JPH06266307A - Display device - Google Patents

Abstract

PURPOSE:To naturally display a straight line which changes in shape over a wide range like a meter needle without requiring any mass-storage memory. CONSTITUTION:This display device displays the straight line approximately by modulating the luminance of respective pixels which are arrayed in matrix. A CPU 2 calculates the straight line y=mx+b to be displayed from an input signal in a step 101. In steps 103-107a,b,c,d the distances (a) between respective coordinate points P on the calculated straight line and the pixel A at the shortest distance to the coordinate point P in a specific direction, e.g. Y-axial direction are found, and display luminance (100, 75, 50, 25, and 0%) of the respective pixels A, (A+1), and (A-1) is determined according to the distances (a). A graphic display unit 1 displays the respective pixels according to the determined luminance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a display device, more specifically,
The present invention relates to a liquid crystal display device or the like that modulates the brightness of each pixel arranged in a matrix to display a straight line, and is suitable as a rotary speedometer, tachometer, etc. for vehicles.

[0002]

2. Description of the Related Art As a display device, there is a display device in which pixels arranged in a matrix are brought into a bright state or a dark state to display arbitrary characters, figures, etc. (hereinafter referred to as images) on a liquid crystal display. However, in this type of display device, since the pixels are arranged in a matrix as described above, the contour of the displayed image has a stepped shape, which often causes an unnatural display. .

Therefore, in order to avoid such an unnatural display, the luminance of the pixels near the contour of the image to be displayed is set to 100%, 75%, 50%, 25% according to a predetermined rule.
A display device in which gradation control is performed in multiple steps such as 0% is disclosed in JP-A-2-213891. Then, this display device determines the brightness of each pixel for each image to be displayed in advance, stores this as pattern data in a memory for each image to be displayed, and appropriately outputs necessary pattern data from this memory. Is read out and gradation is displayed.

[0004]

By the way, recently, as an alternative to conventional rotary speedometers for vehicles, tachometers and the like, development of a display device for displaying a linear meter needle on a display screen has been advanced. There is.

Therefore, it is possible to apply the display device described in the above publication to such an optical display device. However, since the angle range in which the meter hand shakes is generally large, when the display device described in the above publication is applied, the amount of pattern data for performing display that approximates the movement of the conventional mechanical meter hand becomes enormous. However, there is a problem that a large-capacity memory must be prepared, which is not practical.

The present invention has been made in view of the above problems, and it is possible to display a straight line whose shape changes in a wide range, such as a meter needle, in a natural display without requiring a large capacity memory. An object is to provide a display device.

[0007]

In order to solve the above-mentioned problems, a display device according to the present invention is a display device which modulates the brightness of each pixel arranged in a matrix to display a straight line, and Based on a straight line calculating means for calculating a straight line to be displayed, and for each coordinate point on the calculated straight line,
Brightness determining means for determining a distance between the coordinate point and a pixel whose distance to the coordinate point is closest in a predetermined direction, and determining display luminance of each pixel according to the distance, and determining each pixel. Display means for displaying based on the generated brightness.

[0008]

The display device of the present invention periodically calculates a straight line to be displayed based on an input signal, and each time, the display brightness of each pixel is determined and displayed based on the straight line. Therefore, when displaying a straight line with a large change width such as a meter needle of a vehicle speedometer or tachometer, it is not necessary to store the pattern data for each change of the meter needle in the memory in advance. The effect is that there is no need to prepare the memory of.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the overall structure of a display device according to an embodiment.

In FIG. 1, the display device includes a graphic display 1, a CPU 2, a ROM 3, a RAM 4, and a display control I.
And C5.

The graphic display 1 is composed of a liquid crystal display panel in which each pixel is arranged in a matrix or a plasma display, and displays at least a straight line, for example, a meter needle on the screen.

The CPU 2 receives an input signal such as a vehicle speed signal or an engine speed signal from the outside, and periodically executes arithmetic processing as described later to make a one-to-one correspondence with a straight line to be displayed, for example, a meter hand. Corresponding image data is created and output to the display control IC 5.

An operation program for the CPU 2 is stored in the ROM 3 in advance.

The image data created by the CPU 2 is stored in the RAM 4 as bit pattern data.

According to an instruction from the CPU 2, the display control IC 5 once writes the image data created by the CPU 2 in the RAM 4, then sequentially reads the image data from the RAM 4, converts the read image data into an image signal, and then converts it into a graphic signal. Output to the display unit 1. Also,
The display control IC 5 outputs the horizontal synchronizing signal and the vertical synchronizing signal to the graphic display 1.

Next, the arithmetic processing executed by the CPU 2 for creating the image data corresponding to the meter needle to be displayed, that is, the straight line, will be described in order based on the flow chart shown in FIG.

1) First, an equation of a straight line to be displayed: y = mx + b is calculated based on the input signal (step 10).
1).

2) Next, the X coordinate x ₁ of the starting point S (x ₁ , y ₁ ) of the straight line to be displayed is substituted for x in the above equation.
(Step 102).

