JP7711564B2 - Head-up display device - Google Patents

Description

This disclosure relates to a head-up display device mounted on a vehicle, etc.

As disclosed in Patent Document 1, for example, a conventional head-up display device has a display disposed in a recess formed by recessing the upper surface of the instrument panel downward near the position of the vehicle's windshield (windscreen), and the display light from this display is reflected by a colored portion that covers the periphery of the windshield, presenting a virtual image to the driver.

JP 2008-308090 A

However, if an object falls into the recess, the display light is blocked and the virtual image cannot be displayed. Another problem is that it is difficult for the driver to notice.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a head-up display device that can detect an object that is positioned so as to block the display.

The head-up display device 1 of the present invention has a light source 14 that emits light, a display unit 17 that generates display light 2 from the light, and a refraction unit 15 that refracts the light or the display light 2. The head-up display device 1 reflects the display light 2 at a reflection unit 3 and displays it as virtual images V1, V2 to a viewer 4. The head-up display device 1 further includes a hollow cylindrical portion 51 arranged on the display surface 17a side of the display unit 17, and a light detection unit 6 arranged on the cylindrical portion 51 and detecting the illuminance of light 2a refracted in the direction opposite to the direction in which the display light 2 is refracted. The light detection unit 6 outputs the illuminance to a control unit. If the illuminance is below a threshold value, the control unit determines that an abnormality exists and executes a process of issuing a warning to the viewer 4 .

1 is a schematic diagram showing a state in which a head-up display device according to a first embodiment of the present disclosure is mounted on a vehicle. FIG. 2 is a cross-sectional view of a main part of the head-up display device. 3A and 3B are diagrams showing examples of virtual images visually recognized by a driver of the head-up display device according to the embodiment of the present invention. 4A to 4C are diagrams illustrating a case where an object enters a recess of the head-up display device according to the embodiment of the present invention. FIG. 11 is a diagram showing an example of a virtual image visually recognized by a driver in a head-up display device according to a second embodiment of the present disclosure. FIG. 13 is a diagram showing an example of a virtual image visually recognized by a driver in a head-up display device according to a third embodiment of the present disclosure. FIG. 13 is a cross-sectional view of a main part of a head-up display device according to a fourth embodiment of the present disclosure.

An embodiment of the head-up display device of the present disclosure will be described with reference to the attached drawings 1 to 7. The head-up display device of the present disclosure can be applied to a head-up display device mounted on a vehicle such as an automobile or motorcycle, or on a ship, agricultural machinery, or construction machinery. In this embodiment, an example will be described in which the head-up display device is disposed in the instrument panel of an automobile.

In the following description, "front," "rear," "upper," "lower," "right," and "left" follow the definitions of "Fr.", "Re.", "To.", "Bo.", "R," and "L" in Figures 1 to 3.

(First embodiment)
The head-up display device 1 is a so-called head-up display (HUD), which projects display light 2 representing an image of the head-up display device 1 arranged in an instrument panel 5 of the vehicle onto a windshield (reflecting portion) 3, which is a projection member, and reflects the display light 2 toward a driver (viewer) 4 seated in the driver's seat of the automobile. The head-up display device 1 particularly projects and reflects the display light 2 onto a light-shielding portion 3a formed around the windshield 3, and displays the virtual image V1 for the driver 4 to view.

The light-shielding portion 3a is an opaque portion formed on the periphery of the windshield 3 and made of a light-shielding color such as black ceramics. The light-shielding portion 3a is formed for the purposes of preventing deterioration of the adhesive that secures the windshield 3 to the vehicle due to sunlight, concealing the adhesive, and improving the design.

As shown in FIG. 2, the head-up display device 1 has at least an upper case (case body) 11, a lower case (case body) 12, a circuit board 13, a light source 14, a prism 15, an optical member 16, and a display (display unit) 17.

The upper case 11 is made of a black, light-blocking synthetic resin material such as ABS (acrylonitrile butadiene styrene) and is formed in a roughly box-like shape with an open bottom. The upper case 11 has a light-transmitting portion 11a formed in a location facing the display 17. The light-transmitting portion 11a is made of a transparent synthetic resin material such as PMMA (acrylic).

The lower case 12 is made of a black, light-blocking synthetic resin material, such as ABS, and is formed in a roughly box-like shape with an open top. The lower case 12 fits together with the upper case 11 to form a box-like housing, and houses the circuit board 13, light source 14, prism (refractive part) 15, optical member 16, and display 17 inside.

The circuit board 13 is made of a rigid printed circuit board such as a flat glass epoxy substrate. The circuit board 13 mounts various circuit components such as the light source 14, a control chip, resistors, and capacitors, and the various circuit components are connected by wiring patterns to form a circuit. The circuit board 13 is electrically connected to a control unit of the vehicle (e.g., an ECU (Engine Control Unit)) by wiring members such as a harness.

