumination light can be reduced by the diffusion plate 23 while suppressing the decrease in the brightness of the transmitted illumination light by the first condenser lens 23.

  The display on the liquid crystal panel 21, that is, the display on the vehicle head-up display device 1, is not limited to the vehicle speed, and may be simple navigation, night view, or the like.

  In the above example, the second light collecting lens 25 is disposed between the light emitting diode 22 and the diffusion plate 24 and condenses the light emitted from the light emitting diode 22 onto the diffusion plate 24. Even if the optical lens 25 is omitted, the above-described effects can be obtained.

  However, by adding the second condenser lens 25, it is possible to further suppress the decrease in the luminance of the transmitted illumination light while obtaining the above-described effect.

  In the above example, the five second condenser lenses 25 are integrally formed, but can be formed separately.

  In the above example, five light emitting diodes 22 are arranged in one row in the horizontal direction (vertical direction in FIG. 4). However, depending on the shape and size of the liquid crystal panel 21, the light emitting diodes 22 are arranged in one row in the vertical direction. Or other numbers or multiple rows.

  Further, the display device is not limited to the liquid crystal panel 21 and may be any device as long as it transmits light and displays desired information. For example, an indicator or a warning light that is transmitted through a predetermined symbol printed on a transparent sheet. Etc. Indicators and warnings are used to notify the information indicated by the symbol or to give a warning indicated by the symbol by being illuminated.

  The display device 2 according to the present invention can be applied to devices other than the vehicle head-up display device 1.

  As described above, the light that is made uniform and diffused by the diffusion plate 24 is condensed by the first condenser lens 23 and transmitted through the liquid crystal panel 21, so that the viewing angle of the display device 2 is narrowed. . However, since the vehicle head-up display device (HUD) 1 displays the virtual image 2B in the distance and makes the driver visually recognize this, the viewing angle of the HUD 1 can be narrowed. That is, it is allowed to narrow the viewing angle of the display device 2.

  That is, the display device 2 according to the present invention is optimally applied to a vehicle head-up display device or the like that allows a narrow viewing angle.

  Moreover, not only the above-mentioned example but various combinations of the above-mentioned examples and various modifications can be considered.

FIG. 1 is a schematic diagram showing an overall configuration of a vehicle head-up display device 1 according to an embodiment of the present invention. FIG. 2 is a schematic view showing the instrument panel 7, the windshield 8, and the periphery thereof in front of the vehicle interior. FIG. 3 is a schematic perspective view showing the internal configuration of the vehicle head-up display device 1 shown in FIG. 4 is a view taken along arrow VI in FIG. 3 showing the internal configuration of the display device 2 shown in FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a circuit configuration diagram illustrating an electrical circuit configuration of the vehicle head-up display device 1 (display device 2) according to the embodiment of the present invention.

Explanation of symbols

1 Vehicle head-up display (HUD)
2 Display device, 21 Liquid crystal panel (display), 22 Light emitting diode (light source)
Reference Signs List 23 first condenser lens, 24 diffuser plate, 25 second condenser lens 26 printed circuit board, 27 casing part 3 plane mirror (reflecting mirror), 4 concave mirror (reflecting mirror), 5 casing 6 half mirror (reflector), 7 instrument Control panel, 8 windshield, 9 control device, 10 speed sensor, 11 combination meter, 12 ignition switch, 13 battery

Claims (5)

A display for displaying desired information by being transmissively illuminated;
A light source disposed behind the display for illuminating the display;
A diffusion plate for uniformizing the light emitted from the light source;
A display device comprising: a first condensing lens that condenses the light uniformized by the diffusion plate onto the display and transmits the display through the display.   The display device according to claim 1, further comprising: a second condenser lens that is disposed between the light source and the diffusion plate and collects light emitted from the light source onto the diffusion plate. A plurality of the light sources;
3. The display device according to claim 2, wherein the plurality of second condenser lenses are provided corresponding to each of the plurality of light sources. The light source is composed of a light emitting diode,
The display device according to any one of claims 1 to 3, wherein the display unit includes a liquid crystal panel. A vehicle head-up display device comprising the display device according to any one of claims 1 to 4,
A reflective mirror that reflects the display light that passes through the display and represents the desired information toward the windshield of the host vehicle;
A vehicle head-up display device comprising: a reflector that is provided on the windshield side and reflects reflected light from a reflecting mirror.

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