Backlight source chip and LCD display screen

Abstract

The utility model relates to the technical field of semiconductors, in particular to a backlight source chip and an LCD display screen, the backlight source chip comprises a substrate, interdigital electrodes and LED chips distributed on the substrate, and a light color conversion layer covering the surfaces of the LED chips, and the LED chips comprise a blue light LED chip and a green light LED chip; the blue-light LED chip and the green-light LED chip are electrically connected with an external driver through the interdigital electrodes and leads; the light color conversion layer is used for converting the color of light emitted by the blue light LED chip and the green light LED chip into white, compared with a backlight source chip only comprising the blue light LED chip, the backlight source chip has the advantage that a green light component is added, and the color gamut of an LCD display screen can be improved.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor technology, and in particular to a backlight source chip and an LCD display screen. Background Technology

[0002] LCD displays (also known as liquid crystal displays) are mainly composed of a backlight source, a liquid crystal layer, thin film transistors (TFTs), and color filters. They control the rotation direction of liquid crystal molecules in the liquid crystal layer by changing TFT signals and voltages, thereby controlling whether polarized light is emitted from each pixel, thus achieving the display purpose.

[0003] Currently, LCD displays are mainly used in scenarios requiring small display unit area and high resolution. They do not emit light themselves and require an additional backlight source, which primarily consists of a white light source, optical films, and a light guide plate. Currently, the LED chips used in LCD backlights are blue LED chips, with yellow phosphors coated on them to convert blue light into white light. However, backlights obtained in this way have a narrow color gamut when used in LCD displays. Research has found that adding a green light component to the LED chip can broaden the color gamut of the LCD display. One way to add the green light component in the LED industry is to grow epitaxial layers with two main peak wavelengths (455nm and 530nm) during the epitaxial structure growth process. However, due to current manufacturing process limitations, this technological bottleneck is unlikely to be overcome in the short term. Summary of the Invention

[0004] This invention provides a backlight source chip with a simple and reasonable structural design.

[0005] The technical solution adopted is as follows:

[0006] A backlight source chip, characterized in that it comprises:

[0007] Substrate;

[0008] LED chips, including blue LED chips and green LED chips, are distributed on the substrate.

[0009] Intercalation electrodes are distributed on the upper surface of the substrate, and the blue LED chip and green LED chip are electrically connected to an external driver through the intercalation electrodes and leads;

[0010] A light color conversion layer is applied to the surface of the LED chip to convert the light emitted by the blue LED chip and the green LED chip into white.

[0011] Its further feature is that,

[0012] The intercalation electrode includes a first intercalation electrode and a second intercalation electrode. The first intercalation electrode and the second intercalation electrode are disposed opposite to each other and have opposite polarities. Each intercalation electrode includes at least two connection lines. The first intercalation electrode includes a first positive connection line, a second positive connection line to an Nth positive connection line, and a first pad. The second intercalation electrode includes a first negative connection line, a second negative connection line to an Nth negative connection line, and a second pad. The first pad and the second pad are distributed on the upper surface edge of the substrate, where N is an integer and N≥2. One end of the first positive connection line and the second positive connection line to the Nth positive connection line are connected to the first pad, and the other end are respectively connected to the first pad. The second pad extends horizontally. One end of the first negative electrode connection line, the second negative electrode connection line, and the Nth negative electrode connection line are connected to the second pad, and the other end extends horizontally towards the first pad. The first positive electrode connection line and the first negative electrode connection line are parallel to each other to form a first group of connection lines. The second positive electrode connection line and the second negative electrode connection line are parallel to each other to form a second group of connection lines. The Nth positive electrode connection line and the Nth negative electrode connection line are parallel to each other to form a Nth group of connection lines. The blue LED chip and the green LED chip are installed at intervals on the first group of connection lines, the second group of connection lines, and the Nth group of connection lines. The first pad and the second pad are used to connect leads.

[0013] Furthermore, the light-color conversion layer is a phosphor layer or a quantum powder layer.

