CN1185608C - Image display system - Google Patents

Abstract

The present invention relates to an image display system for displaying images for passengers of a vehicle, such as a train. The image display system includes: a series of images (1) arranged along the track of the vehicle; a discharge lamp (11) for instantaneously illuminating each image; a plurality of control units (3). The control device includes: a detector (6) for detecting a vehicle mark; a counter chain (7) measuring the time difference as a measure of the vehicle speed; a microprocessor (8) responsive to detection of the indicia for controlling the illumination means of the at least one image to repeatedly illuminate each individual image of the respective window of the vehicle taking into account the speed of the vehicle and the position of the respective window of the vehicle.

Description

image display system

The present invention relates to an image display system for displaying images for passengers of a vehicle such as a train.

Display systems have been proposed that include a series of images positioned along the vehicle track and illuminate each image in momentary succession as the vehicle passes. Momentary illumination is sufficient to avoid blurring of the image due to vehicle motion when the image is viewed by vehicle occupants. When the vehicle passes by, the illumination of the continuous image can make the image seen by the audience be a single continuous image in the form of a TV image or movie image due to the afterglow effect of vision.

Such an image display system is preferably used as a means for displaying advertisements or text and pictorial information, such as information about the next station along a train line. However, the above proposals have not been successfully implemented in practice due to technical difficulties in implementation, such as the difficulty in triggering the lighting at the correct instant.

According to a first aspect of the present invention there is provided an image display system comprising a series of images arranged in a tunnel along a track of a vehicle having a sequence of windows; lighting equipment for instantaneously illuminating each image; a a control unit for controlling the lighting equipment of said image to continuously illuminate the image as the vehicle passes, wherein the control unit comprises: detector means for detecting the arrival of the vehicle; means for obtaining the magnitude of the vehicle speed; means for obtaining the measured value of the vehicle speed; means for controlling said lighting device, said control means controlling said lighting device to repeatedly illuminate each individual image in response to the detection of the arrival of a vehicle, taking into account the vehicle speed and the position of the various windows of the vehicle, so that when the position of the image corresponds to the position of the vehicle The image is illuminated when the positions of the windows coincide.

In the control unit, the position of the window of the vehicle is represented by a vehicle map showing the presence or absence of windows at positions separated by a predetermined interval, and the respective windows are represented by a tunnel map representing the presence or absence of images at positions separated by a predetermined interval. Image position, said means for controlling said lighting device is arranged to derive in real time the timing of illuminating each image by displacing the vehicle and tunnel map relative to each other at a rate proportional to the resulting vehicle speed, and when the window The image is illuminated when it matches the image position.

The present invention enables accurate timing control of lighting through the use of a simple control system. By taking into account vehicle speed and window positions, the lighting can be controlled to illuminate each image at the exact appropriate position relative to each of the individual images, thereby enabling a series of images to be viewed through each of these corresponding windows. into a single continuous image. Since the present invention controls the lighting taking into account the actual position of the individual windows, the problems of prior art image display systems that only illuminate the image at a rate proportional to the speed of the vehicle are avoided. In such prior systems the image is illuminated at an arbitrary position relative to any given window, so that the image viewed by occupants of the vehicle is blurred.

It is best to configure the detector device to detect the markings on the car. The system can be implemented using tokens with minimal modifications to the vehicle. It is possible to control the lighting of several windows using a single tag, so that it is not necessary to tag every window which is uncomfortable and unsightly.

The vehicle speed is determined from the output of the controller means. In this way, the vehicle speed can be determined with sufficient accuracy using the markings, and the image is illuminated at the same position relative to the window so that there is no image jitter.

Best of all, don't install lighting on vehicles that are inconvenient and undesirable because it includes cutting panels or otherwise modifying the vehicle. The display unit can be equipped with graphics and lighting equipment.

Determining a measure of vehicle speed from the output of the detector means is technically straightforward. This can be done, for example, by detecting the timing of the output of the detector device. One possibility is to detect the time between two features of a marker that are separated by a predetermined distance. The two features could be individual bars of a tape or the length start and end of a mark of discrete length, such as the start and end of a barcode. Another alternative is to use two detectors which are separated by a predetermined distance, in which case the time difference between detection of the same feature of the marking is detected. An advantage of this system is that a measure of the vehicle's speed can be derived from a single marking on the vehicle (eg a strip of tape), which minimizes modifications to the vehicle.

The means for controlling the lighting means preferably includes a microprocessor running a program to calculate the timing of lighting for each image. A microprocessor enables sufficiently accurate timing control.

It is desirable that the control unit controls the lighting devices of a plurality of images in consideration of the positions of the images. This reduces the cost of the system because a separate control unit for each image is avoided. Even when the images are irregularly spaced, which is not possible with prior systems that illuminate the images at a rate proportional to the vehicle speed, the timing of the illumination can be precisely obtained considering the position of the images.

Preferably, the position of each window is represented in the control unit by each bit of the first bit combination representing the existence or non-existence of a window at a position separated by a predetermined interval, and the position of each window is represented by the presence or absence of a window at a position separated by a predetermined interval. The individual bits of the second bit combination of the image represent the respective image positions, and the control unit derives in real time the illuminated individual bits by relatively shifting the first bit combination and the second bit combination at a rate proportional to the obtained vehicle speed. The timing of the images and controlling the lighting of the individual images when the bits of the second bit combination representing the presence of the respective images coincide with the bits of the first bit combination representing the window position. For example, the control unit shifts the first bit combination through a shift register, and uses a second bit combination to transform the bit units of the shift register into the plurality of images, and the second combination represents the shifting of the images. A bit is output at the bit location of the register to control the lighting of the image. This is a particularly advanced way of getting lighting timing because it's simple and reliable.

Preferably, the marker encodes the position of the window along the vehicle and the control unit decodes the output of the detector to obtain the window position and uses the obtained window position to derive the lighting timing. Such use of coded window positions facilitates the calculation of proper lighting timing, thereby improving timing control. Since the proper timing is position divided by vehicle speed, the lighting timing can be easily calculated from the encoded window position. Furthermore, the system can accommodate different window configurations for different types of vehicles or can select the windows for which images are visible by simply changing the coded marking system.

