JP3572427B2 - Display device for vehicles - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a head-up type vehicle display device in which display contrast with respect to a foreground is improved.
[0002]
[Prior art]
As a conventional vehicle display device of this type, for example, there is one as shown in FIG.
That is, a fluorescent display tube 101 for displaying a traveling speed or the like based on a signal from a vehicle speed sensor 107 or the like by the control device 105 is provided, and display light emitted from the fluorescent display tube 101 is reflected by the combiner 102, and the same combiner 102 Is superimposed on the foreground W that passes through and is recognized as a virtual image display Q by the eyes E of the driver. A brightness adjustment circuit 106 is provided between the fluorescent display tube 101 and the control device, and the display brightness is adjusted by a manual switch or the like.
[0003]
[Problems to be solved by the invention]
By the way, the brightness of the foreground of the vehicle greatly changes depending on day and night, weather, and road conditions. As a display device for a vehicle, it is necessary to always keep the display luminance at an appropriate contrast. FIG. 7 shows the relationship between the display luminance and the background luminance (foreground luminance) when the contrast is kept constant. The broken line where the luminance is low is the set contrast, and the contrast is insufficient below this. However, as shown by the solid line, when the foreground luminance is extremely lowered, the display luminance is fixed from a certain level and the display luminance is fixed. However, recognizing is performed.
[0004]
However, as is apparent from FIG. 7, in the conventional vehicle display device, the reflectivity of the combiner is constant with respect to the foreground luminance that changes significantly at day and night, and the appropriate contrast of the display luminance cannot be obtained. In order to maintain this, an ultra-high-luminance display element and a luminance adjustment circuit for appropriately adjusting the luminance are required. Therefore, there has been a problem that the display device is increased in size and the cost is increased.
[0005]
In addition, when a low-luminance display device is used, it is used in combination with a high-reflectance combiner in order to supplement the luminance, so that there is a problem that night-time foreground recognition is hindered.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicular display device that secures the display contrast with respect to the foreground simply and at low cost by focusing on such a conventional problem.
[0006]
[Means for Solving the Problems]
Therefore, the present invention provides a display element that visually displays information, a combiner that reflects display light from the display element and overlaps the foreground, and a display element or a combiner that is disposed between the display element and the combiner. And a neutral density filter whose position can be switched.
[0007]
The neutral density filter is composed of a plurality of split neutral density filters, and can be arbitrarily distributed to the display element side or the combiner side.
Further, the neutral density filter may be supported by a support shaft located between the combiner and the display element, and may be rotated around the support shaft to switch the position.
Further, the neutral density filter is preferably a plate member made of a colored transparent body or a plate member having a highly reflective film on the transparent body.
[0008]
[Action]
When the brightness of the foreground is higher than the display brightness of the display element, if a dimming filter is placed on the combiner side, the light from the foreground passes through the dimming filter, so the foreground brightness is reduced, while the display light is reflected by the dimming filter. Therefore, the contrast between the foreground luminance and the display luminance is improved.
When the foreground luminance is lower than the display luminance, when the dimming filter is superimposed on the display element, the display light is transmitted through the dimming filter, so that the display luminance is reduced. On the other hand, the foreground luminance is not reduced. Is improved.
[0009]
When the neutral density filter is composed of a plurality of divided neutral density filters, the brightness can be adjusted more finely by distributing the neutral density filter to the display element side or the combiner side.
Further, the position can be easily switched by supporting and rotating the neutral density filter on a support shaft located between the combiner and the display element.
The combiner is also rotatable about the support shaft as a common shaft, so that the angle of the combiner and the angle of the neutral density filter can be adjusted individually.
[0010]
【Example】
Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of the first embodiment of the present invention.
The display device 1 includes a fluorescent display tube 4 as a display element, a combiner 5, and a colored neutral density filter 7.
The fluorescent display tube 4 is housed in a housing 3 fixed on the instrument panel 2.
The combiner 5 is made of a semi-transmissive member such as transparent glass or acrylic, and is installed at an angle above the housing 3 substantially along the front windshield S of the vehicle.
