JP2000047606A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device which can be improved in the uniformity of its display screen without lowering the luminance so much. SOLUTION: The display device 10 has light emitting elements arrayed in dots to display an image and also has sets of light emitting elements which are modulated equally. A set of light emitting elements which are modulated equally is constituted by combining light emitting elements which have values of luminous intensity nearly symmetrical about the center of a light emission intensity distribution formed in the area between the maximum light intensity and minimum light intensity of the light emitting elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display device capable of displaying an image by arranging a plurality of light emitting elements in a dot shape.

[0002]

2. Description of the Related Art For example, a light emitting diode (hereinafter referred to as an LED (Light Emitt)
A display device that displays an image using a light-emitting element (hereinafter referred to as a light-emitting element) has been developed. FIG. 8 shows the LEDs mounted on the mounting surface of the display panel of the display device. On the mounting surface 1021 of the display unit 1020, for example, LEDs indicated by a circle are arranged in a horizontal inline arrangement. These LEDs
Are R (red) and G, respectively, as shown in the circles.
(Green) and B (blue), and each of the four RGB LEDs constitutes a pixel 1022 as a set. When a display screen of a display device is formed by the display unit 1020, a plurality of display units 1 are arranged so that the number of pixels is determined according to the resolution of the display device.
020 will be combined. FIG. 9 shows an example of the luminous intensity distribution of the LED.

In the display device shown in FIG. 8, LEDs are connected in series for each color, and are turned on by applying the same signal and modulating the same. Of course each color LED
Can be connected in parallel, but in this case, a constant current source is required four times.

[0004]

Incidentally, such a display unit 1020 is recently used, for example, for a large-screen display device for outdoor advertisement such as a wall surface of a building. However, for example, CRT (Cathode Ray Tud)
e) and the uniformity of color and brightness is poor as compared with a display device using a discharge tube or the like, and it is desired to improve the uniformity of color and brightness for further market expansion. Therefore, there is a tendency to adjust the luminous intensity (intensity) for each pixel even in a display device using LEDs.

However, as shown in FIG. 9, the luminous intensity of the LED varies widely, and the minimum luminous intensity is 1/1 / the average value.
At about 1.4, it is necessary to adjust the luminous intensity to the value of the minimum luminous intensity. Therefore, when the uniformity of color and luminous intensity (luminance) is improved, there is a problem that the luminance is reduced to 1 / 1.4. Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a display device capable of improving the uniformity of a display screen without significantly lowering luminance.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a display device in which a plurality of light emitting elements are arranged in a dot form to display an image. In a display device having a plurality of element sets, the same modulated light-emitting element set is substantially symmetric with respect to the center of the light-emitting luminous intensity distribution formed in a region between the maximum light intensity of the light-emitting element and the minimum light intensity of the light-emitting element. This is achieved by a display device characterized by being configured by combining light emitting elements having luminous intensity values.

According to the present invention, there is provided a display device in which a plurality of light-emitting elements are arranged in a dot shape to display an image, and the display device has a plurality of sets of light-emitting elements which are modulated in the same manner. ing. The same modulated light emitting element set
The light emitting device is configured by combining light emitting devices having substantially symmetric light intensity values with respect to the center of the light emission intensity distribution formed in a region between the maximum light intensity of the light emitting device and the minimum light intensity of the light emitting device. As a result, the uniformity of the display screen can be improved without significantly lowering the luminance.

In the present invention, preferably, the set of light emitting elements that are modulated in the same manner includes a set of light emitting elements that emit red (R), a set of light emitting elements that emit green (G), and a set of light emitting elements that emit blue (B).
Is a set of light emitting elements that emit light. As a result, color display with good screen uniformity can be performed without significantly lowering the luminance.

In the present invention, the region of the luminous intensity distribution is preferably divided by an integral multiple of the number of light-emitting elements that are modulated in the same manner.

In the present invention, preferably, the division width in the region of the luminous intensity distribution is uniform. As a result, the variation of the same color element in the pixel can be made relatively small.

