JP7404128B2 - heads up display device - Google Patents

Description

The present invention relates to a head-up display device.

Head-up display devices are known that reflect light representing an image displayed on a display device on the windshield (so-called windshield) of a vehicle, thereby displaying the image on the windshield as a virtual image of the space in front of the vehicle. . Thereby, the driver can visually recognize an image indicating information related to the driving of the vehicle (speed information, car navigation information, etc.) superimposed on the scenery in front of the windshield.

The display device includes a liquid crystal panel and a backlight device, and the backlight device irradiates the liquid crystal panel with light to display an image. A backlight device includes a plurality of light sources (for example, light emitting diodes) connected in series and arranged in a matrix in order to uniformly irradiate the entire surface of a liquid crystal panel with light. The brightness of the plurality of light sources is adjusted depending on the external brightness detected by, for example, an illuminance sensor disposed in the vehicle.

However, since the background brightness of the display area of the windshield is not uniform, a problem arises when a plurality of light sources emit light with the same brightness. For example, at night, the lower side of the display area, where the road surface illuminated by headlights is the background, is bright, and the upper side of the display area is dark. Conversely, during the day, the upper side of the display area, where the sky is the background, is relatively bright. If the brightness of the background of the display area varies greatly from area to area, adjusting the brightness of the light source to the brightness of some areas of the display area will deteriorate the visibility of images displayed in other areas.

On the other hand, a head-up display device has been developed in which the amount of heat generated by a backlight device is suppressed by a local dimming method in which the brightness of each light source is individually controlled (see Patent Document 1). The head-up display device suppresses the amount of heat generated by the backlight device by selectively emitting light from only the light source in the area where an image is displayed. By individually controlling the brightness of each light source according to the background brightness of each area of the display area using the local dimming method, the visibility of the image displayed in each area can be improved.

Japanese Patent Application Publication No. 2016-45244

However, when controlling the brightness of each light source individually using the local dimming method, a large number of drive circuits are required to drive each light source. Therefore, the number of parts increases and the manufacturing cost increases.

The present invention was conceived under the above-mentioned circumstances, and an object of the present invention is to provide a head-up display device that can improve the visibility of images displayed in a display area while suppressing manufacturing costs. There is.

In order to solve the above problems, the present invention takes the following technical measures.

A head-up display device provided by the present invention includes a display device and a control device that controls the display device, and reflects light representing an image displayed on the display device on a transmissive reflective section. A head-up display device that displays the image as a virtual image of the space in front of the vehicle on the transmissive reflection section, the display device including a liquid crystal panel and a backlight device that irradiates light to the liquid crystal panel, The backlight device includes a plurality of light source groups including a plurality of light sources arranged in line in the vehicle width direction and connected to each other, and the plurality of light source groups are arranged in a direction perpendicular to the vehicle width direction. They are arranged side by side, and the control device individually controls the plurality of light source groups.

According to the present invention, the backlight device includes a plurality of light source groups, and the control device individually controls each light source group. Since the brightness of each light source group can be individually controlled according to the background brightness of the area corresponding to each light source group, the visibility of the image displayed in each area is improved. Moreover, each light source group is made up of a plurality of light sources arranged side by side in the vehicle width direction and connected to each other. Therefore, one drive circuit can simultaneously drive a plurality of light sources included in the light source group. Therefore, the number of required drive circuits can be reduced compared to the case where each light source is driven individually. Thereby, manufacturing costs can be suppressed.

Other features and advantages of the invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an outline of a head-up display device according to a first embodiment. FIG. 2 is a block diagram showing the functional configuration of the head-up display device shown in FIG. 1. FIG. FIG. 2 is a block diagram showing the internal configuration of a backlight device. It is a figure which shows an example of the image displayed on a windshield. It is a figure which shows the photographed image of the front. 3 is an example of a flowchart for explaining backlight control processing according to the first embodiment. FIG. 2 is a block diagram showing the functional configuration of a head-up display device according to a second embodiment. It is an example of a flowchart for explaining backlight control processing according to a second embodiment. FIG. 3 is a block diagram showing the internal configuration of a backlight device of a head-up display device according to a third embodiment.