The indicia may be barcodes, which is advantageous since barcode technology itself is well utilized and its use simplifies the system.

Existing image display systems have attempted to illuminate each image at the same location relative to a given window of the vehicle as closely as possible. This is necessary to prevent occupants in the vehicle from seeing jittery or drifting images.

According to a second aspect of the present invention, there is provided a control device for an image display system that instantaneously illuminates a continuous image of a series of images arranged along a vehicle track when a vehicle passes by, wherein the control device is configured to illuminate images of portions of the series of images whose positions relative to the vehicle differ for subsequent portions.

The second aspect of the invention enables different parts of the series of images to be viewed by passengers at different positions within the viewing window. This is in contrast to existing systems that illuminate images of the same location. This enables many visual effects because the image seen by the passenger is moving. For example, the image of the first part of the series of images is illuminated on one side of the window and the image of the second part of the series of images is illuminated on the opposite side of the window. Coordinate this movement with the content of the image. For example, to discuss the impressions of two persons on opposite sides of a window, the portion of the sequence of images displayed on one side of the window is the image of the first person in question, and the portion of the sequence displayed on the second side of the window is the image of the second person in question. Image of people. Many other effects can use this technique. In each portion of the sequence of images, each image is preferably illuminated at the same position relative to the window so that there is no judder or drift.

According to a third aspect of the present invention, an image display system is provided, which includes: a series of images arranged along the track of the vehicle; lighting equipment for instantaneously illuminating each image; and a control device for controlling the lighting when the vehicle passes The device continuously illuminates the images, wherein the series of images comprises a plurality of periods of an interlaced sequence of images.

The control means are selectively set to display one of the sequence of images by means of different sequences of periodic interlaced scans, in particular by illuminating only the images of this sequence. Thus, if a sequence displays images of different types, the system can change the type of image shown depending on the time of day without actually having to replace the images. This makes the system very versatile.

In addition, interlaced sequences can be used to produce special effects by appropriate selection of image sequences and, if required, to control lighting.

A fourth aspect of the present invention relates to a capacitive discharge circuit for a flashlight of an image display system of the present invention or other systems requiring momentary bright illumination. In such image display systems, the image must be illuminated for a sufficiently short period of time to prevent blurring caused by relative motion of the image when illuminated. For example, a train is expected to move at a typical speed of 30m/s, to limit the relative motion of the train and image to 3mm, the illumination period must be 0.1ms. Flash lamps, such as gas discharge lamps, used in capacitive discharge circuits are known among other applications to provide momentary illumination. However, known capacitive discharge circuits are very expensive, bulky and impractical for such image display systems. This is because the lighting is required to be instantaneous and bright enough that the viewer's eyes perceive the image as having a sufficient total amount of light.

It should be noted that the instantaneous period of illumination on the order of 0.1 ms forms a great contrast compared with TV or movies where each frame of image is visible for a longer proportion of time. A large amount of energy must therefore be stored in the discharge capacitor of the capacitive discharge circuit to achieve a sufficiently bright flash. However, this is incompatible with the discharge requirement that the capacitor must be charged quickly without generating large charge currents. For example, with a typical train speed of 30m/s and a typical window spacing of 2mm, a given strobe needs to flash at a rate of 15Hz. However, charging to a sufficient level so quickly with known capacitive discharge circuits would generate large charging currents, requiring larger and more expensive components to carry the current and also increasing power requirements. In other words, the known capacitive discharge circuits do not meet the requirement of fast enough recharging to produce a sufficiently bright flash without generating an overcharging current.

According to a fourth aspect of the present invention, there is provided a capacitive discharge circuit for a flashlight, the capacitive discharge circuit includes: at least one discharge capacitor for storing charge; a flashlight; a trigger circuit, which is set to be triggered by the flashlight discharging at least one capacitor; and a charging circuit for the at least one discharging capacitor, charging the at least one discharging capacitor through an inductor in series with the at least one discharging capacitor.

Using an inductor in the charging circuit solves the problem of modifying known capacitive discharge circuits to charge to a sufficient level without generating an overcharging current. This is because the RC charging characteristic of known capacitor discharge circuits produces an initial high current due to the exponential shape of the RC characteristic. In contrast, the present invention uses the LC charging characteristic, which allows a faster charging time for a given maximum charging current because the shape of the LC charging characteristic is the initial part of the sine wave. The present invention is also more energy efficient because the inductance of the inductor is used to limit the current rather than a resistive element.

Another advantage of the present invention is that the inductor is a fluorescent tube choke inductor. In many capacitive discharge circuits, the cost of a sufficiently large inductor is prohibitive, but it has been realized that the operating characteristics of flash lamps for image display systems permit the use of inexpensive and readily available fluorescent tube choke-type inductors.

Another advantage of the inductor is that the energy of the inductor can be fed to at least one discharge capacitor, thereby increasing the operating voltage. This reduces the capacitance of the discharge capacitor required for a given energy output. This can be achieved, for example, by a charging circuit comprising at least one storage capacitor having a capacitance greater than that of the at least one discharge capacitor, the storage capacitor being connected to the at least one discharge capacitor and the A series arrangement of inductors is connected in parallel.

Preferably, the charging circuit comprises a switch which disconnects the at least one discharging capacitor from the charging circuit during discharge of the at least one discharging capacitor, for example by supplying a trigger signal provided by the triggering circuit to the switch. This avoids feeding current from the charging circuit into the flash during discharge, which is undesirable because it would allow the duty cycle of the power supply to affect the output of the flash and put the lamp into a lamp-harmful mode of operation.

Preferably, the trigger signal is supplied to the switch via an optocoupler, which employs an optical triac. This has the advantage that the switch is only restarted at the zero crossing of the mains cycle, no resistors are required in the charging circuit, thus improving energy efficiency.

A capacitive discharge circuit may include more than one flash lamp. In this case, each flash lamp preferably has a separate discharge capacitor and a separate trigger circuit, but this is not necessary.

