JPH06165226A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To easily attain check in a short time. CONSTITUTION:This device is equipped with a display part 30, signal electrode driving device 4, and scanning electrode driving device 6. A clock output part and a sampling (picture element) outputting part at the final stage of the signal electrode driving device 4 are equipped with the capturing parts of information A and B, and the clock outputting part of the final stage of the scanning electrode driving device 6 is equipped with the capturing part of information E. Moreover, the capturing part of the information C of the outputting part of a transistor 31, the information D of the gate driving signal output part, and the information F of the voltage output of an entire face transparent electrode 30b is provided at the final driving position of a display part 30. Those information is guided to a fault diagnosing circuit 24 so that a diagnosis from all angles can be quickly attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device which is effective for use in an image display system in which an individual passenger can see an image by disposing a display portion in each seat portion of a passenger plane or a train.

[0002]

2. Description of the Related Art A liquid crystal display device using a liquid crystal display panel is smaller, lighter, and lower in power consumption than a cathode ray tube display device, and a device having a display surface of about 4 to 6 inches is an aircraft, car, or train. Etc. In addition, trains and passenger planes have been developed in which a large number of passenger seats are equipped with these liquid crystal display devices so that individual passengers can enjoy image display. Individual passengers can enjoy video software tailored to their personal tastes during long trips, contributing to improved service for passengers.

By the way, when these display devices are provided in each seat, the work of maintenance and inspection of these seats imposes a great burden on maintenance personnel. In the case of a display device that can be stored in a seat or the like, maintenance personnel take it out, operate the switch, check the image to see if there is any abnormality, and store it at the end.
The more seats there are, the more labor and time this work will take.

[0004]

A train in which a liquid crystal display device is arranged in each of a plurality of seats to provide a service,
Passenger aircraft require a great deal of labor and time for maintenance and inspection. Therefore, an object of the present invention is to provide a liquid crystal display device that can be easily checked in a short time.

[0005]

According to the present invention, signal electrodes and scanning electrodes are provided in a matrix form in the vertical and horizontal directions, and a display portion in which a display element is provided at an electrode intersection and the signal electrodes in the vertical direction are provided. A signal electrode driving device that supplies a signal, a scanning electrode driving device that supplies a scanning signal to the scanning electrodes in the lateral direction, and at least a driving signal at each final stage of the signal electrode driving device and the scanning electrode driving device is detected and derived. And a means for outputting self-diagnosis information.

[0006]

According to the above means, since the device itself can output the diagnosing information, the function of accurately checking the normal state of the device can be enhanced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention and shows a configuration of one system (for example, in a seat portion) mounted on a train, an airplane or the like.

Reference numeral 11 is a tuner circuit, which is a C in the aircraft.
A television signal from the RF cable of the ATB system can be used as an input to select a specific frequency channel. The signal of the tuner circuit 11 is supplied to the RF circuit 12. The RF circuit 12 detects a high frequency signal of a specific channel and converts it into a video signal. The video signal output from the RF circuit 12 is input to the video signal processing circuit 13. The video signal processing circuit 13 separates the input video signal into a luminance signal and a color signal, performs image quality adjustment, gain control, etc., and outputs the three primary color video signals R, G, B and the horizontal synchronizing signal HD,
The vertical synchronizing signal VD is output.

The output of the video signal processing circuit 13 is supplied to the polarity switching and drive circuit 14. The circuit 14 functions to make the input video signal correspond to a level and amplitude suitable for writing liquid crystal. Specifically, the first
In the normally white liquid crystal with negative display, the input video signal is inverted. Second, it amplifies about 3 times. Thirdly, the voltage shifts to the high voltage side by about 2V. Fourth, for the purpose of AC driving for the purpose of preventing deterioration of the liquid crystal, a certain voltage is inverted every horizontal scanning period or vertical scanning period. Fifth, in the liquid crystal panel, a load having a relatively large capacity is used, so current amplification is performed.

The liquid crystal display section 15 is driven by the polarity switching and drive circuit 14. The liquid crystal display unit 15 is
Twisted nematic liquid crystal is sandwiched between two glasses at intervals of several μ, and is twisted by 90 ° by an alignment film.
The liquid crystal display unit 15 outputs diagnostic information for confirming its normal operation and gives it to the failure diagnosing circuit 24 (specifically described later).