[0014] Furthermore, the phosphor layer is a red phosphor layer or a yellow phosphor layer, and the quantum powder layer is a red quantum powder layer or a yellow quantum powder layer.

[0015] Furthermore, the LED chip is a Micro LED chip.

[0016] Furthermore, in the same light source chip, the ratio of the number of blue LED chips to the number of green LED chips is 2:1.

[0017] Furthermore, the dominant wavelength of the blue LED chip is 450nm-460nm.

[0018] Furthermore, the dominant wavelength of the green LED chip is 520nm-540nm.

[0019] Furthermore, it also includes a reflective layer and an insulating layer, which are distributed sequentially from bottom to top on the upper surface of the substrate, and the interdigitated electrode is located in the insulating layer.

[0020] Furthermore, the insulating layer is made of SiO2 or SiN.

[0021] Furthermore, the light color conversion layer covers the entire surface including the LED chip, and connection areas are formed on both sides of the light color conversion layer. The connection areas penetrate the light color conversion layer, exposing the first pad and the second pad.

[0022] Furthermore, a notch is provided on one side of the connection area, and the opening directions of the notches on both sides are opposite, both facing outwards from the substrate.

[0023] An LCD display screen includes a liquid crystal layer, a thin film transistor, a color filter, and a backlight source chip. The backlight source chip is arranged in an array to form a backlight source. The backlight source, the liquid crystal layer, and the color filter are arranged in sequence. The thin film transistor is electrically connected to the liquid crystal layer and is used to control the working state of the liquid crystal layer.

[0024] The backlight source chip of this application contains LED chips of two primary colors: blue LED chips and green LED chips. Compared with backlight source chips that only contain blue LED chips, the backlight source chip of this application adds a green component, which is beneficial to improving the color gamut of the LCD display. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural diagram of the substrate of this application;

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure after the reflective layer is formed in this application;

[0027] Figure 3 This is a three-dimensional structural diagram of the present application after the insulating layer has been formed;

[0028] Figure 4 A schematic diagram of the three-dimensional structure after the first interdigitated electrode and the second interdigitated electrode are formed in this application;

[0029] Figure 5 A top view schematic diagram of the structure after the first interdigitated electrode and the second interdigitated electrode are formed in this application;

[0030] Figure 6 This is a three-dimensional structural diagram of the present application after installing blue LED chips and green LED chips;

[0031] Figure 7 This is a top view of the structure after installing the blue LED chip and the green LED chip in this application.

[0032] Figure 8 A schematic diagram of the three-dimensional structure after the formation of the light-color conversion layer in this application;

[0033] Figure 9 A top view schematic diagram of the structure after the formation of the light color conversion layer in this application;

[0034] Figure 10 This is a schematic diagram of the three-dimensional structure after the light-color conversion layer is formed in another embodiment of this application.

[0035] Reference numerals: 1. Substrate; 2. Connecting region; 3. LED chip; 4. Light color conversion layer; 5. First interdigitated electrode; 6. Second interdigitated electrode; 7. Insulating layer; 8. Reflective layer;

[0036] Green LED chip 301, blue LED chip 302;

[0037] First positive electrode connection line 501, second positive electrode connection line 502, third positive electrode connection line 503, first solder pad 500;

[0038] First negative terminal connection line 601, second negative terminal connection line 602, third negative terminal connection line 603, second solder pad 600. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0040] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this utility model are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0041] The following discloses a specific embodiment of a backlight source chip, which includes: a substrate 1, interdigitated electrodes, an LED chip 3, and a light color conversion layer 4. The LED chip 3 includes a blue LED chip 301 and a green LED chip 302. Both the blue LED chip 302 and the green LED chip 301 are Micro LED chips, which are electrically connected to an external driver through interdigitated electrodes and leads, respectively.