[0011]
The neutral density filter 7 is formed of a transparent body such as colored glass or acrylic, and is rotatably disposed at a front end of an upper wall of the housing 3 and around a support shaft 6 provided at a lower end of the combiner 5. Is established.
The neutral density filter 7 is rotated about the support shaft 6 to move the window 8 facing the combiner 5 of the housing 3 shown in FIG. 2B from the state of being overlapped with the combiner 5 as shown in FIG. The rotation can be switched to the state of covering.
[0012]
The neutral density filter 7 has a predetermined reduced transmittance due to coloring, and has the same reflectance as that of the combiner 5 when it is superimposed on the combiner 5, on the surface facing the indoor side.
The fluorescent display tube 4 is connected to a control device 10 that supplies various information such as a running speed based on a vehicle speed sensor 11 and the like, and is driven by the control device 11 to visually display the information.
[0013]
As shown in FIG. 1, the display light L emitted from the fluorescent display tube 4 passes through the colored extinction filter 7 through the window 8 of the housing 3, is reflected by the combiner 5, and reaches the driver's eyes E. enter. At this time, the display light L is superimposed on the foreground W transmitted through the combiner 5 and is recognized as a virtual image display Z by the driver's eyes E.
[0014]
Next, the operation will be described.
First, when the luminance of the foreground W is higher than the display luminance of the fluorescent display tube 4, as shown in FIG. 2A, the neutral density filter 7 is switched to overlap the combiner 5. As a result, the light from the foreground W passes through the darkening filter 7 after passing through the combiner 5, so that the foreground luminance is reduced according to the transmittance of the darkening filter 7.
At this time, the display light from the fluorescent display tube 4 is reflected by the neutral density filter 7 superimposed on the combiner 5, but the display brightness is the same as the reflectance of the neutral density filter 7 with the reflectivity of the combiner 5. This is the same as when reflected by the combiner 5.
[0015]
As a result, the display luminance becomes, for example, the state A in FIG. 3 showing the relationship between the display luminance and the background luminance (foreground luminance). In this way, the contrast of the display luminance with respect to the foreground luminance is improved. This also means that if the contrast is kept constant, the luminance of the display element can be reduced by the reduction of the foreground luminance.
[0016]
Next, when the foreground luminance is lower than the display luminance, the neutral density filter 7 is rotated around the support shaft 6 and overlaps the window 8 of the housing 3 as shown in FIG. As a result, the light from the foreground W does not pass through the neutral density filter 7, so that the foreground luminance does not change, and the display light from the fluorescent display tube 4 passes through the neutral density filter 7, so that the display is performed according to the transmittance of the neutral density filter. Brightness is reduced.
The display luminance at this time is in the state B in FIG. Thus, the contrast of the display luminance with respect to the foreground luminance is improved. Further, since the display luminance is reduced, it is not necessary to reduce the width of the luminance adjustment, or the luminance adjustment itself becomes unnecessary, so that there is no need to provide a luminance adjustment circuit.
[0017]
Here, in the case of a general display device not using a neutral density filter, assuming that the foreground luminance is Lb and the display luminance is Ld, the contrast C can be expressed by the following equation.
C = Ld / (Lb + Ld)
In the present embodiment, assuming that the transmittance of the neutral density filter 7 is Tf, the contrast CH 1 in the case of FIG.
CH = Ld / (Lb · Tf + Ld)
The contrast CL in the case shown in FIG.
CL = Ld · Tf / (Lb + Ld · Tf)
It is expressed as
[0018]
In the range where the background luminance in FIG. 3 corresponding to FIG. 2A is high, the apparent foreground luminance is lowered by passing through the neutral density filter 7, so that the lower part of the figure in FIG. Is an area that lacks. Conversely, in a range where the background luminance is low, the display luminance is dimmed and reduced. Thus, by operating the neutral density filter 7 to switch the rotation, the display luminance can be adjusted in two stages.
