JPH11305737A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust the position of an effective screen even when a video signal is connected to different external equipment. SOLUTION: This device 17 is equipped with a liquid crystal display part 12 which inputs an image signal, a horizontal synchronizing signal, and a clock signal through a liquid crystal control part 2 and a control part 1. Here, the control part 1 counts clock signals which are inputted from the detection point of the horizontal synchronizing signal applied to the liquid crystal display part 12 to the detection point of the image signal and the liquid crystal control part 2 controls the detection point of the image signal so that the counted number reaches a specific value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, an apparatus of this kind has been filed by the present applicant in Japanese Patent Application No. 10-68551.
According to this application, a liquid crystal display device connected to various personal computers (hereinafter referred to as personal computers) is shown. And various video signals output by the personal computer (for example, 640 × 350 dots to 1024 × 768 dots)
It is configured to correspond to. Further, an input key and a liquid crystal display unit are provided.

[0003]

In the above-described apparatus, when a video signal of, for example, 640.times.350 dots is input, the user presses the "SELECT" key as an input key to select "horizontal position", and presses the up key. By pressing the down key,
Adjust the horizontal back porch. What is a horizontal back porch?
In the liquid crystal display section, this is the distance from the left edge of the entire screen to the left edge of the effective screen, and is usually a black portion without an image. In this way, manual adjustment is performed so that the effective screen is centered in the left-right direction with respect to the entire screen.

[0004] Similarly, the user selects and adjusts the "vertical position" to operate the effective screen so as to be centered in the vertical direction with respect to the entire screen. And, for example, 102
If it is changed to a personal computer that outputs a video signal of 4 × 768 dots and connected, the same horizontal position adjustment and vertical position adjustment are required again, and there is a disadvantage that complicated adjustment work is required. Accordingly, the present invention provides a liquid crystal display device that performs automatic position adjustment of an effective screen even when connected to an external device (a personal computer or the like) having a different video signal in consideration of such a conventional disadvantage.

[0005]

According to a first aspect of the present invention, there is provided a liquid crystal display section to which an image signal, a horizontal synchronizing signal, and a clock signal are inputted via a liquid crystal control section.
A control unit, and the control unit measures the number of clock signals input from the time of detection of the horizontal synchronization signal applied to the liquid crystal display unit to the time of detection of the image signal. The control section controls the detection point of the image signal.

In a first aspect of the present invention, preferably, the control section measures the total number of clock signals input during a period when the image signal is applied, and controls the liquid crystal control section to convert the total number to the number of horizontal dots. Then, the number of clock signals is converted according to the number of horizontal dots.

According to a second aspect of the present invention, there is provided a liquid crystal display section to which an image signal, a horizontal synchronizing signal, and a vertical synchronizing signal are inputted via a liquid crystal control section, and a control section, wherein the control section is provided in the liquid crystal display section. The number of horizontal synchronization signals input from the detection of the applied vertical synchronization signal to the detection of the image signal is measured, and the control unit detects the image signal via the liquid crystal control unit so that the number becomes a predetermined number. It controls the point in time.

[0008] In the first or second aspect of the present invention, preferably, the control unit measures that the measured numbers substantially coincide with each other a plurality of times in succession, and determines that the substantially coincident number is the number of clock signals. Or it is the number of horizontal synchronization signals.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a liquid crystal display according to an embodiment of the present invention will be described with reference to the block diagram of FIG. In FIG. 1, a control unit 1 includes, for example, a CPU and controls the entire control. The liquid crystal control unit (controller) 2 is a DRAM
It has functions of control, LCD control, and counter, and performs gradation control and the like corresponding to an input image signal R / G / B (which forms a part of a video signal). DRAM3,4
Reference numerals 5 and 6 temporarily store the image signals R / G / B. The A / D converter 7 converts an analog signal into a digital signal.

A generator (clock generator) 8 generates a sampling clock signal CLK corresponding to the image signal R / G / B.
Is supplied to the liquid crystal controller 2. The video amplifier 9 amplifies the image signals R / G / B. The display unit 10 is an OS
D (on-screen display) for displaying a message or the like that guides the user to make adjustments.

The storage unit 11 is composed of, for example, a non-volatile memory, and stores a plurality of display parameters (determined from video signals). The liquid crystal display unit 12 is connected to the liquid crystal control unit 2 and the control unit 1, and through the liquid crystal control unit 2, an image signal R / G / B, a clock signal, a horizontal synchronization signal H (described later), and a vertical synchronization signal V (described later) and a display control signal DE (described later) are supplied.