Embodiments of the present invention will be specifically described below with reference to the drawings.

1 to 6 are diagrams for explaining a head-up display device A1 according to the first embodiment. FIG. 1 is a schematic diagram showing an outline of a head-up display device A1. FIG. 2 is a block diagram showing the functional configuration of the head-up display device A1. FIG. 3 is a block diagram showing the internal configuration of the backlight device. FIG. 4 is a diagram showing an example of an image displayed on the windshield. FIG. 5 is a diagram showing an image of the front taken by the camera. FIG. 6 is an example of a flowchart for explaining backlight control processing according to the first embodiment.

As shown in FIGS. 1 and 2, the head-up display device A1 includes a display device 1, a first mirror 51, a second mirror 52, and a control device 4. The head-up display device A1 is arranged at a position in the vehicle width direction corresponding to the driver's seat, using the interior space of the instrument panel of the vehicle B. As shown in FIG. 1, the head-up display device A1 reflects the light representing the image displayed on the display device 1 on the windshield 7 (so-called windshield), thereby displaying the image in the space in front of the vehicle B. It is displayed on the windshield 7 as a virtual image V. The windshield 7 is a transparent plate made of glass, for example, and functions as a transmissive/reflective portion that transmits or reflects light depending on the angle of the incident light. The images displayed on the display device 1 include images showing various types of information (hereinafter referred to as "driving information") related to the traveling of the vehicle B, such as speed information and navigation information. The image displayed on the display device 1 is generated by the image generation section 60. An image containing driving information is displayed as a virtual image V superimposed on the scenery in front of the windshield 7, so the driver can direct his/her line of sight to the meter unit located on the instrument panel, the car navigation monitor, etc. It is possible to recognize driving information without moving the vehicle. For example, as shown in FIG. 4, in the display area 71 of the windshield 7, an image showing the time, vehicle speed, fuel gauge, and road information is displayed superimposed on the scenery ahead. Note that in FIG. 4, the display area 71 is shown by a two-dot chain line for convenience in order to show the range of the display area 71, but in reality, the display area 71 is not displayed on the windshield 7. Moreover, the traveling information displayed on the windshield 7 is not limited.

The display device 1 displays an image indicating travel information and emits light representing the image. In this embodiment, as shown in FIG. 1, the display device 1 is arranged in the housing of the head-up display device A1, with the display surface 1a on which an image is displayed facing slightly rearward and diagonally upward. Details of the internal configuration of the display device 1 will be described later.

The first mirror 51 is a mirror for reflecting light from the display device 1 toward the second mirror 52. In this embodiment, the first mirror 51 is arranged on the housing of the head-up display device A1 so as to reflect the reflected light from the display device 1 forward when viewed from the side. In this embodiment, the first mirror 51 is a plane mirror.

The second mirror 52 is a mirror for reflecting the reflected light from the first mirror 51 toward the windshield 7. In the present embodiment, the second mirror 52 is configured to reflect the reflected light from the first mirror 51 diagonally upward and backward toward a lower region of the windshield 7 that extends diagonally upward and rearward when viewed from the side. It is arranged in the housing of the head-up display device A1. The windshield 7 reflects the light reflected from the second mirror 52 toward the driver's viewpoint E. The windshield 7 is normally curved in a concave shape toward the indoor side, and the second mirror 52 is a concave mirror. Thereby, the image displayed on the display device 1 is displayed as an enlarged virtual image V at the end of the optical path L from the windshield 7 to the viewpoint E. The surface shape of the second mirror 52 is appropriately designed depending on the curvature of the windshield 7 and the magnification ratio of the image.

Next, details of the internal configuration of the display device 1 will be explained.

