JP7163781B2 - head-up display device - Google Patents

Description

The disclosure of this specification relates to a head-up display device (hereinafter abbreviated to HUD device).

2. Description of the Related Art Conventionally, a HUD device configured to be mounted on a vehicle is known. The device disclosed in Patent Literature 1 displays a virtual image superimposed on the scenery outside the vehicle by projecting display light of an image onto a transmissive member. More specifically, the device disclosed in Patent Document 1 includes a display having an image display section and an illumination section having a plurality of light sources. Each light source is controlled by local dimming so that the corresponding light source corresponding to the screen area where the display content is displayed is lit.

Japanese Patent No. 6299523

Now, in the case of displaying a virtual image so as to be superimposed on the scenery outside the vehicle, it is possible to change the arrangement of the displayed content in a timely manner in accordance with the movement or vibration of the vehicle so that it can be appropriately superimposed on the scenery. Conceivable. Depending on the movement of the vehicle or the vibration situation, it may be better to change the layout of the display content in a short period of time.

However, if local dimming control is performed in response to such a short-time change in display content layout, switching between lighting and extinguishing of each light source may occur frequently. As a result, there is concern that the virtual image will flicker and the visibility will deteriorate.

One of the purposes of the disclosure of this specification is to provide a HUD device with good virtual image visibility.

One of the embodiments disclosed herein is configured to be mounted on a vehicle (1), and by projecting display light of an image onto a transparent member (3), a virtual image ( VDP) is a head-up display device that displays
An image display unit (22) having a plurality of screen areas (DPA) on a screen (22a) on which image display content (DC) is arranged, and a plurality of light sources (25) separated from the image display unit. a display (21) having an illumination section (24) for illuminating an image display section;
A display control unit (52) that controls the image display unit and performs local dimming control so that the corresponding light source (25a) corresponding to each screen area among the light sources is turned on based on the arrangement of the display content in each screen area. ) and
The display control unit
Based on the vehicle vibration information, the position of the displayed content on the screen is changed so that the vibration is offset in order to prevent the virtual image from vibrating and being visually recognized.
The corresponding light source corresponding to the screen area where the display content was arranged before the layout change is lit , and the display content is arranged before the layout change for a period set for a predetermined time after the layout change . Continue lighting the corresponding light source corresponding to the screen area selected ,
When the position of the display content is returned due to repositioning due to vibration during the period, the corresponding light source is configured to continue lighting without being turned off .

According to this aspect, the corresponding light source corresponding to the screen area in which the display content was arranged before the layout change continues to be lit during the period set for the predetermined time after the layout change. That is, after the display content arrangement state in the screen area is stopped, lighting is continued for a period set for a predetermined time from the time of arrangement change . Then, for example, in order to appropriately superimpose the virtual image on the scenery outside the vehicle, if the display content is rearranged and the position of the display content is returned within the period in which the lighting continues , the display content will not be displayed for a predetermined period of time from the time of the rearrangement change. The corresponding light source continues lighting without being turned off during the set period. Therefore, even if local dimming control is performed, it is possible to reduce the frequency of switching between lighting and extinguishing of the light source accompanying a change in display content layout in such a short time as to cancel out the vibration of the virtual image. It can suppress the occurrence. As described above, it is possible to provide a HUD device with good visibility of a virtual image.

It should be noted that the reference numerals in parentheses exemplarily indicate the correspondence with the portions of the embodiment described later, and are not intended to limit the technical scope.

It is a figure which shows the mounting state to the vehicle of the HUD apparatus of 1st Embodiment. It is a figure which shows typically the structure of the display device of 1st Embodiment. It is a block diagram which shows the relationship between the indicator and display control part of 1st Embodiment. FIG. 4A is a schematic diagram for explaining the relationship between the change in the display content layout and the light source according to the first embodiment, and FIG. (b) is an example of lighting and display in the case of a temporary change in layout due to vibration. 4 is a flow chart by the display control unit of the first embodiment; 4 is a time chart showing lighting of the corresponding light source of the first embodiment and its emission intensity. It is a time chart which shows lighting of the corresponding|compatible light source of 2nd Embodiment, and its light emission intensity. It is a time chart which shows lighting of the corresponding|compatible light source of 3rd Embodiment, and its light emission intensity. It is a time chart which shows lighting of the corresponding|compatible light source of 4th Embodiment, and its luminous intensity. It is a time chart which shows lighting of the corresponding|compatible light source of 5th Embodiment, and its light emission intensity. It is a time chart which shows lighting of the corresponding|compatible light source of 6th Embodiment, and its luminous intensity.

A plurality of embodiments will be described below with reference to the drawings. Note that redundant description may be omitted by assigning the same reference numerals to corresponding components in each embodiment. When only a part of the configuration is described in each embodiment, the configurations of other embodiments previously described can be applied to other portions of the configuration. In addition, not only the combinations of the configurations specified in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not specified unless there is a particular problem with the combination. .

(First embodiment)
As shown in FIG. 1 , a HUD device 10 according to the first embodiment of the present disclosure is configured to be mounted on a vehicle 1 and accommodated within an instrument panel 2 of the vehicle 1 . The HUD device 10 projects image display light toward the windshield 3 of the vehicle 1 . Thereby, the image is displayed as a virtual image VDP that can be visually recognized by the passenger. That is, when the display light of the image reflected by the windshield 3 reaches the visual recognition area EB set in the interior of the vehicle 1, the occupant whose eye point EP is positioned in the visual recognition area EB can recognize various information. can be done.