The input means 13 has, for example, four keys (ME
NU, SELECT, UP, DOWN), and the output is given to the control unit 1. The input unit 14 includes, for example, a connector, and receives a video signal from an external device (for example, a personal computer) connected to the input unit 14. The video signal includes, for example, an image signal B / G / B, a horizontal synchronization signal H, a vertical synchronization signal V, and the like.

The image signal R / G / B passes through an input section 14 and a buffer 15 and is adjusted to a required level by a video amplifier 9, and then adjusted to an impedance matching amplifier 16R and 1R.
The signal is supplied to the A / D converter 7 through 6G and 16B. Then, the signal is sampled by the A / D converter 7, converted into a digital signal, and input to the liquid crystal control unit 2.

The synchronizing signal H / V comprises a horizontal synchronizing signal H and a vertical synchronizing signal V, and is supplied to the control unit 1 and the liquid crystal control unit 2 through the input unit 14 and the buffer 15. Image signal R
/ G / B is supplied from the liquid crystal control unit 2 together with the horizontal synchronizing signal H, the vertical synchronizing signal V, and the display control signal DE (indicating the period of actual display generated by the liquid crystal control unit 2). Is entered and displayed. On the other hand, the control unit 1 creates a display parameter based on the input image signal R / G / B and the synchronization signal H / V, and causes the liquid crystal control unit 2 to display the display parameter so that the liquid crystal display unit 12 appropriately displays the display parameter. Is set, and stored in the storage unit 11. The liquid crystal display device 17 is configured by the above components.

Next, the operation of the liquid crystal display device 17 will be described with reference to FIG.
It will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the automatic position adjustment in the liquid crystal display device 17, and FIG.
Is a waveform diagram of the liquid crystal display unit 12 and signals applied thereto. When a video signal is input from a personal computer or the like, the liquid crystal display device 17 measures the frequency of the vertical synchronizing signal V and the horizontal synchronizing signal H of the video signal, and determines the value and each polarity of the vertical synchronizing signal V and the horizontal synchronizing signal H. To determine the signal mode of the video signal. Then, display parameters are set in the liquid crystal control unit 2 according to the determined signal mode, and the liquid crystal display unit 12 displays the display parameters. However, since there are many types of video signals from a personal computer or the like, it is necessary to adjust display parameters in order to properly display.

First, the user enters the "MEN"
When the "U" key is pressed, "automatic adjustment, horizontal position, vertical position, ..." is displayed on the display section. The user places the cursor on "Auto Adjust". Press the "SELECT" key,
The operation of automatic position adjustment starts. Then, the controller 1 causes the liquid crystal controller 2 to measure the clock (S1). That is, during a period in which the image signal R / G / B is applied to the liquid crystal display unit 12 (when converted into a distance, a line segment X1), the counter in the liquid crystal control unit 2 controls the input clock signal CLK. Measure the total number.

Next, the control unit 1 determines "whether three consecutive matches" (S2). For example, in the n-th measurement, the total number is A
Step S2 is affirmative if A + 1 ≧ B ≧ A−1 and B + 1 ≧ C ≧ B−1 are satisfied. Then, the control unit 1 adjusts the dot clock (S3). For example, n
The total number A of the clock signals CLK in the second measurement is 62
If the number of horizontal dots obtained by the control unit 1 in the above-described signal mode is 640 based on the input video signal, the liquid crystal control unit 2 converts the total number A into the number of horizontal dots.

If step S2 is denied,
It is determined whether the clock measurement has been performed 100 times (S
4). If less than 100 times, steps S1, S2, S
Repeat 4. If the clock measurement is performed 100 times and the values do not match three times in a row, step S4 is affirmed and the operation of the automatic position adjustment ends.

Next, the control section 1 causes the liquid crystal control section 2 to detect the vertical synchronizing signal V (S5). For example, in FIG.
The rising D of the vertical synchronization signal V is the detection start time. This time coincides with the upper end of the entire screen 18 on the liquid crystal display unit 12. Then, the control unit 1 controls the liquid crystal control unit 2 to
The number of horizontal synchronization signals H having no display data is counted (S6). That is, the counter in the liquid crystal control unit 2 measures the number of the input horizontal synchronization signals H in a period from the detection point D of the vertical synchronization signal V to the detection point E of the image signal R / G / B. .

