JP3077092B2 - Head-up display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle for a vehicle such as a railway vehicle, a car, a ship, or the like, which is operated while looking at the scenery of the outside world in front. (For example, speed information, brake information, time information, etc.) in a superimposed manner. By using such a head-up display, the user does not need to look away from the scene in front of each other to look at the instruments, thereby preventing an accident that occurs while the user is looking away from the scene in front, Work efficiency can be improved.

[0002]

2. Description of the Related Art The conventional head-up display generally has a combiner such as a half mirror or a hologram element disposed in front of a field of view of a user (ie, a pilot), and the combiner emits light beams emitted from a forward scene. Is transmitted in the direction of the user, and the information display light incident on the rear surface of the combiner is reflected or diffracted in the direction of the user. The information projection device for causing the information display light to enter the combiner is a CR light emitting device.
T, an optical information display means such as a plasma display or a light emitting diode display, and an optical member for causing light emitted from the optical information display means to enter the combiner. The optical member usually includes a lens system, a reflecting mirror, and the like, and is configured such that the information display light can be visually recognized by a pilot in a front view.

[0003]

When the above-mentioned conventional head-up display is applied to, for example, a railway vehicle, if the display brightness is constant, the head-up display may be used when traveling in a tunnel or when traveling at night and when traveling on the ground in the daytime. Since the brightness of the outside world of the vehicle is greatly different from the above, there is a problem that even if the display brightness is easy to see in a relatively bright place, it may be too bright in a relatively dark place to obstruct the view of the outside world in front. . In addition, there is a problem in that if there is no problem in display brightness in a dark place, optical information can hardly be visually recognized in a bright place.

[0004] For this reason, head-up displays of railway vehicles and the like need to change the display brightness by several tens to several hundreds of times. The optical information display means includes a transmissive display panel in which transmitted light, such as a transmissive liquid crystal panel, that is, polarized light emitted from a display surface, and a light source (backlight) that illuminates the display panel from behind. When used, the display brightness may be changed by changing the brightness of the light source itself.

[0005] When a railroad vehicle enters a tunnel during the daytime on a sunny day, the brightness of the external scene, which is the background of the display, that is, the background brightness is from 2000 to 5000 Ft-L to 0.1.
To 0.5 Ft-L. For this reason, the display brightness is reduced to about 2,000 Ft-L to about 10 Ft-L in at least several seconds, which is a half.
It was necessary to reduce the light to less than 00. When going out of a tunnel, the opposite is necessary.

In order to use the light source in a bright place such as the daytime, a light source with high luminance is required. As a light source satisfying this necessity, a cathode ray tube, a metal halide lamp, or the like can be adopted. However, with the conventional dimming technique such as phase control, it is difficult to obtain a several-fold change in luminance of the cathode tube because a spatter phenomenon occurs at low luminance. In addition, due to the characteristics of the metal halide lamp, it is impossible to reduce the amount of light required to maintain discharge in the lamp to about 20% or less. For this reason, it was difficult to obtain a large change in luminance required here by changing the luminance of the light source itself.

Accordingly, the present application provides a head-up display using a light source and a polarized light transmission type display panel such as a transmission type liquid crystal display panel disposed in a plane perpendicular to the optical axis of the light source light. Patented invention in which a rotatable polarizing plate is arranged in a plane perpendicular to the optical axis of light emitted from the device, and display brightness is adjusted by adjusting the rotation position of the polarizing plate. Filed. According to the invention, when the vibration direction of the polarized light transmitted through the polarized light transmission type display panel and the vibration direction of the light transmitted through the polarizing plate are set to the same direction, a display with high brightness is obtained, and the polarized light transmitted through the polarized light transmission type display panel is obtained. When the vibration direction of the light is shifted by 90 degrees from the vibration direction of the light transmitted through the polarizing plate, a low-luminance display is obtained. Since the display luminance changes only by rotating the polarizing plate, the display luminance can be adjusted at a high speed.

