Display device

Abstract

To provide a display device with which a display part and a least necessary control part can be arranged inside of a double-glazing glass part contributing to excellent esthetic appearance, and the housing of the display part can be dispensed with, helping reduce the weight.SOLUTION: A display device 10 comprises: a thin-profile display part 12 for displaying a video based on display command signals related to the destination of a vehicle that includes a double-glazing glass part 8 having a hollow layer 8a; a first control part 16 including an LCD drive part that receives display command signals and outputs video signals for displaying a video on the display part 12; and a second control unit 14 including a PWM signal generation part that outputs PWM signals for adjusting the brightness of the video displayed on the display part 12, on the basis of video signals transmitted from the first control part 16. The display part 12 and the second control part 14 are arranged inside of the hollow layer 8a of the double-grazing glass part 8, and the first control part 16 is provided at a place away from the double-grazing glass part 8 in the vehicle interior and is electrically connected to the second control part 16 by a cable part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a display device.

Background Art

[0002] Conventionally, in trains, buses, etc., there have been installed destination indicators for displaying destinations, guidance indicators for displaying stopping stations, advertisement indicators for displaying advertisements, fare indicators for displaying fares, and the like. In recent years, with the spread of thin display devices such as liquid crystal panels, digitization has advanced in these indicators.

[0003] As a technology related to the present invention, for example, Patent Document 1 discloses a display device including a liquid crystal panel, a backlight, and a control device for controlling the liquid crystal panel and the backlight, wherein the control device lights the backlight in a time period when the light transmittance of the liquid crystal panel is changed, with a lighting pattern having N (N is an integer of 2 or more) levels of light emission intensity levels from a first level to an Nth level.

[0004] Further, Patent Document 2 discloses a multilayer glass with a display, which has a glass plate, a transmissive display panel provided on one surface of the glass plate, a light guide plate made of glass disposed opposite to the transmissive display through a hollow layer with respect to the glass plate, and a light source provided at an outer peripheral edge of the light guide plate made of glass.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the invention of Patent Document 1 described above, there is a problem that the display control unit and the display unit cannot be installed at separate locations away from each other and must be integrated. Further, in Patent Document 2, there is a problem that a specific configuration and method for installing the display control device outside are not described.

[0007] An object of the present invention is to provide a display with excellent design. Another object of the present invention is to provide a display that contributes to weight reduction.

Means for Solving the Problems

[0008] A display device installed in a vehicle such as a train or a bus according to the present invention is provided in a vehicle including a multilayer glass part having a hollow layer, and includes a thin display part that displays an image based on a display command signal, an LCD drive part that receives the display command signal and outputs a video signal for displaying the image on the display part, and a first repeater part that amplifies the voltage level of the video signal, a first control part that is hardly affected by noise, a second repeater part that receives the video signal transmitted from the first control part and stabilizes the voltage level, and a PWM signal generation part that outputs a signal for dimming at a frequency that does not interfere with the frequency of the video signal, and a second control part that is easily affected by noise. A power supply unit that supplies power to the first control unit and the second control unit, and a cable unit that electrically connects the first control unit and the second control unit, is provided with, the display part and the second control part are arranged in the hollow layer of the multilayer glass part, and the first control part and the power supply unit is , the provided away from the multilayer glass part described above in a location within the vehicle provided where, The cable part includes a shield wire connected to the ground of the substrate on which the first control part and the second control part are arranged. it is noted that the PWM signal output by the PWM signal generation unit is controlled to a frequency that does not interfere with the frequency of the video signal characterized by this.

Effects of the Invention

[0012] According to the present invention, since the display unit and the minimum necessary control unit can be arranged within the multi-layer glass unit, a display device with excellent design can be achieved. Further, when mounted on a moving body such as a train or a bus, the housing that has hitherto housed the display can be eliminated, contributing to weight reduction.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the following, the same reference numerals are given to the same elements in all the drawings, and redundant explanations are omitted. Also, in the description in the text, the reference numerals described above will be used as necessary.

[0015] FIG. 1 is a diagram showing a state where the display device 10 according to an embodiment of the present invention is installed in a vehicle. The multi-layer glass unit 8 is, for example, a vehicle window or a display installed in the vehicle, and displays images and still images such as destinations, stations, advertisements, fares, etc. FIG. 2 is a configuration diagram of the display device 10.

[0016] FIG. 3 is a diagram showing a state where the first control unit 16 and the second control unit 14 are connected by the cable unit 40 in the display device 10.

[0017] The display device 10 includes a display unit 12, a second control unit 14, a first control unit 16, and a power supply unit 18. The display unit 12 is installed inside the multilayer glass unit 8 having the hollow layer 8a, and is a thin display device that displays an image based on a display command signal including information indicating the vehicle position and information regarding the luminance level of the display.

