JPH0548884B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a liquid crystal display device, and particularly to a liquid crystal display device with a built-in control circuit.

[Background of the invention]

In conventional liquid crystal display devices with built-in control circuits, the user specifies the liquid crystal drive conditions from the outside via software each time the power is turned on, that is, on the control computer program. This has the drawback of making the program creation process cumbersome and making specification errors more likely. In addition, if the above drive conditions are not specified immediately after the device is powered on, the program must be designed so that other initialization processing etc. are prioritized instead of being specified at the beginning of the program due to user inexperience. In this case, there was also damage caused by DC voltage being applied to the liquid crystal during that time.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to reduce the troublesome work of creating programs for the control computer by the user, and to prevent setting errors and the possibility of DC voltage being applied to the liquid crystal display when the power is turned on. An object of the present invention is to provide a liquid crystal display device with a built-in control circuit that can prevent such situations from occurring and suppress deterioration of liquid crystal.

[Summary of the invention]

In order to achieve such an objective, the present invention
A memory storing driving conditions in advance is provided inside the liquid crystal display device, and when the power is turned on, the control circuit itself reads the contents of the memory and sets the driving conditions. Hereinafter, the present invention will be explained in detail using Examples.

[Embodiments of the invention]

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, the area indicated by a broken line is the liquid crystal display device according to the present invention, and 1 is a CPU constituting a control computer. The control circuit 2 is a circuit that controls liquid crystal driving conditions and data, the display memory 3 is a memory that stores data to be displayed on the liquid crystal panel 4, and the driving condition memory (ROM) 5 is a circuit that controls liquid crystal driving conditions and data. This is a non-volatile memory in which driving conditions are written.

Next, the operation of the above configuration will be explained using FIG. When the power of the system is turned on as shown in FIG. 2a, the control circuit 2 starts oscillating with its own oscillator as shown in FIG. 2b (region in the figure). When the power supply is stabilized, the condition capture signal becomes valid (“H” in the example shown) as shown in c in the same figure.
level), and the control circuit 2 is
As shown in FIG. 3, addresses are sequentially outputted to the drive condition memory 5 through the address line 6 in accordance with the oscillation frequency. As a result, data is outputted from the memory 5 in accordance with the address designation, as shown in e of the figure. For example, if data such as the number of time divisions is written to address 0, the number of characters/line to address 1, and the size of one character to address 2, these data are sequentially output. The control circuit 2 takes in these data and transfers them to a predetermined internal circuit to set driving conditions for the liquid crystal (region in the figure). When the condition setting is completed, that is, when the end data indicated by diagonal lines in Fig. 2e is output, the condition capture signal goes to "L" level, and it becomes possible to communicate with the CPU 1 (the area in the figure ).

As described above, according to this embodiment, the optimum driving conditions for the liquid crystal display device can be automatically set without error and without bothering the user. Further, since this condition setting is performed immediately after power is turned on, the time during which a DC voltage is applied to the liquid crystal can be extremely shortened.

The liquid crystal drive conditions that should be stored in advance in the memory 5 are typically and essential, for example, the ones mentioned above, especially the number of time divisions and the number of horizontal dots, but in a device with two control circuits, , master/slave designation is also essential as a basic condition for starting oscillation. In addition, the memory 5 also stores information such as a start address indicating the area where display start data is stored or a memory address indicating the range to be displayed, which indicates which part of all the data stored in the memory is to be displayed. You may let them.

〔Effect of the invention〕

As explained above, according to the present invention, a memory is provided in which driving conditions are stored in advance, and the control circuit itself reads the contents of the memory and sets the driving conditions when the power is turned on.
Since there is no need to include an area specific to the liquid crystal display element in the program of the user's control computer, it is easier to operate and use, there are no setting errors, and deterioration of the liquid crystal can be prevented, extending its life. can.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a time chart showing the operation. 2... Control circuit, 3... Display memory, 4... Liquid crystal panel, 5... Driving condition memory.

Claims (1)

[Claims] 1 In a liquid crystal display device equipped with a liquid crystal panel, a drive circuit, and a control circuit, a nonvolatile memory that stores in advance liquid crystal driving conditions including at least the number of time divisions and the number of characters; and a memory that stores data to be displayed on the liquid crystal panel. After the power is turned on, the control circuit reads the contents of the nonvolatile memory, transfers it to a predetermined internal circuit, sets the liquid crystal drive conditions, and then communicates with the control computer. A liquid crystal display device characterized in that it is configured as follows.