JPS60124533A - Projection type meter display device in automobile - Google Patents

Abstract

PURPOSE:To enhance the visibility of a meter in a meter display device in which meter indication by an light emitter positioned in the upper section of an instrument panel is projected onto a reflector set on the front of a driver's seat, by forming the reflector such that a transparent electro-conductive film is laminated on a transparent substrate. CONSTITUTION:In the front glass 1 of an automobile, a part which is hatched is used as a reflctor 3. That is, an optical interference film 2 is formed on the passenger's compartment side of the front glass within a predetermined area. In the case of that a substance emanating, for example, a bluish green color is used for a fluorescent display type meter, the optical interference film 2 is formed so that it reflects a bluish green color light. That is, optical films 2a made of titaniumoxide which is high refractive index substance and other optical films 2b made of silicon dioxide which is low refractive substance are alternately laminated one upon another in five layers, and an ITO film 2c made of silicon doxide as a transparent electro-conductive film is laminated on the outermost one of the above-mentioned layers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a projection type meter display device for an automobile, and more particularly to a projection type meter display device for an automobile that displays a meter display three-dimensionally on or near the windshield of an automobile.

[Prior art]

Transmissive illumination, transmissive liquid crystal display, light emitting diode display, etc. are known as meter display methods used in automobiles. ) is incorporated and used within. In this case, since the field of view during driving and the position of the meter are different, when the driver looks at the speedometer while driving, it is necessary to shift the driver's line of sight from the field of view while driving.

Therefore, recently, attempts have been made to develop a projection-type meter display device (head-up display) in which a portion of the meter is placed within the driver's field of vision while driving so that the driver can see the meter without moving his/her line of sight. Such a projection type meter display device has a cathode ray tube (C) installed in the upper part of the instrument panel.
RT) is equipped with a light emitter such as a fluorescent display tube, and a reflective plate is installed near the windshield.The reflective plate is a half mirror with a thin metal film coated on the inside of the glass.
is used.

By the way, in such a projection type meter display device, when the reflectance of the half mirror is increased in order to make the meter display of the light emitting body easier to see, the transmittance of the half mirror decreases, which obstructs the forward view. For this reason, it is not possible to increase the reflectance of the half mirror above a certain level (usually, the reflectance is 20 to 30).
%), and as a result, there is a problem that the meter display of the light emitter is difficult to see.

Furthermore, when a half mirror with a reflectance of 20% is used, the ratio of the brightness of the reflected image on the surface of the reflector to the image reflected on the back of the reflector is about 6:1. The images reflected on the back surface overlap, creating a double image. This makes the meter display of the light emitter even more difficult to see.

Furthermore, since the light emitter of the projection meter display device is installed at the top of the instrument panel, it is no longer possible to provide a defroster outlet in the area where the light emitter is installed, and the windshield near the top of the light emitter may fog up. etc., making it difficult to remove.

Therefore, it has been desired to develop a projection-type meter display device for automobiles that allows the meter display of the luminous body to be easily viewed without obstructing the driver's forward view and has an anti-fog function.

[Purpose of the invention]

The present invention has been made in order to solve the problems of the prior art described above, and it is possible to clearly see the meter display, which is the reflected image of the light emitting body, without obstructing the driver's forward vision when driving and without double reflection. It is an object of the present invention to provide a projection type meter display device for an automobile that can be used in a vehicle and has an anti-fog function.

[Structure of the invention]

According to the present invention, in the passenger compartment of an automobile, a reflector is provided in front of the driver's seat, and a light emitter is provided on the upper part of the instrument panel to project a meter display onto the reflector. A projection type meter display device for an automobile, wherein the reflecting plate includes a transparent substrate and an optical interference film laminated on the surface of the transparent substrate, and the optical interference film adjusts the emission spectrum of the light emitter. This is achieved by a projection type meter display device for an automobile, which has a similar reflection spectrum and is characterized by having a transparent conductive thin film in part.

In the present invention, the reflective plate used is one in which an optical interference film is laminated on a transparent substrate.

As the transparent substrate, in addition to general glass, transparent resins such as polymethyl methacrylate and polycarbonate can be used.