In particular, in this embodiment, the occupant can visually recognize the virtual image VDP superimposed on the scenery outside the vehicle 1 through the windshield 3 . That is, the virtual image VDP by the HUD device 10 includes augmented reality (AR) display that augments reality by display content DC (see also FIG. 4) superimposed on the road surface, buildings, or the like.

Hereinafter, unless otherwise specified, the front, rear, up, down, left, and right directions are described with reference to the vehicle 1 on the horizontal plane HP.

In addition, the vehicle 1 in the present embodiment is not limited to an automobile, and may include various vehicles such as a railway vehicle, an aircraft, a ship, and a non-moving game housing (for example, a housing that vibrates itself). broadly construed to include

The windshield 3 of the vehicle 1 is a translucent plate-shaped translucent member made of glass or synthetic resin, for example, and is disposed above the instrument panel 2 . The windshield 3 is arranged so as to be spaced apart from the instrument panel 2 from the front toward the rear. The windshield 3 has a smooth concave or planar reflection portion 3a onto which image display light is projected. The image display light may be projected onto a combiner separate from the vehicle 1, instead of the windshield 3, for example.

The visible area EB is a spatial area where the virtual image VDP is visible, and is also called an eyebox. The visual recognition area EB is typically set so as to overlap the eyelip set on the vehicle 1 . The eyelip is set in a virtual ellipsoidal shape based on an eye range that statistically represents the spatial distribution of eye points EP of the occupant. The eyelip is usually set in the space slightly forward from the seat headrest.

A specific configuration of such a HUD device 10 will be described below with reference to FIGS. 2 and 3 as well. The HUD device 10 includes a housing 11, a display 21, an enlarged light guide section 41, a control unit 51, and the like.

As shown in FIG. 1, the housing 11 is made of, for example, synthetic resin or metal, and has a hollow shape that accommodates the indicator 21, the enlarged light guide portion 41, the control unit 51, and the like. Installed in panel 2. The housing 11 has a window portion 12 which is optically opened on the upper surface portion facing the windshield 3 in the vertical direction. The window portion 12 is covered with, for example, a dustproof sheet 13 capable of transmitting display light.

The display device 21 displays an image on the screen 22 a and projects display light of the image toward the enlarged light guide section 41 . The display 21 of this embodiment is a transmissive liquid crystal display. As shown in FIGS. 2 and 3, the display unit 21 has an image display unit 22 having a screen 22a and an illumination unit 24 for illuminating the image display unit 22. For example, these are housed in a light-shielding box-shaped casing. is configured as

As shown in FIG. 1 , the enlarged light guide section 41 forms an optical path for guiding image display light emitted from the screen 22 a of the display device 21 . The enlarging light guide section 41 has, for example, a plane mirror 42 and a concave mirror 44 .

The plane mirror 42 forms a smooth planar reflecting surface by, for example, vapor-depositing aluminum on the surface of a base material made of synthetic resin or glass. The display light incident on the plane mirror 42 from the display 21 is reflected toward the concave mirror 44 by its reflecting surface.

The concave mirror 44 forms a smooth concave reflecting surface curved in a concave shape, for example, by vapor-depositing aluminum on the surface of a base material made of synthetic resin or glass. The display light incident on the concave mirror 44 from the plane mirror 42 is reflected toward the windshield 3 by its reflecting surface. Here, it is possible to enlarge the virtual image VDP with respect to the image on the screen 22a by reflection on the reflecting surface of the concave mirror 44 having positive optical power.

Further, the concave mirror 44 is rotatable around a rotating shaft 44a extending in the left-right direction according to the drive of the stepping motor controlled by the control unit 51. As shown in FIG. By such rotation, the display position of the virtual image VDP can be adjusted so as to be vertically displaced.

Below, the display 21 and its control of this embodiment will be described in detail. In particular, as shown in FIG. 2, the image display section 22 of the display 21 is a TFT liquid crystal panel using thin film transistors (TFTs). It is an active matrix type liquid crystal panel formed.

The image display section 22 is formed by stacking a pair of polarizing plates and a liquid crystal layer or the like sandwiched between the pair of polarizing plates, and thus has a flat plate shape. Each polarizing plate has a transmission axis and an absorption axis that are substantially perpendicular to each other, and has the property of transmitting light polarized in the direction of the transmission axis and absorbing light polarized in the direction of the absorption axis. A pair of polarizing plates are arranged with their transmission axes orthogonal to each other. By applying a voltage to each liquid crystal pixel, the liquid crystal layer can rotate the polarization direction of light incident on the liquid crystal layer according to the applied voltage. In this way, the image display section 22 can change the ratio of light passing through the polarizing plate on the enlarged light guide section 41 side, that is, the transmittance, for each liquid crystal pixel by rotating the polarization direction.

Therefore, the image display unit 22 displays an image on the screen 22a by controlling the transmittance of each liquid crystal pixel corresponding to the incidence of the light source light from the illumination target surface 22b, which is the surface on the illumination unit 24 side. do. Adjacent liquid crystal pixels are provided with color filters of different colors (for example, red, green, and blue), and various colors are realized by combining these.

