Mask strip

Abstract

The utility model discloses a mask strip, and relates to the technical field of special-shaped display OLED (Organic Light Emitting Diode). The mask strip comprises film forming areas in one-to-one correspondence with the special-shaped display screens, each film forming area comprises an effective film coating area and an etching buffer area, the etching buffer area is located on the periphery of the effective film coating area, and the periphery of the etching buffer area is rectangular; an etching hole of the etching buffer area is a non-through hole, the effective coating area is arranged corresponding to an effective display area of the special-shaped display screen, and the etching hole is a through hole; and the thickness of the mask strip in the effective coating area is smaller than that of the mask strip in the etching buffer area. According to the utility model, the etching buffer area with the rectangular periphery is arranged on the outer side of the effective coating area, and the etching buffer area is a non-through-hole etching area, so that the phenomenon of non-uniform stress of the mask strip during net stretching is reduced, and poor color mixing caused by the wrinkle phenomenon of the mask strip is improved, thereby improving the net stretching yield of the mask strip for the special-shaped display screen.

Description

Technical Field

[0001] The utility model relates to the technical field of special-shaped display OLED, and particularly relates to a mask bar. Background Art

[0002] The AMOLED display panel can be applied to special-shaped displays of wearable devices such as watches and bracelets. AMOLED adopts an evaporation process. After the functional layer materials are heated and vaporized, they pass through the pixel openings of the metal mask bar and are deposited on the TFT substrate circuit to achieve light emission. In particular, the light-emitting layer material requires a high-precision mask plate (FMM) to ensure that the material is accurately evaporated onto a specific area of the substrate. In the prior art, a rectangular effective film-forming area 10 is provided on a conventional mask bar 100. The wire meshing schematic diagram is as Figure 1 shown, and the arrow indicates the pulling force.

[0003] For a special-shaped display OLED, the display circuit area of the TFT substrate is designed to be special-shaped (circular or other non-rectangular shapes), and the corresponding FMM effective film-forming area 10 also needs to be designed to be special-shaped. During the wire meshing process of the mask bar, tension needs to be applied to stretch both ends. The etched opening area of the mask bar is rectangular, so the distribution uniformity of the tension along the cross-section of the mask bar is good. However, if the opening area is special-shaped such as circular, the distribution uniformity of the pulling force along the cross-section of the mask bar is poor, which easily leads to different deformation amounts at different etched areas of the mask bar, and then causes problems such as the offset of the etched opening position and the wrinkle of the mask bar, as Figure 2 shown. Therefore, after the FMM and the TFT substrate are laminated and coated, defects such as shadows and color mixing are likely to occur, directly affecting the product yield, which is also one of the development difficulties of current special-shaped display screens. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a mask bar, which can relieve the problem of uneven pulling force during the wire meshing of the mask bar for special-shaped screens by providing a mask bar with an etching buffer area, and improve the wire meshing yield.

[0005] To solve the above technical problem, an embodiment of the utility model provides a mask bar, which includes a film-forming area corresponding to a special-shaped display screen one by one. Each film-forming area includes an effective coating area and an etching buffer area. The etching buffer area is located outside the effective coating area, and the periphery of the etching buffer area is rectangular; the etching holes in the etching buffer area are non-through holes, the effective coating area is correspondingly arranged with the effective display area of the special-shaped display screen, and the etching holes are through holes; the thickness of the mask bar in the effective coating area is less than the thickness of the mask bar in the etching buffer area.

[0006] Furthermore, the etching buffer area is a rectangular non-through hole etching area formed by etching from both sides of the mask bar.

[0007] Furthermore, the bottom spacing of the etching holes in the rectangular etching area formed by etching from both sides is not less than 2um.

[0008] Further, the thickness range of the mask strip is 20 - 100 um.

[0009] Further, the mask strip is a mask strip made of INVAR36 material.