However, if the display plate brightness is adjusted by continuously rotating the polarizing plate every time the brightness of the external scene, that is, the background brightness changes, a rotating orbital current always flows through the motor, and power consumption is reduced. The problem that it becomes large arises. Therefore, to save power consumption,
While the motor is stopped, the current may be cut to a fraction of the current during rotation (a small current for holding is required). For that purpose, instead of continuously changing the display luminance according to the change of the background luminance, a method of changing the display luminance only when the background luminance exceeds a set specified value,
That is, it is conceivable to adopt a stepwise display brightness control method. When the stepwise display brightness control method is adopted, if the number of steps is large, the power saving effect is reduced, and if the number of steps is small, the display brightness does not change even if the background brightness changes by a certain amount, and the display information is visually recognized. There is a problem that the performance is reduced.

The inventor of the present invention mounted a head-up display on an actual railway vehicle and performed a display test of the head-up display for various background luminances in order to obtain an appropriate value of the number of steps. As a result, with respect to a wide range of background luminance, such as from nighttime to fine weather after snowfall, it is inevitable that the display may be thin and the visibility may be slightly difficult with four-step luminance adjustment. However, it was found that the visibility was sufficiently satisfactory when the luminance was adjusted in five steps, and the visibility was sufficiently satisfactory when the luminance was adjusted in seven or more steps. It was also found that even if the background luminance was divided into seven or more finer steps and the display luminance was finely adjusted, the visibility of the display information did not change much.

The present invention has been made in view of the above circumstances and test results, and has a light source and a polarization transmission type display panel which is disposed perpendicular to the optical axis of the light from the light source and emits polarized light as display light. A polarizing plate disposed perpendicularly to the optical axis and rotatably supported, a background luminance detecting means for detecting the luminance of the front scene, and an increase and decrease of the background luminance detected by the background luminance detecting means. It is an object of the present invention to reduce power consumption without impairing visibility in a head-up display for a railway vehicle provided with a display brightness adjusting means for increasing or decreasing the display brightness by rotating the polarizing plate accordingly.

[0011]

Means for Solving the Problems Next, the invention of the present application devised to solve the above-mentioned problems will be described. For simplicity, the reference numerals of the elements of the embodiment are enclosed in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the embodiments described below is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments. In order to solve the above-mentioned problems, a head-up display according to the present invention comprises an optical information display means (D) having a display surface on which information is displayed, and an information display light (L) emitted from the display surface in a predetermined direction. An information light projecting device (K) having an optical member (A) for projecting light to a light source, and an information light projecting device (K) for transmitting light (J) emitted from a front scene toward a rear viewing position and transmitting the light (J). Information display light (L) projected from
In a head-up display for a railway vehicle provided with a combiner (C) for moving the light to the visual recognition position, the optical information display means (D) includes a light source (D2) and a light source (D2) perpendicular to the optical axis of the light source light. A polarizing transmission type display panel (D1) that is disposed and emits polarized light as display light; a polarizing plate (E) that is disposed perpendicular to the optical axis and rotatably supported; Background luminance detecting means (17) for detecting luminance; and display luminance for increasing or decreasing the display luminance by rotating the polarizing plate (E) in accordance with an increase or decrease in the background luminance detected by the background luminance detecting means (17). Adjusting means (U), wherein the display brightness adjusting means (U) comprises:
A background luminance level detecting means for detecting in which range the background luminance is divided into 5 to 7 levels, and 5 to 7 rotations set corresponding to each of the 5 to 7 levels of background luminance Means for rotating the polarizing plate (E) at a position.