In the present invention, the luminous intensity of each set of light emitting elements to be combined preferably has a certain range. Thereby, the number of combinations of light emitting elements can be reduced.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 shows a preferred embodiment of the display device of the present invention. The display device 10 shown in FIG. 1 has a case (housing) 11, in which a mounting substrate 12 for mounting, for example, a light emitting diode (LED) is provided. The mounting substrate 12 has red (R), green (G), and blue (B) LEDs in, for example, a horizontal in-line arrangement pattern as shown in FIG.
Are arranged. The case 11 has a built-in control device for controlling the LEDs arranged in this manner.

In one pixel 20 of the display device 10, each color per one pixel 20 is composed of two LEDs. That is, one pixel 20 has a red LE
D30R1, 30R2 and green LEDs 30G1, 30
G2 and a total of 6 of the blue LEDs 30B1 and 30B2
LED.

In the display device 10, a plurality of one pixels 20 are arranged in a matrix on the substrate 12 with the case 11 attached thereto, and each LED is arranged in a dot in one pixel 20. ing. The green LEDs 30G1 and 30G2 are electrically connected in series, and the red LEDs 30R1 and 30R2 are also connected in series.
Furthermore, the blue LEDs 30B1 and 30B2 are also connected in series, and are electrically connected to the above-described control device.

In each pixel 20 shown in FIG. 1, the red LEDs 30R1 and 30R2 are the same-modulated light-emitting elements, and the green LEDs 30G1 and 30G2 are also the same-modulated light-emitting elements. And blue (B) LED
The light emitting elements 30B1 and 30B2 are also the same modulated. Each pixel 20 has the following ingenuity in order to improve the luminous intensity of each pixel without reducing the luminance much and to improve the uniformity of the screen.

FIG. 2 shows the minimum luminous intensity (minimum luminous intensity), the maximum luminous intensity (highest luminous intensity), and the center of the emitted luminous intensity (average luminous intensity) of the LED.
An example of the luminous intensity distribution having the following is shown. When the minimum luminous intensity in FIG. 2 is 1, the average luminous intensity, which is the center of the luminous intensity, is 1.4, and the maximum luminous intensity is 1.8. The red LEDs 30R1 and 30R2 in FIG. 1 are divided into two groups (divided into integer multiples), for example, into a group A having a minimum luminosity of 1 to 1.4 and a group B having a minimum luminosity of 1.4 to 1.8. .
That is, the group A and the group B equally divide the emission luminous intensity distribution into two around the average luminous intensity. As an example, red LE
D30R1 is selected as an arbitrary one from the luminous intensity of the group A, and another red LED 30R2 is selected.
Is adopted by selecting an arbitrary one from the luminous intensity of the B group. And these red LEDs 30R1, 3
OR2 is electrically connected in series.

Similarly, the green LED 3 shown in FIG.
As for 0G1, any one of the group A in FIG. 2 is selected, and for the green LED 30G2, any one of the group B is selected and electrically connected in series. Blue LED3
0B1 is selected from any one of the group A, and the blue LED 30B2 is selected from any one of the group B and connected in series. In this way, the selected LE
D30R1, 30R2, 30G1, 30G2, 30B
1, 30B2 constitute one pixel 20. As a result, the minimum luminous intensity of one pixel 20 can be regarded as 1.2, which is an average value of the minimum luminous intensity 1 of the group A and the minimum luminous intensity 1.4 of the group B in FIG. By doing so, it is possible to improve the luminous intensity of one pixel 20 without significantly reducing the luminance.
The display device 20 having good screen uniformity can be realized.

Next, reference is made to FIG. 3 and FIG. 3 and 4
Shows another embodiment of the display device of the present invention.
The display device 40 illustrated in FIG. 3 includes the case 11 and the mounting board 42. A plurality of one pixels 50 are arranged on the mounting substrate 42, and a plurality of LEDs are arranged in a dot in one pixel 50. This one pixel 50 has four green LEDs 60G1, 60G2,
60G3, 60G4 and four red LEDs 60R1,
60R2, 60R3, 60R4 and 4 blue L
It has EDs 60B1, 60B2, 60B3, and 60B4.