Furthermore, an optical thin film is used as the optical interference film.

An optical thin film is a thin film formed on the surface of a substrate such as glass for the purpose of preventing reflection, increasing reflection, etc. on the substrate surface, and utilizes the interference effect of light. The optical thin film may be formed of only one layer, but it may also be formed as a so-called multilayer film in which high refractive index materials and low refractive index materials are alternately laminated. Examples of high refractive index substances include zirconium oxide (ZrO2) and titanium oxide (Ti02).
etc., and silicon dioxide (SiOz), magnesium fluoride (M g F 2), etc. are used as the low refractive index substance.

When the optical thin film is formed as a multilayer film, anti-reflection 'J
As a result, the reflection increasing effect can be further enhanced. In addition, we can prevent reflection, expand the wavelength range of light that causes increased reflection,
In relation to the refractive index of the material forming the thin film, the degree of freedom in selecting the material can be increased.

In the present invention, titanium oxide (T
iO2) and silicon dioxide (S102), zirconium oxide (7,rO2) and magnesium fluoride (MgF
+) laminates, etc. can be used. Further, the thickness of the optical thin film forming the optical interference film is determined so as to produce a reflection spectrum similar to the emission spectrum of the light emitter.

This optical interference film can be formed by a vacuum film forming method such as a vacuum evaporation method, ion blasting, or sputtering.

Further, a transparent conductive thin film is used as a part of the optical thin film forming the optical interference film.

As a transparent conductive thin film, indium oxide (ln203
) and I T Ol, which is a solid solid of tin dioxide (SnO2)
Or indium oxide (In, 0°), tin dioxide (S
nO, ) etc. can be used. Among these, rTo is a suitable material because it has good adhesion to glass and has a low resistance value.

The value of the sheet resistance of the transparent conductive thin film is 20, considering the optimum heating temperature for preventing fogging and the electromotive force of the hesoteri power source.
Less than Ω/mouth, preferably 4 Ω/mouth or more.

2. An electrode is provided as a terminal for supplying current to the transparent conductive thin film. As the electrode, a low-resistance material such as aluminum (A7), nickel (Ni), silver (Ag), or chromium (Cr) can be used. In addition to the vacuum film forming method such as the above, it is formed at the end of the transparent conductive thin film by baking, etc. The film thickness of the electrode is 0.1 μm to 20 μm.
About μm is good. Note that a lead wire is attached to the electrode by soldering, brazing, etc., and this lead wire is connected to an on-vehicle power source via a switch.

The above-mentioned reflecting plate may utilize the windshield itself as a reflecting plate, or may be provided above the instrument panel separately from the windshield.

This reflector is 40 to 6
It is preferable to install it at a 0 degree inclination.

In the present invention, a fluorescent display tube, a cathode ray tube, or the like can be used as the light emitter. This light emitter is located at the top of the instrument panel, and is approximately 4
It is desirable to be able to emit light at an angle of 5 degrees.

[Action of the invention]

In the present invention, part of the light emitted from the light emitter is reflected by the reflecting plate, and the image emitted from the light emitter appears to float at a position symmetrical to the light emitter with respect to the reflector. At this time, the reflection spectrum of the reflector is similar to the emission spectrum of the light emitter, so for example, if the color emitted from the light emitter is blue-green, light other than blue-green will pass through the reflector. It looks bright. Therefore, the reflectance of the reflector can be reduced to 50-70%.
Even if it is larger than the conventional one, it is bright enough and does not obstruct the forward view because it transmits light other than the specific color mentioned above.

Furthermore, since the reflectance can be as high as 50 to 70%, the meter display, which is the reflected image of the light emitter, can be clearly seen. Furthermore, since the light reflected on the back surface of the reflector is much darker than the light reflected on the front surface, the double image is virtually invisible.

Furthermore, since a transparent conductive thin film is used as one of the optical thin films of the optical interference film, it has a heater function and can prevent fogging and dew condensation each time electricity is supplied.

〔Effect of the invention〕

Since the automobile three-dimensional meter display device according to the present invention has five or more configurations, it has the following effects.