The illumination unit 24 illuminates the image display unit 22 via the illumination target surface 22b. The illumination unit 24 is a so-called direct type or a backlight conforming to a direct type, and is arranged between a plurality of light sources 25, a substrate 24a holding the plurality of light sources 25, and the plurality of light sources 25 and the illumination target surface 22b. It is composed of a backlight optical system 30 and the like.

In this embodiment, each light source 25 is mainly composed of one light-emitting diode element. Each light source 25 is electrically connected to a power source through a wiring pattern of an illumination circuit on the substrate 24a. More specifically, each light source 25 is formed by sealing a chip-shaped blue light-emitting diode with a yellow fluorescent material obtained by mixing a yellow fluorescent agent into a translucent synthetic resin. The blue light emitted from the blue light emitting diode according to the amount of current excites the yellow phosphor to emit yellow light. By mixing the blue light and the yellow light, pseudo-white light source light is emitted from each light source 25. be done. Each light source 25 is configured to be individually switchable between a lit state and an extinguished state, and in the lit state, is controlled so as to change the light emission intensity as appropriate.

In this embodiment, a plurality of light sources 25 are arranged along the surface of a substrate 24 a separated from the image display section 22 . For example, the plurality of light sources 25 are arranged two-dimensionally to form a rectangular lattice (see also FIG. 4). The image display section 22 is arranged to be inclined with respect to the surface of the substrate 24a. As a result, when each light source 25 emits light from the light source with the direction substantially perpendicular to the surface of the substrate 24a as the intensity peak direction, the light source light contributing to display is emitted between the illumination target surface 22b and the screen 22a, which are substantially parallel to each other. is obliquely transmitted.

Each light source 25 mainly illuminates an individually corresponding partial area of the illumination target surface 22 b or screen 22 a of the image display section 22 . In other words, screen areas DPA that are virtually divided corresponding to the arrangement of the light sources 25 are set on the screen 22a. Thus, as shown in FIG. 4, one screen area DPA and one corresponding light source 25a form an individual correspondence relationship.

The backlight optical system 30 shown in FIG. 2 adjusts the directivity of the light source light while maintaining the individual correspondence between each screen area DPA and each light source 25 . The backlight optical system 30 has a lens array 31, a Fresnel lens 32 and a diffusion plate 33, for example.

The lens array 31 is formed by arranging a plurality of convex lens elements 31 a according to the number and arrangement of the light sources 25 . Each convex lens element 31a is arranged to face the corresponding light source 25 individually. Each convex lens element 31 a is made of, for example, synthetic resin or glass, and is translucent, and collects the light source light from the corresponding light source 25 .

The Fresnel lens 32 is made of, for example, synthetic resin or glass so as to transmit light. The Fresnel lens 32 further collects and parallelizes the light source light incident from the lens array 31 side.

The diffusion plate 33 is arranged in a state close to or adhered to the illumination target surface 22b, and is formed in a sheet shape by mixing diffusing particles such as microbeads into a base material made of translucent synthetic resin, for example. there is The diffusion plate 33 diffuses the light incident from the Fresnel lens 32 side to further adjust the directivity of the light source light incident on the image display section 22 .

The control unit 51 shown in FIG. 1 is a so-called computer, and is mainly composed of electronic circuits including at least one processor, memory device, and input/output interface. A processor is an arithmetic circuit that executes a computer program stored in a memory device. A memory device is provided by, for example, a semiconductor memory or the like, and is a non-transitional physical storage medium for non-temporarily storing a computer program readable by a processor.

The control unit 51 is communicably connected to the display 21 and the stepping motor of the concave mirror 44 . In addition, the control unit 51 is configured to be able to acquire various types of information from an ECU (Electric Control Unit) or the like of the vehicle 1 by inputting electrical signals using communication. In addition, in the communication between the control unit 51 and each element, various suitable communication methods can be adopted regardless of wired communication or wireless communication.

The control unit 51 includes a control section such as the display control section 52 as a functional section that performs arithmetic processing by executing a computer program. As shown in FIG. 3, the display control unit 52 has an image control unit 53 and an illumination control unit 54 as sub-function units.

The image control unit 53 controls the image display unit 22 so that an image generated by the ECU and input from the ECU is displayed on the screen 22a. Alternatively, the image control unit 53 controls the image display unit 22 so as to generate an image according to information from the ECU and display the image on the screen 22a.

The image displayed on the screen 22 a includes one or more display contents DC that are laid out on the premise that the image is formed as a virtual image VDP superimposed on the scenery outside the vehicle 1 . Specifically, the display content DC is arranged on a portion of the screen 22a. In the display portion of the display content DC, characters or patterns are displayed with the transmittance of the liquid crystal pixels set to an appropriate value. A blank portion in which nothing is substantially displayed is set in the portion other than the display portion. In the blank portion, the image display section 22 is controlled so that the transmittance of the liquid crystal pixels is set to the minimum value and the display light is emitted from the screen 22a as little as possible except for the post-stop period described later.