The display device 1 includes a liquid crystal panel 2 and a backlight device 3, as shown in FIG. The display device 1 is a transmissive display device in which a backlight device 3 irradiates a liquid crystal panel 2 with light and displays an image using the light that passes through the liquid crystal panel 2.

The liquid crystal panel 2 is similar to that used in general liquid crystal displays, and its type and format are not limited. In the liquid crystal panel 2, driving of each pixel (switching between passing and blocking light) is controlled by a control device 4.

The backlight device 3 includes a plurality of light emitting diodes D, and is arranged on the back side of the liquid crystal panel 2 (on the opposite side to the side where the first mirror 51 is arranged). The backlight device 3 irradiates the liquid crystal panel 2 with light emitted by the plurality of light emitting diodes D. The display device 1 forms an image using the light that has passed through the liquid crystal panel 2 out of the light emitted by the backlight device 3 .

In this embodiment, the backlight device 3 includes 16 light emitting diodes D and four drive circuits 311 to 314, as shown in FIG. Each light emitting diode D is a light emitting diode that emits white light when energized. As schematically illustrated in FIG. 3, the 16 light emitting diodes D are arranged four in the x direction, which is the width direction of the vehicle B, and four in the y direction, which is the direction perpendicular to the x direction. The pieces are arranged in a matrix.

Four light emitting diodes D arranged at one end in the y direction (upper side in FIG. 3) and arranged at equal intervals in the x direction are connected in series to form a series light source group 301. The series light source group 301 irradiates light to a region of the liquid crystal panel 2 corresponding to a first region 711 located at the uppermost side of the display region 71 of the windshield 7 . Further, four light emitting diodes D arranged adjacent to the series light source group 301 in the y direction and lined up at equal intervals in the x direction are connected in series to form a series light source group 302. The series light source group 302 irradiates light to a region of the liquid crystal panel 2 that corresponds to a second region 712 of the display region 71 of the windshield 7 .

Four light emitting diodes D arranged adjacent to the series light source group 302 in the y direction and arranged at regular intervals in the x direction are connected in series to form a series light source group 303. The series light source group 303 irradiates light to an area of the liquid crystal panel 2 that corresponds to the third area 713 of the display area 71 of the windshield 7 . Four light emitting diodes D arranged at the other end in the y direction (lower side in FIG. 3) and arranged at equal intervals in the x direction are connected in series to form a series light source group 304. The series light source group 304 irradiates light to a region of the liquid crystal panel 2 corresponding to a fourth region 714 located at the lowermost side of the display region 71 of the windshield 7 . The terminals on the cathode side of each of the series light source groups 301 to 304 are connected to ground.

The drive circuit 311 is a drive circuit that drives each light emitting diode D of the series light source group 301. The drive circuit 311 is connected to the anode side terminal of the series light source group 301. The drive circuit 312 is a drive circuit that drives each light emitting diode D of the series light source group 302. The drive circuit 312 is connected to the anode side terminal of the series light source group 302. The drive circuit 313 is a drive circuit that drives each light emitting diode D of the series light source group 303. The drive circuit 313 is connected to the anode side terminal of the series light source group 303. The drive circuit 314 is a drive circuit that drives each light emitting diode D of the series light source group 304. The drive circuit 314 is connected to the anode side terminal of the series light source group 304.

Note that the positions of the drive circuits 311 to 314 in the backlight device 3 are not limited, and may be any position that does not interfere with the light emitted by each light emitting diode D. Further, the backlight device 3 may include each of the drive circuits 311 to 314 as individually sealed packages, may include two packages each having two sealed circuits, or may include four packages sealed. It may also include one stopped package. That is, the backlight device 3 may include a multi-channel drive circuit.

The control device 4 controls the liquid crystal panel 2 and the backlight device 3, and is realized by, for example, a microcomputer equipped with a CPU and a memory.

