JP2003175744A - Head up display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a virtual image display according to favorite of a driver in a head up display for vehicles. <P>SOLUTION: A liquid crystal panel 12b is movable so as to change an optical path length from the liquid crystal panel 12b to a concave mirror 14. Accordingly, by moving the liquid crystal panel 12b so as to reduce the optical path length, a display size of the virtual image can be reduced and by moving the liquid crystal panel 12b so as to increase the optical path length, the display size of the virtual image can be increased. Thereby, the display size of the virtual image can be adjusted according to the favorite of the driver. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle head-up display.

[0002]

2. Description of the Related Art Conventionally, for example, in a vehicle head-up display, a display device for emitting display information as display light and a concave mirror are fixedly installed on the back side of an instrument panel in a vehicle compartment. . Then, the display light emitted from the display is reflected by the concave mirror and enters the front windshield through the opening of the instrument panel, and the incident light is reflected by the front windshield to display the display information. It is displayed as a virtual image in front of it by the shield.

[0003]

However, since the display size of the virtual image is fixed in the above conventional head-up display, the preset display size may not meet the driver's preference. For example, a driver with low visual acuity, such as an elderly person, feels that the display size is too small and the displayed content is difficult to read. On the other hand, if the display size is increased, the driver feels that the display size is too large for the driver with high visual acuity to hinder the visibility.

In view of the above points, the present invention has an object of providing a virtual image display according to a driver's preference in a vehicle head-up display.

[0005]

In order to achieve the above object, in the invention according to claim 1, the rear surface of the instrument panel (30) located below the front windshield (20) in the passenger compartment of the vehicle. A display device (12b) which is disposed on the side and emits display light representing the display information; and display light from the display device (12b) which is a concave reflection surface (14b).
a) and a concave mirror (14) which reflects through the opening (30a) of the instrument panel (30) toward the back surface of the front windshield (20), and the front windshield (20) extends from the concave mirror (14). In a head-up display in which the reflected light of the display is reflected to display the display information as a virtual image in the front, the display (12b) is changed so as to change the length of the optical path from the display (12b) to the concave mirror (14). ) Is made movable.

As a result, the length of the optical path from the display (12b) to the concave mirror (14) can be changed, so that the display size of the virtual image can be changed. That is, the display (12b) is arranged so that the length of the optical path becomes long.
Can be moved to enlarge the display size of the virtual image, and the length of the optical path can be shortened by the display (12b).
By moving, the display size of the virtual image can be reduced. Therefore, according to the present invention, the display size of the virtual image can be adjusted according to the driver's preference.

By the way, when the display (12b) is a liquid crystal panel, the liquid crystal panel (12) is not required even if the light source (12c) used as a backlight is movable.
If only b) is movable as described above, the display size of the virtual image can be adjusted. However, the light source (1
If the liquid crystal panel (12b) is moved while 2c) is fixed, the brightness of the virtual image changes depending on the position of the liquid crystal panel (12b).

On the other hand, according to the second aspect of the invention, since the light source (12c) is moved together with the liquid crystal panel (12b), the brightness of the virtual image changes as described above. Can be prevented.

Further, as one means for making the display (12b) movable, an actuator (12e) for moving the display (12b), as in the invention described in claim 3,
If a driver is provided with an operation switch means (31) for outputting an actuation signal to the actuator (12e), the driver operates the operation switch means (31) to adjust the display size to a desired one. It is possible and preferable.

The invention according to claim 4 is characterized by comprising an image processing circuit (41) for correcting the distortion of the virtual image in association with the movement of the display (12b).

Thus, when the display (12b) moves and the display size of the virtual image changes, it is possible to prevent the virtual image from being distorted, so that it is possible to maintain a clean image quality.

The reference numerals in parentheses of the above-mentioned means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is an exploded perspective view showing a HUD unit 10 which is a component of a head-up display (hereinafter referred to as HUD) of the present embodiment. The HUD unit 10 is shown in FIG. , A display device 12 and a reflecting mirror 13 are provided inside a casing 11 which is divided into upper and lower parts.
And a concave mirror 14. And H
The UD unit 10 is arranged on the back side of an instrument panel 30 that extends from the lower edge of the front windshield 20 of the vehicle into the vehicle interior.

FIG. 2 is a schematic view of the HUD unit 10 as viewed from above. The display device 12 includes a case 12a, and a transmissive liquid crystal display panel (display) 12b and a thin backlight (light source) 12c. ing. The thin backlight 12c is a well-known backlight including a cold cathode tube, a lamp reflector, a light guide plate, a diffusion plate, a reflection plate, and the like, which are not shown.