Any or all aspects of the invention may be combined.

For a better understanding of the invention, an image display system embodying all aspects of the invention is described below by way of non-limiting example with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of a part of the image display system;

Fig. 2 is a schematic circuit diagram of a part of the image display system;

Figure 3 is a schematic diagram of an alternative control unit for a portion of the image display system;

Fig. 4 is a flow chart of the control program running in the control unit;

Fig. 5 is a side view of a display unit of the image display system;

Figure 6 is a cross-sectional view of the display unit along line XI-XI in Figure 5;

Fig. 7 is a circuit diagram of a capacitive discharge circuit of an image display system;

FIG. 8 is a graph depicting a charge profile of a capacitive discharge circuit;

Figure 9 is a cross-sectional view of a first alternative configuration of a display unit;

Figure 10 is a cross-sectional view of a second alternative configuration of the display unit.

The image display system is provided for displaying images to passengers such as trains. A portion of a display system is shown in FIG. 1 , depicting elements installed in the vicinity of a vehicle, for example in the vicinity of a railway track. This section comprises a plurality of images 1 each mounted in a display unit 2 having lighting means to momentarily illuminate the individual images (described in more detail below). The lighting device is controlled by a control unit 3 which is connected to the display unit 2 via corresponding control lines 4 .

The portion controlled by the control unit 3 may comprise any number of images 1 . Although only 4 images are shown in Figure 1 for clarity, the desired number is larger, typically 24, in order to reduce the number and cost of control units. The image display system may comprise a single portion as shown in Figure 1 or a plurality of successive portions of an image displayed over a longer period of time.

Image 1 is of a suitable size to be seen through a single window of the vehicle, eg A2 if the vehicle is a train.

When viewed in succession, all the images 1 together form a series of steady or changing images. The change can produce motion in the viewed image, for example, the image shown in Figure 1 moves like a bouncing ball, or the change can be a color change or other visual effect. The image 1 can display advertisements or useful text or image information, for example information about the next stop of the vehicle.

Preferably, the image 1 comprises at least one horizontal line (not shown) at a predetermined vertical position relative to the image, more preferably successive lines running above and/or below the main image. These lines are discernible by the viewer's eye and serve as a guide to compensate for vertical displacement of the continuous image due to vehicle mounting position or vehicle motion. These rows are invisible to normal lighting and are resolved by a separate UV light.

The display unit 2 as shown in Figure 1 is wall mounted at the level of the vehicle window, eg on the wall of a tunnel or excavation, although a stand-free display unit would be used where no suitable mounting surface is available. It is often necessary to fix the image 1 around obstacles such as recesses in tunnels along the vehicle track. In this case, the spacing between pictures 1 will increase, which will cause minimal disturbance to the viewed picture and change the frame rate of the picture 1 sequence at that point.

The circuit of the information display system is shown in FIG. 2 , in which the positions of various units in the display unit 2 and the control unit 3 are schematically shown by dotted boxes.

The control unit comprises an infrared laser diode 5 as a source of electromagnetic radiation, which emits light onto passing vehicles. The control unit further comprises a detector 6 with an associated infrared receiver for detecting any radiation reflected by the vehicle from the diode 5 . Fix the detector 6 and the marker on the vehicle at a predetermined height. Infrared radiation is used to reduce the chance of false triggers, eg, from internal light illumination, and to avoid radiation as visible light. An improvement is to use polarization to prevent spurious signals from triggering the detector 6 . For example polarized reflective markers which are only sensitive to polarized radiation are used together with the detector 6 .

The control unit 3 also includes a microprocessor 8 which runs a calculation program when each image is illuminated in response to the output of the detector 6 and outputs control signals at the calculated timing points to trigger the lighting device. The microprocessor also controls and monitors the components of the control unit 3 .

In particular, the microprocessor 8 uses the output of the detector 6 to detect the arrival of a vehicle, thereby deriving a measure of the vehicle's speed and determining the position of the vehicle's windows relative to the marker.

For velocity measurement, the marker consists of two vertically extending bars of reflective tape spaced apart by a predetermined interval. The passage of the strip through the detector generates pulses in the output of the detector 6 . The time difference T between the two pulses is used as a measure of the vehicle speed, since T=d/v. The output of the detector is connected to a counter chain 7 which measures the time difference between the two pulses. The measured time difference T is then supplied to the microprocessor 8 .

The marker also encodes the window position. To achieve this, the marking includes a barcode placed immediately after the two strips. The output of the detector 6 is fed into a commercially available bar code chip machine 9, which is conventional in itself. When the barcode on the vehicle passes, the output of the detector 6 is modulated by the barcode signal generated according to the reflection of the electromagnetic radiation of the barcode. Bar code chip machine 9 decodes with bar code. The decoded barcode is provided to the microprocessor 8 which uses the decoded barcode to determine the window position. In particular, the control unit 3 has a memory table storing the window positions of the different sets of corresponding barcodes and uses the decoded barcode table to look up the memory table. These may be stored in non-volatile memory of the microprocessor 8, eg EPROM.

Measurement of vehicle speed may be accomplished using other forms of indicia. For example, instead of using two strips as the two features for obtaining the time difference T, any feature recognizable in the output of the detector 6, such as the start and end of a horizontally extending reflective strip, may also be used. Alternatively, the two features would be at the beginning and end of the barcode, which would have the advantage of avoiding the need for a reflective strip and thereby reducing the amount of marking on the vehicle.

Another alternative is that the detector 6 comprises two separate detection units 6a and 6b separated by a predetermined distance d, in which case the time difference between the detection of a single feature by the two detection units is used as a measure of the vehicle speed. FIG. 3 shows such a control unit arrangement, which is an alternative to the control unit 3 of FIG. 1 . Figure 3 shows a separate laser diode 5 for each detection unit 6a and 6b, while the signal source is placed on the opposite side of the train track so that the train interrupts the signal source and there are no reflections. While such an arrangement enables velocity to be measured by a single feature, such as a single strip of reflective tape at the beginning or end of a barcode, it has the advantage of reducing the amount of marking on the vehicle.