Next, the control section 1 determines "whether three consecutive matches have occurred" (S7). For example, the total number is A in the n-th measurement, the total number is B in the n + 1-th measurement, and the total number is C in the n + 2-th measurement, and A + 1 ≧ B ≧ A−1, B + 1 ≧ C ≧ B−
If 1 holds, step S7 is affirmed. For example, from time D to time E, 20 horizontal synchronization signals H
And the distance from the upper end of the entire screen 18 to the upper end of the effective screen 19 is called a vertical back porch VB.

The control unit 1 is provided with a vertical back porch VB.
Is adjusted (S8). For example, if the number of horizontal synchronization signals H in the n-th measurement is 20, the vertical back porch VB is larger than the vertical front porch Vb. Therefore, the liquid crystal control unit 2 changes the number of the horizontal synchronization signals H in the period from the time point D to the time point E to a predetermined number (for example, 10). That is, the detection time point of the image signal R / G / B is changed to the point e. As a result, the line segment Y1 of the effective screen 19 is
Eight vertical line segments Y2 are evenly distributed up and down,
The vertical back porch VB is equal to the vertical front porch Vb.

If step S7 is denied,
It is determined whether the horizontal synchronization signal H has been counted 100 times (S9). If less than 100 times, steps S5, S6, S7 and S9 are repeated. Count operation is 10
If the process is performed 0 times and does not match three times in a row, step S
9 is affirmed, and the operation of the automatic position adjustment ends.

Then, the control section 1 causes the liquid crystal control section 2 to detect the horizontal synchronizing signal H (S10). For example, in FIG. 3, the rising F of the horizontal synchronizing signal H is the detection start time. This time coincides with the left end of the entire screen 18 on the liquid crystal display unit 12. Next, the controller 1 causes the liquid crystal controller 2 to count the dot clocks up to the horizontal data (S1).
1). In other words, the counter in the liquid crystal control unit 2 starts detecting the horizontal synchronizing signal H to detect the image signal R / G / B from the detecting time G.
During this period, the number of clock signals CLK is measured.

Next, the control section 1 determines "whether three consecutive matches have been made" (S12). For example, the total number is A in the n-th measurement, the total number is B in the (n + 1) -th measurement, and the total number is C in the (n + 2) -th measurement. A + 1 ≧ B ≧ A−1, B + 1 ≧ C ≧ B
If −1 holds, step S12 is affirmed.
For example, assuming that 40 clock signals CLK (three clock signals are illustrated in FIG. 3 for simplicity) from the time point F to the time point G, the distance from the left end of the entire screen 18 to the left end of the effective screen 19 is set to be horizontal. Called back porch HB.

Then, the controller 1 adjusts the horizontal back porch HB (S13). For example, if the number of clock signals CLK in the n-th measurement is 40, the horizontal back porch HB is larger than the horizontal back porch Hb. Therefore, the liquid crystal control unit 2 determines that the number of clock signals CLK in the period from time F to time G is 4
Zero is converted according to the number of horizontal dots. That is, as in the case where the total number (actually measured values) of 620 clock signals CLK is converted into the number of horizontal dots (described in step S3), the number 40 of clock signals CLK is converted by proportional calculation of the following equation, and the number 41 is converted into 41. obtain. 40 × 640/620 = 41.29 ≒ 4
1 and the liquid crystal controller 2 converts the number 41 of the converted clock signals CLK in the period from the time point F to the time point G into a predetermined number (for example, 20). That is, the detection time point of the image signal R / G / B is changed to the point g. As a result, the horizontal line segment X1 of the effective screen 19 is equally distributed to the left and right with respect to the horizontal line segment X2 of the entire screen 18, and the horizontal back porch HB becomes equal to the horizontal front porch Hb. In this way, the position of the effective screen 19 is automatically adjusted so as to be equal to the left, right, up and down with respect to the entire screen 18, and the normal operation ends.

If step S12 is negative, it is determined whether the dot clock counting operation has been performed 100 times (S14). If less than 100 times, steps S10, S11, S12, and S14 are repeated. The counting operation is performed 100 times, and if they do not match three times in a row, the result of the determination in step S14 is affirmative, and the operation of the automatic position adjustment ends.

