JPH0390439A - Head up display - Google Patents

Abstract

PURPOSE:To improve visibility by a method wherein, in a device which displays various information on the windshield of a vehicle in a state to be overlapped with a scene in front, visible luminance of a background of information display light is detected, and according to visible luminance, display visible luminance is regulated so as to satisfy a specified condition. CONSTITUTION:A head up display is provided with an information projecting device comprising a optical information display means (display) D having a display surface on which information, e.g. a speed, a brake, a time, responding to a display means, is displayed by means of luminance responding to the intensity of a display signal, and an optical member A to project information display light, emitted from the surface thereof, in a given direction. Information display light is reflected or diffracted in a direction in which the information display light is visible by an operator by means of a combiner (windshield). In this case, visible luminance of the background of the information display light is detected, and when the visible luminance is 1-100cd/m<2>, based on a relation chart where the lateral bar of a logarithmic scale is background visible luminance and the longitudinal bar thereof is luminance magnification, display visible luminance is set so that luminance magnification is within a given range.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Field of Application The present invention provides a method for controlling a vehicle such as an aircraft or a car while looking at the scenery in front of the outside world. The present invention relates to a head-up display that displays various information (for example, speed information, brake information, time information, etc.) superimposed on the external scene in front of the vehicle.

Using such a head-up display eliminates the need for the driver to look at the instruments while averting his/her line of sight from the outside world, thereby making it possible to prevent unexpected accidents that may occur while the driver's line of sight is averted from the outside world.

(2) Prior Art The conventional head-up display described above usually has a combiner such as a half mirror or a hologram element placed in front of the driver's visual field, and the combiner directs light rays emitted from the external scenery in the direction of the driver. It is configured to transmit information display light and reflect or diffract the information display light incident on the combiner from inside the cockpit toward the operator.

The information projecting device that makes the information display light enter the combiner includes an optical information display means such as a CRT, a plasma display, or a light emitting diode display, and the light emitted from the optical information display means and makes the light emitted from the optical information display means enter the combiner. and an optical member. The optical member is generally located at the bottom of a lens system, a reflecting mirror, etc., and is located at the bottom so that the information display light can be visually recognized by the driver in the front field of view.

(3) Problems to be solved by the invention The above-mentioned conventional handheld displays have either a constant brightness of the displayed optical information or a variable one according to a detection signal of the brightness of the outside world. There was something. When such a head-up display is applied to a railway vehicle, etc., if the brightness is kept constant, the brightness of the outside world of the vehicle will differ greatly between when driving in a tunnel or at night and when driving on the ground during the day. However, even if the brightness is easy to see in a relatively bright place, it may be too bright in a relatively dark place, making it difficult to see the outside world in front of you. Another problem is that if the brightness is acceptable in a dark place, optical information becomes almost invisible in a bright place.

In addition, although there are conventional devices with variable brightness, the brightness of the background in the field of view where the pilot visually recognizes the optical information of the head-up display (i.e., the background visible brightness) is about LCD/RD. This device appropriately controls the brightness of the hand-held display over a wide range of background visible brightness, from when driving at night or in a tunnel to when driving on the ground during the day when the background visible brightness is about 1000 cd/rrr. unknown.

This means that when the background visible brightness changes over a wide range as mentioned above, the display visible brightness (
This is because they did not know what value to control the brightness of the information display light of the head-up display that is visually recognized by the pilot so that the pilot could easily or easily see the information display light.

Therefore, the present inventors investigated the range of display visible brightness values that are easy for a plurality of operators to see with respect to a wide variety of background visible brightness values.

As shown in FIG. 5, the horizontal axis of the logarithmic scale is the background visible brightness E, and the vertical axis of the logarithmic scale is the brightness magnification B/E defined as (display visible brightness B/background visible brightness E).
The data of the survey results were plotted on the coordinate plane. As a result, it was found that the data were distributed along the straight line L0 shown by the broken line in FIG. This straight line L0 has a background visible luminance of I Ft-L (Footlam
bert), that is, the straight line portion L□ of 3°43 (cd/rrr) or more, and I Ft-L, that is, 3.43 (cd
/rrf) The straight line below. It has The coordinates of points Q, ~Q, on the straight line L0 are as shown in Table 1 (see next page).