The green LEDs 60G1 to 60G4 are electrically connected in series, and similarly, four red LEs
D60R1 to 60R4 are also connected in series, and four blue L
The EDLEDs 60B1 to 60B4 are also connected in series.

The following contrivance has been made to improve the pixel luminosity of one pixel 50 of the display device 40 of FIG. 3 and to improve the uniformity of the screen without significantly lowering the luminance.
FIG. 4 shows an example of the luminous intensity distribution of the LEDs of the display device 40 of FIG. In FIG. 4, unlike the case of FIG. 2, the A1 group is further finely divided, and has a minimum luminosity of 1 to a maximum luminosity of 1.2, an A2 group of a minimum luminosity of 1.2 to a maximum luminosity of 1.4, B2 group in the area of minimum luminosity 1.4 to maximum luminosity 1.6 and B of minimum luminosity 1.6 to maximum luminosity 1.8
It is divided into four groups. For example, one pixel 5
0G green LED 60G1 is any one of group A1, LED 60B2 is any one of group B1, and LED 60G3 is any one of group A2.
No. 4 employs and combines any one of the B2 group. Such a combination is provided by red LEDs 60R1 to 60R4.
Similarly, the blue LEDs 60B1 to 60B4 are taken out and combined. As a result, the average value of the minimum luminous intensity of the A1 group and the minimum luminous intensity 1.6 of the B1 group in FIG. 4 is 1.3, and the average of the minimum luminous intensity 1.2 of the second group and the minimum luminous intensity 1.4 of the B group is 1.4. The value is also 1.3, and the minimum luminous intensity (total luminous intensity) in one pixel 50 in FIG. 3 can be regarded as 1.3.

Although not shown, in the luminous intensity distribution chart of FIG. 2 or FIG. 4, the luminous intensity per pixel is 1.333 when dividing into six, and one when dividing into eight. The luminous intensity per pixel is 1.35, which is closer to the luminous intensity of the pixel when the minimum luminous intensity and the maximum luminous intensity are combined and then combined one by one such as one inside.

Next, FIGS. 5 and 6 show still another embodiment of the present invention. Case 1 of the display device 70 of FIG.
1 is provided with a mounting plate 72. A plurality of pixels 90 are arranged on the mounting plate 72. 1
In one pixel 90, a plurality of LEDs are arranged in a dot shape. One pixel 90 has three green LEDs 100G
1,100G2,100G3 and red LED100R
1,100R2,100R3 and blue LED100B
1, 100B2 and 100B3. The three green LEDs 100G1, 100G2, and 100G3 are periodically connected in series, and similarly, the red LED 100R
1,100R2,100R3 are also connected in series, and blue L
The EDs 100B1, 100B2, and 100B3 are also connected in series.

FIG. 6 is a luminous intensity distribution diagram of the LED.
It shows an example divided into two. In FIG. 6, the minimum luminous intensity is 1
A group having a maximum luminous intensity of 1.27, a C group having a minimum luminous intensity of 1.27 to a maximum luminous intensity of 1.53, and a B group having a minimum luminous intensity of 1.53 to a maximum luminous intensity of 1.8. . For example, the green LED 100G1 of one pixel 90 in FIG. 5 is selected as any one of group A, 100G2 is selected as any one of group B, and
G3 is combined as any one of group C.
Such processing is performed not only for the green LED but also for the red L
Both the ED and the blue LED are used, and one pixel 90 is constituted by such selected LEDs. As a result, A
The average of the minimum luminous intensity 1 of the group and the minimum luminous intensity 1.53 of the group B is 1.27, and the minimum luminous intensity of the group C is also 1.27, so the luminous intensity (total luminous intensity) of one pixel 90 is 1.27. Can be considered.
If the luminous intensity distribution is close to the normal distribution, only group C remains,
In this case, one pixel may be formed by any three sets in the group C.

FIG. 7 shows an example in which each LED of one pixel 90 of the display device 70 as shown in FIG. The luminous intensity width in FIG. 7 is not uniform, and the number of LEDs belonging to each group is the same. That is, LEs belonging to the groups A, C and B respectively
The number of D is the same.