Also, the arrangement of such display content DC on the screen 22 a is changed based on the position information of the vehicle 1 . The positional information of the vehicle 1 includes, for example, information such as the latitude and longitude of the vehicle 1 detected by GPS or the like, and information such as orientation and vibration of the vehicle 1 detected by a gyro sensor or the like.

As an example, when the vehicle 1 turns left or right to change its direction, the positional relationship between the virtual image VDP and the scenery outside the vehicle 1 is changed. When the building located in front moves to the side, the display content DC showing the information of the building is rearranged according to the positional relationship with the building.

As another example, when the vehicle 1 vibrates up and down due to unevenness of the road surface, there is concern that the display content DC of the virtual arrow image that should be displayed so as to be superimposed on the road surface vibrates up and down at high speed and is visually recognized. . As shown in FIG. 4, in order to prevent the virtual arrow image from vibrating and being visually recognized, the display content DC of the virtual arrow image is rearranged in a direction opposite to the vibration (to offset the vibration).

When the image is generated by the ECU, this layout change may be performed by the ECU, or may be performed by the image control section 53 . When the image is generated by the image control unit 53, the image control unit 53 performs this layout change (see also S110 in FIG. 5).

The illumination control unit 54 cooperates with the image control unit 53 to perform local dimming control (also referred to as partial drive control) on the plurality of light sources 25 of the illumination unit 24 (see also step S111 in FIG. 5). Specifically, the illumination control unit 54 individually switches the light source 25 between the lighting state and the light-extinguishing state. The illumination control unit 54 lights the corresponding light source 25a corresponding to each screen area DPA in the arrangement state of the display content DC among the plurality of light sources 25, respectively. Therefore, switching between the lit state and the extinguished state of each light source 25 occurs according to the layout change of the display content DC.

In FIG. 4, the light source 25 in the lit state is represented by a square without hatching, and the light source 25 in the off state is represented by a square with dot hatching. On the screen 22a, the display content DC is represented without hatching, the portion of the blank portion illuminated by the illumination unit 24 is represented by thin dot hatching, and the portion of the blank portion not illuminated by the illumination unit 24 is represented by hatching. It is represented by dark dot hatching. A two-dot chain line represents a section of the screen area DPA.

Here, one screen area DPA and one corresponding light source 25a corresponding thereto, which constitute the individual correspondence relationship, will be described in detail. The screen regions and the corresponding light sources that form other individual correspondences are also controlled in the same way, and therefore descriptions thereof will be omitted.

The illumination control unit 54 of the first embodiment lights the corresponding light source 25a during the display period in which the display content DC is arranged in the screen area DPA. During the display period, the corresponding light source 25a lights up with a light emission intensity sufficient to display the display content DC while maintaining the same light emission intensity.

Along with this, the lighting control unit 54 controls the display content DC to be stopped for a predetermined time after the display content DC is stopped in the screen area DPA (that is, the display content DC is no longer arranged in the screen area DPA). Lighting of the corresponding light source 25a is continued in the latter period as well. In this post-stop period, the lighting control unit 54 keeps the corresponding light source 25a lighting while maintaining the same light emission intensity as that at the time of stop.

The predetermined time that defines the length of the post-stop period is set to, for example, 500 msec or longer. Then, when the layout of the display content DC is changed every 500 to 1000 msec in accordance with the vibration of the vehicle 1, which is usually about 1 to 2 Hz, it is possible to prevent the corresponding light source 25a from frequently switching between lighting and extinguishing. can do.

Further, when the arrangement state of the display content DC in the screen area DPA is started again within the predetermined time, the lighting control unit 54 immediately ends the post-stop period and restarts the display period.

A specific control example 1 will be described with reference to FIG. In this example, it is assumed that the predetermined time is 1000 msec, for example.

First, the timing of changing the layout of the display content DC in this control example 1 will be described. It is a period in which the display content DC is not arranged in the screen area DPA until time t1, and the display content DC is rearranged at time t1 to enter the display period. The display period continues until time t2 after 600 msec, for example. At time t2, the display content DC is rearranged, the arrangement state of the display content DC is stopped (that is, time t2 corresponds to the stop time), and the post-stop period begins. Further, at time t3 after 500 msec, the layout of the display content DC is changed again, and the display period begins. The display period continues until time t4 after 500 msec, for example. At time t4, the display content DC is rearranged, the arrangement state of the display content DC is stopped (that is, time t4 corresponds to the stop time), and the post-stop period begins. After that, there is no change in the arrangement of the display content DC, and the post-stop period continues until time t5 after 1000 msec, for example.

The corresponding light source 25a is controlled as follows for such a layout change of the display content DC. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t2 is the display period, the corresponding light source 25a is turned on and the same light emission intensity is maintained. Since the period from time t2 to time t3 is the post-stop period, the lighting of the corresponding light source 25a is continued, and the light emission intensity remains the same as when stopped. Since the period from time t3 to time t4 is the display period, the lighting of the corresponding light source 25a is continued and the same light emission intensity is maintained.

Since the period from time t4 to time t5 is the post-stop period, the lighting of the corresponding light source 25a is continued, and the light emission intensity remains the same as when stopped. Since the post-stop period ends at time t5, the corresponding light source 25a is turned off.

In summary, at times t1, t2, t3, and t4, although the layout of the display content DC related to the screen area DPA was changed four times in total, switching between lighting and extinguishing of the corresponding light source 25a was There are only two times in total: switching to lighting at time t1 and switching to lighting off at time t5.