[0018] The multilayer glass unit 8 is composed of glass plates having opposing first main surfaces and second main surfaces, and a hollow layer 8a filled with dry air is formed between the first main surface and the second main surface. By enclosing dry air to enhance the heat insulation effect, dew condensation is suppressed, and a sound insulation effect is also provided. Here, the thickness of the hollow layer 8a is described as being set to 16 mm, but of course, it can be appropriately changed.

[0019] The glass plates constituting the first main surface and the second main surface include ordinary glass plates, tempered glass plates, partially tempered glass plates, etc. used for vehicle window glass. These glass plates may be colored to such an extent that their transparency is not impaired. The glass plate is preferably, for example, a glass plate manufactured by a known float method, but of course, it may be formed by other methods.

[0020] The display unit 12 includes a liquid crystal panel unit 20 and a backlight unit 22. In the liquid crystal panel unit 20, a plurality of pixels (display elements) are arranged in a matrix along each of the vertical direction and the horizontal direction. The liquid crystal panel unit 20 includes a liquid crystal layer (not shown). Further, the liquid crystal panel unit 20 may include a color filter (not shown).

[0021] The backlight unit 22 has a function of irradiating the liquid crystal panel unit 20 with light such as white light. The backlight unit 22 is disposed on the back side of the liquid crystal panel unit 20 so as to overlap the liquid crystal panel unit 20.

[0022] The backlight unit 22 has a plurality of LEDs as light sources. A diffusion sheet for diffusing the light emitted from the LEDs may be provided in the backlight unit 22. By controlling the light emission intensity of the LEDs, the light emission intensity of the light emitting surface of the backlight unit 22, that is, the light emission state of the backlight unit 22 can be controlled.

[0023] The first control unit 16 includes a first repeater unit 32, an external I / F 34, an LCD drive unit 36, a video signal control unit 37, a backlight control unit 38, and a CFCARD 39. The frequencies of the video signal output by the LCD drive unit 36 (the frequency of the horizontal synchronization signal and the frequency of the vertical synchronization signal) and the frequency of the PWM signal output by the PWM signal generation unit 28 are controlled to frequencies that do not interfere with each other.

[0024] The first repeater unit 32 has a function of amplifying the voltage level of the video signal. The first repeater unit 32 receives the input video signal and outputs a waveform conforming to the LVDS standard. Here, the first repeater unit 32 amplifies and outputs the voltage level at ±250 mV or more so that the received voltage of the second repeater unit 24 becomes ±100 mV or more conforming to the LVDS standard.

[0025] The external I / F 34 is an interface circuit that acquires a display command signal transmitted from the upper system. The display command signal transmitted from the upper system includes information regarding the luminance level ("bright", "dark", "OFF") and vehicle position information, etc.

[0026] The LCD drive unit 36 outputs a video signal for displaying a video related to the destination of the vehicle, etc. on the display unit 12. The frequency of the video signal output by the LCD drive unit 36 is such that the vertical synchronization signal is about 60 Hz and the horizontal synchronization signal is several tens of kHz. On the other hand, the frequency of the PWM signal output by the PWM signal generation unit 28 is controlled to several hundreds of Hz that does not interfere with these.

[0027] A display command signal including information regarding the image data to be displayed by the display unit 12 and information regarding the luminance level is input to the LCD drive unit 36 via the external I / F 34.

[0028] Based on the display command signal, the LCD driving unit 36 reads the display data to be displayed from the CFCARD 39 and generates a video signal. The video signal is a vertical synchronization signal and a horizontal synchronization signal for controlling the display timing of the liquid crystal panel unit 20.

[0029] When the video signal control unit 37 receives the Enable signal output from the video signal control unit 25 on the second control unit 14 side, it turns on the power of the first repeater unit 32. After switching the power of the first repeater unit 32 from ON to OFF, it outputs a video signal for display to the second control unit 14.

[0030] The backlight control unit 38 has a function of setting the brightness level ("bright", "dark", "OFF") of the backlight unit 22 based on the display command signal transmitted from the upper system. It receives the display command signal from the upper system via the external I / F 15, generates information regarding the brightness level, and transmits it to the second control unit 14.

[0031] The CFCARD 39 stores display data such as videos and still images to be displayed on the display unit 20.

[0032] The second control unit 14 includes a second repeater unit 24, a video signal control unit 25, a backlight control unit 26, a PWM signal generation unit 28, and a backlight power supply unit 30.

[0033] The second repeater unit 24 receives the video signal attenuated to near ±100 mV compliant with the LVDS standard output from the first control unit 16, stabilizes it to ±100 mV, and outputs it to the liquid crystal panel unit 20.