Then, the light emitted from the thin backlight 12c enters the liquid crystal panel 12b, and the driving circuit 41
The display light representing the display information is emitted from the display surface 12d of the liquid crystal panel 12b toward the reflection surface 13a of the reflection mirror 13 by the liquid crystal panel 12b driven by the optical path K1.
reference). Incidentally, as the type of display information, in addition to speedometer display and warning display, there are navigation route guidance, night vision (night vision), and the like.

The display device 12 includes a liquid crystal panel 12
An electric motor (actuator) 12e for moving b is provided, and when the motor 12e is driven, the liquid crystal panel 12b moves on a rail 12f arranged in the case 12a. It should be noted that this moving direction is based on the display surface 12
It is parallel to the emission direction of the display light from d. Therefore, the liquid crystal panel 12b moves while the display surface 12d maintains a predetermined angle with respect to the optical path K1.

Reference numeral 31 indicates an operation switch (means) provided on the surface of the instrument panel 30, and when the operation switch 31 is operated by the driver of the vehicle, an operation signal is sent from the controller 32 to the motor 12e. Is output. Specifically, when the operation switch 31 is operated to the side of the symbol A, the liquid crystal panel 12b moves in the direction of the arrow A, and the reflecting mirror 1 is moved from the display surface 12d of the liquid crystal panel 12b.
The length of the optical path K1 to the reflection surface 13a of No. 3 is shortened. On the other hand, when the operation switch 31 is operated to the side of the symbol B, the liquid crystal panel 12b moves in the direction of the arrow B, and the length of the optical path K1 is lengthened.

Further, the concave mirror 14 has a parabolic concave reflecting surface 14a, and through the dustproof cover 33 (made of transparent resin or glass) attached to the opening 30a of the upper wall of the instrument panel 30, the visual field area. It is arranged so as to incline so as to face the portion 20a and the reflecting surface 13a of the reflecting mirror 13.

The display light from the reflecting surface 13a of the reflecting mirror 13 is incident on the reflecting surface 14a of the concave mirror 14 (see optical path K2). The display light from the reflecting surface 14a of the concave mirror 14 passes through the dustproof cover 33 and is incident on the back surface of the field-of-view area 20a of the front windshield 20 (optical path K
3).

Here, a well-known combiner 21 formed by attaching a vapor-deposited film of titanium oxide or the like to the inside of the shield 20 as a semi-transmissive reflective film is attached to the view field portion 20a of the front windshield 20. There is. Then, the display light that has entered the view field portion 20a is reflected by the combiner 21 and enters the eyes of the driver through directly above the steering wheel W (not shown) of the vehicle (optical path K4.
reference).

As a result, the driver has the illusion that display light has entered both eyes from the front of the front windshield 20, and visually recognizes the display information as a virtual image 22 in front of the front windshield 20. Become.

FIG. 3 is a schematic diagram showing the relationship between the position of the liquid crystal panel 12b and the size of the virtual image. When the image extending from the point P to the point Q is moved to the position a, the code The light emitted from Q forms an image at the point indicated by the code Q ′, and from the point indicated by the code P ′ at the position indicated by the code a ′, the code Q ′
The driver visually recognizes the virtual image extending to the point. Similarly, when the images shown by the symbols P and Q are moved to the positions shown by the symbol b,
The driver visually recognizes the virtual images indicated by the symbols P ′ and Q ′ at the position indicated by the symbol b ′.

Therefore, the operation switch 31 is used to bring the liquid crystal panel 12b closer to the reflecting mirror 13 by the arrow A shown in FIG.
When the liquid crystal panel 12b is moved in the direction of, the liquid crystal panel 12b moves from the position of the reference sign b to the position of a shown in FIG. That is, the images indicated by the symbols P and Q move so as to approach the concave mirror 14, the optical path lengths K1 and K2 from the liquid crystal panel 12b to the concave mirror 14 become shorter, and the display size of the virtual image indicated by the symbol P'Q '. Can be reduced.

On the other hand, the arrow B shown in FIG. 2 is used to move the liquid crystal panel 12b away from the reflecting mirror 13 by the operation switch 31.
When the liquid crystal panel 12b is moved in the direction of, the liquid crystal panel 12b moves from the position of the symbol a shown in FIG. That is, the images shown by the symbols P and Q move away from the concave mirror 14, the lengths K1 and K2 of the optical paths from the liquid crystal panel 12b to the concave mirror 14 become long, and the virtual image shown by the symbol P′Q ′ is displayed. The size can be increased.

