Light emitting unit, pixel unit of LED display and LED display thereof

Abstract

The application relates to the technical field of display devices, in particular to a light-emitting unit of an LED display, a pixel unit and an LED display thereof, wherein the light-emitting unit comprises an LED chip group, the LED chip group comprises N LED chips arranged in parallel, N is a positive integer greater than or equal to 2; the saturation threshold voltages of at least two LED chips in the N LED chips are different; and the sum of the saturation luminances of all the LED chips in the LED chip group is equal to the preset luminance of the light-emitting unit; in the light-emitting unit, two or more LED chips are arranged in parallel and have different saturation threshold voltages, so that the adjustment range of the driving voltage is effectively shortened, and the flexibility of circuit adjustment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display devices, in particular to a light-emitting unit of an LED display, a pixel unit and an LED display having the light-emitting unit. BACKGROUND

[0002] Micro light-emitting diode (Micro LED) is a miniaturization and matrix technology of light-emitting diode, which has good stability, long service life and operating temperature advantage, and also inherits the advantages of low power consumption, color saturation, fast response speed and strong contrast of LED, and has great application prospect.

[0003] The Micro LED display made of Micro light-emitting diode is the mainstream development direction of display devices in the future; and the existing Micro LED display is composed of a plurality of pixel units, each pixel unit comprising a light-emitting unit of red, green and blue colors, and the LED in each light-emitting unit can individually control the brightness thereof, and the three colors are mixed to achieve the required display color.

[0004] In the prior art, each light-emitting unit only includes one LED chip, and the brightness of the LED chip can be controlled by adjusting the driving voltage of the light-emitting unit; as shown in FIG. Figure 1 As shown in FIG. 1, the adjustment range (0 to V0) of the driving voltage of the existing light-emitting unit from zero brightness to saturated brightness L0 of the LED chip is large, which is not convenient for flexible adjustment of the circuit. SUMMARY

[0005] In order to overcome the above-mentioned defects, the purpose of the present application is to provide a light-emitting unit capable of flexibly adjusting the brightness of the LED chip, a pixel unit and an LED display having the light-emitting unit.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] The present application is a light-emitting unit of an LED display, comprising: an LED chip group,

[0008] The LED chip group comprises N LED chips arranged in parallel, N being a positive integer greater than or equal to 2;

[0009] The saturated threshold voltages of at least two LED chips in the N LED chips are different;

[0010] The sum of the saturated brightness of all LED chips in the LED chip group is equal to the preset brightness of the light-emitting unit.

[0011] In the present application, the saturated threshold voltages of each LED chip in the LED chip group are different.

[0012] In the present application, the LED chip comprises an N-type layer and a P-type layer, and the product of the doping concentration of the N-type layer and the doping concentration of the P-type layer is a doping concentration product; the doping concentration product of each LED chip in the LED chip group is different.

[0013] In the present application, the saturation threshold voltage of any LED chip in the LED chip group does not exceed the safe voltage of the LED chip with the smallest saturation threshold voltage.

[0014] In the present application, the light-emitting unit further comprises a first thin film transistor, the gate of the first thin film transistor is connected with a scanning line, the source of the first thin film transistor is connected with a signal line; the drain of the first thin film transistor is connected with the gate of a second thin film transistor, and the drain of the second thin film transistor is connected with the LED chip group.

[0015] In the present application, the saturation brightness of each LED chip in the LED chip group is equal.

[0016] The present application is a pixel unit of an LED display, which comprises the light-emitting unit as described above, and the number of the light-emitting unit is three.

[0017] In the present application, the three light-emitting units are respectively a red light-emitting unit, a green light-emitting unit and a blue light-emitting unit.

[0018] The present application is an LED display, which comprises the pixel unit as described above, and the number of the pixel unit is more than one.

[0019] In the present application, the LED display further comprises a data signal driver and a scanning signal driver, the data signal driver is connected with the light-emitting unit in the pixel unit through a signal line, and the scanning signal driver is connected with the light-emitting unit in the pixel unit through a scanning line.

[0020] The light-emitting unit of the present application is provided with two or more LED chips connected in parallel and with different saturation threshold voltages, which effectively shortens the adjustment range of the driving voltage and improves the flexibility of circuit adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0021] For easy description, the present application is described in detail by the preferred embodiments and the accompanying drawings.

