JP3240085B2 - 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, various information necessary for driving the vehicle, for example, the vehicle speed, the information that should always be seen during driving, such as the distance between the vehicles, is projected onto the windshield, and the reflection of the windshield,
A head-up display (hereinafter referred to as HUD for simplicity) in which an image is formed as an optical virtual image in the front field of view outside the windshield as viewed from the driver, so that driving information can be viewed in an overlapping manner with the outside scene in the traveling direction. The present invention relates to a display device for a vehicle.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional apparatus, wherein 101 is a windshield, 102 is an instrument panel, 1
Reference numeral 03 denotes a steering wheel, and driving information such as vehicle speed that is always required to be viewed during driving is displayed as a HUD driving information image 104 in a front view of the windshield 101, and driving information 105 that is sometimes desired to be viewed such as a remaining fuel amount is the same as before. It is displayed on the front of the instrument panel 102. A projection unit for projecting HUD operation information toward the windshield is not shown in FIG. 8 but is mounted inside the instrument panel 102.

FIG. 9 is a simplified cross-sectional view showing an example of the configuration of a projection unit according to the prior art. The operation of the projection unit will be described with reference to the drawing. A light beam 5a emitted from a light source 2 is converged by a reflecting mirror 3 and then a concave lens. At 4, the light beam is converted into a substantially parallel light beam 5 c, passes through the LCD 1 as liquid crystal display means, advances toward a windshield 101 (not shown), reflects on the inner surface of the windshield 101, enters the driver's eyes, and is viewed from the driver. A driving information image 104 (not shown) is formed as an optical virtual image of the driving information displayed on the LCD 1 in front of the windshield 101.

An optical system for imaging including a lens or a mirror (not shown) is inserted between the LCD 1 and the windshield 101 so that the driving information image 104 appears as an optical virtual image of an appropriate size. Sometimes. The LCD 1 is of a transmissive type in which a required stippling portion of a character or a number to be displayed changes to a transmissive state in accordance with a signal of driving information.

[0005] Since the driver can see the driving information image 104 overlapping with the outside scene ahead, the driving information image 104 may be weakened when external light is strong, resulting in a washout phenomenon that impairs visibility. In order to prevent washout, it is necessary to increase the density of the luminous flux passing through the LCD 1 and entering the driver's eyes. For this purpose, the following means have conventionally been used.

First, a high-intensity lamp such as a halogen lamp is used as the light source 2 to increase the amount of the light beam 5a emitted from the light source. Second, a concave lens 4 is provided between the light source 2 and the LCD 1 in order to effectively use the light beam emitted from the light source 2.

The operation of the concave lens 4 will be described. First, in order to increase the density of light flux entering the driver's eyes, the LCD 1
It is necessary that the light beam 5c reaching from the driver's eyes to the driver's eye is almost a parallel light beam. On the other hand, the light beam 5a emitted from the light source 2 is
In order to concentrate the light beam 5b, it is necessary to converge the light beam 5b to the focal point 6 by the reflecting mirror 3. That is, the concave lens 4 contributes to the effective use of the light beam emitted from the light source by converting the convergent light beam 5b from the light source 2 toward the LCD 1 into a parallel light beam 5c toward the driver's eyes.

[0008]

As shown in FIG. 9, the focal point 6 is the second focal point of the reflecting mirror 3. In order to concentrate as much of the light beam 5a emitted from the light source 2 as possible on the LCD 1, the focal point 6 is located at the focal point 6. The opening angle of the converging light beam 5b becomes very large, and the focal length of the concave lens 4 for converting this converging light beam into a parallel light beam needs to be very short, and the curvature of the lens surface becomes large. Moreover, since the outer shape of the concave lens 4 needs to be substantially the same size as the outer shape of the LCD 1, the thickness of the lens becomes extremely thick, which not only hinders the miniaturization of the HUD projection unit but also reduces the empty space and reduces the size of the light source lamp. There is a drawback that the dissipated heat is poorly dissipated.

The LCD 1 is of a transmissive type in which a stippled portion of a character or a number to be displayed changes to a light-transmitting state in accordance with a signal of driving information, and transmits the stippled portion to be displayed. Since only the light beam is effective for forming the driving information image 104, there is a problem that the utilization rate of the light beam emitted from the light source 2 is poor.

Therefore, in view of the above-mentioned conventional problems, the present invention reduces the thickness of a negative lens placed between a light source and an LCD to reduce the size, improve the heat dissipation, and improve the light source. It is an object of the present invention to provide a vehicle display device in which the driving information image is increased in luminance by improving the use efficiency of the light and the visibility of the driving information image is improved.

[0011]

In order to achieve the above object, a vehicle display device according to the present invention comprises a transmission type liquid crystal display means for displaying driving information, a light source for projection, and a light source for projection and imaging. A vehicle display device comprising an optical system, wherein the driving information displayed on the liquid crystal display means is projected toward a windshield of the vehicle, and formed as a driving information image outside and forward of the windshield. The liquid crystal display hand
A lens plate is disposed between the step and the lens plate.
On the liquid crystal display means on the side adjacent to the crystal display means.
Negative lens corresponding to each character element of driving information
And the negative lens is not formed
A light reflecting layer covering the entire surface, and the lens
Light incident on the plate is converted into a parallel light beam by the negative lens
Out of the negative lens as
The light that does not exit from the light reflecting layer is reflected by the light reflecting layer,
It can be reused as light incident on the lens plate from the light source.
To return to the light source side through the lens plate
It is characterized in that the.