[0012]

The head-up display according to the present invention having the above-described features includes a polarization transmission type display panel (D1) and a rotatable polarizing plate (E) disposed perpendicular to the optical path of the light source light. I have. A display luminance adjusting means (U) for increasing or decreasing the display luminance by rotating the polarizing plate (E) in accordance with the increase or decrease of the luminance of the front scene detected by the background luminance detecting means (17) is provided. I have. Therefore, when the polarizing plate (E) is rotated to make the vibration direction of the polarized light passing through the polarizing transmission type display panel (D1) the same as the vibration direction of the light passing through the polarizing plate (E), high brightness is obtained. When the oscillation direction of polarized light passing through the polarization transmission type display panel (D1) and the oscillation direction of light passing through the polarizing plate are shifted to nearly 90 degrees, a display with low luminance is obtained. Since the display luminance changes only by rotating the polarizing plate (E), the display luminance can be adjusted at a high speed. The display luminance adjusting means (U) includes a background luminance level detecting means for detecting in which range the background luminance is divided into 5 to 7 levels, and a display luminance adjusting section (U) corresponding to each of the 5 to 7 levels of background luminance. Means for rotating the polarizing plate (E) at five to seven set rotation positions. Therefore, while the background luminance is within a predetermined range (predetermined stage), the polarizing plate (E) does not rotate even if the background luminance changes within that range. Therefore, power consumption is reduced as compared with the case where the display luminance is continuously changed according to the change in the background luminance (that is, the polarizing plate (E) is continuously rotated according to the change in the background luminance). can do. When the background luminance and the display luminance are divided into five or more levels, sufficient visibility can be obtained for any background luminance. Then, even if the background luminance and the display luminance are divided into more than seven levels, the visibility of the display information does not change so much.

[0013]

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, a driver's cab 2 is installed at the front end of a train 1. In the cab 2, an instrument panel 4 is provided in front of a seat 3 for the operator P. Further, a windshield C as a combiner is disposed in front of the cab 2 between the lower part 5 of the train and the ceiling 6 of the train 1.
As shown in FIG. 1, the windshield C is arranged so as to be inclined downward as it goes forward.

An information projector K for a head-up display is provided on the instrument panel 4 of the operator's cab 2. The information light projecting device K has a casing 10. As shown in FIG. 3 and FIG.
And optical information display means D. This optical information display means D is composed of a transmission type liquid crystal display panel (polarization transmission type display panel) D1 for emitting polarized light and a light source D2 disposed on the back surface thereof. The liquid crystal display panel D1 is driven by the liquid crystal drive circuit 11, and necessary information (for example, speed information or brake pressure information) is displayed on its display surface. The light source D2 comprises a reflector 12 and a metal halide lamp 13 supported by the reflector.

The optical member A comprises a lens system A1, a mirror A2, a convex lens A3, etc., and is arranged so that information display light L emitted from the optical information display means D is incident on the windshield C. Have been. A polarizing plate E is provided between the optical member A and the optical information display means D. The polarizing plate E is provided with a gear 14 at a portion where a central angle slightly larger than 90 degrees of the outer periphery is expected. ing. A groove (not shown) is formed in the casing 10 so that the gear 14 can rotate at an outer peripheral portion where a central angle slightly larger than 180 degrees is viewed. The gear 14 and the polarizing plate E are formed together. It is rotatable within a range of an angle slightly larger than 90 degrees.

A stepping motor S is provided on an upper portion of the outer surface of the casing 10.
The pinion 15 fixed to the output shaft is meshed with the gear 14. Then, when the stepping motor S rotates and the polarizing plate E rotates in a range of 0 to 90 degrees,
The deviation between the polarization direction of the information display light L passing through the liquid crystal display panel D1 and the polarization direction of the polarizing plate E, that is, the deviation of the optical phase varies between 0 and 90 degrees. At this time, the brightness of the information display light L is adjusted.

The stepping motor S is configured to operate by a motor drive circuit 16, and the motor drive circuit 16 is configured to operate according to a control signal of a microcomputer M (see FIG. 4). The microcomputer M is
The light amount of the external scene light J detected by the light amount sensor 17, that is, the range of the external background luminance signal in the graph of FIG. 5 is detected, and the display luminance corresponding to the background luminance is determined. Then, the microcomputer M outputs a control signal of the stepping motor S to the motor drive circuit 16 according to the determined display luminance.