Further, the above-mentioned drive circuit 41 for driving the liquid crystal panel 12b so that the display light is emitted as display information.
A signal of the operation switch 31 from the controller 32 is input to the. The drive circuit 41 also functions as an image processing circuit that corrects the distortion of the virtual image in conjunction with the movement of the liquid crystal panel 12b.

Thus, by controlling the display opposite to the display image distortion caused by the enlargement or reduction, an appropriate display can be held even if the display size is changed. For example, if the displayed image without distortion has a rectangular outer shape, and if the image point shifts from the correct position to the outside due to a change in the display size, resulting in so-called pincushion-shaped distortion, it is corrected to shift it inward. To do. Further, when the image point shifts from the correct position to the inside due to the change in the display size to cause so-called barrel distortion, the image point is corrected so as to be shifted to the outside.

As described above, according to the present embodiment, the driver operates the operation switch 31 to adjust the display size of the virtual image according to the driver's preference.

Incidentally, at the vehicle mounting position of the HUD unit 10 in this embodiment, the distance from the display surface 12d of the liquid crystal panel 12b to both eyes of the driver is 1.2 m to 2 m, and the liquid crystal panel 12b is about 20 mm. The distance is set to be movable. The diagonal distance when the display surface 12d is moved to the position indicated by the alternate long and short dash line in FIG. 2 to maximize the display size of the virtual image is the diagonal distance when the display surface 12d is moved to the solid line position in FIG. It is set to be about 1.5 times the distance.

(Second Embodiment) In the first embodiment,
Whereas only the liquid crystal panel 12b is moved by driving the electric motor 12e, in the present embodiment,
As shown in FIG. 4, the thin backlight 12c and the liquid crystal panel 12b are integrated into a unit, and the thin backlight 12c is moved together with the liquid crystal panel 12b. This can prevent the brightness of the virtual image from changing when the liquid crystal panel 12b is moved.

(Other Embodiments) In the first and second embodiments, the display light from the liquid crystal panel 12b is reflected by the reflecting mirror 13.
Although the light is reflected by the concave mirror 14 and then is incident on the concave mirror 14, the reflecting mirror 13 may be omitted and the display light from the liquid crystal panel 12b may be directly incident on the concave mirror 14 in implementing the present invention. In this case, the liquid crystal panel 12b may be moved in the direction parallel to the optical path K2 shown in FIG.

In the first and second embodiments, the thin backlight 12 is used as the backlight of the liquid crystal panel 12b.
Although c is used, it goes without saying that a bulb, a light emitting diode or the like may be used as the backlight. In implementing the present invention, a self-luminous EL panel (electroluminescence panel), a light emitting diode, a cold cathode discharge tube, or the like is used instead of the liquid crystal panel 12b and the light source 12c of the first and second embodiments. You may.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a HUD unit according to a first embodiment of the present invention.

FIG. 2 is a schematic view of the HUD unit of FIG. 1 viewed from above.

FIG. 3 is a schematic diagram showing the relationship between the position of a liquid crystal panel and the size of a virtual image in the first embodiment.

FIG. 4 is a schematic view of a HUD unit according to a second embodiment of the present invention viewed from above.

[Explanation of symbols]

12b ... Liquid crystal panel, 12c ... Thin backlight, 14
... concave mirror, 20 ... front windshield, 30 ... instrument panel, 30a ... opening.

Claims (4)

[Claims] 1. A display device (12b), which is arranged on the back side of an instrument panel (30) located below a front windshield (20) in a vehicle interior of a vehicle and emits display light representing display information. The display light from the display (12b) is reflected by the concave reflection surface (14a) to the instrument panel (30).
A concave mirror (14) that reflects through the opening (30a) toward the back surface of the front windshield (20), and the front windshield (20) reflects the reflected light from the concave mirror (14). In the head-up display in which the display information is displayed forward as a virtual image, the display (12b) is changed so as to change the length of the optical path from the display (12b) to the concave mirror (14). A heads-up display characterized by being movable. 2. The display device (12b) is a liquid crystal panel, comprising a light source (12c) used as a backlight of the liquid crystal panel (12b), and the light source (12c) together with the liquid crystal panel (12b). The head-up display according to claim 1, wherein the head-up display is moved. 3. An actuator (12e) for moving the indicator (12b), and the actuator (12e) operated by a vehicle driver.
The head-up display according to claim 1 or 2, further comprising: an operation switch means (31) for outputting an operation signal. 4. The image processing circuit (41) according to claim 1, further comprising an image processing circuit (41) for correcting the distortion of the virtual image in association with the movement of the display device (12b). Head-up display.