[0012]

In the above construction, the lens plate placed between the light source and the liquid crystal display means has a surface side adjacent to the liquid crystal display means.
The negative lens for converting the convergent light flux into a parallel light flux, because it is formed to correspond to the character elements of the operation information displayed on the liquid crystal display <br/> Display unit, is displayed on the liquid crystal display device may be any character or approximately equal magnitude to the dimensions of the elements of the operation information, touched be larger eg negative lenses surface curvature of
The thickness of the lens plate lens is formed it requires thin compared to the lens of the prior art.

Further, the lens plate is adjacent to the liquid crystal display means.
Cover the entire surface where no negative lens is formed
By providing the light reflection layer , the liquid
A light reflecting layer is formed on the portion of the lens plate that does not correspond to the characters to be displayed on the crystal display means or its elements, and
Light incident on the lens plate is converted into a parallel light beam by the negative lens.
In other words, the light exits the negative lens but exits the negative lens.
Light that does not shine is reflected by the light reflecting layer and is reflected from the light source.
Lens plate so that it can be reused as light incident on the lens plate
Is returned to the light source side, so that the light flux of the light source is effectively used.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a simplified cross-sectional view showing an embodiment of a HUD type vehicle display device according to the present invention, wherein 1 is an LCD as a liquid crystal display means, 2 is a light source, and 3 is a reflecting mirror, each of which is the same as the prior art. Function.

In the present invention, a lens plate 7 is provided between the light source 2 and the LCD 1, and the lens plate 7 has a negative lens 4A corresponding to characters of driving information displayed on the LCD 1.
Is formed on the surface side adjacent to the LCD 1, and a light reflection layer 8 is provided on a portion of the lens plate 7 where the negative lens 4 </ b> A is not formed on the surface side adjacent to the LCD 1.

As a representative example, the case where the driving information displayed on the LCD 1 is the vehicle speed will be described.
The arrangement of the upper negative lens 4A is as shown in FIG.
This is performed according to the character shape of the vehicle speed number displayed on the LCD 1. In this embodiment, the negative lens 4A is composed of a cylindrical concave lens 4E as shown in FIG. 3, and is made of, for example, plastic having a high light transmittance, and is attached to the lens plate 7 by an appropriate method such as injection molding. Are integrally formed. Further, as shown in FIG. 2B, the negative lens 4A
The light reflecting layer 8 is provided on a portion of the lens plate 7 where the is not arranged by a suitable method such as metal plating.

The operation of the negative lens 4A will be described with reference to FIG. 4. If the light beam 5b emitted from the light source 2 (not shown) and converged by the reflecting mirror 3 (not shown) enters the negative lens 4A, the light beam shown in FIG. As shown, the light beam 5c is converted into a substantially parallel light beam 5c by the negative lens 4A, passes through the LCD 1, and passes through the HU.
It is a light flux for forming the driving information image of D.

The purpose of the light beam conversion action of the negative lens 4A is to prevent washout. As described above, in order to improve the effect of preventing washout, the negative lens 4A is used.
The focal length of A needs to be very short, so that the curvature of the lens surface becomes large, and in the prior art, the thickness of the lens becomes extremely large, which hinders the miniaturization of the HUD projection unit. .

In the present embodiment, the negative lens 4A is
2, the curvature in the longitudinal direction is zero, and the dimension in the width direction is substantially equal to the width of the stippled number of the vehicle speed displayed on the LCD 1 as shown in FIG. For example, even if the curvature of the lens surface is large, the thickness of the lens may be small, which is advantageous for reducing the size of the HUD projection unit and dissipating the heat emitted from the light source lamp.

Further, in FIG. 4, a light beam 5 emitted from the light source 2 is shown.
The light flux not incident on the negative lens 4A out of b is reflected by the reflection layer 8, becomes a light flux 5d returning to the light source, and is added again to a part of the light flux of the light source, so that the utilization efficiency of the light flux emitted from the light source 2 is improved. Contributes to preventing washout.

FIG. 5 is a perspective view of the lens plate 7 in the second embodiment of the present invention, and FIG. 6 is a front view of the lens plate 7 in the embodiment of FIG. The difference from the first embodiment is
The negative lens 4B arranged on the lens plate 7 is formed of a cylindrical concave lens corresponding to each display segment of the driving information displayed on the LCD 1, and the dimension of the negative lens 4B in the width direction corresponds to the width of the segment. As compared with the conventional negative lens 4, the thickness of the lens may be thinner, and the number of lenses arranged on the lens plate 7 is small, so that manufacture is easy.