Reference numeral 21 denotes a local area network (LAN) controller, which is a circuit for bidirectional communication with a host computer in the aircraft. This is CA
It may be connected to a LAN cable provided independently of the TV RF coaxial cable, or the same cable may be used by multiplexing a signal on the LAN with a television signal.

22 is a microprocessor, LAN
A signal from the controller 21 is introduced. A keypad and a remote control device 23 are connected to the microprocessor 22. Keypad and remote control device 2
3 is an interface between a person and this system.
By operating the keypad and remote control device 23, in addition to program selection and volume adjustment, various orders for in-flight services, personal computer game operations, information retrieval such as news and tourist information, and offices such as word processors Automation (O
A) You can receive equipment services.

Further, the microprocessor 22 also has a function of fetching the diagnosis result from the failure diagnosis circuit 24 and transmitting it to the central host computer via the LAN controller 21.

An on-screen circuit 25 is composed of an image memory, a graphic controller, etc., and supplies its output display signal to the video signal processing circuit 13 under the control of the microprocessor 22. This has the function of displaying characters on the TV screen and displaying an information screen. It is also possible to output a failure detection reference signal and a timing signal according to a program from the microprocessor 22.

Reference numeral 26 is a power supply circuit, and 27 is a backlight using a small fluorescent tube or the like, which is arranged on the back side of the liquid crystal display unit 15 and serves to illuminate the transmissive liquid crystal panel. Power supply circuit 2
6 is a high voltage A for lighting the fluorescent tube from a low voltage DC
Generate a C voltage. If the backlight 27 becomes unlit due to the life of the backlight, current will not flow to the fluorescent tube,
This information is provided to the microprocessor 22 as the current becomes unstable. FIG. 2 specifically shows the relationship between the liquid crystal display unit 15 and the information acquisition unit of the failure diagnosis circuit 24.

The liquid crystal display unit 15 has a display unit 30. The display unit 30 is provided with signal electrodes and scanning electrodes in a matrix in the vertical and horizontal directions, and display elements are provided at the electrode intersections. In the figure, about 200 to 500 signal electrodes are provided with symbols 1 (1) to 1 (2n), and scanning electrodes are provided with 2
The symbols (1) to 1 (m) are attached. Also, the signal electrode 1
The display element 3 at the intersection of (2) and the scanning electrode 2 (3) is shown as a representative. The display element 3 is a thin film transistor (TF).
T) and other active elements, and a unit pixel portion formed by sandwiching liquid crystal between transparent electrodes. When current flows simultaneously in the vertical and horizontal electrodes to which the active element is connected, the active element turns on,
The liquid crystal of the unit pixel is driven.

A signal electrode driving device 4 for supplying a video signal to the vertical signal electrodes 1 (1) to 1 (2n) is provided. Further, a scan electrode driving device 6 that supplies a scan signal to the horizontal scan electrodes is provided. The signal electrode driving device 4 includes shift registers 41a and 41b connected in series so as to have the number of horizontal pixel stages, and a sampling hold circuit S (1) for sampling and holding a video signal at each stage.
~ S (2n) and this sampling and holding circuit S (1) ~ S
It is composed of gate circuits G (1) to G (2n-1) which are three-state buffer circuits which simultaneously apply the holding signal of (2n) to the signal electrodes at the timing of the output instruction signal. However, the output B of G (2n) is used for another purpose described later. When the start pulse synchronized with the horizontal synchronizing signal is given to the shift registers 41a and 41b, they are sequentially shifted to the right from the first stage based on the clock. As a result, a sampling pulse is generated from each stage, and the video signal is sampled in the sampling hold circuits S (1) to S (2n) provided corresponding to each stage. When the sampling up to the final stage is completed,
The clock A at the final stage is obtained. Next, in order to output the pixel signals of the sampling hold circuits S (1) to S (2n) to the vertical signal electrodes all at once, output instruction pulses are given to the gate circuits G (1) to G (2n). Then, a pixel signal is output to each signal electrode, and the display element at a portion intersecting with the driven scanning electrode is turned on according to the pixel signal. At this time, the pixel signal B sampled at the end is output from the gate circuit G (2n).

The scan electrodes 2 (1) to 1 (m) are driven by the scan electrode driving device 6. A start pulse synchronized with the vertical synchronizing signal is supplied to the shift register 42, and transfer is performed with a clock synchronized with horizontal scanning. A drive voltage is output to the scan electrode corresponding to this transfer stage. As a result, the written pixel is displayed from the signal electrode.