Instead of using markers, the speed of the vehicle may be measured in some other way, for example using radar or an acoustic measurement system.

In the above solution, the tag encodes the position of the window and the control unit obtains the position of the window from the tag. This has the advantage of enabling different vehicles with different window configurations to use the system, but is not required. If the image display system is used where the vehicle has windows of the same, known position, the positions of the windows can be stored in the control unit 3 , for example in a non-volatile memory of the microprocessor 8 . The site-specific window positions are stored in the control unit 3 when the image display system is set up.

Alternatively, some other means (such as a transponder mounted on the vehicle) could be used to transmit the information indicative of the window position. In this case, the module would have a receiver to receive the information and transmit the information to the microprocessor 8 . Other information may be communicated between the train and the control unit using the vehicle transponder and display system receiver or transceiver, such as control information to select one of a plurality of series of interlaced scanned images for illumination. Therefore, the barcode chip machine is not necessary.

The presence and form of the mark is not essential. For example, the arrival of a train could be detected in some other way, such as by a change in the detector output when the front of the train arrives or when some other feature on the side of the train has appeared. Other forms of detector 6 may be used. For example, detectors do not have to use infrared radiation. The system also does not have to rely on reflected radiation. The signal source may be placed on the opposite side of the train so that the train interrupts detection of the incoming beam, or the signal source may be omitted entirely if the detector 6 relies on ambient radiation.

Where the vehicle comprises a plurality of linked cars, separate markings can be provided on the different cars so that the different cars independently control the lighting in response to the individual markings. This allows the system to use the velocity measured individually for each car, which allows for more precise timing control in situations where, for example, the train is accelerating or decelerating or there is movement in the coupler between the cars so that the cars pass the image at slightly different speeds .

The program running in the microprocessor 8 is shown in the form of a flowchart in FIG. 4 .

In step S1 the microprocessor 8 monitors the output of the detector 6, checks for the first characteristic of the marker, and repeats step S1 until the first characteristic of the marker is present.

When the first characteristic is detected, the program continues to step S2 where the output of the controller 6 is monitored to check the flag and the second characteristic. If the second characteristic of the marker is not checked, the program proceeds to step S3 where the microprocessor 8 monitors the output of the counter chain 7 to determine if the time elapsed since the detection of the first characteristic exceeds a threshold. If the threshold is not exceeded, the program repeats step S2. Let the threshold be set slightly larger than the maximum desired time difference T. If the time elapsed before the detection of the second feature exceeds a threshold value, the procedure returns to step S1 to look again (find) the first feature of the marker. In this way, even if a spurious signal is present in the output of the detector 6, the threshold value can prevent the occurrence of false operation starting the lighting.

If the second signature is detected before the elapsed time exceeds the threshold, the program proceeds to step S4. In step S4 the microprocessor 8 inputs the time difference T between two pulses from the counter chain as a measure of the vehicle speed.

Finally, in step S5, the microprocessor 8 determines the appropriate lighting timing and transmits control signals on the control line 4 at these timing points, thereby illuminating the image 1 in the corresponding display unit 2.

The microprocessor 8 obtains the timing of illuminating each image associated with it so that each image is repeatedly illuminated for different windows of the vehicle. This enables the sequence to be viewed from each of these windows. For this calculation, the microprocessor 8 takes into account the position _xw of each window relative to the marker, in particular divided by _xw by the measured vehicle speed. The microprocessor 8 also takes into account the position x _I of the image 1 relative to the detector 6 when the control unit 3 normally controls multiple images at different positions. Generally speaking, the timing t i,w of the i-th image at position _xI illuminated by the Wth window at position _xw can be obtained from the measured time difference by the following equation _:

t _{i, w} = (x _i +x _w )T/d (1)

By storing exactly the image position _xi , the timing of each image of the illumination sequence at the same position relative to any given window can be controlled. This avoids lateral displacement of the viewed image from one image to the next which can produce drift relative to the window. For the same reason, it is important to use consistent window position values for all display units 2 in sequences controlled even by different control units 3 . However, the relative value _xw of the window positions is not critical, if the images are viewed at slightly different positions relative to different windows, as long as the images are still visible through the windows and each image is illuminated at the same position for any individual window , the relative value of the window position is acceptable.

Instead of viewing all images at the same position relative to a given window, the timing can be controlled to illuminate corresponding parts of an image or series of images at corresponding part positions relative to different vehicles (P14). This is accomplished by adding selection offsets to the stored image locations x _i in equation (1) above. This technology enables many visual effects because the image viewed by the passenger can be moved around. For example, images of a first part of a sequence of images may be illuminated on one side of the window and images of a second part of the sequence illuminated on the opposite side of the window. Coordinate this movement with the content of the image. For example, to discuss the impressions of two persons on opposite sides of a window, the portion of the sequence of images displayed on one side of the window is the image of the first person in question, and the portion of the sequence displayed on the second side of the window is the image of the second person in question. Image of people. In each portion of the sequence of images, each image is preferably illuminated at the same position relative to the window so that there is no judder or drift.

Another alternative is to control the timing of illuminating successive images at graduated positions relative to the windows. This is accomplished by adding gradation compensation to the stored image position _xi in equation (1) above. This technique allows the viewer to see a moving image that itself moves relative to the window.

In general, there are many ways for the microprocessor 8 to handle the properly timed calculations in step S5. However, the preferred technique used in the described embodiments is as follows.

The corresponding image position x _w is represented by a bit pattern known as a "train map". Each bit of the train map represents the presence or absence of a window at a constant predetermined interval r apart. If the train map is 10100101, it means that the window appears at the position x _w =r, 3r, 6r, 8r.

Similarly, corresponding image positions x _i are represented by bit patterns known as "tunnel maps". Each bit of the tunnel map represents the presence or absence of image 1 at positions separated by a predetermined interval r. If the tunnel map is 00101001, it means that the image appears at positions x _wi =3r, 5r, 8r.