[0027]

As described above, according to the first aspect of the present invention, the control unit determines the number of clock signals input from the detection of the horizontal synchronization signal applied to the liquid crystal display unit to the detection of the image signal. The liquid crystal controller controls the time when the image signal is detected so that the number is measured and the number becomes a predetermined number. In this way, the length of the horizontal back porch is changed to a predetermined length by adding or subtracting the number of clock signals in the horizontal back porch (from detection of a horizontal synchronization signal to detection of an image signal) to a predetermined number. .

As a result, the horizontal back porch is equal to the horizontal front porch, and the effective screen is automatically adjusted so as to be equal to the left and right with respect to the entire screen. Also,
Since the counter for measuring the number of clock signals is provided in the liquid crystal control unit, it can be manufactured at low cost without using a complicated electric circuit to measure the horizontal back porch.

According to the second aspect of the present invention, the control section measures the total number of clock signals input during the period when the image signal is applied, and controls the liquid crystal control section to convert the total number into the number of horizontal dots. , The number of clock signals is converted into the number of horizontal dots. As described above, the total number of clock signals is converted into the number of horizontal dots, and the number of clock signals existing on the horizontal back porch (measured value) is converted according to the number of horizontal dots. Become. As a result, the length of the horizontal back porch can be accurately measured. Further, since the total number of clock signals is converted into the number of horizontal dots, the total number of clock signals present on the horizontal back porch can be accurately obtained even if the number of horizontal dots of an external device connected to the liquid crystal display device is different. .

According to the third aspect of the present invention, the control section determines the number of horizontal synchronization signals input from the time of detection of the vertical synchronization signal applied to the liquid crystal display section to the time of detection of the image signal (vertical back porch). measure. Then, by adding or subtracting this number to a predetermined number, the length of the vertical back porch is changed to a predetermined length, and by making the length equal to the length of the vertical front porch, the effective screen is vertically shifted with respect to the entire screen. Automatic position adjustment is possible evenly. Further, since a counter for measuring the number of horizontal synchronizing signals is provided in the liquid crystal control unit, it can be manufactured at low cost without using a complicated electric circuit for measuring the vertical back porch.

According to the fourth aspect of the present invention, it is measured that the number of measured clock signals or horizontal synchronization signals substantially coincides a plurality of times in succession, and the substantially coincident number is determined as the number of clock signals or horizontal synchronization signals. Judge as the number. As described above, since the number that substantially coincides a plurality of times is used, a true value of the number can be obtained even if there is a variation in each signal.

[Brief description of the drawings]

FIG. 1 is a block diagram of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of automatic position adjustment in the liquid crystal display device.

FIG. 3 is a waveform diagram of a liquid crystal display unit used in the liquid crystal display device and signals applied to the liquid crystal display unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control part 2 Liquid crystal control part 12 Liquid crystal display part

Continuation of the front page (72) Inventor Hiroyuki Matsumoto 3-201 Minamiyoshikata, Tottori City, Tottori Prefecture Tottori Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. A liquid crystal display unit to which an image signal, a horizontal synchronizing signal, and a clock signal are input via a liquid crystal control unit, and a control unit, wherein the control unit is applied to the liquid crystal display unit. The number of the clock signals input from the detection time of the horizontal synchronization signal to the detection time of the image signal is measured, and the liquid crystal control unit is controlled so that the number becomes a predetermined number. A liquid crystal display device characterized by being controlled. 2. The control unit measures a total number of the clock signals input during a period in which the image signal is applied, controls the liquid crystal control unit to convert the total number into a horizontal dot number, 2. The liquid crystal display device according to claim 1, wherein the number of the clock signals is converted according to the number of horizontal dots. 3. A liquid crystal display unit to which an image signal, a horizontal synchronization signal, and a vertical synchronization signal are input via a liquid crystal control unit, and a control unit, wherein the control unit is applied to the liquid crystal display unit. The control unit measures the number of the horizontal synchronization signals input from the detection time of the vertical synchronization signal to the detection time of the image signal, so that the number becomes a predetermined number, via the liquid crystal control unit, A liquid crystal display device, which controls a detection time point of the image signal. 4. The control unit measures that the measured numbers substantially continuously match a plurality of times, and the number of substantially matched numbers is the number of the clock signals or the number of the horizontal synchronization signals. The liquid crystal display device according to claim 1 or 3, wherein: