Design process for solving front light source light spot

Abstract

The invention provides a design process for solving light spots of a front light source, which relates to the technical field of liquid crystal display, and comprises the following steps: designing a backlight structure of the front light source, and attaching a black mylar on a backlight LED of the front light source; the black mylar is used for absorbing and covering light spots of front light when an LED is powered on to emit light, the problem of front light source backlight lamp eyes is solved, the attaching process of the black mylar is the change of the attaching process of the front light source backlight, the change only relates to the adjustment of the attaching process, other structures are not changed, net points are designed on the front face of a light guide plate of the front light source backlight, and the front light source backlight lamp eyes are arranged on the front face of the light guide plate. The light guide plate and the LED light bar are designed in an inverted mode, through the structural design of the front light source backlight, a piece of black mylar is pasted on the front light source backlight LED, when the LED is powered on to emit light, the black film can absorb and cover light spots of front light, only the pasting technology of the front light source backlight needs to be changed, operation is convenient and easy, and the problem of front light source backlight lamp eyes can be effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of liquid crystal display technology, and more specifically, relates to a design process for solving front light source spot problem. Background Art

[0002] Liquid crystal display (LCD) is a mainstream display technology. Its front-light reflective LCD display has become increasingly popular in recent years due to its advantages such as eye protection and energy saving. The front-light backlight design of this type of display has its own characteristics:

[0003] Structural differences: The dots are designed directly on the front of the light guide plate, the light guide plate and LED light strip adopt an inverted structure, and there is no diffusion film and brightness enhancement film of traditional backlight.

[0004] Technical bottleneck: Due to the lack of optical adjustment of the diffusion film and the brightening film, it is extremely difficult to process the lamp mouth effect, and the "lamp eye" (light spot) problem is prone to occur, resulting in uneven display and affecting the user experience.

[0005] Existing technology is insufficient

[0006] Optimization limitations: Simply optimizing the light guide plate dot design cannot completely solve the light spot problem and may affect the overall brightness uniformity.

[0007] Complex process: Some existing solutions solve the problem by adding optical film layers or changing the light guide plate structure, but this will increase costs and significantly increase the complexity of the process, which is not conducive to large-scale production.

[0008] Industry pain point: The light spot problem of front light source and backlight has long plagued the display industry, and a low-cost and easy-to-implement solution is urgently needed. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a design process for solving the light spot of the front light source to solve the above problems.

[0010] A design solution for solving front light source spot problems includes: attaching a black Mylar layer to the surface of the LED lamp of the front light source backlight, wherein the black Mylar layer has an absorbance of ≥90% and is used to absorb direct light generated by the LED to cover the spot; the front surface of the light guide plate of the front light source backlight is provided with a mesh point, and the light guide plate and the LED light bar are in an inverted structure without a traditional diffusion film or brightness enhancement film. The black Mylar layer has a thickness of 5-50μm and a transmittance of ≤1%, and is made of polyethylene terephthalate (PET) with a black coating. The black Mylar layer is attached to cover the light-emitting surface of the LED lamp and a surrounding area of ​​5-10mm, and the distance between the edge and the LED lamp is ≤2mm.

[0011] The attachment process uses optically clear adhesive (OCA) or hot-pressed adhesive for bonding, with a bonding accuracy of ±0.1mm. After bonding, the bubble rate between the black Mylar layer and the surface of the LED lamp is ≤0.5%. The front light source backlight module also includes a Coverlens, a touch film (TouchFilmBT) and a flexible circuit board (FPC) covering the light guide plate. The black Mylar layer is located between the LED lamp and the touch film. The edge of the black Mylar layer is provided with a light-shielding ink coating to prevent side light leakage. The coating width is 0.5-1mm.

[0012] The LED lamp has a light emission wavelength of 450-650nm, and the black Mylar layer has a light absorption rate of ≥95% in this wavelength range. After the attachment process, a constant temperature and humidity test is required. The test conditions are 85°C / 85% RH for 48 hours. The black Mylar layer does not fall off or change color. The front light source backlight is applied to a liquid crystal display module, and the display module includes a mobile phone, a tablet computer, a car display or an industrial control display. The black Mylar layer is formed by a die-cutting process with a molding accuracy of ±0.05mm and an edge roughness Ra≤1μm.

[0013] This patent proposes a design that attaches black Mylar (BT) above the LED light by optimizing the structure of the front light source and backlight. The specific implementation is as follows:

[0014] Structural design: Black Mylar is directly attached to the surface of the LED lamp. Utilizing the light absorption characteristics of black Mylar, when the LED is powered on and emits light, the black film can absorb and cover the light spot generated by the front light.

[0015] Process adjustment: Only the lamination process of the front light source and backlight needs to be changed, without changing the core components such as the light guide plate and LED flip-chip structure, which is convenient to operate.

[0016] Material selection: Black Mylar is a high-absorbency material. Its thickness and transmittance must meet the optical requirements of the display module and have good lamination compatibility.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Light spot elimination: The light absorption characteristics of black Mylar can effectively absorb direct LED light, cover light spots, and improve the brightness uniformity of the display screen by ≥90%, meeting industry standards.

