JP3206679B2 - Display device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for a vehicle.
In particular, display light from a self-luminous display device that displays the driving status of the vehicle is finally reflected and projected toward a front windshield by a holographic optical element (HOE), and the display image is displayed. The present invention relates to a vehicle display device generally called a head-up display (HUD), in which a driver is visually recognized by superimposing on a foreground view ahead of a windshield.

[0002]

2. Description of the Related Art Conventionally, as a device of this type, FIG.
There was something like that shown. In FIG. 1, reference numeral 1 denotes a display device for displaying a driving state of a vehicle such as a traveling speed and a warning, and is specifically constituted by a fluorescent display tube and a liquid crystal display. Reference numeral 2 denotes a reflecting member that reflects light from the display device 1 toward the front windshield 3 of the vehicle, and is specifically configured by a HOE or a reflecting mirror, the reflecting surfaces of which are the display surface of the display device 1 and the windshield. 3 are directed toward the inner surface.

[0003] Reference numeral 4 denotes a dashboard of the vehicle, in which a display unit including the display device 1 and the reflection member 2 is accommodated, and an opening 4 formed in the upper surface thereof.
In a, an opening of the display unit for projecting the light reflected by the reflection member 2 onto the windshield 3 is located. The display device 1 reflected and projected by the reflection member 2 is provided on the inner surface of the windshield 3.
A special reflection coding is applied to a portion that reflects light from the driver in the direction of the driver so as not to obstruct the front view.

With the above arrangement, the light of the display image from the display device 1 is reflected by the reflection member 2 and projected on the windshield 3 of the vehicle through the opening 4a of the dashboard 4, and the projected light is transmitted to the windshield. By being further reflected toward the driver on the inner surface of 3, the display image of the display device 1 can be visually recognized by the driver as a virtual image X in front of the windshield 3.

[0005] By the way, some drivers have various physiques or some have various driving postures. For this reason, the driver's head, that is, the position taken by the eyes has a certain range. This is called an eye range, and when represented by E, it is necessary that the display image of the display device 1 can be normally recognized even at the upper and lower limit positions.

However, in order to configure the apparatus so as to cover such an eye range E, the size of the reflection member 2 made up of a HOE or a reflection mirror becomes large, and the opening 4a of the dashboard 4 and furthermore, The area of the reflection coding applied to the inner surface of the windshield 3 must be increased. When the opening 4a of the dashboard 4 is large, not only the interior appearance is deteriorated, but also the solar rays inserted from the outside through the windshield 3 easily enter the device. As described above, when the sunlight enters the apparatus, a so-called washout phenomenon occurs on the surface of the display device 1 to make it difficult to see a display image, and also to prevent the display device 1 from being damaged due to a rise in temperature due to the incident sunlight. There were inconveniences such as the need for heat measures.

Therefore, in order to ensure a sufficient eye range E even if the opening 4a of the dashboard 4 is made small, as shown by an arrow in FIG. 11, a reflecting member composed of a HOE or a reflecting mirror in FIG. 2 is made movable so that the angle of incidence and reflection of light of a display image from the display device 1 can be changed.

By making the reflecting member 2 movable as shown in FIG. 11, the opening 4a of the dashboard 4 can be made smaller as described above, and the reflection coding of the inner surface of the windshield 3 as well as the reflecting member 2 itself can be performed. The area can be reduced.

A drive mechanism for moving the reflection member 2 in FIG. 11 supports the reflection member 2 rotatably by a rotating shaft 21 as shown in, for example, a perspective view of FIG.
The rotation force of the motor 22 is transmitted to the rotation shaft 21 via the gears 23 and 24. The motor 22 is operated by operating an operation button (not shown) provided in the driver's seat.
By rotating the reflecting member 2 to a desired angle position in accordance with which one of the upper and lower limit positions of the eye range E as shown in FIG. The display image can be visually recognized in the eye range.

However, in the case of a device employing a drive mechanism for moving the reflection member 2 as shown in FIG. 12, the drive mechanism has a mechanically movable portion, so that the gear rattles with aging. There is a problem that the display image on the windshield 3 fluctuates easily due to vibration during running of the vehicle.

Further, a drive mechanism as shown in FIG.
There is also a problem that incorporation into a device causes an increase in the cost of the device.

