JPS6252312B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a matrix panel display device using LEDs as light-emitting pixels, and an object to improve the apparent resolution without changing the number and arrangement of LEDs forming the matrix panel. The purpose is to

Matrix panels, in which LEDs are used as light-emitting pixels, are arranged in a matrix at equal intervals in rows and columns depending on the aspect ratio, but there are various problems such as the difficulty of arranging LEDs at high density and the complexity of the drive circuit. Therefore, it is inevitable that the resolution will be lower than that of a normal cathode ray tube. For example, forming luminescent pixels
When an average current of 0.5 mA is passed through the LED, sufficient brightness can be obtained for normal television display. If, for example, 150 LEDs are connected to one scanning electrode, a current 150 times that of a single LED flows through the driver of the scanning panel generation circuit. Furthermore, if the number of picture elements in the vertical direction is 100, one scanning line must work at a duty of 1/100, so the driver
A pulse current of 7.5A will flow. If we were to double the number of picture elements in the vertical direction, the pulse current of the driver would need to be 15A, which would be extremely difficult to achieve.

In view of these points, the present invention has been developed by devising the connection between the LEDs on the matrix panel and the scanning electrodes and the order in which the scanning voltages are applied, that is, the combination of displaying light emission for each pair of adjacent scanning lines. The present invention proposes a matrix panel display device that improves the apparent resolution without making any changes to the prime numbers or drive current.

The details of the present invention will be explained below with reference to the drawings. As can be understood from FIG. 1, which shows an enlarged view of the main part of the matrix panel used in the present invention, the row and column arrangement of the LEDs forming the light-emitting picture elements is as follows.
There is no special feature, but the connection between each LED and the scanning electrode is unique.

Now, the arrangement of the LEDs is as shown in Figure 1: L ₁₁ , L ₁₂ , L ₁₃ ...L ₁ n along the row (horizontal) direction, and L ₁₁ , L ₂₁ , L ₃₁ ... along the column (vertical) direction. Lm ₁ , generally indexing the LED of the mth row and nth example as Lmn, the LEDs of each row are connected to two series of scanning electrodes.

Taking the first row of LEDs as an example,
L ₁ , 2k−1 (k is an integer), that is, the odd number
All LEDs are connected to the A electrode, L ₁ , 2k, that is, even numbered
All the LEDs are connected to the B electrode, and in the same way, the odd-numbered LEDs in the second row of LEDs are connected to the C electrode, the even-numbered LEDs are connected to the D electrode, and so on. be done.

The signal electrodes SG are provided in parallel on a ceramic substrate or an aluminum plate treated with oxidation insulation by a photo-etching method or the like, passing under each row of LEDs. Furthermore, for scanning electrodes such as AB, CD, etc., wire bonding of ultra-fine gold wires may be used, but a transparent conductive pattern as shown in the figure is deposited on a transparent plate, and the terminals of each LED and pattern It is also possible to use a method of connecting to the upper connection point via a conductive adhesive. In addition, SG1, SG
2, SG3... indicate signal electrodes.

Next, a description will be given with reference to FIG. 2, which shows a block diagram of the drive circuit of the matrix panel _MP , and FIG. 3, which shows an explanatory diagram of operating waveforms.

In the device of the present invention, basically, of the LED groups in adjacent rows, the odd-numbered LED groups in one row and the even-numbered LED groups in the other row are turned on simultaneously in 1H units. If this relationship is shown in the order in which the scan pulses are applied, it will be as shown in Figure 3A, and each scan electrode A,
The scan pulses applied to B, C, . . . are expressed on the time axis as shown in FIG. 3B. In other words, each column is connected line by line via the horizontal driver circuit _HD .
A brightness (PWM) signal corresponding to the light emission information of the LED group constituting the line (one of two adjacent lines) is applied to the LED group all at once, and the output of the vertical driver circuit V _D2 is applied to the LED group. Then, scan pulses as shown in FIG. 3B are applied to each scan electrode synchronously,
This configuration employs a configuration in which the LED groups are arranged in pairs and the light emitting lines are sequentially shifted from the top to the bottom.