(Effect)
The effects of the first embodiment described above will be described again below.

According to the first embodiment, the corresponding light source 25a corresponding to a certain screen area DPA is lit not only during the display period but also during the post-stop period. That is, lighting is continued for a predetermined time after the arrangement state of the display content DC in the screen area DPA is stopped. Then, for example, in order to appropriately superimpose the virtual image VDP on the scenery outside the vehicle 1, when the display content DC is moved and the position of the display content DC is returned within a predetermined time, a certain screen area DPA is temporarily displayed. Even if the arrangement state of the display content DC is stopped, the corresponding light source 25a is not turned off in the post-stop period, and the display period is resumed. Therefore, even if local dimming control is performed, it is possible to reduce the frequency of switching between lighting and extinguishing of the light source 25 due to the layout change of the display content DC in a short period of time, so that flickering of the virtual image VDP can be suppressed. As described above, it is possible to provide the HUD device 10 with good visibility of the virtual image VDP.

Further, according to the first embodiment, when the corresponding light source 25a is turned on during the post-stop period, the same light emission intensity as that during the stop is maintained. Therefore, it is possible to suppress the change in the light emission intensity when returning from the post-stop period to the display period again, so it is possible to suppress the flickering of the virtual image VDP that accompanies the layout change of the display content DC in a short period of time.

(Second embodiment)
As shown in FIG. 7, the second embodiment is a modification of the first embodiment. The second embodiment will be described with a focus on points different from the first embodiment.

One screen area DPA and one corresponding light source 25a corresponding thereto, which form an individual correspondence relationship in the second embodiment, will be described in detail. The screen regions and the corresponding light sources that form other individual correspondences are also controlled in the same way, and therefore descriptions thereof will be omitted.

The lighting control unit 54 of the second embodiment turns on the corresponding light source 25a during the display period as in the first embodiment, and continues lighting of the corresponding light source 25a during the post-stop period. However, the illumination control unit 54 of the second embodiment continues lighting of the corresponding light source 25a so as to linearly decrease the light emission intensity from the light emission intensity at the time of the stop during the post-stop period.

A specific control example 2 will be described with reference to FIG. The setting of the predetermined time and the timing of changing the layout of the display content DC are the same as in Control Example 1 in the first embodiment.

The corresponding light source 25a is controlled as follows. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t2 is the display period, the corresponding light source 25a is turned on and the same light emission intensity is maintained. Since the period from time t2 to time t3 is the post-stop period, the lighting of the corresponding light source 25a continues, but the light emission intensity gradually decreases linearly from the light emission intensity at the time of stop. At time t3, the emission intensity is increased instantaneously and discretely. Since the period from time t3 to time t4 is the display period, the lighting of the corresponding light source 25a is continued and the same light emission intensity is maintained.

Since the period from time t4 to time t5 is the post-stop period, the lighting of the corresponding light source 25a continues, but the light emission intensity gradually decreases linearly from the light emission intensity at the time of stop. Due to the gradual decrease in light emission intensity, the light emission intensity becomes 0 just at the end of the post-stop period at time t5, and the corresponding light source 25a is extinguished.

According to the second embodiment described above, when the corresponding light source 25a is turned on in the post-stop period, the light emission intensity linearly decreases from the light emission intensity at the time of stop. Therefore, in the transition to the off state at the moment when the post-stop period expires, it is possible to reduce the amount of change in the light emission intensity, so that flickering of the virtual image VDP can be suppressed.

(Third Embodiment)
As shown in FIG. 8, the third embodiment is a modification of the first embodiment. The third embodiment will be described with a focus on points different from the first embodiment.

One screen area DPA and one corresponding light source 25a corresponding thereto, which form an individual correspondence relationship in the third embodiment, will be described in detail. The screen regions and corresponding light sources that form other individual correspondences are also controlled in the same manner, so the following description will be substituted.

The lighting control unit 54 of the third embodiment turns on the corresponding light source 25a during the display period as in the first embodiment, and continues lighting of the corresponding light source 25a during the post-stop period. However, the illumination control unit 54 of the third embodiment reduces the light emission intensity in the post-stop period from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time increases with the passage of time. Thus, the lighting of the corresponding light source 25a is continued.

A specific control example 3 will be described with reference to FIG. The setting of the predetermined time and the timing of changing the layout of the display content DC are the same as in Control Example 1 in the first embodiment.

The corresponding light source 25a is controlled as follows. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t2 is the display period, the corresponding light source 25a is turned on and the same light emission intensity is maintained. Since the period from time t2 to time t3 is the post-stop period, the lighting of the corresponding light source 25a continues, but the light emission intensity continuously decreases from the light emission intensity at the time of stop so that the reduction width increases with the passage of time. do. Before and after the time t2, the value of the time-order primary derivative of the emission intensity is continuous. At time t3, the emission intensity is increased instantaneously and discretely. Since the period from time t3 to time t4 is the display period, the lighting of the corresponding light source 25a is continued and the same light emission intensity is maintained.