(b) Double reflection is eliminated and visibility is improved.

(b) The meter display, which is the reflected image of the light emitter, can be clearly seen.

(c) The driver's forward view is not obstructed by the reflector.

(iv) Since it has a heater function, it can prevent fogging and dew condensation, and can maintain good visibility.

〔Example〕

Next, preferred embodiments of the present invention will be described with reference to the drawings.

(First Example) The first example is an example in which a windshield is used as a reflector.

Here, FIG. 1 is a schematic configuration diagram showing an example in which a projection type meter display device for an automobile according to a first embodiment of the present invention is applied to an automobile, and FIG. 2 is a sectional view taken along line nn of FIG. 1. Figure 3 is the second
4 is a graph showing the emission spectrum of the fluorescent display meter used in the first embodiment of the present invention and the reflection spectrum of the optical interference film. FIG. 5 is a graph showing the reflection spectrum of the optical interference film. It is a schematic configuration diagram seen from the driver's seat.

In FIG. 1, 1 is the windshield of a car;
The notched portion of this windshield 1 was used as a reflector. That is, as shown in FIG. 2, an optical interference film 2 is formed in a predetermined area on the interior side of the windshield 1, and the windshield 1 and the optical interference film 2 form a reflection plate 3. Below the reflecting plate 3 and above the instrument panel 4, a fluorescent display tube 5 as a light emitter is provided. - The optical interference film 2 was configured to reflect blue-green colors because the fluorescent display type meter 6 used one that emits blue-green colors. That is, as shown in FIG. 3, an optical thin film 2a of titanium oxide (n-2, 3), which is a high refractive index material, and silicon dioxide (n-1,
Five optical thin films 2b of No. 45) were laminated alternately, and only the outermost layer was an ITO film 2C as a transparent conductive thin film, so that a total of six layers were laminated. At this time, the thickness of the optical thin film 2a of titanium oxide is 162 nm, and the thickness of the optical thin film 2b of silicon dioxide is 32 nm.
It was set to 5 nm. In addition, the thickness of the outermost ITO film 2C is
30 to suppress reflections other than the main reflection wavelength in the visible light range.
It was set to 5 nm. The above film thickness is 60 nm from a 3/4λ film with a maximum emission intensity wavelength of 505 nm for a blue-green fluorescent display tube.
It is about 20% thicker considering that light enters from the angle direction.

As a result, as shown in FIG. 4, a reflection spectrum b was obtained which was very similar to the emission spectrum a of the luminescent material.

When I looked at this three-dimensional meter display with the engine switched on, I found that about 50% of the light emitted from the blue-green fluorescent meter was reflected by the reflector, making it look like the meter was at position 4a. Looked. Figure 5 schematically shows how it looks at this time, and the display on the fluorescent display meter is as follows:
For example, when the speed is 5Qkm/h, 6Qk in Fig.
m/h appears to be floating.

This meter display image is in the visible light range (380 nm to 78 nm).
The average reflectance at 0 nm) was 22%, but the reflectance was about 50% for a fluorescent display tube, so it looked bright and clear.

In addition, sunlight reflects only the blue-green color of the reflector, so
Colors other than blue-green are transmitted through without being reflected,
It looked bright from the driver's seat.

Furthermore, in the three-dimensional meter display of this embodiment, there are two
The double image is no longer visible. This means that when a half mirror with a reflectance of 20% is used as a reflector as in the past, the ratio of the brightness of the image reflected on the front surface of the half mirror and the image reflected on the back surface is: front: back = 0.2: 0.8xO, 094x
O,8=3.3:1, whereas in the case of this example, front: back=0.5:0.5X0.094X0.5
#21: 1, which is understood to be because the brightness of the image reflected on the back surface becomes relatively small and becomes almost invisible.

In addition, the sheet resistance of ITO film 2C is 10Ω/mouth,
Sufficient calorific value can be obtained. Therefore, it was possible to easily prevent fogging and dew condensation.

(Second Embodiment) The second embodiment is an example in which a reflective plate is provided in front of the windshield (on the driver's seat side).