Real-time lighting timing is obtained using the train map and tunnel map by relatively moving two bit combinations at a rate proportional to the vehicle speed, proportional to the ratio of the predetermined distance d to the predetermined interval r, so that when the corresponding window and image 1 are relative to each other The corresponding bits of adjacent time tunnel graph and train graph are consistent. The corresponding image is illuminated when this coincidence occurs. This is achieved by moving the tunnel graph along the shift register with a predetermined shift timing _ts given by the following equation:

t _s =(r/d)T (2)

The tunnel map transforms each bit position of the shift register into the corresponding image 1. For the corresponding image 1 the bits of the shift register are transferred to the control lines 4 using a tunnel diagram. The bits of the shift register at the bit positions representing the appearance of image 1 in the tunnel diagram are used as control signals and connected to the corresponding control lines 4 corresponding to image 1 .

Therefore, the control pulses are automatically generated on the control line 4 at the correct timing using a shift register in real time. A shift register is the preferred way to do this because it can obtain the timing with a minimum amount of processing power, and does not need to calculate and store all timings at the initial step for all images and windows. Simultaneous supply of control signals to different images 1 can also be controlled because the bits are fed parallel to each other along the different control lines 4 at the outer edge of the shift register.

The size of the predetermined interval r is the resolution of the window map and the tunnel map. The value of the predetermined interval r can be chosen according to the on-board display requirements and the location of the image display system in question. In general, in order to avoid restricting the positioning of the display unit 2, it is preferred to use a low predetermined spacing r. This has the additional operation of increasing the length of the bit combinations making up the train and tunnel maps, but the microprocessor 8 can still easily handle such long bit combinations.

The control signals output by the microprocessor 8 are fed to the control signal lines 4 through an array of driver circuits 12 designed to level shift the digital control signals to a sufficient level for the control lines 4 .

Each display unit 2 is provided with a capacitive discharge circuit 10 which causes the lighting device to illuminate the image 1 in the display unit 2 . The structure of the capacitive discharge circuit 10 and the lighting device will be described in detail below. Each of the control lines 4 is connected to and triggers the capacitive discharge circuit 10 of an individual display unit 2 .

The display unit 2 is depicted in FIGS. 5 and 6 . A top box 17 formed of a thin steel plate serves as a base of the display unit, which is installed in an arbitrary orientation on an installation surface near a driveway. The open face of the case 17 is covered with a transparent substrate 13 of glass. Image 1 is a transparent painting of the backlight located on the substrate cart 3 . The display unit 2 has a hinged frame 14 supporting a glass transparent cover 15 . The frame 14 (as shown in FIG. 5 ) can be opened to remove the image and insert the image 1 and can also be closed to sandwich the image 1 between the base plate 13 and the cover plate 15 . The capacitive discharge circuit 10 is formed on a printed circuit board 16 which is mounted on a cartridge base 17 . The lighting must be illuminated instantaneously enough to avoid blurring of the displayed image when viewed from the vehicle. In fact, the viewer will perceive the image to move by an amount equal to the speed of the train times the period of illumination, and such movement will blur the image. Therefore, the lighting cycle must be short relative to the speed of the vehicle, preferably on the order of 1 ms or less, more preferably 0.5 ms or 0.1 ms or less.

Despite the brief illumination period, the illumination level must be sufficiently high in order for image 1 to be seen. If the lighting is sufficiently strong relative to ambient light, the image display system will work in any ambient light condition, including daylight. Therefore, choose a lighting intensity high enough for the ambient light of the system used.

In order to meet these requirements, the lighting device preferably consists of at least one xenon discharge lamp 11, although other gas discharge lamps or flash lamps may be used. In this embodiment the lighting device consists of four xenon discharge lamps 11 connected mechanically and electrically to a printed circuit board 16 . Near the periphery of the printed circuit board 16, the discharge lamps 11 are arranged at intervals so that the light generated by the discharge lamps 11 is transmitted through the rear of the image 1. As shown in FIG.

In order to meet the above instantaneous and bright lighting requirements, the capacitive discharge circuit 10 is designed as follows. FIG. 7 shows a circuit diagram of the capacitive discharge circuit 10 . For the sake of clarity, the circuit diagram of FIG. 7 only shows a single discharge lamp 11 , while in fact all the circuit elements shown in dotted lines in FIG. 7 are repeated for each discharge lamp 11 parallel to each other.

Each discharge lamp has two discharge capacitors, specifically a main discharge capacitor C3 and an impact discharge capacitor C2. The main discharge capacitor C3 is actually an electrolytic capacitor (usually 33 to 100 μF, preferably 68 μF) that provides the main discharge energy for the lamp 11 to emit light. The main discharge capacitor C3 has a low internal resistance and is made to withstand high current pulses during discharge. In order to compare the dynamic characteristics of fast-enhanced flash, the surge discharge capacitor C2 is a non-electrolytic small capacitor (preferably 0.1 to 1 μF) and has low internal resistance and inductance. The discharge capacitors C3 and C2 are connected in parallel with the xenon discharge tube 11 .

The control line 4 is connected to the terminal 19 . The control signal from the microprocessor 8 is supplied via terminal 19 to the thyristor TH1 through an optocoupler O1 of conventional type. Thyristor TH1 forms part of a trigger circuit with connected resistor R2, capacitor C4 and transformer T1 in a conventional manner to provide an EHT trigger pulse to discharge lamp 11, thereby triggering the discharge of capacitors C3 and C2 through lamp 11.

The capacitor discharge circuit 10 further includes a charging circuit for charging the discharge capacitors C2 and C3 by an AC240V power supply, and the AC240V power supply is connected to a pair of terminals 18 . The charging circuit includes a bridge rectifier D1 which rectifies the power and applies the rectified DC power to the positive and negative power lines 27 and 28 . The rectified DC power is supplied to the discharge capacitors C2, C3 through a diode D2 and an inductor L1 connected in series with the discharge capacitors C2, C3. Inductor L1 is a conventional fluorescent tube choke. The effect of using this type of inductor is a substantial cost savings as it is much cheaper than any other type of inductor of comparable size.