Since the period from time t4 to time t5 is the post-stop period, the lighting of the corresponding light source 25a is continued, but the light emission intensity continuously decreases from the light emission intensity at the time of stop so that the reduction width increases with the passage of time. do. Due to the gradual decrease in light emission intensity, the light emission intensity becomes 0 just at the end of the post-stop period at time t5, and the corresponding light source 25a is extinguished. Before and after time t5, the value of the time-order primary derivative of the emission intensity becomes discontinuous.

According to the third embodiment described above, when the corresponding light source 25a is turned on in the post-stop period, the light emission intensity decreases from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time increases with the passage of time. do. That is, due to the decrease in the light emission intensity, it is possible to reduce the amount of change in the light emission intensity in the transition to the extinguished state at the moment when the post-stop period expires. Furthermore, since the width of decrease immediately after the start of the post-stop period is small, for example, it is possible to reduce the amount of change in light emission intensity when returning from the post-stop period to the display period again in a short period of time in response to high-frequency vibrations of the vehicle 1 or the like. . Since the amount of change in the light emission amount is reduced in each situation, flickering of the virtual image VDP can be suppressed.

(Fourth embodiment)
As shown in FIG. 9, the fourth embodiment is a modification of the first embodiment. The fourth embodiment will be described with a focus on the differences from the first embodiment.

One screen area DPA and one corresponding light source 25a corresponding thereto, which form an individual correspondence relationship in the fourth embodiment, will be described in detail. The screen regions and corresponding light sources that form other individual correspondences are also controlled in the same manner, so the following description will be substituted.

The lighting control unit 54 of the fourth embodiment turns on the corresponding light source 25a during the display period as in the first embodiment, and continues lighting of the corresponding light source 25a during the post-stop period. However, the illumination control unit 54 of the fourth embodiment reduces the light emission intensity in the post-stop period from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time decreases with the passage of time. Thus, the lighting of the corresponding light source 25a is continued.

A specific control example 4 will be described with reference to FIG. The setting of the predetermined time and the timing of changing the layout of the display content DC are the same as in Control Example 1 in the first embodiment.

The corresponding light source 25a is controlled as follows. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t2 is the display period, the corresponding light source 25a is turned on and the same light emission intensity is maintained. Since the period from time t2 to time t3 is the post-stop period, the lighting of the corresponding light source 25a is continued, but the light emission intensity continuously decreases from the light emission intensity at the time of stop so that the reduction width decreases with the passage of time. do. Before and after the time t2, the value of the time-order primary derivative of the emission intensity becomes discontinuous. At time t3, the emission intensity is increased instantaneously and discretely. Since the period from time t3 to time t4 is the display period, the lighting of the corresponding light source 25a is continued and the same light emission intensity is maintained.

Since the period from time t4 to time t5 is the post-stop period, the lighting of the corresponding light source 25a is continued, but the light emission intensity continuously decreases from the light emission intensity at the time of stop so that the reduction width decreases with the passage of time. do. Due to the gradual decrease in light emission intensity, the light emission intensity becomes 0 just at the end of the post-stop period at time t5, and the corresponding light source 25a is extinguished. Before and after time t5, the value of the time-order primary derivative of the emission intensity is continuous.

According to the fourth embodiment described above, when the corresponding light source 25a is turned on in the post-stop period, the light emission intensity decreases from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time decreases with the passage of time. do. In other words, considering human visibility characteristics theorized by Weber-Fechner's law, etc., by reducing the width of decrease when the light emission intensity is reduced, the flickering when the corresponding light source 25a is turned off can be greatly reduced. It can be made difficult to feel.

(Fifth embodiment)
As shown in FIG. 10, the fifth embodiment is a modification of the first embodiment. The fifth embodiment will be described with a focus on points different from the first embodiment.

One screen area DPA and one corresponding light source 25a corresponding thereto, which form the individual correspondence relationship in the fifth embodiment, will be described in detail. The screen regions and corresponding light sources that form other individual correspondences are also controlled in the same manner, so the following description will be substituted.

The illumination control unit 54 of the fifth embodiment turns on the corresponding light source 25a during the display period as in the first embodiment, and continues lighting of the corresponding light source 25a during the post-stop period. However, in the first half of the post-stop period, the lighting control unit 54 of the fifth embodiment controls the light emission intensity in such a manner that the decrease in the light emission intensity per unit time from the light emission intensity at the time of stop increases with the passage of time. Lighting of the corresponding light source 25a is continued so as to decrease the . In the latter half of the post-stop period, the lighting of the corresponding light source 25a is continued so that the light emission intensity is reduced from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time decreases with the passage of time. . The emission intensity in the post-stop period changes, for example, along a sinusoidal curve.

Although the first half and the second half of the post-stop period are obtained by dividing the predetermined time into two, the time does not necessarily have to be allocated to exactly 5 minutes and 5 minutes, and the allocation can be set as appropriate.

A specific control example 5 will be described with reference to FIG. The setting of the predetermined time and the timing of changing the layout of the display content DC are the same as in Control Example 1 in the first embodiment.

The corresponding light source 25a is controlled as follows. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t2 is the display period, the corresponding light source 25a is turned on and the same light emission intensity is maintained. Since the period from time t2 to time t3 is the post-stop period, the lighting of the corresponding light source 25a continues, but the light emission intensity continuously decreases from the light emission intensity at the time of stop so that the reduction width increases with the passage of time. do. Before and after the time t2, the value of the time-order primary derivative of the emission intensity is continuous. Time t3 is reached in the first half of the post-stop period, and the emission intensity is instantaneously and discretely increased at time t3. Since the period from time t3 to time t4 is the display period, the lighting of the corresponding light source 25a is continued and the same light emission intensity is maintained.