[0034] When the power of the second control unit 14 is turned on, the initialization of the video signal control unit 25 starts. When the initialization is normally completed, it transmits an Enable signal to the first control unit 16 and has a function of turning on the power of the second repeater unit 24.

[0035] The backlight control unit 26 has a function of receiving the information of the brightness level set by the backlight control unit 38 of the first control unit 16 and setting the duty ratio of the PWM signal generation unit 28. Note that the backlight unit 22 is dimmed by the duty ratio of the PWM signal.

[0036] The PWM signal generation unit 28 outputs a PWM signal, which is a dimming control signal for adjusting the brightness of the video displayed on the display unit 12 based on the video signal transmitted from the first control unit 16. The brightness of the video displayed on the display unit 12 is adjusted by the PWM signal generated by the PWM signal generation unit 28.

[0037] The frequency of the PWM signal output by the PWM signal generation unit 28 is controlled to a frequency that does not interfere with the frequency of the video signal (the frequency of the horizontal synchronization signal and the frequency of the vertical synchronization signal) output by the LCD driving unit 36. The PWM signal is a PWM signal with a duty ratio set for driving the backlight unit 22.

[0038] The PWM signal generation unit 28 generates a PWM signal based on the information indicating the brightness level received from the backlight control unit 26. The PWM signal is a signal for the backlight power supply unit 30 to drive the LEDs of the backlight unit 22.

[0039] The backlight power supply unit 30 is connected to a plurality of LEDs of the backlight unit 22 and has a function of controlling the output of each LED based on the PWM signal transmitted from the PWM signal generation unit 28.

[0040] The power supply unit 18 supplies power to the first control unit 16 and the second control unit 14 and is provided at a location away from the multilayer glass unit 8. The power supply unit 18 includes a DC / DC converter that boosts or buck-boosts a DC power supply to a desired voltage. The stabilized DC power supply is supplied to the first control unit 16 and the second control unit 14 by the power supply unit 18.

[0041] The display unit 12 and the second control unit 14 are disposed in the hollow layer 8a of the multilayer glass unit 8. The display unit 12 is directly attached and mounted on the first main surface located on the outer side of the vehicle window so that, for example, an image such as the destination of the vehicle can be visually recognized from the outside of the vehicle. The second control unit 14 is attached to the multilayer glass unit 8 in the vicinity of the display unit 12.

[0042] The first control unit 16 is provided at a location away from the multilayer glass unit 8 inside the vehicle and is electrically connected to the second control unit 14 by the cable unit 40. In the installation environment of a railway vehicle used as a public transportation vehicle, generally, the cable unit 40 often requires a cable length of 10 m or more.

[0043] The cable unit 40 includes a shielded wire connected to the ground of the substrate on which the first control unit 16 and the second control unit 14 are disposed. Here, the communication interface for transmitting signals via the cable unit 40 is the LVDS standard (EIA / TIA-644), and the data format is described as the standard format (JEIDA-59-1999) for the digital interface of flat panels such as liquid crystal displays. Of course, it is also applicable to other standards.

[0044] As shown in FIG. 3, the cable unit 40 is composed of STP (Shielded Twisted Pair), and the shielded wire is connected to the SG (Signal Ground) of the substrates of both the first control unit 16 and the second control unit 14, strengthening the SG between the devices. Each SG is connected to the SG (ground) plane of the inner layer of the substrate.

[0045] Subsequently, the operation of the display device 10 having the above configuration will be described. FIG. 4 is a flowchart showing the procedure for displaying an image on the display unit 12.

[0046] First, in the second control unit 14, when the power supply of the video signal control unit 25 is turned on (S2), initialization is started (S4), and the state of the DIN is checked (S6). Here, DIN is an abbreviation for Digital Input input from the first control unit 16, and it is setting information of the luminance level (three levels of bright, dark, and OFF).

[0047] After the step of S6, it is determined whether the luminance level is in either the "bright" or "dark" state (S8). In the step of S8, when the luminance level cannot be confirmed, that is, in the "OFF" state, after a predetermined time has elapsed, the process returns to the step of S6 again.

[0048] In the step of S8, when it is determined that the luminance level is in either the "bright" or "dark" state, in the PWM signal generation unit 28, a PWM signal is output (S10). At this time, it is output at a duty ratio corresponding to the setting of the luminance level ("bright" or "dark").

[0049] After the step of S10, an Enable signal is output to the first control unit 16 (S12). Then, the power supply of the first repeater unit 32 that functions as a video repeater is turned on (S14). Thereby, the video signal amplified by the first repeater unit 32 of the first control unit 16 is output to the second repeater unit 24 of the second control unit 14.