Further, in the conventional apparatus, the reflection member 2 is a regular reflection type, and therefore, FIG.
As shown in (1), there is a problem that a ghost image occurs due to interference between the reproduction light and the reflected light from the surface of the hologram.

Further, in an apparatus using a regular reflection member, the windshield 3 and the opening 4 of the dashboard 4 are provided.
When external light such as sunlight enters through a, the external light is directed toward the display device via the regular reflection member 2 as shown in FIG. 13B, so that the display device such as a washout is adversely affected. There was also a problem of giving.

[0013]

In order to achieve the above object, a vehicle display device according to the present invention reflects a display light from a self-luminous display device for displaying a driving state of a vehicle by a reflecting member, and The reflected light is projected through an opening formed on the upper surface of the dashboard and is incident on a translucent reflecting member provided in the front view of the driver, and the incident light is reflected toward the driver by the translucent reflecting member. A display image of the self-luminous display device for a driver to visually recognize as a virtual image behind the translucent reflective member, wherein the reflective member is seen by reflecting the reflective member.
The position of the display image is changed depending on the angle at which the display image is viewed.
Using non-specular holographic optical elements
The upper limit position and the lower limit position of the driver's viewpoint.
The optical path for recognizing the same point on the display image is
Near the opening between the material and the translucent reflecting member
So that the non-specular reflection characteristics of the reflection member
Incident display light of the self-luminous display device to the reflective member
Corners, from the reflective member to the self-luminous display device
It is characterized by setting a distance .

The optical path of the display light when viewed at the upper limit position and the lower limit position of the driver's viewpoint intersects near the opening.

[0015]

According to the above construction, the display light of the self-luminous display device is reflected by the non-specular reflection holographic optical element, and the reflected light is further reflected by the translucent reflection member through the opening on the upper surface of the dashboard of the vehicle. , virtual image of the display image of the self-luminous display device Ru is visible to the driver. Non-specular reflection hologram
Of the self-luminous display device reflected by the
The displayed image is displayed when the driver's viewpoint is between the upper and lower positions.
When it changes, its visible position changes, and the same point on the displayed image
The optical path to see the light crosses somewhere
However, this position is the opening between the reflecting member and the translucent reflecting member.
And the spontaneous reflection characteristics of the reflective member
The angle of incidence of the display light of the optical display device on the reflection member and the reflection
The distance from the member to the self-luminous display device is set.
Display image in the vicinity of the opening
Therefore, the expansion of the optical path of the display light required for the operation is minimized.
Therefore, in order for the driver to visually recognize the virtual image of the display image, the area of the opening on the dashboard upper surface through which the reflected light needs to pass,
The size can be reduced as compared with a case where a regular reflection member is used or a case where the above-described setting is not adopted.

In particular, the optical path of the display light when viewed at the upper and lower limit positions of the driver's viewpoint intersects near the opening. There is no need to increase the size, and the opening area can be minimized.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a vehicle display device according to the present invention, in which the same or corresponding parts as those of the conventional device described above with reference to FIGS. 10 and 11 are denoted by the same reference numerals, and detailed description thereof is omitted. I do. As the display device 1, a self-luminous display such as a VFT or a liquid crystal display such as a VHC having a backlight disposed on the back is used.

In FIG. 1, reference numeral 12 denotes a reflection member made of a non-specular reflection type HOE, which is substantially the same except that the reflection member 12 is replaced by the regular reflection type reflection member 2 of the conventional apparatus shown in FIG. .

With this configuration, as shown in FIG. 1, the display light from the display device 1 is reflected by the non-specular reflection HOE 12, and the reflected light is projected on the windshield so that the virtual image can be visually recognized by the driver. Has become.

In the non-specular reflection type HOE, a display image (virtual image) X
There is a feature that the visible position of the display image changes depending on the angle (direction) at which the image is viewed. Therefore, the position of the display image when visually recognized at the upper limit position and the lower limit position of the eye range E is as shown in FIG.
Will be different as shown. By changing the position of the display image in this way, as shown in FIG. 3, the optical paths of the display light when viewed at the upper limit position and the lower limit position of the eye range E cross each other. Therefore, by setting the position where the optical paths intersect to the position of the opening 4a on the upper surface of the dashboard 4, the opening 4a can be minimized.