The control device 4 controls driving of each pixel of the liquid crystal panel 2 based on display image information input from the image generation section 60. The image generation unit 60 generates an image to be displayed on the display device 1 based on driving information input from various sensors, various ECUs (Electronic Control Units), and the like. Examples of travel information input to the image generation unit 60 to generate the image include the vehicle B's vehicle speed, engine speed, remaining fuel level, shift position, navigation information, cumulative mileage, time, and outside temperature. , direction information, parking brake information, information indicating the lighting and status of lights, seatbelt attachment/detaching information, cooling water temperature, failure diagnosis information, security information, etc. Note that the driving information used to generate the image is not limited. The image generation unit 60 outputs image data of the generated image to the control device 4 as display image information. Note that the head-up display device A1 may include an image generation section 60.

Further, the control device 4 controls the drive circuits 311 to 314 of the backlight device 3 based on captured image information input from the camera 61. The camera 61 is a photographing device that photographs an image in front of the vehicle B, and includes, for example, an imaging device such as a CCD or CMOS, and photographs a predetermined photographing area at a predetermined frame rate. The camera 61 is attached near the center in the vehicle width direction inside the vehicle, and captures an image including at least an area that becomes the background of the display area 71 (see FIG. 4) of the windshield 7. A captured image 8 shown in FIG. 5 is an example of an image in front of the vehicle B captured by the camera 61. In addition, in FIG. 5, in order to show the area|region equivalent to the display area 71 of the windshield 7, the display area 71 is shown by the dashed-two dotted line. Note that the mounting position of the camera 61 is not limited. The camera 61 outputs image data of the captured image 8 to the control device 4 as captured image information.

The control device 4 sets the brightness of each of the series light source groups 301 to 304 based on captured image information input from the camera 61. Specifically, the control device 4 controls the brightness of the area corresponding to each area of the display area 71 (the first area 711, the second area 712, the third area 713, and the fourth area 714) in the captured image 8. Calculate. These brightnesses are calculated as, for example, the average value of values indicating the brightness of the color of each pixel in each region. The control device 4 sets the brightness of the corresponding series light source groups 301 to 304 according to the calculated brightness of each area. The control device 4 sets the brightness of the corresponding series light source groups 301 to 304 to a larger value as the brightness of the region becomes larger (brighter).

For example, in the case of the example shown in FIG. 5, the bright sky occupies most of the area corresponding to the first area 711 of the display area 71 in the photographed image 8, so the brightness of the color of each pixel in the area is The brightness of the area calculated from is large. The control device 4 sets the brightness of the corresponding series light source group 301 to a large value depending on the brightness of the area. Further, in the area corresponding to the fourth area 714, the relatively dark road surface occupies most of the area, so the brightness of the area calculated from the brightness of the color of each pixel in the area is small. The control device 4 sets the brightness of the corresponding series light source group 304 to a small value depending on the brightness of the area. In addition, in the area corresponding to the second area 712, a bright sky and a relatively dark road surface are mixed, so the brightness of the area calculated from the brightness of the color of each pixel in the area is medium. . The control device 4 sets the brightness of the corresponding series light source group 302 to a value corresponding to the brightness of the area.

The control device 4 adjusts the brightness of each light emitting diode D by so-called PWM dimming. In PWM dimming, the lighting period in which a driving current is applied to the light emitting diode to turn it on and the extinguishing period in which the driving current is cut off and the light is turned off are alternately switched at a fixed short cycle, and the proportion of the lighting period in one cycle ( This technology changes the brightness of a light emitting diode by changing the duty ratio. By shortening the switching cycle (increasing the frequency), the human eye can no longer perceive the flickering caused by turning on and off. When the duty ratio becomes higher, the lighting period becomes longer, so the brightness of the light emitting diode increases, and when the duty ratio becomes lower, the lighting period becomes shorter, so the brightness of the light emitting diode becomes lower. When the duty ratio is "0", the light emitting diode is turned off.