Since the period from time t4 to time t5 is the post-stop period, the lighting of the corresponding light source 25a is continued. Luminescence intensity decreases. In the second half, the luminous intensity continuously decreases from the luminous intensity at the time of stop so that the reduction width decreases with the lapse of time. Due to the gradual decrease in light emission intensity, the light emission intensity becomes 0 just at the end of the post-stop period at time t5, and the corresponding light source 25a is extinguished. Before and after time t5, the value of the time-order primary derivative of the emission intensity is continuous.

According to the fifth embodiment described above, in the lighting of the corresponding light source 25a in the first half of the post-stop period, the light emission intensity is reduced from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time increases with the passage of time. decreases. Since the width of decrease immediately after the start of the post-stop period is small, for example, when returning from the post-stop period to the display period again in a short time in response to high-frequency vibrations of the vehicle 1, the amount of change in light emission intensity can be reduced. Along with this, when the corresponding light source 25a is turned on in the first half of the post-stop period, the light emission intensity decreases from the light emission intensity at the time of stop in such a manner that the reduction width of the light emission intensity per unit time decreases with the passage of time. In other words, considering human visibility characteristics theorized by Weber-Fechner's law, etc., by reducing the width of decrease when the light emission intensity is reduced, the flickering when the corresponding light source 25a is turned off can be greatly reduced. It can be made difficult to feel.

(Sixth embodiment)
As shown in FIG. 11, the sixth embodiment is a modification of the fifth embodiment. The sixth embodiment will be described with a focus on the differences from the fifth embodiment.

In the sixth embodiment, one screen area DPA and one corresponding light source 25a that constitutes the individual correspondence relationship will be described in detail. The screen regions and corresponding light sources that form other individual correspondences are also controlled in the same manner, so the following description will be substituted.

The lighting control unit 54 of the sixth embodiment lights the corresponding light source 25a during the display period, and continues lighting of the corresponding light source 25a during the post-stop period as in the fifth embodiment. However, the illumination control section 54 of the sixth embodiment changes the light emission intensity during the display period. Specifically, in the display period, a rise period is set for a while from the start of the display period.

The rise period is set to the same time as the post-stop period or a shorter time than the post-stop period, specifically 500 msec or less, preferably about 100 to 200 msec. In the rising period, the emission intensity of the corresponding light source 25a is continuously changed from the emission intensity at the start to a target intensity higher than the emission intensity at the start. Before and after the start of the display period, within the rising period, and before and after the end of the rising period, the light emission intensity of the corresponding light source 25a is controlled so that the values of the first-order derivatives of the light emission intensity follow a continuous curve. More preferably, the light emission intensity of the corresponding light source 25a is controlled so that the values of the time-second derivative of the light emission intensity follow a continuous curve before and after the start of the display period, within the rise period, and before and after the end of the rise period. be done.

When the display period starts from a period in which the corresponding light source 25a is turned off, the value of the first time derivative at the start is 0, so that the emission intensity gradually increases throughout the rising period. The corresponding light source 25a lights up. The emission intensity in the rising period changes, for example, along a sinusoidal curve.

On the other hand, if the post-stop period does not expire and the display period starts in the middle of the post-stop period, the value of the primary time derivative at the start is negative. , and then the corresponding light source 25a is turned on so that the emission intensity gradually increases.

Further, after the rising period in the display period ends, the corresponding light source 25a is turned on so that the same emission intensity as the target intensity is maintained.

A specific control example 6 will be described with reference to FIG. The setting of the predetermined time and the timing of changing the layout of the display content DC are the same as in Control Example 1 in the first embodiment. However, it is assumed that the end times of the rise period are time t1x and time t3x.

The corresponding light source 25a is controlled as follows. Until time t1, the corresponding light source 25a is turned off. Since the period from time t1 to time t1x is the rising period, the corresponding light source 25a is turned on and the light emission intensity gradually increases. From time t1x to time t2, the corresponding light source 25a is turned on so that the same emission intensity is maintained. The period from time t2 to time t3 is the same as in the fifth embodiment.

Since the period from time t3 to time t3x is the rising period, the corresponding light source 25a is turned on so that the emission intensity gradually increases from the emission intensity at the end of the post-stop period up to time t3. From time t3x to time t4, the corresponding light source 25a is turned on so that the same emission intensity is maintained. Moreover, after the time t4, it is the same as that of 5th Embodiment.

According to the sixth embodiment described above, in the lighting of the corresponding light source 25a during the rising period, the light emission intensity continuously changes to a higher intensity than the light emission intensity at the start. Therefore, instantaneous and discrete changes in light emission intensity are suppressed at the start of the display period, so flickering of the virtual image VDP can be suppressed. Furthermore, since the length of the rise period is set to be equal to or less than the predetermined time that defines the length of the post-stop period, it is possible to reduce discomfort due to the brightness of the display content DC never increasing. Therefore, it is possible to provide the HUD device 10 with good visibility of the virtual image VDP.