The light source 14 is composed of a light emitting diode (LED), and a plurality of LEDs are mounted on the upper surface of the circuit board 13. The light source 14 emits light by a light emitting circuit (not shown) based on a control signal supplied from the control chip. The light source 14 emits light toward the prism 15.

The prism 15 is disposed on the light source 14 side of the optical member 16, and is composed of a base material 15a and a refracting portion 15b. The base material 15a is composed of a translucent flat-plate-shaped synthetic resin sheet, such as PC (polycarbonate). The refracting portion 15b is composed of a translucent transparent resin formed into an uneven shape by potting or the like on the light source 14 side of the base material 15a. As shown in FIG. 2, the refracting portion 15b is formed in a cross section of a continuous triangular shape (sawtooth shape) that narrows toward the light source 14 side, and the triangle has optical anisotropy due to its asymmetric shape. The refracting portion 15b refracts the light from the light source 14 due to this anisotropy, and irradiates this light toward the display 17 at a predetermined angle. The light that passes through the display 17 is irradiated toward the windshield 3.

The prism 15 is designed according to the emission direction of the display light 2 emitted from the head-up display device 1. The shape and optical characteristics of the refracting portion 15b of the prism 15 are determined so that the display light 2 is reflected by the light-shielding portion 3a of the windshield 3 and viewed by the driver 4 at an optimal angle (a reflection angle at which the light appears to be highly bright). Here, the display light 2 is determined to be emitted at an angle of approximately 20 degrees with respect to the normal direction of the display surface 17a of the display 17.

The optical members 16 are disposed between the display 17 and the prism 15, and diffuse the illumination light emitted from the prism 15. There are three optical members 16: two prism sheets with striped irregularities on the display 17 side, and one diffusion sheet with granular irregularities on the back. The prism sheets are optical films such as BEF (Brightness Enhancement Film) with irregularities on the surface. The number, order, and type of the optical members 16 may be set and arranged as appropriate.

The prism 15 is formed with an uneven shape, which creates dark lines (black streaks visible when viewed) according to the shape. The optical member 16 can diffuse light, making these dark lines less noticeable.

The display 17 is a segment-type LCD (Liquid Crystal Display) of the TN (Twisted Nematic) type negative type (display characters are translucent when lit and opaque when off. The background is opaque both when lit and off) type, with segmented pixels formed by sandwiching and sealing a liquid crystal material between two rectangular glass substrates, with polarizing plates attached to the front and back. The display 17 displays the design portion 17b formed by the segments as an image. The design portion 17b has vehicle information such as a vehicle speed design, a gear positioning design, a remaining fuel design, and an indicator design.

The vehicle speed design displays the vehicle's speed using units and multiple segment designs. The gear positioning design displays the gear position using P, R, N, and D designs. The remaining fuel design displays the remaining fuel using F, E, and multiple rectangular scale designs. The indicator design displays operating lights and warning lights with various designs such as turns.

The display 17 switches the design section 17b based on a control signal supplied from the control chip. The display 17 generates display light 2 by transmitting light emitted by the light source 14 through the design section 17b. The virtual image V1 formed by the display light 2 displays a vehicle speed display V11, a gear positioning display V12, a remaining fuel display V13, and an indicator display V14, which correspond to the vehicle speed design, gear positioning design, remaining fuel design, and indicator design. Here, the vehicle speed display V11 and the remaining fuel display V13 are important images that are more important than the gear positioning display V12 and the indicator display V14.

The instrument panel 5 has a recess (cylindrical portion) 51 that is recessed downward. The recess 51 is a hollow cylindrical recess with a rectangular cross section that is long in the left-right direction to correspond to the display 17, and is composed of a front wall 51a, a rear wall 51b, a side wall 51c, and a bottom hole 51d. The front wall 51a is a standing wall on the windshield 3 side and is formed so as to be continuous with the windshield 3. The rear wall 51b is a standing wall on the driver 4 side that faces the front wall 51a. The side wall 51c is a standing wall that connects the front wall 51a and the rear wall 51b. The bottom hole 51d is a rectangular hole that opens at the bottom downward.

The display 17 is disposed below the recess 51 so that the display surface 17a faces the bottom hole 51d. In this manner, the display light 2 passes through the recess 51, is reflected by the light-shielding portion 3a of the windshield 3, and is visually recognized by the driver 4 as a virtual image V1.

However, as shown in FIG. 4, for example, the head-up display device 1 has a problem in that if object B falls into this recess 51 and blocks the display light 2, causing the display such as the vehicle speed display V11 to be missing, the vehicle speed cannot be displayed correctly to the driver 4. In addition, when object B is small, the missing portion of the display of the virtual image V1 is also small, so the driver 4 cannot notice that object B has fallen into the recess 51. In addition, since the recess 51 is located on the windshield 3 side, which is set back from the driver 4 in the instrument panel 5, and is a narrow opening, it is difficult for the driver 4 to retrieve object B. Therefore, there is a problem in that the driver 4 must go to an automobile repair shop, and it is necessary to notice that object B has fallen into the recess 51 as soon as possible.