The control signal of the stepping motor S output from the microcomputer M according to the determined display luminance is such that the higher the determined display luminance, the more the polarization direction of the information display light L and the polarization of the polarizing plate E. The stepping motor S is driven so that the deviation from the direction, that is, the deviation of the phase is reduced. Further, the control signal drives the stepping motor S such that the difference between the polarization direction of the information display light L and the polarization direction of the polarizing plate E decreases as the determined display luminance decreases. The components indicated by the reference numerals 14 to 17 and M constitute a display luminance adjusting means U (see FIG. 4). The display luminance adjusting means U of the present embodiment includes a background luminance level detecting means for detecting in which range the background luminance is divided into 5 to 7 levels, and a display luminance adjusting means U corresponding to each of the 5 to 7 levels of background luminance. Means for rotating the polarizing plate at 5 to 7 rotation positions set as described above.

The windshield C is arranged so as to transmit a part of the information display light L incident from the optical member A and reflect the remainder toward the operator P. Further, the windshield C is arranged so as to reflect a part of the external light J incident from an external scene or the like, and transmit the remainder toward the pilot P. That is, the windshield C of this embodiment itself has a function as a combiner. The combiner is
It is also possible to configure separately from the windshield.
An information light projecting device K is constituted by the optical member A and the optical information display means D, and a head-up device is provided by the windshield C functioning as the combiner, the information light projecting device K, the display brightness adjusting means U, and the like. Display H
(See FIGS. 1 and 4).

Next, the operation of the embodiment of the present invention having the above configuration will be described. An external ray J traveling from the outside to the windshield C from the outside on the left side in FIG. 1 is partially reflected by the windshield C to the outside, and the rest passes through the windshield C as it is, and goes straight ahead. To the eyes of the person P. Thereby, the pilot P can visually recognize the external scene as it is. On the other hand, the information display light L emitted from the optical information display means D of the information light projecting device K is a polarized light, and this polarized light depends on the rotation position of the polarizing plate E when passing through the polarizing plate E. To adjust the amount of transmitted light. The information display light L passing through the polarizing plate E and the optical member A
Enters the windshield C. A part of the information display light L incident on the windshield C is transmitted through the windshield C and emitted to the outside world, but the rest is reflected and reaches the eyes of the pilot P. As a result, the operator P receives the information display light L
Can be visually recognized. The luminance of the information displayed on the optical information display means D, that is, the luminance of the information display light L is controlled by the rotation position of the polarizing plate E.

Next, a method of controlling the rotation position of the polarizing plate E will be described with reference to FIG. The rotation position of the polarizing plate E is controlled by a program (polarization plate rotation position control flow execution program) stored in the memory Me of the microcomputer M. When the polarizer rotation position control flow shown in FIG.
In step 1, the background luminance detected by the optical sensor 17 is read. Next, in step S2, the display luminance corresponding to the background luminance is determined using the data stored in the memory Me, that is, the data defining the equation of the graph shown in FIG. The motor rotation position (that is, the polarization plate rotation position) is determined. Next, in step S3, the current rotation position of the stepping motor S, that is, whether the rotation position of the polarizing plate E is correct, that is, the polarization plate E is at the rotation position corresponding to the determined display luminance. Determine whether or not. If yes (Y), the process returns to the step S1, and if no (N), the process moves to the next step S4.