[0019]
As described above, the present embodiment uses a combiner to reflect the display light from the fluorescent display tube in a manner superimposed on the foreground and reflect the display light to provide various information to the driver as a virtual image display. A rotatable colored dimming filter 7 is provided between the window of the housing 3 housing the housing 4 and the combiner 5, and the colored dimming filter is provided on the combiner 5 side or the fluorescent display tube 4 side in accordance with a change in foreground luminance. Because of the overlapping, the fluorescent display tube does not require an expensive ultra-high-brightness display and does not require a complicated brightness adjustment circuit. Can be obtained.
[0020]
FIG. 4 shows a second embodiment of the present invention.
In this embodiment, a single dimming filter 21 is used instead of one dimming filter 7 in the previous embodiment.
In this display device 20, the divided neutral density filter 21 is composed of three colored neutral density filters 21A, 21B and 21C which can be independently rotated around the support shaft 6 ', respectively. Is equally divided among these three neutral density filters. Each of the neutral density filters 21 </ b> A, 21 </ b> B, and 21 </ b> C has the same reflectance as that of the combiner 5 when it is superimposed on the combiner 5, the surface facing the indoor side.
Other configurations are the same as those of the first embodiment.
[0021]
In use, in the first state where the foreground luminance is particularly higher than the display luminance, three neutral density filters 21A, 21B, and 21C are used while being superposed on the combiner 5. The foreground luminance from the foreground W is reduced according to the transmittance of the three neutral density filters.
On the other hand, the display light from the fluorescent display tube 4 is reflected by the neutral density filter 21C. However, since the reflectance is the same as the reflectance of the combiner 5, the display luminance does not change.
This state is shown as A in FIG. 5 showing the relationship between the display luminance and the background luminance (foreground luminance).
[0022]
In the second state, in which the foreground luminance is higher than the display luminance but the difference is not as great as in the first state, the dimming filters are switched to overlap the two dimming filters 21A and 21B on the combiner 5; The neutral density filters 21C are superimposed on the window of the housing 3. Thus, the light from the foreground W is reduced according to the transmittance of the two neutral density filters 21A and 21B, and the display light from the fluorescent display tube 4 is reduced according to the transmittance of the single neutral density filter 21C. This state is shown as B in FIG.
[0023]
Similarly, in the third state in which the foreground luminance is lower than the display luminance, a single dimming filter 21A is superimposed on the combiner 5 by the same switching operation, and the two dimming filters 21B and 21C are connected to the window 8 of the housing 3. Layer on. This state is shown as C in FIG. The contrast is in a good state.
[0024]
Then, in the fourth state where the foreground luminance is particularly low, all of the three neutral density filters 21 </ b> A, 21 </ b> B and 21 </ b> C are overlaid on the window 8 of the housing 3. As a result, the display luminance is reduced because the display light from the fluorescent display tube 4 passes through the three neutral density filters, while the foreground luminance does not change because it does not pass through one neutral density filter after passing through the combiner 5. . Is shown as D in FIG.
As shown in FIGS. 5A to 5D, the contrast is well maintained even when the foreground luminance changes.
[0025]
As described above, according to the present embodiment, by allocating each of the neutral density filters of the divided neutral density filter 21, in addition to the effect of the first exemplary embodiment, there is an advantage that luminance adjustment can be performed more finely. Have.
In this embodiment, the attenuation is equally divided while the transmittance of each of the divided neutral density filters is kept constant. However, the present invention is not limited to this, and the filters may have different transmittances.
[0026]
Further, in the embodiment, the reflectance of the surface facing the indoor side of each neutral density filter is the same as the reflectance of the combiner, but may be different from each other. In this case, when the reflectance of the neutral density filter 21A on the combiner 5 side is reduced and the reflectance of the neutral density filter 21C on the fluorescent display tube 4 side as a display element is increased, the foreground luminance is particularly large with respect to the display luminance. It is sometimes preferred to effectively balance the contrast.