Therefore, the present disclosure addresses the above-mentioned problems, and as shown in FIG. 2, the head-up display device 1 has a front wall hole (hole portion) 51e and a photodetector (photodetection portion) 6.

The front wall holes 51e are cylindrical holes opened in the front wall 51a of the recess 51. As shown in FIG. 3, five front wall holes 51e are arranged side by side in the left-right direction. The front wall holes 51e allow leakage light 2a to pass through.

Leakage light 2a is light refracted toward the front wall hole 51e in the opposite direction to the refracted direction of display light 2. Specifically, if display light 2 is refracted in a direction of approximately 20 degrees relative to the normal direction of the display surface 17a of the display unit 17, leakage light 2a is light refracted in a direction of approximately minus 20 degrees relative to the normal direction of the display surface 17a of the display unit 17. In other words, the refracting section 15b separates the light from the light source 14 into light that is refracted toward the windshield 3 to become display light 2, and light that is refracted toward the front wall hole 51e to become leakage light 2a. Leakage light 2a is approximately 10% of the light from the light source 14, and is unnecessary light that is not used for displaying the head-up display device.

The light detector 6 is made up of a sensor board 61 and a light sensor 62. The sensor board 61 is made of a hard printed circuit board similar to the circuit board 13, and has five light sensors 62 mounted thereon. The light detector 6 is disposed and fixed on the outside of the front wall 51a (opposite the inside of the recess 51 (the side through which the display light 2 passes)). The sensor board 61 is electrically connected to the vehicle's control unit by a harness or the like.

The light sensors 62 can be, for example, photodiodes, and are arranged in each of the five front wall holes 51e. The light detectors 6 detect the illuminance of the leaked light 2a that passes through the front wall holes 51e and output the illuminance data to the vehicle's control unit.

The photodetector 6 is driven simultaneously with the lighting of the light source 14 and the driving of the display 17. As shown in FIG. 2, when the photodetector 6 detects light (leakage light 2a) above the threshold while the display 17 is driven, it determines that the light is normal and does not perform any specific processing. As shown in FIG. 4, when an object B falls into the recess 51, the photodetector 6 detects that the light (leakage light 2a) detected while the display 17 is driven is blocked by the object B or the like and remains below the threshold for a predetermined period of time, determines that an abnormality has occurred, and performs processing to warn the driver 4 by sound or display.

The warning is given by displaying a message such as "There may be a foreign object in the head-up display unit. Please contact your dealer" on a display device other than the head-up display device 1, such as the meter 7, or by emitting a similar sound message from a speaker installed in the meter 7.

The head-up display device 1 may drive the photodetector 6 only for a specific period of time to save power, rather than constantly. For example, it may drive the photodetector 6 only for one hour after the vehicle is turned on (when the ACC (accessory) is turned on or the IGN (ignition) is turned on).

By being configured in this manner, the head-up display device 1 can quickly notify the driver 4 of an abnormality using the photodetector 6 if an object B falls into the recess 51, blocking the display light 2 and preventing the virtual image V1 from being displayed.

Second Embodiment
A second embodiment of a display device according to the present disclosure will be described with reference to Fig. 5. The same parts and equivalent parts as those in the first embodiment will be described with the same reference numerals.

The display 17 was a segment-type LCD with a fixed design portion 17b, but in this embodiment, the display 17 is a full-color TFT (Thin Film Transistor) type LCD that displays various designs at the same location. The display 17 displays at least the same types of designs as in the first embodiment. In addition, the display 17 displays an inspection display V21 on the virtual image V2 when the vehicle is turned on. The inspection display V21 is a rectangular image that emits light in a single color.

By forming it in this manner, when an object B falls into the recess 51 and blocks the display light 2, the driver 4 can see the partially missing inspection display V21, and can sense the deterioration of the object B in the recess 51. Furthermore, even if the driver 4 does not notice an abnormality in the inspection display V21, the head-up display device 1 can quickly notify the driver 4 of the abnormality using the photodetector 6.

Third embodiment
A second embodiment of the display device according to the present disclosure will be described with reference to Fig. 6. The same parts and equivalent parts as those in the second embodiment described above will be denoted by the same reference numerals.

In the previous embodiment, there were five front wall holes 51e, but in this embodiment, the front wall holes 51e are formed in only two locations, corresponding to the vehicle speed display V22 and remaining fuel display V23 of the important images, and the optical sensors 62 are placed only at these locations. By forming them in this manner, the head-up display device 1 can reduce the cost of the optical detector 6 by reducing the number of optical sensors 62, etc.