The PWN signal that drives the horizontal driver circuit H _D is a standard (TV) video signal determined by the number of light emitting pixels per line, which is determined by the reference clock pulse generation circuit S _C
an AD conversion circuit A D that samples and AD converts the output of the AD converter A _D , and one line memory LM and PWM that stores the output for one line of the matrix panel.
It is created by a combination circuit of modulation circuit _PWM . Said
The AD conversion circuit A _D is a comparator C _OM as shown in the figure.
, sampling hold circuit SPH and e.g.
It consists of a bit encoder E _D , but since it is basically well known, a detailed explanation will be omitted. The PWM modulation circuit _PWM connected to each signal electrode is preset with the corresponding output of a one-line memory _LM ,
A down counter (not shown) that counts the output of the PWM modulation clock pulse generation circuit _PCP ;
It is composed of a flip-flop circuit (not shown) which is set by a preset pulse _P1 synchronized with the vertical scanning pulse and reset by the output of the down converter, and supplies a PWM signal to the corresponding signal electrode.

The clock pulse generation circuit PCM changes its frequency according to the number of gradations during A-D conversion according to the gradation of the sampled original signal. For example, from 0 to 7 is ₁ = 551 KHz, and from 8 to 15 teeth
By setting it to 157KHz, the input signal pair
Approximating the γ correction curve of the PWM signal width, it is non-linear.
PWM modulation is applied to ensure the linearity of the overall optical input versus optical output characteristics.

Further, the vertical scanning driver circuit V _D receives a scanning pulse as shown in FIG. 3B from the scanning pulse generating circuit S _G to energize each scanning electrode. It is considered obvious to those skilled in the art that the pulses shown in FIG. 3B can be logically created from the horizontal synchronizing signal in the original composite video signal, so a description thereof will be omitted.

In FIG. 3B, odd-numbered scanning electrodes A,
A pulse with a scanning period of 2H is applied to C, E, G, I, K... in a shifted form, and at that time,
The LEDs connected to these scanning electrodes receive a PWM output corresponding to the odd-numbered sampling information of every H's information from the corresponding signal electrode SG 2k-1.
On the other hand, even-numbered scan electrodes B, D, F,
PWM output corresponding to even-numbered sampling information among the information for each H is input to H....

As described above, according to the present invention, the
Among the LEDs, odd-numbered LEDs in one row and even-numbered LEDs in the other row, or vice versa, are paired as a pair, and the amount of light is sequentially applied to the corresponding signal electrode for each line. Even when displaying light-emitting elements, for example, with half the number of lines as the number of horizontal scans, the video signal of one horizontal scan period sampled every two horizontal scans is displayed during two horizontal scan periods as in the conventional example. Rather, the video signal sampled for each horizontal scanning line is sequentially displayed by the odd-numbered LEDs in one row and the even-numbered LEDs in the other row, or vice versa. The apparent resolution can be improved without increasing the number of LEDs. Also, two adjacent rows in one horizontal scanning period
Since driving current is supplied to two scanning electrodes at the same time,
It is possible to reduce the peak drive current by half.

[Brief explanation of the drawing]

The drawings all relate to the matrix display device of the present invention; FIG. 1 is an enlarged front view of the main part of the matrix panel, FIG. 2 is a block diagram of the drive circuit, and FIG. 3 is an explanatory diagram of operating waveforms. M _P ...Matrix panel, L...LED, SG
...Signal electrode, A, B, C...One scanning electrode,
PWM...PWM circuit, _HD ...horizontal driver circuit, _VD ...vertical driver circuit.

Claims (1)

[Claims] 1 Odd-numbered LEDs among the LEDs in each row (horizontal column) of a matrix panel that uses LEDs as light-emitting pixels
and the even-numbered LEDs are connected to independent common odd-numbered and even-numbered scanning electrodes, and the LEDs of each column (column) are connected to a common signal electrode, respectively.
Odd scan electrodes on the lth row (where l is a positive integer) and even scan electrodes on the l+1th row, even scan electrodes on the lth row and odd scan electrodes on the l+1th row, and odd scan electrodes on the l+1th row and the l+2th row. Even scan electrode of row, l+1st
The even-numbered scanning electrodes of the rows and the odd-numbered scanning electrodes of the (l+2)th row are each set as a set, and in this order, they are sequentially energized every horizontal scanning period, and the odd-numbered scanning electrodes of one of the adjacent rows are energized in each horizontal scanning period. LED and even-numbered LED in the other row or even-numbered LED in one row
A matrix panel display device configured so that the odd-numbered LEDs in the other row combine to emit light.