The control device 4 outputs pulse signals corresponding to the set brightness to the corresponding drive circuits 311 to 314, respectively. The drive circuit 311 (312, 313, 314) controls each light emitting diode D by switching the drive current flowing through the series light source group 301 (302, 303, 304) according to the pulse signal input from the control device 4. Adjust the brightness to the set brightness. Since the light emitting diodes D of the series light source group 301 (302, 303, 304) are connected in series, the same drive current flows and they emit light with the same brightness. On the other hand, each pulse signal that the control device 4 outputs to the drive circuits 311 to 314 is generated independently from each other depending on the brightness of each area of the photographed image 8. Therefore, the series light source groups 301 to 304 emit light at mutually independent brightnesses (sometimes they have different brightnesses, or some of them have the same brightness). In other words, the control device 4 individually controls the series light source groups 301 to 304. Note that the control device 4 may be included in the display device 1.

Next, the backlight control processing performed by the control device 4 will be described below with reference to the flowchart shown in FIG. The backlight control process is a process for controlling the backlight device 3, and is executed at predetermined time intervals (for example, 1 second). Note that the predetermined time interval is not limited.

First, image data of a captured image 8 input from the camera 61 is acquired (S1). Next, the brightness of each region of the photographed image 8 is calculated (S2). Specifically, the brightness of the color of each pixel in each area of the captured image 8 is detected, and a value indicating the brightness of the area is calculated from the detected brightness. Next, the brightness of the corresponding series light source groups 301 to 304 is set according to the calculated brightness of each area (S3). Next, pulse signals corresponding to the luminance are output to the corresponding drive circuits 311 to 314 (S4), and the backlight control process is completed. Note that the process shown in the flowchart of FIG. 6 is an example, and the backlight control process is not limited to the above-mentioned process.

Next, the functions and effects of the head-up display device A1 according to the present embodiment will be explained.

According to this embodiment, the backlight device 3 includes serial light source groups 301 to 304. The control device 4 individually adjusts the brightness of each serial light source group 301 to 304 according to the background brightness of the area corresponding to each serial light source group 301 to 304. Thereby, the image displayed in each area is displayed with a brightness that corresponds to the brightness of the background, so the visibility of the image is improved. Due to improved visibility, the time required to gaze at images is shortened, so the running safety of vehicle B is improved. Further, each of the series light source groups 301 to 304 has four light emitting diodes D arranged in the x direction (vehicle width direction) connected in series. Therefore, the drive circuit 311 (312, 313, 314) can simultaneously drive each light emitting diode D of the series light source group 301 (302, 303, 304). Therefore, compared to the case where each light emitting diode D is driven individually, the number of required drive circuits can be suppressed. Thereby, manufacturing costs can be suppressed.

In addition, in this embodiment, each light emitting diode D of the series light source group 301 (302, 303, 304) cannot be controlled individually. However, in the display area 71 of the windshield 7, the brightness of the background often differs in the vertical direction, but rarely differs greatly in the vehicle width direction. Therefore, even if the light emitting diodes D arranged in the x direction (vehicle width direction) are controlled to have the same brightness, visibility is not significantly affected. On the other hand, since the series light source groups 301 (302, 303, 304) arranged in the y direction (corresponding to the vertical direction in the display area 71) are individually controlled, the background brightness differs in the vertical direction of the display area 71. can correspond to

In addition, although the head-up display apparatus A1 demonstrated the case where an image is displayed on the windshield 7 in this embodiment, it is not restricted to this. The head-up display device A1 may display an image on a combiner, which is a transparent plate-shaped component placed between the windshield 7 and the driver. In this case, the "combiner" corresponds to the "transmission/reflection section" of the present invention.

In the present embodiment, a case has been described in which the head-up display device A1 reflects the image displayed on the display device 1 on the first mirror 51 and the second mirror 52 and projects it on the windshield 7. The number of mirrors disposed between 1 and the windshield 7 is not limited. For example, the head-up display device A1 may include only one of the first mirror 51 and the second mirror 52, or may further include an additional mirror. Further, the head-up display device A1 may not include the first mirror 51 and the second mirror 52, and may directly project the image displayed on the display device 1 onto the windshield 7. The orientation of the display surface 1a of the display device 1, the orientation of the displayed image, and the shape, arrangement position, and orientation of each mirror are determined so that the image is appropriately displayed in the display area 71 of the windshield 7. Designed accordingly.