[0042] The intercalation electrodes include a first intercalation electrode 5 and a second intercalation electrode 6 arranged opposite to each other and with opposite polarities. The first intercalation electrode 5 and the second intercalation electrode 6 are distributed in an insulating layer 7 on the upper surface of the substrate 1, and the upper surface of the intercalation electrodes is flush with the upper surface of the insulating layer 7 to facilitate the mounting of the LED chip 3 and the soldering of leads. In this embodiment, the insulating layer 7 is preferably made of SiO2. The insulating layer 7 prevents electrical interference between the first intercalation electrode 5 and the second intercalation electrode 6.

[0043] The first interdigitated electrode 5 includes a first positive electrode connection line 501, a second positive electrode connection line 502...the Nth positive electrode connection line, and a first pad 500. The second interdigitated electrode 6 includes a first negative electrode connection line 601, a second negative electrode connection line 602...the Nth negative electrode connection line, and a second pad 600. The first pad 500 and the second pad 600 are distributed on the upper surface edge of the substrate 1 and are used to connect leads. N is an integer and N≥2. In this embodiment, each interdigitated electrode includes three connection lines, i.e., N=3. Therefore, the first interdigitated electrode includes a first positive electrode connection line 501, a second positive electrode connection line 502, a third positive electrode connection line 503, and a first pad 500, and the second interdigitated electrode 6 includes a first negative electrode connection line 601, a second negative electrode connection line 602, a third negative electrode connection line 603, and a second pad 600.

[0044] When N=3, the specific distribution structure of the first finger electrode 5 and the second finger electrode 6 is as follows: one end of the first positive electrode connection line 501, the second positive electrode connection line 502, and the third positive electrode connection line 503 is connected to the first pad 500, and the other end extends horizontally towards the second pad 600 respectively. One end of the first negative electrode connection line 601, the second negative electrode connection line 602, and the third negative electrode connection line 603 is connected to the second pad 600, and the other end extends horizontally towards the first pad 500 respectively. The first positive electrode connection line 501 and the first negative electrode connection line 601 are parallel to each other to form the first group of connection lines. The second positive electrode connection line 502 and the second negative electrode connection line 602 are parallel to each other to form the second group of connection lines. The third positive electrode connection line 503 and the third negative electrode connection line 603 are parallel to each other to form the third group of connection lines.

[0045] It should be noted that this application does not specify the number of positive and negative connection lines. The number of positive and negative connection lines is the same. When designing the backlight source chip, the specific number of positive and negative connection lines can be flexibly set according to the LED chip size, backlight source chip size, backlight source chip brightness requirements, and other conditions.

[0046] To ensure that the light emitted by the blue LED chip 302 and the green LED chip 301 displays white after passing through the color conversion layer 4, the blue LED chips 302 and the green LED chips 301 are configured in a reasonable ratio, and a suitable color color conversion layer 4 is selected. The color conversion layer 4 covers the entire surface containing the blue LED chips 302 and the green LED chips 301. In this embodiment, the color conversion layer is preferably a yellow phosphor layer. Based on the peak emission wavelength and light output of the blue LED chips 302 and the green LED chips 301, as well as the luminous flux of the color conversion layer 4, the ratio of blue LED chips 302 to green LED chips 301 in the same light source chip is set to 2:1. Compared to a light source chip that only contains blue LED chips 302, the backlight light source chip of this application adds a green component, which is beneficial for improving the color gamut of the LCD display.

[0047] In addition, to facilitate the soldering of leads for the backlight chip and its electrical connection to an external driver via these leads, in this embodiment, connection regions 2 are formed on both sides of the light color conversion layer 4. The connection regions 2 penetrate the light color conversion layer, exposing the first pad 500 and the second pad 600. A notch is formed on one side of each connection region 2, with the opening directions of the two notches being opposite, both facing outwards from the substrate. The first pad 500 and the second pad 600 are positioned close to the edge of the substrate, further facilitating the soldering of leads at the first pad 500 and the second pad 600.