The switch S1 realized by a bipolar transistor or a MOSFET transistor in the form of a transistor is adopted, and the switch S1 is connected in series with the inductor L1. Switch S1 disconnects discharge capacitors C2, C3 and lamp 11 from the power supply when lamp 11 is activated. Switch S1 is thus switched by supplying a control signal from terminal 17 via a second optocoupler O2, usually of conventional transistor type, to switch S1 when the phase of the control signal supplied to thyristor TH1 is reversed. This prevents the current from the power supply from passing directly through the discharge lamp during lighting of the discharge lamp 11 . Avoiding power duty cycle effects on the output of the flash and preventing the flash 11 from entering harmful modes of operation.

In addition, the bridge rectifier is powered through a resistor R1 and a storage capacitor C1 is connected between the positive and negative power supply lines 27 and 28 . Current limiting resistor R1 and storage capacitor C1 are not necessary for reasons discussed below.

The operation of the capacitive discharge circuit 10 is described below.

After power is applied, current flows through diode D2, inductor L1 and switch S1 to charge discharge capacitors C2, C3 until the voltage prevents current flow through diode D2. Under normal conditions this voltage is in the range of 270V to 400V. This is the quiescent state of the capacitive discharge circuit 10 .

When the control signal is supplied to the control terminal 19, the discharge lamp 11 is triggered, and the charges on the discharge capacitors C2 and C3 are discharged through the lamp 11 to generate the required instantaneous lighting cycle. Of course, all four flashes 11 are triggered simultaneously. During this period, the control signal turns off the switch S1, thereby disconnecting the lamp 11 from the power supply, and the current flowing through the lamp 11 is only the discharge current from the discharge capacitors C2 and C3.

Immediately after removal of the trigger, switch S1 closes and charges discharge capacitors C2 and C3 via inductance L1. Using inductor L1 in the charging circuit has many advantages as follows. The main LC circuit formed by the combination of inductor L1 and discharge capacitors C2 and C3 determines the charging characteristics. The resulting charging curve 20 is shown in FIG. 8 and is characterized by the initial part of the sinusoid. Thus, the charge time to the peak voltage is quick without generating an overcharge current. It is very important to control the charging current because overcharging current can damage the components. Because the charge current is equal to the total capacitance of the discharge capacitors C2 and C3 times the rate of change of voltage, the charge current is proportional to the slope of the charge curve. It can be seen from FIG. 8 that the LC charging curve 20 is approximately linear during charging.

This is quite different from charging in a conventional capacitive discharge circuit through a resistor with RC characteristics. A typical RC charging curve 21 is also shown in FIG. 8 . Compared with the LC charging curve 20, it can be seen that at the beginning of the RC charging curve 21 with the largest slope, the charging time is longer and the maximum charging current is higher. If the charging time of the RC charging curve 21 is shortened by reducing the resistance in the charging circuit, the charging current becomes higher. Thus, using an inductor in the charging circuit can improve the balance of obtaining a fast charging time without generating an overcharging current.

Furthermore, providing an inductor L1 means that the current is limited by the reactance of the inductor L1 rather than by a resistive element, so less energy is consumed.

Further, the use of the inductor L1 allows the energy stored in the inductor L1 to be fed back to the discharge capacitors C2 and C3 to increase the operating voltage of the system as a whole. This will reduce the required size of discharge capacitors C2 and C3 for a given output energy. Since energy is proportional to the capacity of the discharge capacitor, and energy is proportional to the square of the voltage, this allows the use of much smaller capacitors and thus a significant cost savings.

To utilize the energy stored in the inductor in this manner, the charging circuit includes a storage capacitor C1 across the power supply such that the charging circuit is connected in parallel with the series combination of discharging capacitor C2, discharging capacitor C3 and inductor L1. The storage capacitor C1 is a large electrolytic capacitor (preferably 220 μF) whose capacitance is much larger than that of the discharge capacitors C2 and C3. On the contrary, if the storage capacitor C1 is omitted, the discharge capacitors C2 and C3 have a smaller capacitance. Storage capacitor C1 filters the rectified DC supply voltage and provides a filtered peak DC voltage above the RMS supply value.

In operation, the energy stored in the inductor L1 is fed back to the discharge capacitors C2 and C3 during the discharge cycle, which has the effect of faster recovery of the storage capacitor C1 and the discharge capacitors C2, C3, but also enables the energy stored in the discharge capacitors C2 and A higher total voltage is maintained across C3.

In this solution, a current-limiting resistor R1 is set in series with the AC power supply to prevent the surge current of the storage capacitor C1 from being too large during power-on and operation. A small 100 μF capacitor (not shown) may be connected in parallel with the input of the unrectified side of rectifier D1, but is not required.

For the working condition of the flashlight working at high frequency (for example higher than 15Hz), it is better to provide storage capacitor C1 and resistor R1. However, at lower flash rates, it is not necessary to provide storage capacitor C1, which saves costs. In this case, optocoupler O2 is preferably an opto-triac, which turns on the opto-triac and deactivates switch S1. This has the advantage of restarting switch S1 only at the zero crossing of the mains cycle. This provides a soft start and thus does not require a current limiting capacitor C1 which improves energy efficiency.

Various modifications can be made to the capacitive discharge circuit 10 shown in FIG. 7 as follows.

Instead of separate optocouplers O1 and O2, a single optocoupler (either a transistor circuit or an optical triac) is used to both trigger the flash 11 and control the switch S1. Preferably, a single optocoupler is arranged to connect a further charging capacitor (not shown) to the gate of thyristor TH1 when the switch is on, so that the control signal applied to thyristor TH1 generates pulsation. Said further charging capacitor may be connected directly to the control input of switch S1. In this case another resistor is connected in series in the line from the charging capacitor to the thyristor TH1 to give the pulse a suitable time constant. For example, another capacitor and another resistor have a capacitance value of 10nF and a resistance value of 1.5k[Omega], respectively. The other capacitor remains discharged when the optocoupler is on, thereby deactivating switch S1 in the usual manner. For charging, said other capacitor is connected in series with a larger resistor (150 kΩ) between the positive supply line 27 and the negative supply line 28, so that the rectified DC power filtered by the storage capacitor C1 passes through this larger resistor to the other The capacitor charges. The voltage across the other capacitor is preferably limited by eg a Zener diode. The advantage of using pulses to deliver power to the thyristor TH1 is that it is not necessary to maintain the thyristor in its state. Such a modification requires that the common terminal of the transformer T1 should be connected to the negative supply line 28 instead of the cathode of the flash lamp 11 shown in FIG. 7 .