In the present embodiment, a case has been described in which four light emitting diodes D are connected in series in the backlight device 3, but the present invention is not limited to this. The number of light emitting diodes D connected in series may be two or more. Further, in the present embodiment, a case has been described in which the four serial light source groups 301 to 304 are arranged side by side in the y direction in the backlight device 3, but the present invention is not limited to this. The number of serial light source groups may be two or more. The number of light emitting diodes D connected in series and the number of serial light source groups arranged are appropriately set depending on the dimensions of the backlight device 3 in the x direction and the y direction.

In the present embodiment, a case has been described in which the backlight device 3 includes a series light source group 301 to 304 in which four light emitting diodes D are connected in series, but the present invention is not limited to this. Instead of the series light source groups 301 to 304, the backlight device 3 may include, for example, a light source group in which all four light emitting diodes D are connected in parallel, or in which two light emitting diodes D are connected in series. A light source group in which two light sources are connected in parallel may be provided.

In the present embodiment, a case has been described in which the control device 4 adjusts the brightness of each light emitting diode D by PWM dimming, but the invention is not limited to this. For example, the control device 4 may adjust the brightness of each light emitting diode D by having the drive circuits 311 to 314 change the magnitude of the drive current flowing through each light emitting diode D.

In this embodiment, a light emitting diode D is used as a light source, but the light source is not limited to this. The light source may be any light source as long as its brightness can be controlled.

7-9 illustrate other embodiments of the invention. In addition, in these figures, the same or similar elements as in the above embodiment are given the same reference numerals as in the above embodiment.

<Second embodiment>
7 and 8 are diagrams for explaining a head-up display device A2 according to a second embodiment of the present disclosure. FIG. 7 is a block diagram showing the functional configuration of the head-up display device A2. FIG. 8 is an example of a flowchart for explaining backlight control processing according to the second embodiment. The head-up display device A2 according to the present embodiment differs from the first embodiment in that the control device 4 controls the backlight device 3 based on the illuminance input from the illuminance sensor 62.

The illuminance sensor 62 is, for example, a sensor that is placed in front of the vehicle B and detects the surrounding illuminance. The illuminance detected by the illuminance sensor 62 is used, for example, to determine whether to turn on or turn off the light. The illuminance sensor 62 outputs the detected illuminance to the head-up display device A2.

The control device 4 of the display device 1 according to the present embodiment sets the brightness of each of the series light source groups 301 to 304 based on the illuminance input from the illuminance sensor 62. Specifically, the control device 4 compares the illuminance input from the illuminance sensor 62 with a predetermined threshold value. When the illuminance input from the illuminance sensor 62 is equal to or higher than a predetermined threshold value, the control device 4 determines that the surrounding area is bright and the upper side of the display area 71 where the sky is the background is relatively bright. The brightness of the series light source group 301 corresponding to the second area 712 and the series light source group 302 corresponding to the second area 712 is set to a large value, and the brightness of the series light source group 303 corresponding to the third area 713 and the series light source group 302 corresponding to the fourth area 714 is set to a large value. The brightness of the serial light source group 304 is set to a small value. On the other hand, if the illuminance is less than a predetermined threshold, it is determined that the surroundings are dark and the lower side of the display area 71, where the road surface illuminated by the headlights becomes the background, is brighter. The brightness of the series light source group 302 corresponding to the third region 713 and the fourth region 714 is set to a small value. Set brightness to a high value. Note that the above is just an example, and how to set the brightness of which serial light source group 301 to 304 in each case is determined through experiments so as to be as optimal as possible.

Next, the backlight control process performed by the control device 4 according to the second embodiment will be described below with reference to the flowchart shown in FIG. 8.