[0019] Process simplification: Only the lamination process is changed, without the need for new equipment or complex procedures, production efficiency is increased by 30%, and the yield rate is maintained at above 98%.

[0020] Strong compatibility: Applicable to existing front light source and backlight production lines, compatible with designs such as flip-chip light guide plate structures and FPC circuit connections, without the need to redevelop molds.

[0021] Through the structural design of the front light source backlight, a black mylar film is placed on the front light source backlight LED. When the LED is powered on and emits light, the black film can absorb and cover the light spot of the front light. Only the lamination process of the front light source backlight needs to be modified. It is convenient and easy to operate, and can effectively solve the problem of front light source backlight eye. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the LED spot elimination structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the existing front light source backlight structure;

[0024] Figure 3 It is a schematic diagram of the backlight shielding structure of the front light source of the present invention. DETAILED DESCRIPTION

[0025] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0026] See also Figure 1-Figure 3 The present invention provides a design solution for solving the light spot of the front light source, including: attaching a black Mylar layer on the surface of the LED lamp of the front light source backlight, the black Mylar layer has an absorbance of ≥90%, and is used to absorb direct light generated when the LED emits light to cover the light spot; the front side of the light guide plate of the front light source backlight is provided with a mesh, and the light guide plate and the LED light bar are in an inverted structure, without a traditional diffusion film and a brightness enhancement film, the black Mylar layer has a thickness of 5-50μm and a transmittance of ≤1%, and is made of polyethylene terephthalate (PET) based on a black coating. The attachment position of the black Mylar layer covers the light-emitting surface of the LED lamp and the surrounding area of ​​5-10mm, and the distance between the edge and the LED lamp is ≤2mm.

[0027] The lamination process uses optically clear adhesive (OCA) or hot pressing adhesive for lamination, with a lamination accuracy of ±0.1mm. After lamination, the bubble rate between the black Mylar layer and the surface of the LED lamp is ≤0.5%. The front light source backlight module also includes a Coverlens covering the light guide plate, a touch film (TouchFilmBT) and a flexible circuit board (FPC). The black Mylar layer is located between the LED lamp and the touch film. The edge of the black Mylar layer is provided with a light-shielding ink coating to prevent side light leakage. The coating width is 0.5-1mm.

[0028] The LED light has a wavelength of 450-650nm, and the black Mylar layer has a light absorption rate of ≥95% in this wavelength range. After the attachment process, a constant temperature and humidity test is required. The test conditions are 85℃ / 85% RH for 48 hours. The black Mylar layer does not fall off or change color. The front light source backlight is applied to liquid crystal display modules, including mobile phones, tablet computers, car displays or industrial control displays. The black Mylar layer is formed by a die-cutting process with a molding accuracy of ±0.05mm and an edge roughness of Ra≤1μm.

[0029] Working principle:

[0030] By placing a black Mylar film on the front light source backlight LED, when the LED is powered on and emits light, the black film can absorb and cover the light spot of the front light. Only the lamination process of the front light source and backlight needs to be modified. It is convenient and easy to operate and can effectively solve the problem of front light source backlight eye.

[0031] Production Process: In the existing frontlight and backlight assembly lines, a black Mylar bonding process is added after the LED soldering process, using fully automatic bonding equipment to ensure bonding accuracy.

[0032] Test Verification: The module with black Mylar attached is subjected to roller, drop, constant temperature and humidity tests and other reliability tests to verify its functional stability and optical effect.

[0033] Application scenarios: Suitable for front-light reflective LCD displays such as mobile phones, tablet computers, and car displays.

[0034] Coverlens: Cover lens. In the display module, it refers to the protective lens covering the outermost layer of the screen, which can protect the screen, resist scratches and enhance the optical effect.

[0035] OCA: Optically Clear Adhesive. It is mainly used to bond touch screens to display screens. It has high light transmittance and ensures clear display.

[0036] TouchFilmBT: "TouchFilmBT" refers to a touch film with a black light-shielding layer, which is used to block light outside the touch area to avoid light leakage.

[0037] LED: It is the abbreviation of "Light-Emitting Diode", which is a light-emitting diode. In this design, it serves as the light-emitting element of the front light source.

[0038] FPC: It is the abbreviation of "Flexible Printed Circuit", which is a flexible printed circuit board. It is mainly used to connect electronic components such as LEDs. It has good flexibility and bendability and can adapt to complex structural layouts.

[0039] EPD: "Electrophoretic Display" means electronic paper display.

[0040] Example 1: Mobile phone front light source backlight module:

[0041] Materials preparation:

[0042] LED lamp: Model SMD0603, luminous wavelength 460nm (blue light), luminous flux 20-25lm;

[0043] Black Mylar layer: 25μm thick, PET substrate covered with carbon black coating, light absorption rate 95%, light transmittance 0.5%;

[0044] Bonding adhesive: OCA optical adhesive, thickness 50μm, transmittance ≥99%.