(Other embodiments)
Although a plurality of embodiments have been described above, the present disclosure is not to be construed as being limited to those embodiments, and can be applied to various embodiments and combinations within the scope of the present disclosure. can be done.

Specifically, as Modified Example 1, various configurations can be adopted for the backlight optical system 30 within a range that does not deviate from the backlight configuration conforming to the direct type. Also, the backlight optical system 30 itself may not be provided.

As a modification 2, one light source 25 may be configured with a plurality of light emitting diode elements as a unit.

As a modification 3, the plurality of light sources 25 divides one OLED (Organic Light-Emitting Diode) lighting panel into a plurality of divided areas by control, and each divided area can be individually switched on and off. It may be realized by configuring

As a fourth modification, the correspondence between the image area DPA and the corresponding light source 25a may not be a one-to-one individual correspondence. For example, two light sources 25, a first corresponding light source and a second corresponding light source, correspond to a first image region, and a second corresponding light source and a third light source correspond to a second image region adjacent to the first image region. A plurality of image regions may correspond to one light source 25, such as two light sources 25 corresponding to the corresponding light sources of .

As a modification 5, at least part of the processing by the control unit 51 may be realized in hardware by a classical analog circuit, FPGA (Field-Programmable Gate Array), etc. It may be implemented by an intelligent algorithm.

The controller and techniques described in this disclosure may be implemented by a special purpose computer comprising a processor programmed to perform one or more functions embodied by a computer program. Alternatively, the apparatus and techniques described in this disclosure may be implemented by dedicated hardware logic circuitry. Alternatively, the apparatus and techniques described in this disclosure may be implemented by one or more special purpose computers configured in combination with a processor executing a computer program and one or more hardware logic circuits. The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible recording medium.

1: vehicle, 3: windshield (transmissive member), 10: HUD device, 21: display, 22: image display unit, 22a: screen, 24: lighting unit, 25: light source, 25a: corresponding light source, 52: display Control unit, DPA: screen area, DC: display content, VDP: virtual image

Claims (9)

A head-up display device configured to be mounted on a vehicle (1) and displaying a virtual image (VDP) superimposed on the scenery outside the vehicle by projecting image display light onto a transmission member (3). and
an image display unit (22) having a plurality of screen areas (DPA) on a screen (22a) on which the display content (DC) by the image is arranged; and a plurality of light sources (25) separated from the image display unit. ), a display (21) having an illumination unit (24) for illuminating the image display unit;
The image display unit is controlled, and local dimming control is performed so that the corresponding light source (25a) corresponding to each screen area among the light sources is turned on based on the arrangement of the display content in each screen area. A display control unit (52),
The display control unit
Based on the information of the vibration of the vehicle, the position of the display content on the screen is changed so that the vibration is canceled in order to suppress the virtual image from vibrating and being visually recognized;
The corresponding light source corresponding to the screen area in which the display content was arranged before the layout change is turned on, and also during a period set for a predetermined time after the layout change , before the layout change. continuing lighting of the corresponding light source corresponding to the screen area where the display content was arranged ;
The head-up display device is configured to continue lighting without turning off the corresponding light source when the position of the display content is returned due to repositioning due to the vibration during the period . 2. The head-up display device according to claim 1, wherein the display control unit keeps the corresponding light sources lighting at the same light emission intensity as the light emission intensity at the time of the arrangement change during the period . 2. The head-up display device according to claim 1, wherein the display control unit continues lighting of the corresponding light source so as to linearly decrease the light emission intensity from the light emission intensity at the time of the arrangement change during the period . . The display control unit controls, in the period , the corresponding light source to decrease the emission intensity from the emission intensity at the time of the arrangement change in such a manner that the reduction width of the emission intensity per unit time increases with the passage of time. The head-up display device according to claim 1, wherein the lighting of the head-up display device is continued. In the period , the display control unit reduces the light emission intensity from the light emission intensity at the time of the arrangement change in such a manner that the reduction width of the light emission intensity per unit time decreases with the passage of time. The head-up display device according to claim 1, wherein the lighting of the head-up display device is continued. In the first half of the period , the display control unit reduces the light emission intensity from the light emission intensity at the time of the arrangement change in such a manner that the reduction width of the light emission intensity per unit time increases with the passage of time. 2. The head-up display device according to claim 1, wherein in the second half of the interval, lighting of the corresponding light source is continued so that the emission intensity is reduced in a manner that the reduction width of the emission intensity per unit time decreases with the lapse of time. The display control unit changes the light emission intensity at the start of lighting from the light emission intensity at the start of lighting in a rise period set to a time equal to or shorter than the period from the start of lighting of the corresponding light source. The head-up display device according to any one of claims 1 to 6, wherein the corresponding light sources are lit so as to continuously change the emission intensity to a target intensity greater than the target intensity. The display control unit temporarily decreases the light emission intensity when the position of the display content is returned in the middle of the period set by the predetermined time from the time of the layout change , and then gradually increases the light emission intensity. 8. The head-up display device according to claim 7, wherein the corresponding light source is turned on so as to light up. The head-up display device according to any one of claims 1 to 8, wherein the predetermined period of time is a period of time set to be equal to or longer than the time interval between the layout changes according to the frequency of vibration of the vehicle.

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