[0022] Figure 1 The figure is a relationship between the driving voltage and the brightness in the prior art;

[0023] Figure 2 The figure is a relationship between the driving voltage and the brightness in the embodiment 1 of the present application;

[0024] Figure 3 A circuit structure schematic diagram of the light emitting unit in the present application;

[0025] Figure 4 A graph of the relationship between the driving voltage and the brightness in Embodiment 2 of the present application;

[0026] Figure 5 A circuit structure schematic diagram of the LED display in the present application. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0028] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0029] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected. It can be mechanical connection, or electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] Embodiment 1

[0031] In the following, a light emitting unit of an LED display of the present application is specifically described with an embodiment, please refer to Figures 2 to 3It mainly comprises two thin film transistors (TFT), a capacitor and a light emitting diode (LED) chip set;

[0032] The first thin film transistor T1 is connected with a scanning line SCAN at the gate, and connected with a signal line DATA at the source; the drain of the first thin film transistor T1 is connected with the gate of the second thin film transistor T2, one end of the capacitor is connected with the source of the second thin film transistor T2, and the other end of the capacitor is connected with the gate of the second thin film transistor T2; the drain of the second thin film transistor T2 is connected with an LED chip set, which comprises four LED chips in parallel, i.e. a first LED chip D1, a second LED chip D2, a third LED chip D3 and a fourth LED chip D4; wherein the saturation threshold voltage V D1 of the first LED chip is the same as the saturation threshold voltage V D2 of the second LED chip, the saturation threshold voltage V D3 of the third LED chip is the same as the saturation threshold voltage V D4 of the fourth LED chip; and the saturation threshold voltage V D1 , V D2 of the first and second LED chips is less than the saturation threshold voltage V D3 , V D4 of the third and fourth LED chips, i.e. V D1 = V D2 , V D3 = V D4 , and V D2 < V D3 .

[0033] In the embodiment, the saturation threshold voltage of any LED chip in the LED chip set does not exceed the safety voltage of the LED chip with the smallest saturation threshold voltage; i.e. the saturation threshold voltage of D3 and D4 does not exceed the safety voltage of D2 and D1, which effectively protects the first and second LED chips D1 and D2 from being damaged due to the excessively high saturation threshold voltage of the third and fourth LED chips D3 and D4. Each of the LED chips comprises an N-type layer and a P-type layer, and the product of the doping concentration of the N-type layer and the doping concentration of the P-type layer is a doping concentration product; the doping concentration products of D1 and D2 are different from the doping concentration products of D3 and D4, which makes the saturation threshold voltages of D1 and D2 different from the saturation threshold voltages of D3 and D4.

[0034] In the embodiment, the saturation luminance of the first, second, third and fourth LED chips are equal, i.e. L1=L2=L3=L4=L0 / 4, and the sum of the saturation luminance of the first, second, third and fourth LED chips is equal to the preset luminance L0 of the light emitting unit, i.e. L1+L2+L3+L4=L0. The preset luminance L0 of the light emitting unit is the maximum luminance that the light emitting unit can emit. Therefore, the relationship between the driving voltage and the luminance of the first, second, third and fourth LED chips is shown in Table 1:

[0035] Table 1, relationship table of driving voltage and luminance

[0036]

[0037] Therefore, only the driving voltage V of the light emitting unit needs to be adjusted from 0 to V D2 , where V D2 is far less than the saturation threshold voltage V0 of a single LED chip, so that the luminance adjustment of the light emitting unit from 0 to L0 can be realized. This not only saves energy consumption, but also reduces the amplitude of the driving voltage, making the luminance adjustment of the light emitting unit more flexible.

[0038] Embodiment 2

[0039] In the following, another embodiment of a light emitting unit of an LED display of the present application is described in detail. Please refer to Figures 3 to 4 , which is composed of two thin film transistors (TFT), a capacitor and a light emitting diode (LED) chip group, which includes:

[0040] The gate of the first thin film transistor T1 is connected with a scan line SCAN, and the source of the first thin film transistor T1 is connected with a signal line DATA; the drain of the first thin film transistor T1 is connected with the gate of the second thin film transistor T2, and the source of the second thin film transistor T2 is connected with one end of the capacitor, and the other end of the capacitor is connected with the gate of the second thin film transistor T2; the drain of the second thin film transistor T2 is connected with an LED chip group, and the LED chip group includes four LED chips in parallel, which are a first LED chip D1, a second LED chip D2, a third LED chip D3 and a fourth LED chip D4; wherein the saturation threshold voltage V D1 of the first LED chip, the saturation threshold voltage V D2 of the second LED chip, the saturation threshold voltage V D3 of the third LED chip and the saturation threshold voltage V D4 of the fourth LED chip are different from each other; and the saturation threshold voltage V D4The saturation threshold voltage V of the third LED chip D3 The saturation threshold voltage V of the second LED chip D2 The saturation threshold voltage V of the first LED chip D1 .