[0050] After that, the power supply of the second repeater unit 24 is turned on (S16), and the second repeater unit 24 outputs the video signal amplified and transmitted from the first repeater unit 32 to the display unit 12 in a stabilized manner.

[0051] After the step of S16, an Enable signal is output to the backlight power supply unit 30 (SS18), and based on the PWM signal transmitted from the PWM signal generation unit 28, each LED is controlled and the video is displayed on the liquid crystal panel unit 20 (S20).

[0052] Thus, according to the display device 10, the control unit for controlling the display unit 12 is divided into a first control unit 16 and a second control unit 14. The second control unit 14, which is susceptible to noise, is arranged near the display unit 12 to minimize the influence of noise, and the first control unit 16, which is less susceptible to noise, is installed at a position away from the display unit 12. Also, the power supply unit 18 can be installed at a location away from the display unit 12 and the second control unit 14.

[0053] In this way, by minimizing the control functions arranged near the display unit 12 and making it smaller, the display unit 12 and the second control unit 14 can be installed in the hollow layer 8a of the multilayer glass unit 8, thus achieving a remarkable effect of contributing to the improvement of visibility and design. Also, by installing the display device 10 in a moving body such as a train or a bus, the housing that used to house the display can be eliminated, thus contributing to weight reduction.

[0054] Since the first control unit 16 and the second control unit 14 are divided, by providing both with the control unit for video signal / backlight, it is constantly checked whether there is an abnormality in either the first control unit 16 or the second control unit 14.

[0055] Also, since the display unit 12 and the second control unit 14 are enclosed in the multilayer glass unit 8, there is no risk of short circuit caused by iron powder, dust, etc., and there is no need to apply a coating material, etc., which has cost advantages.

[0056] As described above, the first control unit 16 and the second control unit 14 are divided and are connected by a cable unit 40 having a cable length of 10 m or more. Generally, the voltage drops along with the length of the cable, but since the video signal output from the LCD driving unit 36 of the first control unit 16 has its voltage level amplified by the first repeater unit 32, it is designed so that data can be received on the second control unit 14 side.

[0057] Furthermore, instead of directly inputting the video signal amplified by the first repeater unit 32 into the liquid crystal panel 20, the voltage level is stabilized in the second repeater unit 24 within the second control unit 14 and then input into the display unit 12. As a result, a clean waveform can be input, enabling a clean video to be displayed.

[0058] Also, although there is concern about the influence of noise due to the cable length being 10 m or more, the cable section 40 adopts an STP cable, and the shield wire is connected to the substrates within the first control unit 16 and the second control unit 14, thereby strengthening the SG (Signal Ground), so that the influence of noise can be suppressed to the maximum extent.

[0059] Note that, as described above, the display device 10 is, for example, a destination display device that displays a video related to the destination of a vehicle, but it may also display other content, such as a guidance display device for displaying the stops of trains or buses, a fare display device for displaying the fare, or an advertisement display device for displaying advertisements using videos.

Explanation of Reference Numerals

[0060] 8 Multi-layer glass section, 8a Hollow layer, 10 Display device, 12 Display unit, 14 Second control unit, 16 First control unit, 18 Power supply unit, 20 Liquid crystal panel unit, 22 Backlight unit, 24 Second repeater unit, 25 Video signal control unit, 26 Backlight control unit, 28 PWM signal generation unit, 30 Backlight power supply unit, 32 First repeater unit, 36 LCD drive unit, 37 Video signal control unit, 38 Backlight control unit, 39 CFCARD, 40 Cable section.

Claims

【Claim 1】 A thin display unit provided in a vehicle including a multi-layer glass part having a hollow layer, for displaying an image based on a display command signal; an LCD drive unit that receives the display command signal and outputs a video signal for causing the display unit to display the image, and a first repeater unit that amplifies the voltage level of the video signal, and a first control unit that is less affected by noise; a second repeater unit that receives the video signal transmitted from the first control unit and stabilizes the voltage level, and a PWM signal generation unit that outputs a signal for dimming at a frequency that does not interfere with the frequency of the video signal, and a second control unit that is easily affected by noise; a power supply unit that supplies power to the first control unit and the second control unit; a cable unit that electrically connects the first control unit and the second control unit; characterized by comprising; the display unit and the second control unit are disposed in the hollow layer of the multi-layer glass part; the first control unit and the power supply unit are provided at a location inside the vehicle away from the multi-layer glass part; the cable unit includes a shield wire connected to the ground of the substrate on which the first control unit and the second control unit are disposed, and the PWM signal output by the PWM signal generation unit is controlled to a frequency that does not interfere with the frequency of the video signal. A display device.

Images