Table 1 Also, in Figure 5, the horizontal axis X (= (log E) + 2) and the vertical axis Y (= Clog B/E) + 1) were used instead of the horizontal axis E and the vertical axis B/E, respectively. In this case, the straight line portion LOI has a slope of −0,333; 2 has a slope of -0,602.

The data obtained as a result of the above survey is distributed unevenly above and below the straight line L0, and the value of the display visible brightness that is easy to see varies for each individual, and the brightness magnification of the control pitch display, which is generally weak in eyesight, varies from person to person. It was found that the values tended to be large.

In addition, the average background visibility brightness when driving in a tunnel or on the ground at night with the headlights placed at the front of the vehicle turned on is 1 cd/nf, and the average background visibility when driving on the ground during the daytime. The value of the luminance magnification that allows multiple operators to comfortably (or easily) see the information display light over a wide range of background visibility luminance changes between 103 cd/m and 103 cd/m is described in the following (a). I found it to be within the range.

(a) When the background visible luminance is (1=1000) cd/m2, the background visible luminance is plotted on the horizontal axis of the logarithmic scale, and the luminance magnification (i.e., display visible luminance/background visible luminance) is plotted on the vertical axis of the logarithmic scale. The point where the horizontal axis is lcd/m2 and the vertical axis is 7 is P1, the horizontal axis is lcd/m2 and the vertical axis is 30 is P3, the horizontal axis is 1000cd/rrf and the vertical axis is 1 is P3. %
The point where the horizontal axis is 1000 cd/rd and the vertical axis is 5 is P,
If the straight line connecting the points P1 and P3 is Lls, and the straight line connecting the points P and P4 is L2, then the value of the luminance magnification is between the straight line L1 and the straight line L2.

The present invention has been made in view of the above-mentioned problems and research results, and is designed to enable the pilot to always easily see the information display light of the head-up display even if the background visible brightness changes over a wide range. The challenge is to

B0 Structure of the Invention (1) Means for Solving the Problems In order to solve the above-mentioned problems, the head-up display of the present invention provides information corresponding to the display signal output from the display signal output means based on the intensity of the display signal. An information projector comprising: an optical information display means having a display surface that displays information at a brightness corresponding to the display surface; and an optical member that projects information display light emitted from the display surface in a predetermined direction; It is installed so as to be tilted forward, and transmits light from the outside world from the front to the rear so that the driver can see the scene in the outside world in front of him, and also controls the information display light projected from the information projection device. A head-up display for a vehicle, comprising a combiner that reflects or diffracts in a direction visible to a person, and makes the information display light visible to the operator at a predetermined display visibility brightness, the information display light being visible to the operator. A background visible brightness detection means for detecting the visible brightness of the background of the information display light is provided, and the display visible brightness is adjusted as described in (a) below in accordance with the background visible brightness detected by the background visible brightness detection means. Features.

(a) When the background visible luminance is (1 to 1000) cd/m2, the background visible luminance is plotted on the horizontal axis of the logarithmic scale, and the luminance defined as (display visible luminance/background visible luminance) is plotted on the vertical axis of the logarithmic scale. Take the magnification, P1 is the point where the horizontal axis is 1cd/rrf and 7 is the vertical axis, Pt is the point where the horizontal axis is lcd/rrf and the vertical axis is 30, and 1 is the point where the horizontal axis is 1000cd/nf and the vertical axis is 1. P
3. The point where the horizontal axis is 1000cd/fTf and the vertical axis is 5 is P4
If the straight line connecting the points P1 and P is Ll, and the straight line connecting the points Pg and P4 is L2, then the value of the luminance magnification is between the straight lines L1 and L2.

(2) Effect The head-up display of the present invention having the above-mentioned features has a background visible luminance of (1 to 1000) cd/rrf.
When , the value of the brightness magnification is between the straight line L2 and the straight line L2, so even if the background visible brightness changes within that range, the pilot always uses the information display light of the rear up display. Can be easily recognized visually.

(3) Examples An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a driver's cab 2 is installed at the front end of a train 1. In this driver's cab 2, an instrument g14 is arranged in front of the seat 3 for the operator M.

Further, in front of the driver's cab 2, a windshield C as a combiner is arranged between the lower part 5 of the car body of the electric train 1 and the ceiling 6. This windshield C is arranged so as to be inclined downward as it goes forward.

The instrument panel 4 of the driver's cab 2 includes an optical member A and a CRT (Cathode Ray) as an optical information display means.
A display tube (cathode ray tube) is installed.

The display surface of this CR7 display tube is divided into pixels of, for example, 512×512 dots, and necessary information (for example, information shown in FIG. 3, which will be described later) is displayed by controlling the brightness of each pixel. The optical member A is a lens system A.

It is composed of a mirror A2, a convex lens A1, etc.
The information display light emitted from the CR7 display tube is arranged so as to be incident on the windshield C. The values of the light transmittance T□ of the lens system A, the light reflectance RA3 of the mirror A2, the light transmittance TA3 of the convex lens A, and the light transmittance Tc and reflectance Re of the windshield C are shown in Table 2. It is as follows.

Table 2 Note that, instead of the CR7 display tube, it is also possible to employ a flat optical information display means such as a liquid crystal display, a plasma display, or a light emitting diode display.

The windshield C is arranged so as to transmit a part of the information display light incident from the optical member A and reflect the remaining part towards the operator M, and also transmits external light incident from an external scene etc. It is arranged so that a part of J is reflected and the rest is transmitted toward the operator M.

That is, the windshield C of this embodiment itself has a function as a combiner. Note that the combiner can also be configured separately from the windshield.

An information projecting device K is constituted by the optical member A and the CR7 display tube, and a head-up display is connected to the windshield C1 functioning as the combiner, the information projecting device, and the display signal output means U, which will be described later. H (see FIG. 3) is constructed.

FIG. 2 is an explanatory diagram of the display signal output means U of the head-up display H.

The display signal output means υ includes a display information output means U, and
A display signal output circuit U2 that outputs a display signal based on an input signal from the display information output means UI, and a display signal output circuit U2 that adjusts the intensity of the display signal output from the display signal output circuit U2.
a brightness adjustment circuit U that adjusts the display brightness on the R7 display tube;
It is composed of.

The display information output means U1 includes a door opening/closing sensor 7 that detects the open/closed state of the door, a speedometer 8 that outputs speed information, a brake pressure sensor 9 that outputs brake pressure information, a schedule memory 10. and clock 1 that outputs the current time
1st prize.

The schedule memory 10 stores names of stations to be reached (that is, all names of stations stopped or passed through) and estimated times of arrival at those stations, and outputs this information.

The display signal output circuit U2 includes the display information output means U.
It includes a display information control section 12 that outputs display data based on an input signal from I, and a display memory 13 into which the display data is written.

The display data written in the display memory 13 is CR
It is read out by a read address signal generated by the T controller 14 and synchronized with the scanning of the CR7 display tube. The display data read from the display memory 13 is converted into serial data by the parallel-to-serial converter 15 and output as a display signal 15a. The display signal output circuit U2 is constituted by the numerals 12 to 15.

The display signal 15a output from the display signal output circuit Uz is configured to be supplied to the cathode of the CR7 display tube via the drive amplifier 16 of the brightness adjustment circuit U.

The brightness adjustment circuit U3 adjusts the background visible brightness (that is, the brightness in front of the combiner C that is visually recognized by the operator M).
The driving amplifier 16 includes an amplifier 17 that outputs a brightness adjustment signal 17a according to an input signal from a background visible brightness sensor S serving as background visible brightness detection means for detecting background brightness.

The drive amplifier 16 is constituted by a voltage-controlled variable amplifier circuit, and its amplification factor is controlled by the voltage value of the brightness adjustment signal 17a. The cathode potential of the CR7 display tube changes in accordance with the voltage value of the brightness adjustment signal 17a, and the brightness is controlled.

Next, the operation of the embodiment of the present invention having the above-described configuration will be explained.

External light rays J proceeding toward the windshield C from the outside world on the left side of FIG. It reaches Pilot M's eyes. This allows the operator M to visually recognize the scene in the outside world as it is. On the other hand, the information display light emitted from the CR7 display tube of the information projecting device passes through the optical member A and enters the windshield C. Part of the information display light incident on the windshield C passes through the windshield C and is emitted to the outside world, but the remaining part is reflected and reaches the eyes of the operator M. This allows the operator M to visually recognize the information display light.

FIG. 3 is an explanatory diagram of an example of display information.

In FIG. 3, the part indicated by the broken line shows the field of view F when the driver is looking ahead, and within the field of view F, the railway ahead is visible.

Information regarding whether the door of the train 1 is closed or open is displayed at the lower left position of the visual field F as "door closed" or "door open." In addition, "Brake air pressure is rook/d" is displayed at the lower right position.

Further, the speed information of the train 1 is displayed by a numerical value string n in units of h indicating speed per hour and a pointer p arranged along a straight line l with a scale.

In addition, at the upper right side of the field of view F, the illuminated part of the curved bar graph arranged in a circular shape (blacked out part)
displays the remaining time in seconds from the current time to the expected arrival time of the next letter. Further, the value of the remaining time in minutes is displayed numerically inside the circle of the curved bar graph. One memory of the bar graph indicating the remaining time in units of seconds is one second. Therefore, FIG. 3 shows that the remaining time until the next letter of arrival is 2 minutes and 17 seconds.

Further, the characters displayed below this curved bar graph indicate the name of the next station to be reached and whether the train stops at or passes through that station. FIG. 3 shows that the vehicle stops at the next destination.

Furthermore, in the display information shown in FIG. 3, the letters below the arrival station name on the garment indicate the estimated time of arrival at the next arrival letter.

Note that instead of displaying all of the next destination (that is, all stations including the next stop station and the next passing station) as shown in Fig. It is also possible to display only stations.

When performing the above-mentioned display, it is necessary to control the display visible brightness to an appropriate value, but in this embodiment, the brightness magnification B/
E is controlled so that it lies on the straight line L0 shown by the broken line in FIG. That is, as shown in FIG. 4, let the brightness of external light J in front of the vehicle be E, and the background visible brightness when the external light J passes through the windshield C and is detected by the background visible brightness sensor behind it is E. E, and the display brightness of optical information displayed on the display surface of the CR7 display tube is B.
l, the brightness of the information display light after being emitted from the display surface and passing through the lens system A1 is BZ, the brightness of the information display light after being reflected by the mirror A2 is 83, the information after passing through the convex lens A3; When the brightness of the display light is 84 and the brightness of the information display light after reflection from the windshield C, that is, the display visible brightness, is B, the value of B/E, that is, the brightness magnification is on the straight line L0 in FIG. 5. The display brightness B1 is controlled as follows. This control method will be explained in detail below.

From Figure 4, B I X TAI X RAt X Ta2 X
TC=B------=(+). This (1
) Substituting the values in Table 2 above into the formula, 0.25xB+B-'-BI=4XB
・・・−(2) By the way, as shown in the above-mentioned FIG. 5, X = (log E) + 2 −・−
--------(3) Y = (log B/E)
+ 1～−−−−−−−−1・−・−・−・−・−−
-----(4), and the straight line Lo+ is 2≦X≦5
In the range of , it is expressed by the following equation (5), and the straight line Log is O
In the range of ≦X≦2, it is expressed by the following equation (6).

Y=-0,333X+2.666-(5)Y
−−0,602X+3.204 ・−・−(6
) The above formulas (3), (4), (6) and (3),
From equations (4) and (5), the following equations (7) and (8) are obtained. In addition, in the following equations (7) and (8), when a value in the unit (Ft-L) is used as the value of the background visible brightness E, the value of the display visible brightness B is also (Ft-L), When a value in the unit (cd/rrf) is used as the value of the background visible luminance E, the value of the display visible luminance B is also (Cd/m2).

0≦X≦2, that is, 10-”(Ft-L)≦E≦1(F
tL), that is, 3.43
d/rrf)≦E≦3.43 (cd/m), B-10E0・A&? −・−・−・ −〜−
-・-- E≦3.43
When 103 (cd/rrf), B = 10 E
'-39s-----------48) (7) above, (
From equation 8) and equation (2) above, the following equations (9) and (10)
is obtained.

3,43 X 10-” (cd/m)≦E≦3.43
(cd/m), B+=4X10E""" (cd/rr?) -----
−−−−−−−(9) 3, 43 (cd#+f)≦E
When ≦3.43 X 10' (cd/rrf), Bl = 4xl OE""" (cd/m2) ・-
(10) Display brightness B determined by formulas (9) and (10) above
, if the information is displayed on the CR7 display tube, 3.43
10-”(cd/m2)≦E≦3.43X10”(c
d/m2), the brightness magnification B/E lies on the straight line L0 in FIG.