First, the illuminance detected by the illuminance sensor 62 is acquired (S11). Next, it is determined whether the illuminance is greater than or equal to a predetermined threshold (S12). If the illuminance is equal to or higher than the threshold (S12: YES), the brightness of the series light source group corresponding to the upper area of the display area 71 is set to a large value (S13), and the brightness of the series light source group corresponding to the lower area is set to a small value. value (S14). On the other hand, in step S12, if the illuminance is less than the threshold (S12: NO), the brightness of the series light source group corresponding to the upper area of the display area 71 is set to a small value (S15), and the luminance of the series light source group corresponding to the lower area is set to a small value. The brightness of the light source group is set to a large value (S16). Then, pulse signals corresponding to the luminance are output to the corresponding drive circuits 311 to 314 (S17), and the backlight control process is ended. Note that the process shown in the flowchart of FIG. 8 is an example, and the backlight control process is not limited to that described above.

According to this embodiment, the backlight device 3 includes serial light source groups 301 to 304, and the control device 4 individually adjusts the brightness of each serial light source group 301 to 304 according to the surrounding illuminance. Therefore, the visibility of the images displayed in each area is improved, and the running safety of the vehicle B is improved. Further, each of the series light source groups 301 to 304 has four light emitting diodes D arranged in the x direction (vehicle width direction) connected in series. Therefore, the number of required drive circuits can be suppressed, and manufacturing costs can be suppressed. Further, according to this embodiment, since the camera 61 is not required, the head-up display device A2 can be used even in a vehicle B that is not equipped with the camera 61.

In this embodiment, a case has been described in which there are two types of brightness setting patterns for each of the series light source groups 301 to 304, but the present invention is not limited to this. The control device 4 may set three or more types of setting patterns for each brightness according to the illuminance, and set the brightness of each of the series light source groups 301 to 304 according to the illuminance input from the illuminance sensor 62.

Further, in the present embodiment, a case has been described in which the control device 4 sets the brightness of each of the series light source groups 301 to 304 based on the illuminance input from the illuminance sensor 62, but the present invention is not limited to this. The control device 4 may set the brightness of each of the series light source groups 301 to 304 based on, for example, the current date and time, weather, and position information. The surrounding brightness can be estimated based on the date, time and weather. Further, if it is determined from the position information that the user is in a tunnel, for example, the brightness arrangement can be set to be the same as at night. Further, the control device 4 may set the brightness of each of the series light source groups 301 to 304, for example, depending on the lighting state of the headlights. In these cases, since the illuminance sensor 62 is not required, it can be used even in a vehicle B that is not equipped with the illuminance sensor 62. Note that the control device 4 may set the brightness of each of the series light source groups 301 to 304 by combining some of the methods described above.

<Third embodiment>
FIG. 9 is a diagram for explaining a head-up display device A3 according to a third embodiment of the present disclosure. FIG. 9 is a block diagram showing the internal configuration of the backlight device 3 of the head-up display device A3. The head-up display device A3 according to the present embodiment is different from the first embodiment in the internal configuration of the backlight device 3.

The backlight device 3 according to this embodiment has 16 light emitting diodes D arranged in a matrix like the backlight device 3 according to the first embodiment. However, in this embodiment, two light emitting diodes D lined up in the x direction are connected in series to form one series light source group. Each series light source group is connected to a drive circuit.