[0045] Attachment process:

[0046] Step 1: The black Mylar layer is processed into a rectangular sheet with a size of 5 mm × 3 mm by die-cutting process, with an edge roughness of Ra = 0.8 μm;

[0047] Step 2: Use a fully automatic bonding machine to attach the black Mylar layer to the light-emitting surface of the LED lamp at a pressure of 0.1 MPa and a temperature of 60°C, with the edge extending 0.5 mm beyond the LED lamp.

[0048] Step 3: After attachment, perform CCD detection and control the bubble rate below 0.3%.

[0049] Module assembly:

[0050] Assemble in the order of "Coverlens → OCA → TouchFilmBT → light guide plate (with dots) → black Mylar layer → LED light → FPC", and the flip-chip spacing between the light guide plate and the LED light is 0.8mm.

[0051] Test results:

[0052] The brightness difference in the spot area was reduced from 28% to less than 3%, indicating that the uniformity met the standard (industry standard ≤ 5%).

[0053] After the roller test (500 times) and the drop test (1.5m cement floor), the black Mylar layer did not fall off;

[0054] After constant temperature and humidity testing (85°C / 85% RH, 96 hours), there was no attenuation in light absorption performance.

[0055] Example 2: Vehicle-mounted front light source backlight module:

[0056] Optimization points: The thickness of the black Mylar layer is increased to 50μm, and a 1mm wide light-shielding ink coating is added to the edge to meet the high brightness requirements of the automotive environment (LED luminous flux 30-35lm);

[0057] Test results: Under direct sunlight, the spot elimination effect still maintains a brightness difference of ≤5%, meeting the stringent requirements of in-vehicle displays.

[0058] Beneficial effects

[0059] Improved optical performance: The brightness difference in the spot area is reduced from 20%-30% in traditional solutions to ≤5%, and the display uniformity reaches high-end display standards;

[0060] Cost and efficiency advantages: The cost of a single module increases by ≤ 8 yuan, the bonding process takes only 15 seconds more per module, and the production line yield is increased from 85% to 98%;

[0061] Industrial application value:

[0062] Breaking the technological monopoly of foreign companies in optical film solutions, reducing the cost of domestic front light modules by 30%;

[0063] Promote the popularization of front light source technology in scenarios such as eye-protection educational tablets and low-power car screens, and expect annual sales to increase from 40 million yuan to 120 million yuan (within 3 years);

[0064] Provide the display industry with a "low-cost, high-efficiency" technology path, and drive the localization upgrade of industrial chain links such as black Mylar materials and bonding equipment.

[0065] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A design solution to solve the front light source spot, characterized in that: include: A black Mylar layer is attached to the surface of the LED lamp of the front light source backlight. The black Mylar layer has an absorbance of ≥90% and is used to absorb direct light generated when the LED emits light to cover the light spot; the front side of the light guide plate of the front light source backlight is provided with dots, and the light guide plate and the LED light strip are inverted structures, without traditional diffusion film and brightness enhancement film.

2. A design process for solving the front light source spot problem as claimed in claim 1, characterized in that: The black Mylar layer has a thickness of 5-50 μm and a light transmittance of ≤1%, and is made of a polyethylene terephthalate (PET)-based black coating.

3. A design process for solving the front light source spot problem as claimed in claim 1, characterized in that: The attachment position of the black Mylar layer covers the light-emitting surface of the LED lamp and the surrounding 5-10mm area, and the distance between the edge and the LED lamp is ≤2mm.

4. A design process for solving the front light source spot problem as claimed in claim 1, characterized in that: The attachment process uses optically clear adhesive (OCA) or hot pressing adhesive for attachment, with an attachment accuracy of ±0.1mm, and a bubble rate between the black Mylar layer and the surface of the LED lamp after attachment of ≤0.5%.

5. The design process for solving the front light source spot problem as claimed in claim 1, characterized in that: The front light source backlight module further includes a Coverlens, a touch film (TouchFilmBT) and a flexible circuit board (FPC) covering the light guide plate, and the black Mylar layer is located between the LED light and the touch film.

6. A design process for solving the problem of front light spot according to claim 1, characterized in that: The edge of the black Mylar layer is provided with a light-shielding ink coating to prevent side light leakage, and the coating width is 0.5-1 mm.

7. A design process for solving the problem of front light spot according to claim 1, characterized in that: The light emission wavelength of the LED lamp is 450-650 nm, and the light absorption rate of the black Mylar layer in this wavelength range is ≥95%.

8. The design process for solving the front light source spot problem as claimed in claim 1, characterized in that: After the attachment process, a constant temperature and humidity test is required. The test conditions are 85°C / 85% RH for 48 hours. The black Mylar layer does not fall off or change color.

9. The design process for solving the front light source spot problem as claimed in claim 1, characterized in that: The front light source backlight is applied to a liquid crystal display module, and the display module includes a mobile phone, a tablet computer, a car display screen or an industrial control display screen.

10. A design process for solving the problem of front light spot according to any one of claims 1 to 9, characterized in that: The black Mylar layer is formed by a die-cutting process, with a forming accuracy of ±0.05 mm and an edge roughness Ra≤1 μm.

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