[0041] In the embodiment, the saturation threshold voltage of each LED chip in the LED chip group is not more than the safety voltage of the LED chip with the minimum saturation threshold voltage; that is, the saturation threshold voltage of the fourth LED chip D4, the third LED chip D3 and the second LED chip D2 is not more than the safety voltage of the first LED chip D1, which effectively protects the first LED chip D1 from damage due to the excessively high saturation threshold voltage of any one LED chip. Moreover, each LED chip comprises an N-type layer and a P-type layer, and the product of the doping concentration of the N-type layer and the doping concentration of the P-type layer is a doping concentration product; the doping concentration products of D1, D2, D3 and D4 in the LED chip group are not the same. Since the doping concentration products of the LED chips are not the same, the saturation threshold voltages of D1, D2, D3 and D4 are different.

[0042] In the embodiment, the saturation luminance of the first, second, third and fourth LED chips is equal, that is, L1=L2=L3=L4=L0 / 4, and the sum of the saturation luminance of the first, second, third and fourth LED chips is equal to the preset luminance L0 of the light emitting unit, that is, L1+L2+L3+L4=L0. The preset luminance L0 of the light emitting unit is the maximum luminance that the light emitting unit can emit. Therefore, the relationship between the driving voltage and the luminance of the first, second, third and fourth LED chips is shown in Table 2.

[0043] Table 2, relationship table of driving voltage and luminance

[0044]

[0045] Therefore, only the driving voltage V of the light emitting unit needs to be adjusted from 0 to V D4 wherein V D4 which is much smaller than the saturation threshold voltage V0 of a single LED chip, so that the luminance of the light emitting unit can be adjusted from 0 to L0. The embodiment not only saves energy consumption, but also reduces the amplitude of the driving voltage, making the luminance adjustment of the light emitting unit more flexible; and the modulation precision is more detailed and flexible than that of the first embodiment.

[0046] The present application is a pixel unit SPR of an LED display, which is composed of three light emitting units, wherein the three light emitting units are a red light emitting unit R, a green light emitting unit G and a blue light emitting unit B respectively; and each light emitting unit can comprise a light emitting unit structure as described in Embodiment 1 or Embodiment 2. In the pixel unit SPR, the luminous brightness of the red light emitting unit R, the green light emitting unit G and the blue light emitting unit B is adjusted respectively, so as to adjust and mix the proportions of the red, green and blue colors in the pixel unit SPR, to achieve the required display color.

[0047] Please refer to Figure 5 The present application is an LED display, which comprises a data signal driver and a scanning signal driver, the data signal driver is connected with the gate of the first thin film transistor T1 in the red light emitting unit R, the green light emitting unit G and the blue light emitting unit B in the pixel unit SPR respectively through a signal line DATA, the scanning signal driver is connected with the source of the first thin film transistor T1 in the red light emitting unit R, the green light emitting unit G and the blue light emitting unit B in the pixel unit SPR respectively through a scanning line SCAN; and the number of the pixel unit SPR in the LED display is more than one.

[0048] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0049] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A light-emitting unit of an LED display, characterized in that: include: LED chipset, The LED chipset comprises N LED chips of the same color arranged in parallel, where N is a positive integer greater than or equal to 2; At least two of the N LED chips have different saturation threshold voltages; the saturation threshold voltage of any LED chip in the LED chip group does not exceed the safe voltage of the LED chip with the smallest saturation threshold voltage; The sum of the saturated brightness of all LED chips in the LED chip group is equal to the preset brightness of the light-emitting unit.

2. The light-emitting unit of the LED display according to claim 1, characterized in that: The saturation threshold voltage of each LED chip in the LED chip group is different.

3. The light-emitting unit of the LED display according to claim 1, characterized in that: The light-emitting unit also includes: a first thin film transistor, the gate of the first thin film transistor is connected to the scan line, the source of the first thin film transistor is connected to the signal line; the drain of the first thin film transistor is connected to the gate of the second thin film transistor, and the drain of the second thin film transistor is connected to the LED chip group.

4. The light-emitting unit of an LED display according to any one of claims 1 to 3, characterized in that: The saturated brightness of each LED chip in the LED chip group is equal.

5. A pixel unit of an LED display, characterized in that: include: The light-emitting unit according to any one of claims 1 to 4, wherein the number of the light-emitting units is three.

6. The pixel unit of the LED display according to claim 5, characterized in that: The three light-emitting units are respectively: a red light-emitting unit, a green light-emitting unit, and a blue light-emitting unit.

7. An LED display, characterized in that: include: The pixel unit according to any one of claims 5 to 6, wherein the number of the pixel units is more than one.

8. The LED display according to claim 7, characterized in that: The LED display further comprises: a data signal driver and a scan signal driver. The data signal driver is connected to the light emitting unit in the pixel unit through a signal line, and the scan signal driver is connected to the light emitting unit in the pixel unit through a scan line.

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