[0048] It should be further explained that, in another embodiment, to facilitate the soldering of leads at the first pad 500 and the second pad 600 of the backlight source chip, the color conversion layer 4 may only cover the areas where the blue LED chip and the green LED chip are located. For example, the color conversion layer 4 may be configured as a quadrilateral, with the edges of the substrate 1, the reflective layer 8, and the insulating layer 7 where the first pad 500 and the second pad 600 are located protruding from both sides of the color conversion layer 4, forming a "convex" shape. (Refer to...) Figure 10 .

[0049] The specific installation method of blue LED chips 302 and green LED chips 301 in the interdigitated electrodes is as follows: blue LED chips 302 and green LED chips 301 are evenly spaced on the first set of connecting lines, the second set of connecting lines, and the third set of connecting lines. That is, two blue LED chips 302 are installed in the first set of connecting lines with spacing, two green LED chips 301 are installed in the second set of connecting lines with spacing, and two blue LED chips 302 are installed in the third set of connecting lines with spacing. In this embodiment, there are four blue LED chips 302 and two green LED chips 301. The positive and negative electrodes of the two blue LED chips 302 are connected to the first positive electrode connecting line 501 and the first negative electrode connecting line 601, respectively. The positive and negative electrodes of the two green LED chips 301 are connected to the second positive electrode connecting line 502 and the second negative electrode connecting line 602, respectively. The other two blue LED chips 302 are connected to the third positive electrode connecting line 503 and the third negative electrode connecting line 603, respectively.

[0050] It should be noted that this application does not specifically limit the ratio of blue LED chips 302 to green LED chips 301. The number of blue LED chips 302 and green LED chips 301 can be flexibly set according to their emission peak wavelength, light output, light flux of the light color conversion layer, and light source chip size.

[0051] To improve the light extraction efficiency of the backlight source chip, a reflective layer 8 is also provided in the backlight source chip, which is distributed on the upper surface of the substrate 1. The reflective layer 8 is a DBR reflective layer or a metal reflective layer; the DBR reflective layer includes SiO2. 2、 Ti3O5, the metal reflective layer includes Ag and Al. In this embodiment, the reflective layer 8 is preferably a DBR reflective layer.

[0052] A method for fabricating the above-mentioned light source chip, specifically comprising the following steps: S1, providing a substrate 1 (reference) Figure 1 ), and several LED chips 3, including blue LED chips and green LED chips;

[0053] S2. A reflective layer 8 and an insulating layer 7 are sequentially deposited on the upper surface of substrate 1, specifically including:

[0054] S21. Using electron gun evaporation, a metal film is deposited on the upper surface of the substrate to form a reflective layer 8. (Refer to...) Figure 2 The reflective layer is either a metal reflective layer or a DBR reflective layer. The reflective layer is used to reflect the light emitted by the LED chip 3, which helps to improve the light output efficiency of the backlight source chip.

[0055] S22. An insulating layer 7 is grown using PECVD or chemical vapor deposition (CVD / ALD), see reference. Figure 3The material of the insulating layer 7 is preferably SiO2 or SiN.

[0056] S3. Fabricating intercalation electrodes on the substrate 1, specifically including: S31. Using photolithography and etching processes, etching the insulating layer 7 to form a first etching trench and a second etching trench, the shapes of the first etching trench and the second etching trench matching the shapes of the first intercalation electrode 5 and the second intercalation electrode 6.

[0057] Specifically: S311, a first photoresist is coated on the surface of the insulating layer 7;

[0058] S312. Expose the first photoresist based on the first photomask;

[0059] S313, Development, to expose the area to be etched in the insulating layer 7;

[0060] S314. Using dry etching or wet etching, the area to be etched is etched to form a first etching trench and a second etching trench; the depth of the first etching trench and the second etching trench is less than the thickness of the insulating layer 7.

[0061] S315, Clean and remove residual first photoresist.

[0062] S32. Using electron beam evaporation or magnetron sputtering deposition, a conductive material is deposited on the upper surface of the insulating layer 7 in the first etching tank and the second etching tank. In this embodiment, copper is preferred as the conductive material.