Here, the display unit 30 includes signal electrodes 1 (1) -1
(2n), scan electrodes 2 (1) to 2 (2n), an array substrate 30a provided with a display element FET group, a counter substrate 30b provided with a transparent electrode on the entire surface, and a liquid crystal between the substrates. However, the following configuration is also added.

That is, on the array substrate 30a, the FE is provided at the intersection of the signal electrode 1 (2n) and the scanning electrode 2 (m-1) which is the final stage.
The source and gate of T31 are connected, and when this position is in the drive state, the drain output C of the FET 31 can be taken out. This part is the lower right corner on the screen and is outside the display area. Also, the output D of the final scan electrode applied to the gate of the FET 31
Can also be taken out. Furthermore, the transfer output E at the final stage of the scan electrode driving device 6 and the counter substrate 3
The transparent electrode F of 0b can also be taken out.

As described above, the liquid crystal display unit 15 can obtain the above-mentioned signals A to F (that is, diagnostic information) from various positions in order to grasp various operating conditions. This information is input to the failure diagnosis circuit 24 shown in FIG.

In the failure diagnosing circuit 24, whether or not the above-mentioned diagnostic information A to F each have a preset value,
It also determines whether it is timing and gives the result to the microprocessor. For example, when the information A is normally obtained, the signal electrode scanning device 4 is normally performing clock generation up to the final stage. When the information B is normally obtained (for example, the potential indicating the clamp level)
When, it means that the output instruction is normally performed and the sampling is normally operating. Further, when the information C and D are obtained, it means that the signal electrode and the scan electrode at the final stage are normally driven, and only one of them (C or D)
Is not obtained, it means that the signal electrode or the scan electrode is abnormal. Further, if the information E is obtained normally, it means that the scan electrode driving device 6 is operating normally. The information F is a material for determining whether or not a normal voltage is applied to the transparent electrode.

As a result, in the system shown in FIG. 1, the self-diagnosis result information of the liquid crystal display unit 15 and the power supply information are provided to the microprocessor 22. Therefore,
If this information is transmitted to the central monitoring unit inside the aircraft via the network, it can be easily determined whether the liquid crystal display system installed in many seats is normal, and the labor and time of the maintenance personnel can be greatly reduced. Is reduced to.

The timing for transmitting information to the host computer in the central center may be such that the microprocessor 22 outputs it when a data request is made from the host computer side via the LAN controller 21. From time to time, if a failure is found, its address (eg seat position) will be sent to the host computer.
May be transmitted.

Further, as the diagnostic information, the liquid crystal display unit 15 is used.
Not only those related to the above, but also the diagnostic information in other circuit blocks such as the tuner circuit 11, the RF circuit 12, the video signal processing circuit 13 may be transmitted.

[0026]

As described above, the apparatus according to the present invention can be easily and inexpensively inspected in a short time, and the inspection work is easy even if a large number of them exist.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is a structural explanatory view showing an example of a main part of the present invention.

[Explanation of symbols]

11 ... Tuner circuit, 12 ... RF circuit, 13 ... Video signal processing circuit, 14 ... Polarity switching and drive circuit, 1
5 ... Liquid crystal display part, 21 ... LAN controller, 22 ... Microprocessor, 23 ... Keypad and remote control device, 24 ... Failure diagnosis device, 26 ... Power supply circuit, 27 ... Backlight.

Claims (3)

[Claims] 1. A display unit in which signal electrodes and scanning electrodes are provided in a matrix form in a matrix and a display element is provided at an electrode intersection, and a signal electrode driving device for supplying a video signal to the signal electrodes in a vertical direction. And a scanning electrode driving device for supplying a scanning signal to the scanning electrodes in the horizontal direction, and at least a self-diagnosis information output means for detecting and deriving a driving signal of each final stage of the signal electrode driving device and the scanning electrode driving device. A liquid crystal display device characterized by the above. 2. The liquid crystal display device according to claim 1, wherein the self-diagnosis information output means further comprises means for outputting a sampling signal output from the final stage in the signal electrode driving device. 3. The liquid crystal display device according to claim 1, wherein the self-diagnosis information output means further includes a transistor driven by a signal line and a scanning line at a final drive position of the display section.