Here, FIG. 6 is a schematic configuration diagram showing an outline of a projection type meter display device for an automobile according to a second embodiment of the present invention, FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6, and FIG. 7 is a graph showing the emission spectrum of the fluorescent display type meter and the reflection spectrum of the optical interference film used in the second embodiment of the present invention.

As shown in FIG. 6, a reflector plate 3 is provided on the driver's seat side parallel to the windshield 1. Further, a fluorescent display tube 5 was used as a light emitter for projecting an image of the meter display onto the reflecting plate 3, and was attached to the upper part of the instrument panel 4. This reflecting plate 3 is composed of a glass 6 as a transparent substrate and an optical interference film 2, and this optical interference film 2 is composed of a six-layer film in which an ITO film 2C and an optical thin film 2b of silicon dioxide are laminated. This optical interference film 2 was formed on glass 6 by sputtering.

The thickness of the optical interference film 2 was set in accordance with the red emission spectrum of the fluorescent display tube 5 so as to reflect light of the same tone. That is, the ITO film 2C shown in FIG.
The film thickness of the silicon dioxide optical thin film 2b was set to 270 nm, and the film thickness of the silicon dioxide optical thin film 2b was set to 370 nm. However, only the outermost optical thin film 2b of silicon dioxide had a thickness of 90 nm in order to suppress reflections other than the main reflection in the visible light range. At this time, the light from the fluorescent display tube 5 is
Considering that the light is incident on the reflection plate 3 at an angle of 45 degrees, the film thickness is set to be 10% thicker.

In the automobile projection meter display device obtained as a result, as in the first embodiment, the meter display as a reflected image can be seen brightly and clearly, and there is no double reflection, and it does not obstruct the view in the iii direction. Ta.

Further, the sheet resistance of 1TO1% was 4Ω/mouth, and a sufficient amount of heat generation was obtained.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. .

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an example in which a projection type meter display device for an automobile according to a first embodiment of the present invention is applied to an automobile, FIG. 2 is a cross-sectional view taken along line nn of FIG. 1, and FIG. is a cross-sectional view taken along line m-m in Fig. 2, Fig. 4 is a graph showing the emission spectrum of the fluorescent display type meter used in the first embodiment of the present invention and the reflection spectrum of the optical interference film, and Fig. 5 is a graph showing the reflection spectrum of the optical interference film. 1 is a schematic configuration diagram seen from the driver's seat, FIG. 6 is a schematic configuration diagram showing an outline of a projection type meter display device for an automobile according to a second embodiment of the present invention, and FIG. (2) Line sectional view FIG. 8 is a graph showing the emission spectrum from the fluorescent display type meter used in the second embodiment of the present invention and the reflection spectrum of the optical interference film. 1 ------- Windshield 2 ---- Optical interference film 2 a ------- Titanium oxide film (optical thin film) 2 b -
----m=silicon oxide film (optical thin film) 2 c ----
-I TO film (transparent conductive thin film) 3-----Reflector plate 4--Instrument panel 5-------Fluorescent display tube (light-emitting body) 6-------- -Glass applicant Toyota Motor Corporation Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 9 Figure 7 Figure 8 Wavelength (pm) Procedural amendment (method) March 1939 λ Japanese Patent Application No. 231827, filed in 1982, 2, Name of the invention: Projection type meter display device for automobiles 3, Relationship with the case of the person making the amendment Patent applicant address: 1 Toyota-cho, Toyotafu, Aichi Prefecture Address: 471 1980
February 28, 2015 5. Specification subject to amendment 6. Contents of amendment

Claims (1)

[Claims] (1) A projection type meter for an automobile, which has a reflector provided in front of the driver's seat in the interior of the automobile, and a light emitting body provided at the top of the instrument panel to project the meter display onto the reflector. In the display device, the reflecting plate includes a transparent substrate and an optical interference film laminated on the surface of the transparent substrate, the optical interference film having a reflection spectrum similar to the emission spectrum of the light emitter, and A projection type meter display device for an automobile, characterized in that a portion thereof has a transparent conductive thin film. (2. The projection type meter display device for an automobile according to claim 1, wherein the transparent substrate is windshield glass.