[0010] The technical solution of the embodiment of the present utility model has at least the following advantages:

[0011] 1. By providing an etching buffer zone with a rectangular periphery outside the effective coating area, and the etching buffer zone is a non-through-hole etching area, the phenomenon of uneven force on the mask strip during mesh stretching is reduced, and the color mixing defect caused by the wrinkling of the mask strip is improved, thereby improving the mesh stretching yield of the mask strip for a special-shaped display screen;

[0012] 2. By thinning the effective coating area, the sag amount of the mask strip can be reduced to a certain extent, the fitting condition between the mask strip and the glass substrate is improved, and the coating shadow effect is improved, thereby improving the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present utility model will be further described below with reference to the accompanying drawings in conjunction with embodiments.

[0014] Figure 1 It is a schematic diagram of mask strip mesh stretching in a rectangular etching area in the prior art;

[0015] Figure 2 It is a schematic diagram of uneven mask strip mesh stretching tension in a special-shaped etching area in the prior art;

[0016] Figure 3 It is a schematic diagram of the mask strip etching production process in the prior art;

[0017] Figure 4 It is a top view of the mask strip in the embodiment of the present utility model;

[0018] Figure 5 It is a schematic diagram of the film-forming area of the mask strip in the embodiment of the present utility model;

[0019] Figure 6 It is a cross-sectional schematic diagram of the film-forming area hole-opening process in the embodiment of the present utility model;

[0020] Figure 7a It is a top view of the rectangular etching area on the first etching surface of the mask strip in the embodiment of the present utility model;

[0021] Figure 7b It is a top view of the rectangular etching area on the second etching surface of the mask strip in the embodiment of the present utility model;

[0022] Figure 8 It is a cross-sectional schematic diagram of the etching process on the first etching surface and the second etching surface in the embodiment of the present utility model;

[0023] Figure 9 It is a top view schematic diagram of the process of forming a special-shaped opening on the second etching surface in an embodiment of the present invention;

[0024] Figure 10 It is a cross-sectional schematic diagram of the process of forming a special-shaped opening on the second etching surface in an embodiment of the present invention. Specific implementation manners

[0025] By providing a mask strip in an embodiment of the present invention, the problem of uneven tension during stretching of the mask strip for a special-shaped screen is alleviated, and the stretching yield is improved.

[0026] An embodiment of the present invention provides a mask strip 100, as Figures 4 to 6 shown, including a film-forming area 10 provided corresponding to the special-shaped display screen one by one. Each film-forming area 10 includes an effective coating area 1 and an etching buffer area 2. The etching buffer area 2 is located outside the effective coating area 1, and the outer turn of the etching buffer area 2 is rectangular; the etching holes in the etching buffer area 2 are non-through holes, and the effective coating area 1 is provided corresponding to the effective display area of the special-shaped display screen, and the etching holes are through holes; the thickness of the mask strip in the effective coating area 1 is less than the thickness of the mask strip in the etching buffer area 2.

[0027] By providing an etching buffer area 2 with a rectangular outer periphery outside the effective coating area 1 (the effective coating area 1 and the etching buffer area 2 overlap to form a complete rectangular area), and the etching buffer area 2 is a non-through hole etching area, the phenomenon of uneven force on the mask strip 100 during stretching is reduced, and the color mixing defect caused by the wrinkling phenomenon of the mask strip 100 is improved, thereby improving the stretching yield of the mask strip for a special-shaped display screen. By thinning the design of the effective coating area 1, the sag amount of the mask strip 100 can be reduced to a certain extent, the fitting condition of the mask strip 100 and the glass substrate is improved, and the coating shadow effect is improved, thereby improving the product yield.

[0028] In a possible implementation manner, the etching buffer area 2 is a rectangular non-through hole etching area formed by etching from both sides of the mask strip 100. The bottom spacing of the etching holes in the rectangular etching area formed by etching from both sides is not less than 2 um.

[0029] In a possible implementation manner, the thickness range of the mask strip 100 is 20-100 um, and the material is made of INVAR36 material.

[0030] The above mask strip 100 can be manufactured by the following method, including:

[0031] Step 1, use an etching process to form a rectangular non-through hole etching area on both sides of the mask strip 100;

[0032] Specifically, it may include the following steps:

[0033] The first etching surface 101 of the mask strip 100 is etched after being developed by the first photomask 201, and the etching area is rectangular. The first etching surface is the contact surface between the mask strip and the TFT substrate.