The difference between this embodiment and the first embodiment is that the negative lens 4B arranged on the lens plate 7 is a cylindrical concave lens corresponding to each display segment of the LCD 1, and the longitudinal direction of the negative lens 4B. Is only slightly smaller than the negative lens 4A of the first embodiment, so that the optical axis of the lens is oriented in the most appropriate direction with respect to the light source 2 or the reflecting mirror 3 as in the first embodiment. , And the washout prevention effect by the improvement of the utilization rate of the light flux emitted from the light source 2 is large.

FIG. 7 shows a lens plate 7 according to a third embodiment of the present invention. The difference from the first embodiment is that the negative lens 4C arranged on the lens plate 7 is a spherical concave lens arranged along the display segment of the LCD1. Negative lens 4
Since the dimension of C is very small as compared with the negative lens 4A of the first embodiment, it is possible to set the optical axis of each lens in the most appropriate direction with respect to the light source 2 or the reflecting mirror 3. Further, the effect of preventing washout by improving the utilization of the light flux emitted from the light source 2 is further enhanced.

In the fourth embodiment of the present invention, a spherical concave lens is used instead of the cylindrical concave lens corresponding to each character of the driving information. The optical axis of the lens can be set in the most appropriate direction with respect to the light source or the reflecting mirror, the effect of preventing the washout by improving the utilization of the light flux emitted from the light source, and the lens on the lens plate 7 It is easy to manufacture because the number of arrays is small.

The present invention is also applicable to the following embodiments. (1) As a material of a lens plate forming a lens, a material having transmission wavelength selectivity to heat rays is used. Alternatively, a filter formed of such a material is used in combination.
(2) The curved surface of the cylindrical concave lens is not limited to a circular column, but may be a parabolic column or an elliptic column. (3) The curved surface of the spherical concave lens is not limited to a spherical surface, but may be a paraboloid of revolution, a spheroid or a toric surface.

[0026]

As described above, according to the present invention, a convergent light beam placed between a light source and a liquid crystal display means is converted into a parallel light beam in order to prevent washout and enhance the visibility of a driving information image. The thickness of the lens plate on which the negative lens is formed can be reduced, which is advantageous in miniaturizing the apparatus and dissipating the heat generated by the light source.

Also, a negative lens which is incident on the lens plate from the light source
Are converted into parallel light beams by the
Is reflected by the light reflection layer, and from the light source to the lens plate.
Through the lens plate so that it can be reused as incident light
The light is returned to the light source side and enters the lens plate from the light source.
Te is reused, thereby improving the display luminance of the driving information image, the visibility of the driving information image is improved. In particular, the light reflecting layer
Is the same surface as the surface on which the negative lens is formed.
A negative lens is formed on the side of the plate adjacent to the liquid crystal display
Since it is provided to cover the entire surface that is not
All from the light source to the lens plate without any restrictions
Light is incident, and the light to be emitted from the negative lens
Of the light incident on the lens plate
So that all light that does not exit from is reflected and reused
Configuration that can use the light from the light source most efficiently
It has become.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an embodiment of a vehicle display device according to the present invention.

FIG. 2 is a detailed view showing a first embodiment of a lens plate according to the present invention, wherein (a) shows an arrangement of negative lenses on the lens plate;
(B) is sectional drawing of XX '.

FIG. 3 is a perspective view showing a cylindrical concave lens formed on a lens plate according to the present invention.

FIG. 4 is a diagram illustrating the operation of a negative lens and a reflective layer formed on a lens plate according to the present invention.

FIG. 5 is a perspective view showing a second embodiment of the lens plate according to the present invention.

FIG. 6 is a front view of the lens plate according to the present invention of FIG. 5;

FIG. 7 is a detailed view showing a third embodiment of the lens plate according to the present invention.

FIG. 8 is a perspective view showing an example of a front portion of a vehicle driver's seat with a head-up display type vehicle display device attached.

FIG. 9 is a schematic diagram illustrating a configuration example of a projection unit of a HUD according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LCD (liquid crystal display means) 2 Light source 3 Reflecting mirror 4A-4C Negative lens 7 Lens plate 8 Light reflection layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/13 G02F 1/1335

Claims (1)

(57) [Claims] 1. A vehicle comprising a transmission type liquid crystal display means for displaying driving information, a light source for projection, and an optical system for projection and imaging, wherein the driving information displayed on the liquid crystal display means is provided on a windshield of a vehicle. In a vehicle display device that projects toward the outside and forms a driving information image outside and forward of the windshield , a lens plate is disposed between the light source and the liquid crystal display unit.
The lens plate has a surface adjacent to the liquid crystal display means,
The character element of the driving information displayed on the liquid crystal display means
A negative lens is formed correspondingly, and the negative lens
A light reflecting layer that covers the entire surface on which the lens is not formed, and transmits light incident on the lens plate from the light source to the negative lens.
Is converted into a parallel light beam and emitted from the negative lens.
In addition, the light that does not exit from the negative lens is reflected by the light.
Reflected by the layer and incident on the lens plate from the light source
Through the lens plate so that it can be reused as light
A display device for a vehicle, wherein the display device is returned to the light source side .