The unfiltered supply voltage, through appropriate diodes and resistors, can be used as an auxiliary power supply for optocouplers O1 and O2 (or a single optocoupler, if a single optocoupler is used) and/or thyristor TH1, thus, It is guaranteed that the devices will never remain latched in the event of a fault in the circuit.

Instead of providing each flashlight 11 with a resistor R2, a capacitor C4 and a transformer T1, a common trigger circuit can be used to trigger the flashlight 11, or all four flashlights 11 can be provided with a common resistor R2 and a capacitor C4 for corresponding transformers. T1 feed.

For safety, large resistors (330 kΩ) can be connected in parallel with the discharge capacitors C2 and C3 and with the storage capacitor C1 to allow the charge stored in these capacitors to leak when the capacitive discharge circuit 10 is disconnected from the power source AC.

Finally, the anode of the additional diode is connected to the node between switch S1 and inductor L1 and the cathode of the additional diode is connected to the positive supply line 27 . Operation of such a diode is only meaningful when the operating frequency becomes higher than expected, in which case the switch is turned off before the capacitor is fully recharged. In this case, such a diode prevents damage to the switch due to overvoltage. This also has the advantage of feeding excess energy from the inductor L1 back to the storage capacitor C1.

The series of pictures 1 may comprise an interlaced sequence of pictures 1 of multiple periods. For example, two sequences representing different motion pictures may be determined alternately along the sequence. Under the control of the microprocessor 8, one of the sequences is allowed to be selectively displayed. This makes it very easy to vary the image shown without having to actually shift the image. For example, to control changes based on the time of day.

Preferably, the microprocessor 8 monitors the illumination rate of each image and cuts off the illumination when the illumination rate falls below a threshold value. The threshold is selected at a relatively low illumination rate that could be hazardous or damaging to spectators on the vehicle, or at a relatively low illumination rate that would cause flickering of the image. In general, there is no universal value for threshold and it varies with flash and ambient light levels, but a typical cutoff is 16 or 20 illuminance per second.

An optional feature that may be added to the system described above is some means of drawing the viewer's attention to an upcoming sequence of images. This optimizes the display and prevents the viewer from missing the beginning of the sequence. One possibility of such a device is to mount a display unit 2 of the above-mentioned type in front of the sequence of images and to display brightly colored or patterned images or attractive images. Another possibility is to place lights in front of the image sequence. The lights can be colored lights or flashing lights. Move the lights perpendicular to each other to create a jet effect. The lights are activated with a control system similar to the display unit 2 described above or a simpler control system that only detects moving trains or signs. In addition, alarm devices that generate sounds, such as those that generate chimes, speech, or music, may be used.

Darkens Image 2 to reduce the visibility of the image when there is no lighting. This will reduce image clutter caused by images that are to some extent visible even when there is no illumination due to, for example, stray light reflections from vehicles. Such slight visibility creates image confusion as the vehicle moves relative to the passing window. A preferred way to darken the image is to make the substrate 13 and/or the cover 15 of the display unit 2 from a blackened material. Alternatively, the image 1 itself can be darkened. When the image 1 becomes darker, the illumination level of the lamp 11 must be increased to compensate.

Other forms of display unit 2 may be used.

Another alternative design of the display unit 2 is shown in FIG. 9 . In this structure, the image 1 is fixed in a closed steel box. The lamp is positioned behind and below the image 1, and the reflector 23 behind the image 1 directs the light from the lamp 11 out through the image 1.

Another alternative design of the display unit 2 is shown in FIG. 4 . The image 2 is mounted on the main surface of the transparent plate 24 . In a housing 25 attached to the lower edge of the plate 24 is housed a lamp 11 which emits light into the edge of the plate 24 .

The image 1 is illuminated by light exiting through the transmission 24 by total internal reflection and emitted through the main surface of the plate 24 . How much light is emitted through the major surface of the etched plate 24 can be controlled. Preferably, etching causes the proportion of incident light emitted relative to the proportion of internal reflection to increase with distance from the lamp, making the absolute amount of light emitted through a given area more uniform. An advantage of using the plate 24 for internal direct light is that the thickness of the mold can be reduced compared to using reflectors.

A shutter shutter is optionally provided to assist in controlling the momentary illumination of the image 1. Such a shutter shutter is shown in Figures 9 and 10, which is located between the lamp 11 and the optical system directing the light from the lamp to the mounted figure, i.e. the reflector in the display unit 2 of Figure 2 26 or the transparent plate 24 in the display unit 2 of FIG. 10 . The shutter shutter 26 is preferably an optical element with controllable transmittance, such as a liquid crystal shutter.

In the display unit 2 of FIGS. 5 and 6 , the shutter is provided by forming the cover plate 15 as an optical element having controllable transmittance, such as liquid crystal. Other types of optical shutters or mechanical shutters can be used.

Set a shutter if the lamp is of the type that is difficult to turn on and/or off quickly by controlling the power supply alone. For example, gas discharge elements have been developed to maximize their efficiency and minimize power consumption, but it is still difficult to accurately control the start and stop of light emission. The illuminance level has a distinct rise or fall time. It is also impossible to cut off the driving voltage of the capacitor discharge immediately. This makes it difficult to limit the lighting duration. These problems can be avoided by using a shutter. Opening the shutter can activate the lighting device, closing the shutter can turn off the lamp and/or lighting device that was previously switched on, and consequently cut off the light. The shutter may cut off the illumination during at least part of the rise time or fall time of the illuminance, so as to provide illumination only at the highest illuminance. The opening and closing of the shutter is controlled by a control signal with precise timing for the illumination.