3) Next, y = mx + b is calculated to obtain the Y coordinate y ₁ of the starting point S (step 103).

[0021] 4) Next, the closest pixel A (x _A in the Y axis direction with respect to y _1, to determine the y _A) (Step 10
Four).

5) Next, the Y coordinate y _A of the pixel A is subtracted from y ₁ to obtain the distance a in the Y axis direction between the starting point S and the pixel A (step 105).

6) Next, the magnitude of the distance a is determined (step 106). Here, when the distance between pixels in the Y-axis direction is "1", the determination criterion is "1/4", "-1".
/ 4 ”and“ 0 ”.

7 _a ) When a> 1/4, the brightness of the pixel A is determined to be 100%, and the brightness of the pixel (A + 1) adjacent to the pixel A in the positive direction of the Y axis is set to 75%. Decide,
Further, a pixel (A−, which is adjacent to the pixel A in the negative direction of the Y-axis)
The luminance of 1) determining to 0% (step 107 _a).

7 _b ) If 0 ≦ a ≦ 1/4, pixel A
The brightness of 100%, 50% brightness of the pixel (A + 1), 25% of the luminance of the pixel (A-1), respectively determined (step 107 _b).

7 _c ) -1 / 4≤a <0, the brightness of pixel A is 100%, the brightness of pixel (A + 1) is 25%,
The brightness of the pixel (A-1) is determined to be 50%.
(Step 107 _c).

[0027] 7 _d) if it is a <-1/4, 100% of the luminance of the pixel A, 0% luminance of the pixel (A + 1), the luminance of the pixel (A-1) 75%, respectively determined (step 107 _d). 8) Next, until the end point E (x ₂ , y ₂ ),
It is determined whether or not the brightness determination of the pixels A, (A + 1), and (A-1) is completed (step 108). At this point in time, only the brightness determination for the starting point S is completed,
The determination is “NO”, and the process proceeds to step 109.

9) Next, x is incremented by "1" (step 109) and the process proceeds to step 103.

10) Thereafter, X coordinates (x ₁ +1), (x ₁
+2), ... Repeatedly performing the same arithmetic processing as above to determine the brightness of the pixels A, (A + 1), (A-1) for each X coordinate x from the start point S to the end point E, and end point By finishing the brightness determination for E (step 10
8) Then, a series of arithmetic processing ends. Note that the series of arithmetic processing described above is periodically and repeatedly executed at appropriate time intervals.

In step 104, the pixel A,
The determination of (A + 1) and (A-1) is performed with respect to a point P (x, y) on a straight line: y = mx + b, as shown in FIG.
A pixel closest to the point P in the Y-axis direction is determined as A, an upper pixel adjacent to the point P is determined as (A + 1), and a lower pixel is determined as (A-1).

A straight line is displayed on the graphic display 1 with the brightness determined as described above. For example, straight line: y
In the case where = mx + b is as shown in FIG. 3, the graphic display 1 displays an unnatural display as a straight line, as shown in FIG.

The straight line shown in FIG. 3 is y = mx + b
Shows the case of x ₁ <x ₂ and −1 ≦ m ≦ 1, but in the case of x ₁ > x ₂ , if the arithmetic processing described above is executed by an algorithm in which the start point S and the end point E are exchanged. Well, in the case of m <−1 or m> 1, if the above-mentioned arithmetic processing is executed by an algorithm based on the X coordinate instead of the Y coordinate, a display that is not unnatural will be displayed as a straight line.

As described above, the display device of this embodiment periodically calculates a straight line to be displayed, for example, a meter hand, based on the input signal, and each time, the display brightness of each pixel is determined based on the straight line. To display. Therefore, it is not necessary to store the pattern data for each change of the meter needle or the like in the memory in advance, so that it is not necessary to prepare a large-capacity memory, which is practical.

In the above embodiment, the three pixels A,
Although the luminances of (A + 1) and (A-1) are determined and displayed, the present invention is not limited to this, and for example,
As shown in FIG. 5, 100% luminance display may be omitted, or as shown in FIG. 6, 100% luminance display pixels may be displayed in two columns.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a display device according to an embodiment.

FIG. 2 is a flowchart showing a calculation process of a CPU.

FIG. 3 is an explanatory diagram for explaining a method of determining a pixel A.

FIG. 4 is a display pattern diagram of the graphic display.

FIG. 5 is a display pattern diagram of another example.

FIG. 6 is a display pattern diagram of still another example.

[Explanation of symbols]

1 Graphic Display (Display Means) Step 101 Linear Calculation Means Steps 103 to 107 _a , _b , _c , _d Luminance Determining Means

Claims (1)

[Claims] 1. A display device that modulates the brightness of each pixel arranged in a matrix to approximately display a straight line, and a straight line calculating means for calculating a straight line to be displayed based on an input signal; For each coordinate point on the defined straight line, the distance between the coordinate point and the pixel having the closest distance to the coordinate point in the predetermined direction is calculated, and the display brightness of each pixel is determined according to the distance. And a display unit that displays each pixel based on the determined brightness.