In step S4, the stepping motor S is driven to a rotation position corresponding to the display luminance determined in step S2. That is, when the light amount of the external scenery light J detected by the light amount sensor 17 is larger than the display luminance corresponding to the detected rotation position of the stepping motor S (the rotation position of the polarizing plate E) (the When the calculated display luminance is large), the stepping motor S is driven so that the phase shift in the polarization direction (the polarization direction of the transmitted light of the liquid crystal display panel D1 and the polarization direction of the polarizing plate E) becomes small. At this time, the brightness of the information display light L increases. Further, the polarizing plate E is provided with the light amount sensor 17.
Is driven by the stepping motor S so that the phase shift in the polarization direction becomes large when the light amount of the external scenery light J detected is small. At this time, the brightness of the information display light L decreases.

Next, in step S5, it is determined whether or not the polarizing plate rotation position control flow has been completed. No (N)
In this case, the process returns to step S1. If the determination is yes (Y) (the power is off), the process ends.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do. For example, the position where the polarizing plate is arranged can be arranged at an arbitrary position in the optical path from the light source to the person who views the display.

[0025]

According to the head-up display of the present invention having the above-described features, the polarization direction of the polarized light passing through the polarization transmission type display panel and the vibration direction of the light transmitted through the polarization plate are adjusted by rotating the polarizing plate. , The display brightness can be adjusted at a high speed. Further, the display brightness adjusting means may be configured to select one of the background brightnesses divided into 5 to 7 levels.
It is configured to maintain a constant display luminance (a constant display luminance that does not impair the visibility) without rotating the polarizing plate while changing in a range of one step. Therefore, power consumption can be reduced without impairing the visibility of the display.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which an embodiment of a head-up display of the present invention is installed in a railway vehicle.

FIG. 2 is a partial plan view of the embodiment.

FIG. 3 is a side sectional view of a main part of the embodiment.

FIG. 4 is an enlarged perspective view of a main part of the embodiment.

FIG. 5 is an explanatory diagram of a luminance adjustment method according to the embodiment.

FIG. 6 is a diagram illustrating a flow of controlling the rotation position of the polarizing plate according to the embodiment.

[Explanation of symbols]

A: Optical member, C: Combiner (front glass), D
... optical information display means, D1 ... polarized light transmission type display panel,
D2: light source, E: polarizing plate, H: head-up display, J: external scene light, K: information projection device, L: information display light, P: pilot, U: display brightness adjusting means U17: background brightness Detection means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuyuki Kinoshita 1 Sanjo Plant, Nishinokyo Kuwaharacho, Nakagyo-ku, Kyoto, Kyoto Prefecture (72) Inventor Shigeru Kitayama 1-1-1 Meieki Station, Nakamura-ku, Nagoya-shi, Aichi Prefecture No. 4 Tokai Passenger Railway Co., Ltd. (72) Inventor Kazuhiko Kobayashi 1-1-4 Meieki Station, Nakamura-ku, Nagoya City, Aichi Prefecture Tokai Passenger Railway Co., Ltd. (56) References JP-A-4-325323 (JP, A JP-A-4-229892 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 35/00-37/00

Claims (1)

(57) [Claims] 1. An information projection device comprising: an optical information display means having a display surface on which information is displayed; and an optical member for projecting information display light emitted from the display surface in a predetermined direction. A head-up display for a railway vehicle, comprising: a combiner that transmits light emitted from a scene toward a rear viewing position and transmits information display light emitted from the information projection device to the viewing position. The optical information display means is a light source, a polarization transmission display panel that is disposed perpendicular to the optical axis of the light source light and emits polarized light as display light, and is disposed perpendicular to the optical axis. A polarizing plate rotatably supported, a background luminance detecting unit for detecting the luminance of the front scene, and rotating the polarizing plate according to an increase or decrease in the background luminance detected by the background luminance detecting unit. Display luminance adjusting means for increasing or decreasing the display luminance, the display luminance adjusting means detects in which range the background luminance is divided into 5 to 7 levels, and a background luminance level detecting means, A head-up display for a railway vehicle, comprising: means for rotating the polarizing plate at 5 to 7 rotation positions set corresponding to each of 5 to 7 levels of background luminance.