Fourth embodiment
A fourth embodiment of the display device according to the present disclosure will be described with reference to Fig. 7. The same parts and equivalent parts as those in the third embodiment will be described with the same reference numerals.

The prism 15 was previously positioned on the light source 14 side of the optical member 16, but in this embodiment, it is positioned between the light-transmitting portion 11a and the display 17. The refracting portion 15b refracts the light that has passed through the display 17 and irradiates this light toward the windshield 3. By being formed in this manner, the prism 15 can irradiate the display light 2 toward the windshield 3 at an optimal angle for the driver 4 to view, just like in the first embodiment.

In this embodiment, the upper case 11 has an extension 11b extending toward the front wall 51a. The front wall hole 51e was formed in the front wall 51a, but in this embodiment, it is an extension hole (hole) 11e that is a cylindrical hole opened in the extension 11b. The extension hole 11e allows leakage light 2a to pass through. The light sensor 62 is disposed in each of the extension holes 11e. The light detector 6 was fixed to the outside of the front wall 51a, but in this embodiment, it is sandwiched and fixed between the extension 11b and the fixing member 18 and disposed outside the extension 11b.

The sensor board 61 was previously electrically connected to the vehicle's control unit, but in this embodiment, the sensor board 61 is electrically connected to the control unit of the circuit board 13 of the head-up display device 1 by a harness or the like. In other words, the photodetector 6 is formed integrally with the head-up display device 1.

The extension hole 11e has a light-guiding member 63 molded from a translucent synthetic resin (such as acrylic), which collects the leaked light 2a and guides it to the light sensor 62. By being formed in this manner, the head-up display device 1 can further improve the detection accuracy of the leaked light 2a.

(Modification)
Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims.

For example, the head-up display device 1 has been described as projecting the display light 2 onto the light-shielding portion 3a of the windshield 3, but it may also be a head-up display device that projects onto a transparent portion of the windshield 3 and allows the driver 4 to view a real image or a virtual image. It may also be a head-up display device that projects onto, for example, a transparent or opaque reflecting portion (a so-called combiner) provided on the driver 4 side of the windshield 3.

The prism 15 is disposed on the light source 14 side of the optical member 16 or between the light-transmitting portion 11a and the display 17, but it may be disposed between the display 17 and the optical member 16. The prism 15 may be a so-called light guide molded from a light-transmitting synthetic resin.

1 Head-up display device 11 Upper case (case body)
11a Transparent part 11b Extension part 11e Extension part hole (hole)
12 Lower case (case body)
13 Circuit board 14 Light source 15 Prism 15a Base material 15b Refraction portion 16 Optical member 17 Display (display portion)
17a Display surface 17b Design portion 18 Fixing member 2 Display light 2a Leaking light 3 Front glass (reflecting portion)
3a Shading part 4 Driver (visitor)
5 Instrument panel 51 Recess 51a Front wall 51b Rear wall 51c Side wall 51d Bottom hole 51e Front wall hole (hole)
6 Photodetector (photodetector section)
61: sensor board 62: optical sensor 63: light guide member 7: meter B: object V1: virtual image V11: vehicle speed display V12: gear positioning display V13: remaining fuel display V14: indicator display V2: virtual image V21: inspection display V22: vehicle speed display V23: remaining fuel display

Claims (8)

A light source that emits light;
a display unit that generates display light using the light;
a refraction unit that refracts the light or the display light,
In a head-up display device, the display light is reflected by a reflecting portion and displayed as a virtual image to a viewer,
A hollow cylindrical portion disposed on a display surface side of the display portion;
a light detection unit disposed in the cylindrical portion and configured to detect an illuminance of light refracted in a direction opposite to a direction in which the display light is refracted;
Equipped with
The light detection unit outputs the illuminance to a control unit,
The control unit determines that an abnormality exists when the illuminance is equal to or lower than a threshold value, and performs processing to issue a warning to the viewer . The reflecting portion is a windshield of a vehicle,
the cylindrical portion is a recess formed in an instrument panel of the vehicle,
2. The head-up display device according to claim 1, wherein the display light is projected onto a light-shielding portion formed on a periphery of the windshield. The head-up display device according to claim 1, characterized in that the refraction portion is disposed between the display portion and the light source. The head-up display device according to claim 1 , wherein the illuminance is blocked by an object and falls below the threshold value . The head-up display device according to claim 1, characterized in that the light detection unit is disposed on the reflecting portion side of the cylindrical portion. the display unit has an important image having a high degree of importance,
The head-up display device according to claim 1 , wherein the light detection unit is disposed at a position corresponding to the important image. The head-up display device according to claim 1, characterized in that the display unit displays an inspection display. The head-up display device according to claim 1 , wherein the light detection unit detects the illuminance for a specific period of time after the vehicle is powered on .