In addition, the display allows selection of different images for display. For example, a plurality of images 1 are printed on an endless cylinder, and the cylinder can rotate around a track defined by a roller (roller), thereby selectively placing any one of the images 1 on a possible position on the front surface of the display unit 2. Depending on the position, the scroller (scroller) used in the stage lighting system to change the color of the color filter in front of the lamp is adopted.

Another alternative is for the front surface of the display unit 2 to be formed by a controllable LCD display displaying selectable images 1 . This would have the advantage of avoiding the need to actually change the installed image. Preferably, but not necessarily, the above described LCD display is combined with a backlight. The cost of LCD displays is currently prohibitive, but the system is technically feasible and the cost is likely to drop to an acceptable level.

Another alternative is to use front-lit posters. However, it is better to use backlighting, because in the unlit state, backlit transparencies reflect less ambient light and are darker than posters, especially outdoors. This means that the transparent picture of the non-luminous backlight is almost invisible and does not affect the viewed image.

Instead, an optical system may project a small backlit image onto the surface of the display unit as a screen. This also has the advantage that the image is not visible at all when the lighting is switched off and the image can be easily changed. However, optical systems of satisfactory quality are expensive and difficult to obtain images of satisfactory quality.

Claims (18)

1. graphical presentation system comprises:

A series of in the tunnel along the image of track configurations of vehicle with series of windows;

Instantaneous each visual light fixture that illuminates; And

A control module, when vehicle by the time control described image light fixture illuminate image continuously, wherein this control module comprises:

The detector assembly that detection vehicle arrives;

Obtain the device of vehicle speed measurement value;

The device of each position of window of storage and/or acquisition vehicle;

Control the device of described light fixture, described control device is considered car speed and each position of window of vehicle, the detection that the response vehicle arrives is controlled described light fixture and is repeated to illuminate each single image, illuminates this image during with the position consistency of the position of box lunch image and vehicle window

It is characterized in that

In described control module, use the position existence that is illustrated in the predetermined space of being separated by or do not exist the vehicle figure of window to represent the vehicle position of window, exist or do not exist the tunnel figure of image to represent described each position of image with the position that is illustrated in the predetermined space of being separated by, the described device that is used to control described light fixture is configured to draw in real time by be shifted toward each other with the speed that is directly proportional with the resultant speed of a motor vehicle vehicle and tunnel figure the timing of each image of illumination, and it is visual to throw light on when window is consistent with position of image.

2. graphical presentation system as claimed in claim 1, wherein detector assembly is configured to detect the mark on the vehicle, and mark is to encoding along each position of window of vehicle and control module comprises the output of detector assembly decoded and obtains the device of the window's position.

3. graphical presentation system as claimed in claim 2, wherein decoding device is configured to by the storage list of searching the different group windows of storage position the output of detector assembly be decoded.

4. as the described graphical presentation system of the arbitrary claim in front, wherein control module is configured to detect mistiming in the output of described detector assembly as the measured value of the described speed of a motor vehicle.

5. graphical presentation system as claimed in claim 1, wherein

Described vehicle figure comprises that first bit pattern and described tunnel figure comprise second bit pattern, the described device that is used to control described light fixture is configured to by the incompatible timing that draws each image of illumination in real time of be shifted toward each other with the speed that is directly proportional with the resultant speed of a motor vehicle first bit pattern and second hyte, and it is visual to throw light on when the position of second bit pattern of presentation image is consistent with the position of first bit pattern of expression the window's position.

6. graphical presentation system as claimed in claim 5, wherein said control module is configured to by shift register described first bit pattern is shifted, use second bit pattern that the bit location of shift register is transformed to described a plurality of image, control the illumination of corresponding image at the bit location place of shift register carry-out bit.

7. as the described graphical presentation system of the arbitrary claim in front, the device that wherein is used for controlling described light fixture is configured to illuminate sequential image so that they appear at the same position of each window.

8. as the described graphical presentation system of arbitrary claim of claim 1 to 6, the device that wherein is used for controlling described light fixture is configured to illuminate sequential image so that they appear at the gradual change position of each window.

9. any described graphical presentation system as claim 1 to 6, the device that wherein is used to control described light fixture is configured to illuminate the image of a plurality of positions of a series of images, so that the image of each part appears in each window on the same position different with the position of the image of other parts.

10. as the described graphical presentation system of the arbitrary claim in front, wherein image is the transparency of back illumination.

11. as the described graphical presentation system of the arbitrary claim in front, wherein light fixture comprises the control signal by described control module at least one discharge lamp that triggers and the capacitive discharge circuits of lighting at least one lamp that is used for each image.

12., comprise further that in advance notice with spectators is attracted to the device on the image series as the described graphical presentation system of the arbitrary claim in front.

13. one kind as the described graphical presentation system of the arbitrary claim in front, wherein said light fixture comprises and is used for each visual flashlamp that described control module comprises a capacitive discharge circuits that is used for each flashlamp, comprising:

At least one discharging capacitor is used for stored charge;

A flashlamp;

Trigger circuit are configured to trigger at least one capacitor discharge by flashlamp; And

A charging circuit that is used at least one discharging capacitor, this charging circuit are configured to give at least one discharging capacitor charging by the inductor of connecting with at least one discharging capacitor.

14. graphical presentation system as claimed in claim 13, wherein the trigger pip that also will be applied on the trigger circuit by photo-coupler is supplied with a switch, described switch be provided at least one discharging capacitor discharge during with at least one discharging capacitor and charging circuit disconnection.

15. graphical presentation system as claimed in claim 14, wherein photo-coupler is a light TRIAC.

16. the described graphical presentation system of arbitrary claim as claim 13 to 15, wherein discharge circuit comprises at least one holding capacitor, the electric capacity of described holding capacitor is bigger than the capacity of described at least one discharging capacitor, and the assembled in series of described holding capacitor and described at least one discharging capacitor and described inductor is in parallel.

17. the described graphical presentation system of arbitrary claim as claim 13 to 16 is characterized in that being powered to charging circuit by the AC power supplies of rectification.

18., it is characterized in that inductor is a fluorescent tube choking coil as the described graphical presentation system of arbitrary claim of claim 13 to 18.

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