And E≦3.43×10-”(cd/rrf)
(that is, when it is very dark), B obtained by substituting E=3.43
Using the value of 1 (constant value), E≧3.43 X 10'
(cd/m2) (that is, when it is very bright), the value of B+ (constant value) obtained by substituting E=3.43xlO3 in the above equation (10) is used.

When display brightness B+ is controlled as described above, background visible brightness E becomes 1 (cd/m2)≦E≦103 (cd/m2)
), the value of the brightness magnification B/E is on the straight line L0 in FIG. 5, and is ultimately on the straight line.

and the straight line L2.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various design changes can be made without departing from the scope of the invention described in the claims. It is possible.

For example, the background visible luminance E is 3.43X10-2(c
d/rrr) ≦E≦3.43
rf), instead of adjusting the brightness magnification by varying it over a range of 1 (rf), which is the average brightness at night or in a tunnel.
cd/m2) and daytime average brightness 103 (cd/rrf
), that is, 1 (cd/nf)≦E≦10
It is also possible to adjust the brightness magnification only in the range of (cd/rrr) and keep it at a constant value in the other ranges of E.Also, adjustment of the display visible brightness B is as follows: Instead of setting the intensity of the display signal outputted by the display signal output means U at 11 points, a light transmission amount adjustment member such as a liquid crystal panel is placed in the middle of the optical path of the information display light, and the light transmission amount UR is adjusted accordingly. It is also possible to perform this with a member.Furthermore, it is also possible to display the current time as display information, and the present invention can be applied to various vehicles other than trains.

C1 Effects of the Invention In the head-up display of the present invention described above, when the background visible luminance is (1 to 1000) cd/ytf, the value of the luminance magnification is between the straight line L+ and the straight line. Even if the background visible brightness changes over a wide range, the driver can always easily see the information display light on the headlight up display.

[Brief Description of the Drawings] Fig. 1 is a diagram showing an embodiment of the head-up display of the present invention installed in a train, Fig. 2 is a detailed explanatory diagram of the display signal output means of the embodiment, Figure 3 is an explanatory diagram of an example of display information, Figure 4 is a diagram to explain that the intensity of light changes when transmitted or reflected through an optical member, and the brightness perceived by the operator changes, and Figure 5. is an explanatory diagram of a range of brightness magnification that allows display information to be easily recognized with respect to changes in background visible brightness. A... Optical member, C... Combiner (windshield), D... Optical information display means (CRT), H...
・Head-up display, K... information projection device,
L...information display light, M...pilot, S...background visible brightness detection means (background visible brightness sensor), U...display signal output means,

Claims (1)

[Scope of Claims] An optical information display means having a display surface on which information corresponding to a display signal output from the display signal output means is displayed with a brightness corresponding to the intensity of the display signal; an information projecting device including an optical member that projects information display light in a predetermined direction; and an information projecting device that is installed to be inclined in front of the operator so that the external scene in front of the operator can be viewed from the outside world. a combiner that transmits the light beam from the front to the rear and reflects or diffracts the information display light projected from the information projection device in a direction visible to the driver, and the combiner transmits the information display light to a predetermined display visibility. In a head-up display for a vehicle that is made visible to the operator using brightness, a background visible brightness detection means for detecting the background visible brightness of the information display light that is visually recognized by the operator is provided, and the background visible brightness detection means is provided. A head-up display for a vehicle, characterized in that the display visible brightness is adjusted as described in (a) below in accordance with the background visible brightness detected by the means. (a) When the background visible luminance is (1 to 1000) cd/m^2, the background visible luminance is plotted on the horizontal axis of the logarithmic scale, and the background visible luminance is defined as (display visible luminance/background visible luminance) on the vertical axis of the logarithmic scale. The horizontal axis is 1 cd/m^2 and the vertical axis is 7, and the horizontal axis is 1 cd/m^2 and the vertical axis is 30.
The point is P_2, the horizontal axis is 1000cd/m^2, and the vertical axis is 1
The point is P_3, the horizontal axis is 1000cd/m^2, and the vertical axis is 5
The point is P_4, the straight line connecting the points P_1 and P_3 is L_1, and the straight line connecting the points P_2 and P_4 is L_4.
_2, the value of the luminance magnification is between the straight line L_1 and the straight line L_2.