Although the size of the opening 4a cannot be minimized, at least the reflection member 1 made of a non-specular reflection type HOE is used.
2, and by setting the intersection of the optical paths near the opening 4a, compared with the case of the regular reflection member,
The area of the opening 4a on the upper surface of the dashboard 4 through which the display light passes can be made sufficiently small.

That is, in FIG. 3, the dashed line shows the display light from the upper and lower ends and the center of the display image when the reflection member 12 made of the non-specular reflection type HOE is used is viewed at the center and upper and lower limit positions of the eye range. The two-dot dashed line indicates the optical path when the display light from the upper and lower ends and the center of the display image when the regular reflection type HOE is used is viewed at the center and upper and lower limit positions of the eye range, respectively.

As can be seen from the figure, the size of the opening 4a on the upper surface of the dashboard 4 required in the case of the non-specular reflection type HOE in which the virtual image position changes depending on the viewing position is K ₁ is the specular reflection type HOE. Is smaller than K _{2 in} the case of. Also, the area R ₁ of the reflection surface on the windshield 3
Is smaller than R _{2 in} the case of the specular reflection type HOE.

Next, the rate at which the opening 4a becomes smaller as described above will be examined for various incident angles of display light and the curvature R thereof with respect to the reflection member 12 made of a non-specular reflection type HOE. In conducting this study, the specifications of each part were set as shown in FIG. That is, the distance between the non-specular reflection type HOE 12 and the opening 4a is set to 100 mm, the angle between the dashboard and the windshield is set to 35 °, and the incident / reflection angle of the reflection member on the windshield is set to 67.5 °. ing.

In this specification, first, as shown in FIG. 5, a recording light composed of parallel light is incident on one surface of the hologram recording medium at an incident angle of 60 °, and a reference light composed of parallel light is obtained. Is incident on the other surface of the hologram recording medium at an incident angle θ, and a reflecting member 12 made of a non-specular reflection type HOE formed as a plane mirror (R = ∞) is used.
FIG. 6 shows the result of the aperture reduction ratio when the incident angle θ is changed. This result is obtained when the distance between the display device and the reflection member 12 is fixed to 200 mm. FIG.
As can be seen from FIG. 7, when the incident angle is 60 ° (specular reflection), the aperture is exactly the same size as that of the regular reflection plane mirror, and the aperture reduction ratio is 0%. Then, when the absolute value of the incident angle θ is near 0 °, there is an optimum value at which the reduction ratio becomes maximum.

Next, the non-specular reflection type H formed by setting the incident angle of the parallel recording light to 60 ° and the incident angle of the parallel reference light to 0 °.
A reflection member 12 made of OE is used.
FIG. 7 shows the result of the aperture reduction ratio when the distance between the device and the display device is changed. From FIG. 7, it can be seen that the larger the distance between the reflective member 12 and the display device is, the longer the distance of the display image is, the larger the aperture reduction ratio is.

In the case of FIG. 7, the non-specular reflection type H
When the reflecting member 12 made of OE was formed as a concave mirror and its curvature was changed variously, it was found that the aperture reduction ratio became slightly smaller as the curvature decreased, but the difference was slight.

In short, the aperture reduction ratio is best when the reflection member 12 made of a non-specular reflection type HOE constitutes a plane mirror, and there is an optimum value for the display light incident angle. The greater the distance, the greater the reduction ratio.

The reflection member 12 is a non-specular reflection type HO.
Since E is used, as shown in FIG. 8, even if external light is incident, the surface reflected light of the reflecting member 12 is not incident on the display device 1, and the reflected light ( (Reproduction light) is reduced, which is advantageous in measures such as washout and heat generation of the display device.

By the way, in general, display on the windshield is limited to be performed in a region B around the central region A of the windshield 3 defined by JISR3212, as shown in FIG. 9A. But,
Since the area of use of the regular reflection member is large, the display image must be moved downward as a whole as shown in FIG. However, the display of the HUD is preferably performed at a position as high as possible so as to be in front of the driver. In this regard, when the reflection member 12 made of the non-reflection type HOE is used, the use area on the windshield 3 is reduced, so that the display can be moved upward as a whole and the visibility can be improved. be able to. Further, since the reflection processing area on the windshield 3 can be reduced, the mask phenomenon on the reflection processing surface that blocks the front view can also be reduced.