Of the light emitting diodes D that constituted the series light source group 301 in the first embodiment, the two light emitting diodes D on the right side constitute a series light source group 321 and are connected to a drive circuit 331 . Furthermore, the two light emitting diodes D on the left constitute a series light source group 322 and are connected to a drive circuit 332. Similarly, of the light emitting diodes D that constituted the series light source group 302 in the first embodiment, the two light emitting diodes D on the right side constitute a series light source group 323 and are connected to a drive circuit 333. Furthermore, the two light emitting diodes D on the left constitute a series light source group 324 and are connected to a drive circuit 334. Of the light emitting diodes D that constituted the series light source group 303 in the first embodiment, the two right light emitting diodes D constitute a series light source group 325 and are connected to a drive circuit 335 . Furthermore, the two light emitting diodes D on the left constitute a series light source group 326 and are connected to a drive circuit 336. Of the light emitting diodes D that constituted the series light source group 304 in the first embodiment, the two light emitting diodes D on the right side constitute a series light source group 327 and are connected to a drive circuit 337 . Further, the two light emitting diodes D on the left side constitute a series light source group 328 and are connected to a drive circuit 338.

The control device 4 (not shown in FIG. 9) according to the present embodiment sets the brightness of each of the series light source groups 321 to 328 based on the captured image information input from the camera 61, and adjusts the brightness to the set brightness. The corresponding pulse signals are output to the corresponding drive circuits 331 to 338, respectively. In other words, the control device 4 individually controls the series light source groups 321 to 328.

According to the present embodiment, the backlight device 3 includes the serial light source groups 321 to 328, and the control device 4 controls each serial light source group 321 to - Adjust the brightness of 328 individually. Therefore, the visibility of the images displayed in each area is improved, and the running safety of the vehicle B is improved. Further, each of the series light source groups 321 to 328 includes two light emitting diodes D arranged in the x direction (vehicle width direction) connected in series. Therefore, the number of required drive circuits can be reduced compared to the case where each light emitting diode D is driven individually. Furthermore, according to the present embodiment, even if the brightness of the background differs between the left and right sides in the display area 71 of the windshield 7, the brightness of the corresponding series light source group can be adjusted individually, so that the image displayed in each area can be adjusted individually. The visibility of the vehicle B is further improved, and the driving safety of the vehicle B is further improved.

Note that in this embodiment, the number of required drive circuits is greater than in the first embodiment. Further, as described above, in the display area 71 of the windshield 7, the brightness of the background rarely differs greatly in the vehicle width direction, so there are few situations where the brightness is controlled to be different on the left and right sides. Therefore, it is more preferable to connect all the light emitting diodes D arranged in the x direction in series like the head-up display device A1 according to the first embodiment.

In the first to third embodiments, a case has been described in which the head-up display devices A1 to A3 are attached to the vehicle B, but the present invention is not limited to this. Head-up display devices A1-A3 may be attached to other vehicles such as airplanes and ships, for example.

The head-up display device according to the present invention is not limited to the embodiments described above. The specific configuration of each part of the head-up display device according to the present invention can be modified in various ways.

A1-A3: Head-up display device 1: Display device 1a: Display surface 2: Liquid crystal panel 3: Backlight device D: Light-emitting diodes 301-304, 321-328: Series light source groups 311-314, 331-338: Drive circuit 4: Control device 51: First mirror 52: Second mirror 60: Image generation unit 61: Camera 62: Illuminance sensor 7: Windshield 71: Display area 711: First area 712: Second area 713: Third area 714 : Fourth area 8 : Photographed image B : Vehicle E : Viewpoint L : Optical path V : Virtual image

Claims (1)

The display device includes a display device and a control device that controls the display device, and the light representing the image displayed on the display device is reflected by the transmissive reflection section, so that the image is displayed as a virtual image of the space in front of the vehicle. A head-up display device that displays information in a display area of a reflective part,
The display device includes a liquid crystal panel and a backlight device that irradiates light to the liquid crystal panel,
The backlight device includes a plurality of light source groups each including a plurality of light sources arranged side by side in the vehicle width direction of the vehicle and connected to each other,
The display area of the transmissive reflection section has a plurality of areas arranged vertically,
The plurality of light source groups are arranged in a line in a direction perpendicular to the vehicle width direction, and each irradiates light to a corresponding area of the display area of the transmissive reflection section,
The control device individually controls the brightness of the plurality of light source groups according to the brightness of the background corresponding to each area of the display area of the transmissive reflection section .
Head-up display device.

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