[0027]
In each of the embodiments described above, the neutral density filter 7 or the split neutral density filter 21 is rotated about the support shaft. However, the present invention is not limited to this. For example, the neutral density filter may be inserted and removed in a sliding manner. It may be.
In addition, a fluorescent display tube is used as a display element, and in addition, a self-luminous element such as a light emitting diode, a transmissive liquid crystal display element, and a combination of a back light such as a cold cathode tube, electroluminescence or incandescent lamp are combined. Things and the like can be used.
[0028]
Furthermore, in each embodiment, the combiner 5 includes a transparent glass or acryl or the like, a clear glass or acryl or the like having a film for increasing the reflectance, a colored glass or acryl, or a transparent glass. Alternatively, a material having a film for lowering the reflectivity such as acrylic can be selected, and a plate member such as a windshield of a vehicle can be used.
In addition, in addition to colored glass or acrylic, a plate member having a film for increasing the reflectance with transparent glass or acrylic can be used for the neutral density filter.
In addition, the rotation of the neutral density filter 7 and the split neutral density filter 21 can be switched manually. However, it is automatically operated according to the driving environment using a light ON / OFF signal or an output signal of an optical sensor. It may be.
[0029]
【The invention's effect】
As described above, the present invention relates to a vehicular display device that superimposes display light from a display element on a foreground and reflects and displays the reflected light toward a driver using a combiner, between the display element and the combiner, on the display element side or A dimming filter that can switch the position is provided on the combiner side, so that the dimming filter is superimposed on the combiner side or the display element side according to the change in foreground luminance, thereby reducing the luminance on the higher side and reducing the display contrast. Can be improved.
This eliminates the need for an ultra-high-luminance display element and a luminance adjustment circuit for adjusting the luminance of the display element, thereby making it possible to reduce the size and cost of the device.
[0030]
In particular, by adjusting the neutral density filter to a plurality of split neutral density filters and appropriately allocating the neutral density filter to the display element side or the combiner side, the luminance adjustment can be performed more finely.
Further, the position can be easily switched by supporting and rotating the neutral density filter on a support shaft positioned between the combiner and the display element.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the operation of the embodiment.
FIG. 3 is a diagram showing the relationship between the contrast between the background luminance and the display luminance according to the embodiment.
FIG. 4 is a diagram showing a configuration of a second exemplary embodiment of the present invention.
FIG. 5 is a diagram showing the relationship between the contrast between the background luminance and the display luminance according to the second embodiment.
FIG. 6 is a diagram showing a conventional example.
FIG. 7 is a diagram illustrating a relationship between display luminance and background luminance when the contrast is kept constant.
[Explanation of symbols]
1, 20 display device 2 instrument panel 3 case 4 fluorescent display tube 5 combiner 6 support shaft 7 dimming filter 8 window 10 control device 11 vehicle speed sensor 21 split dimming filter 101 fluorescent display tube 102 combiner 106 brightness adjustment circuit 107 vehicle speed Sensor E Driver's eye L Display light Q Virtual image display S Front windshield W Foreground Z Virtual image display

Claims (7)

A display element for visually displaying information;
A combiner for reflecting display light from the display element and superimposing the display light on the foreground;
A display device for a vehicle, comprising: a neutral density filter disposed between the display element and the combiner and capable of switching a position between the display element and the combiner. The vehicle display device according to claim 1, wherein the neutral density filter is composed of a plurality of split neutral density filters, and can be arbitrarily distributed to the display element side or the combiner side. 3. The device according to claim 1, wherein the neutral density filter is supported by a support shaft located between the combiner and the display element, and is rotated around the support shaft to switch the position. Display device for vehicles. The vehicle display device according to claim 3, wherein the combiner is rotatable around the support shaft as a common shaft. 5. The vehicle display device according to claim 1, wherein the neutral density filter is a plate member made of a colored transparent body. The vehicle display device according to claim 1, wherein the neutral density filter is a plate member having a highly reflective film on a transparent body. 6. The vehicle display device according to claim 1, wherein the reflectance of the neutral density filter is set substantially equal to the reflectance of the combiner.

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