[0063] S33. The conductive material is ground using a chemical mechanical polishing machine to reduce its thickness, that is, the conductive material on the upper surface of the insulating layer 7 is removed, and the conductive materials remaining in the first etching tank and the second etching tank are the first interdigitated electrode 5 and the second interdigitated electrode 6, respectively.

[0064] It should be noted that, in another embodiment, a photolithography, coating, and stripping process can be used to prepare patterned first interdigitated electrodes 5 and second interdigitated electrodes 6 on the surface of the insulating layer 7. Specifically, a third photoresist is coated on the surface of the insulating layer, the third photoresist is exposed and developed, and a conductive material is deposited on the surface of the third photoresist using an electron beam evaporation method or a magnetron sputtering coating process. Based on the developed pattern, the conductive material is stripped to obtain the patterned first interdigitated electrodes 5 and second interdigitated electrodes 6.

[0065] S3. Install the blue LED chip 302 and the green LED chip 301 onto the interdigitated electrode. In this embodiment, the blue LED chip 302 and the green LED chip 301 are both flip-chip Micro LED chips with a size between 1μm and 100μm, which can achieve flip-chip connection with the interdigitated electrode.

[0066] S4. A light color conversion layer 4 is covered on the surface of the blue LED chip 302 and the green LED chip 301. The specific preparation steps of the light color conversion layer 4 include: S41. Using a coating machine, a light color conversion material is coated on the entire surface of the blue LED chip 302 and the green LED chip 301. The light color conversion material includes, but is not limited to, quantum powder material or phosphor material. In this embodiment, yellow phosphor material is preferred.

[0067] S42. Heating to solidify the light-color conversion material, forming the light-color conversion layer 4;

[0068] S43. Using photolithography and etching processes, a local area of ​​the light color conversion layer 4 is etched to form a third etching trench and a fourth etching trench. The third etching trench and the fourth etching trench are the connection areas 2 located on both sides of the light color conversion layer.

[0069] Specifically: S431, a second photoresist is coated on the surface of the light color conversion layer 4;

[0070] S432. Expose the second photoresist based on the second mask;

[0071] S433, Development, to expose the area to be etched in the light color conversion layer 4;

[0072] S434. Using dry etching or wet etching, the area to be etched in the light color conversion layer 4 is etched to form the third etching trench and the fourth etching trench.

[0073] S435, Clean and remove residual second photoresist.

[0074] When driving and controlling the backlight source chip, the blue LED chip 302 is electrically connected to the external driver through the first set of connection lines / the third set of connection lines, the first pad and the second pad, and the lead wire, while the green LED chip 301 is electrically connected to the external driver through the second set of connection lines, the first pad and the second pad, and the lead wire.

[0075] When emitting light, an external driver sends a driving current signal. This driving current signal is transmitted via leads, the first pad 500 and the second pad 600, and the first / third set of connecting lines to the corresponding blue LED chip 302. It is then transmitted via the first pad 500 and the second pad 600, and the second set of connecting lines to the corresponding green LED chip 301, causing both the blue LED chip 302 and the green LED chip 301 to emit light simultaneously. The light emitted by the blue LED chip 302 and the green LED chip 301 is converted to white by a yellow phosphor layer. This backlight source chip contains LED chips of two primary colors: blue LED chip 302 and green LED chip 301. Compared to backlight source chips that only contain blue LED chips, this application's backlight source chip adds a green component, which is beneficial for improving the color gamut of the LCD display.

[0076] When the aforementioned backlight chip is applied to an LCD display, the LCD display also includes a liquid crystal layer, thin-film transistors (TFTs), and color filters. The backlight chip, liquid crystal layer, and color filters are arranged sequentially from bottom to top. The TFTs are electrically connected to the liquid crystal layer for driving and controlling the liquid crystal layer. LCD displays using the backlight chip of this application have a wider color gamut, and the display effect of the LCD display is significantly improved.