In FIG. 7, minimum luminous intensity 1 to maximum luminous intensity 1.35.
, A C group having a minimum luminous intensity of 1.35 to a maximum luminous intensity of 1.45, and a B group having a minimum luminous intensity of 1.45 to a maximum luminous intensity of 1.8. For example, the green LED 100G of FIG.
1 is selected as an arbitrary one in the group A, and the LED 10
0G2 is selected as any one of the group C, and the LED
100G3 is selected and combined as an arbitrary one of the group B. By performing such processing together with the red LED and the blue LED, one pixel 90 is configured. As a result, the minimum luminous intensity 1 of the group A and the minimum luminous intensity 1.
The average value of 35 and the minimum luminous intensity of 1.45 of the B group is 1.27.
Therefore, the luminous intensity (total luminous intensity) of one pixel 90 is
It can be regarded as 1.27.

As described above, according to the present invention, when a plurality of LEDs are used for one pixel, by combining LEDs that are substantially symmetrical with respect to the center of the luminous intensity distribution, the luminance at the time of display on the entire display device is improved. And a display device with good screen uniformity can be realized. Further, by dividing the luminous intensity distribution evenly by an integral multiple of the number of each LED per pixel, it is possible to realize a display device with good screen uniformity without a significant decrease in luminance. It can be used without waste, and the combination effort is relatively small.

Conventionally, in a display in which LEDs having large variations in brightness (luminous intensity) are arranged, the luminous intensity of all LEDs is adjusted to the minimum luminous intensity of the LEDs.
However, in the present invention, when a plurality of LEDs are used in one pixel, it is possible to design with an average luminous intensity by using a combination of symmetrical luminous intensity with respect to the variation center, and about 1.4.
Double the luminosity or the total price of all LEDs to 1 / 1.4
Can be.

The present invention is not limited to the above embodiment, and other types of light emitting elements besides LEDs can be employed. The electrical connection of the LED may be not only a serial connection but also a parallel connection to the control device.

[0030]

As described above, according to the present invention,
The uniformity of the display screen can be improved without significantly lowering the luminance.

[Brief description of the drawings]

FIG. 1 is a front view showing a preferred embodiment of a display device of the present invention.

FIG. 2 is a luminous intensity distribution diagram showing an example of selection of an LED in one pixel of the display device of FIG. 1;

FIG. 3 is a front view showing another embodiment of the display device of the present invention.

FIG. 4 is a luminous intensity distribution chart for selecting an LED in one pixel of the display device of FIG. 2;

FIG. 5 is a front view showing still another embodiment of the display device of the present invention.

FIG. 6 is a luminous intensity distribution chart for selecting an LED of one pixel of the display device of FIG. 5;

FIG. 7 is a luminous intensity distribution diagram for selecting an LED of one pixel of the display device of FIG. 5;

FIG. 8 is a diagram showing a conventional display device.

FIG. 9 is a graph showing the luminous intensity distribution of LEDs of a conventional display device.

[Explanation of symbols]

10 ... display device, 20 ... one pixel, 30G
1, 30G2, 30G3 ... green LED, 30R
1, 30R2, 30R3 ... red LED, 30B
1, 30B2, 30B3 ... blue LED.

Claims (5)

[Claims] 1. A display device in which a plurality of light emitting elements are arranged in a dot shape to display an image, wherein the display device has a plurality of sets of light emitting elements that are modulated in the same manner. Is configured by combining light emitting elements having substantially symmetric light intensity values with respect to the center of the light emission intensity distribution formed in the region between the maximum light intensity of the light emitting element and the minimum light intensity of the light emitting element. A display device characterized by the above-mentioned. 2. A set of light-emitting elements that perform the same modulation includes a set of light-emitting elements that emit red (R), a set of light-emitting elements that emit green (G), and a light-emitting element that emits blue (B). The display device according to claim 1, wherein: 3. The display device according to claim 1, wherein the area of the luminous intensity distribution is divided by an integral multiple of the number of light-emitting elements that are modulated in the same manner. 4. The display device according to claim 3, wherein a division width in a region of the luminous intensity distribution is uniform. 5. The display device according to claim 1, wherein the luminous intensity of each set of light emitting elements to be combined has a certain width.