Although it is not stated in the above-mentioned embodiment, by using a non-specular reflection holographic optical element having an absolute value of the incident angle smaller than the reflection angle as the reflection member, the upper and lower limits of the eye range can be obtained. If the display image (virtual image) to be viewed in the above moves, and the optical path of the display light intersects between the reflecting member composed of the non-specular reflection holographic optical element and the translucent reflecting member, The area of the opening on the upper surface of the dashboard through which the reflected light needs to pass in order to visually recognize the virtual image of the display image can be made smaller than that of the regular reflection member. Also, it is clear that the optimum value of the incident angle becomes a value other than 0 ° when the specifications change.

[0032]

As described above, according to the present invention, the display image (virtual image) when viewed at the upper and lower limit positions of the eye range moves, and the optical path of the display light comprises a non-specular reflection holographic optical element. The intersection between the reflective member and the translucent reflective member is made near the opening on the dashboard upper surface, so that the driver does not need to make the reflective member movable so that the driver can see the virtual image of the displayed image. The area of the opening on the upper surface of the dashboard where light needs to pass, compared with the case where a regular reflection member is used or the case where the above setting is not adopted,
Can be smaller. In addition, it is possible to obtain an inexpensive vehicle display device that eliminates the generation of a ghost image and does not cause any inconvenience to a display device even when external light enters.

In particular, since the optical path of the display light when viewed at the upper limit position and the lower limit position of the driver's viewpoint intersects in the vicinity of the opening, even if the viewing position changes, the opening is almost completely changed. There is no need to increase the size, and the opening area can be minimized.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a vehicle display device according to the present invention.

FIG. 2 is a view showing a state of movement of a display image when visually recognized at upper and lower limit positions of an eye range in the vehicle display device of FIG. 1;

FIG. 3 is a diagram showing a comparison between a display operation of a vehicle display device according to the present invention and a display operation of a conventional device.

FIG. 4 is a diagram showing an example of specifications of each unit in the apparatus of FIG.

FIG. 5 is a diagram showing a method of manufacturing a non-specular reflection type HOE.

FIG. 6 is a graph showing a relationship between an incident angle and an aperture reduction ratio.

FIG. 7 is a graph showing a relationship between a distance from a display device and an aperture reduction ratio.

FIG. 8 is a diagram showing an example of an effect when a non-specular reflection type HOE is used.

FIG. 9 is a diagram showing another example of the effect when a non-specular reflection type HOE is used.

FIG. 10 is a diagram showing an example of a conventional device.

FIG. 11 is a diagram showing another example of a conventional device.

FIG. 12 is a perspective view showing details of a part of FIG. 11;

FIG. 13 is a diagram for explaining a problem of the conventional device.

[Explanation of symbols]

 Reference Signs List 1 self-luminous display device 12 reflecting member 3 translucent reflecting member (wind shield) 4 dashboard 4a opening E eye range X virtual image

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 35/00 G02B 5/32 G02B 27/02 G09F 9/00 359

Claims (2)

(57) [Claims] 1. A display member for displaying a driving state of a vehicle from a self-luminous display device is reflected by a reflecting member, and the reflected light is projected through an opening formed on an upper surface of a dashboard to be provided in a front view of a driver. Incident on the light-transmitting reflective member, and reflects the incident light toward the driver by the light-transmitting reflective member to display the display image of the self-luminous display device to the driver behind the light-transmitting reflective member. In the display device for a vehicle which is made to be visually recognized as a virtual image , the reflection member may be configured to reflect the reflection member.
Change the position of the image according to the angle at which the displayed image is viewed.
Using non-specular holographic optical elements
The display image from the upper limit position and the lower limit position of the driver's viewpoint.
The optical path for visually recognizing the same point above is the reflection member and the
Intersect in the vicinity of the opening with the translucent reflecting member
As described above, the non-specular reflection characteristic of the reflection member and the self-emission
The incident angle of the display light of the display device on the reflection member,
And the distance from the reflective member to the self-luminous display device.
A display device for a vehicle, wherein the display device is set. 2. The vehicular display device according to claim 1, wherein an optical path of display light when viewed at an upper limit position and a lower limit position of the driver's viewpoint intersects near the opening. .