[0077] It is understood that the above detailed description of this utility model is for illustrative purposes only and is not intended to limit the technical solutions described in the embodiments of this utility model. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to this utility model to achieve the same technical effects; as long as the usage requirements are met, they are all within the protection scope of this utility model.

Claims

1. A backlight source chip, characterized in that, It includes: Substrate (1); LED chips (3) are distributed on the substrate (1), including blue LED chips (302) and green LED chips (301). Intercalation electrodes are distributed on the upper surface of the substrate (1), and the blue LED chip (302) and green LED chip (301) are electrically connected to the external drive through the intercalation electrodes and leads; A light color conversion layer (4) is applied to the surface of the LED chip to convert the light emitted by the blue LED chip (302) and the green LED chip (301) into white.

2. The backlight source chip according to claim 1, characterized in that, The interdigitated electrodes include a first interdigitated electrode (5) and a second interdigitated electrode (6). The first interdigitated electrode (5) and the second interdigitated electrode (6) are disposed opposite to each other and have opposite polarities. Each interdigitated electrode includes at least two connecting lines. The first interdigitated electrode includes a first positive electrode connecting line (501), a second positive electrode connecting line (502) to the Nth positive electrode connecting line, and a first pad (500). The second interdigitated electrode includes a first negative electrode connecting line (601), a second negative electrode connecting line (602) to the Nth negative electrode connecting line, and a second pad (600). The first pad (500) and the second pad (600) are distributed on the upper surface edge of the substrate (1). N is an integer and N≥2. One end of the first positive electrode connecting line (501) and the second positive electrode connecting line (502) to the Nth positive electrode connecting line are connected to the first pad (500), and the other end is respectively connected to the first pad (500). Extending horizontally towards the second pad (600), one end of the first negative electrode connection line (601), the second negative electrode connection line (602) to the Nth negative electrode connection line is connected to the second pad (600), and the other end extends horizontally towards the first pad (500). The first positive electrode connection line (501) and the first negative electrode connection line (601) are parallel to each other to form the first group of connection lines. The second positive electrode connection line (502) and the second negative electrode connection line (602) are parallel to each other to form the second group of connection lines. The Nth positive electrode connection line and the Nth negative electrode connection line are parallel to each other to form the Nth group of connection lines. The blue LED chip (302) and the green LED chip (301) are installed at intervals on the first group of connection lines, the second group of connection lines to the Nth group of connection lines. The first pad (500) and the second pad (600) are used to connect leads.

3. The backlight source chip according to claim 1 or 2, characterized in that, The light conversion layer (4) is a phosphor layer or a quantum powder layer.

4. The backlight source chip according to claim 3, characterized in that, The phosphor layer is a red phosphor layer or a yellow phosphor layer, and the quantum powder layer is a red quantum powder layer or a yellow quantum powder layer.

5. The backlight source chip according to claim 4, characterized in that, The LED chip (3) is a Micro LED chip.

6. The backlight source chip according to claim 1 or 5, characterized in that, In the same light source chip, the ratio of the number of blue LED chips (302) to the number of green LED chips (301) is 2:

1.

7. The backlight source chip according to claim 6, characterized in that, It also includes a reflective layer (8) and an insulating layer (7), which are distributed sequentially from bottom to top on the upper surface of the substrate (1), and the interdigitated electrode is located on the insulating layer (7).

8. The backlight source chip according to claim 2, characterized in that, The light color conversion layer (4) covers the entire surface containing the LED chip. Connection areas (2) are provided on both sides of the light color conversion layer (4). The connection areas (2) penetrate the light color conversion layer (4), exposing the first pad (500) and the second pad (600).

9. An LCD display screen, comprising a liquid crystal layer, thin-film transistors, a color filter, and a backlight source chip, characterized in that, The backlight source chip is the backlight source chip as described in claim 1. The backlight source chip array is distributed to form a backlight source. The backlight source, liquid crystal layer, and color filter are arranged sequentially from bottom to top. The thin film transistor is electrically connected to the liquid crystal layer and is used to control the working state of the liquid crystal layer.

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