[0034] The second etching surface 102 of the mask strip 100 is developed by the second photomask 201, and the etching area is rectangular. The second etching surface is the deposition surface of the evaporation material. A rectangular non-through hole etching area is fabricated through etching on both surfaces.

[0035] The etching areas of the first photomask 201 and the second photomask 202 are rectangular. The two rectangular areas are symmetrically arranged and have the same area (as shown in Figure 7a and Figure 7b ). The opening size within the etching area of the first photomask 201 is smaller than the opening size within the etching area of the second photomask 202 (as shown in Figure 8 ). Each rectangular area includes a large number of non-through etching holes.

[0036] Step 2: Etch the rectangular non-through hole etching area corresponding to the effective coating area 1 again to form a through hole that penetrates to the designed opening size, so that the evaporation material can pass through and be deposited on the TFT substrate circuit to form the effective display area 1, as shown in Figure 9 . The process of forming the special-shaped opening on the second etching surface includes applying photoresist, developing, and the second etching; the remaining rectangular non-through hole etching area is the etching buffer area 2.

[0037] By forming a rectangular etching buffer area 2 around the effective coating area 1, and the etching buffer area 2 is a rectangular non-through hole etching area, the phenomenon of uneven force on the mask strip 100 during screen stretching is reduced, and the color mixing defect caused by the wrinkling of the mask strip 100 is improved, thereby improving the screen stretching yield of the mask strip for the special-shaped display screen.

[0038] In a preferred implementation, in step 2, etching the rectangular non-through hole etching area corresponding to the effective coating area again to form a through hole that penetrates to the designed opening size specifically includes:

[0039] As shown in Figure 10 , the second etching surface 102 of the mask strip 100 is developed by the third photomask 203. The opening area of the third photomask 203 is correspondingly arranged with the effective coating area 1. Through etching, a through hole is formed that penetrates to the designed opening size corresponding to the effective display area of the display screen, and the overall thickness of the mask strip in the effective coating area 1 is thinned. By simultaneously forming the through hole in the effective coating area 1 and thinning the overall thickness of the mask strip through the third photomask 203, the uneven force on the mask strip 100 during screen stretching can be reduced while reducing the sag amount of the mask strip 100, improving the fitting situation between the mask strip 100 and the glass substrate, and improving the coating shadow effect, thereby improving the product yield.

[0040] The mask strips of the prior art FMM currently use a double-sided etching process to produce pixel openings, such as Figure 3 shown, including steps of coating (photoresist), developing, etching, and cleaning. The manufacturing process of the mask strip 100 according to the embodiments of the present invention includes:

[0041] Coating photoresist on the first etching surface 201 and the second etching surface 202;

[0042] Using the first photomask 201 and the second photomask 202 to develop the first etching surface 201 and the second etching surface 202 respectively;

[0043] Etching the first etching surface 201 and the first etching of the second etching surface 202;

[0044] Cleaning;

[0045] Coating photoresist on the second etching surface 202;

[0046] Using the third photomask 203 to develop the second etching surface 202;

[0047] The second etching of the second etching surface 202;

[0048] Cleaning.

[0049] The present invention reduces the phenomenon of uneven stress on the mask strip during mesh stretching by setting an etching buffer zone with a rectangular periphery outside the effective coating area, and the etching buffer zone is a non-through-hole etching area, improving the color mixing defect caused by the wrinkling phenomenon of the mask strip, thereby improving the mesh stretching yield of the mask strip for special-shaped display screens; by performing a thinning design on the effective coating area, the sag amount of the mask strip can be reduced to a certain extent, improving the fitting condition between the mask strip and the glass substrate, and improving the coating shadow effect, thereby improving the product yield.

[0050] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments we described are illustrative rather than used to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope protected by the claims of the present invention.

Claims

1. A mask strip, characterized in that, It includes a film-forming area corresponding to a special-shaped display screen one by one. Each film-forming area includes an effective coating area and an etching buffer area. The etching buffer area is located outside the effective coating area, and the periphery of the etching buffer area is rectangular. The etching holes in the etching buffer area are non-through holes, and the effective coating area is correspondingly arranged with the effective display area of the special-shaped display screen, and the etching holes are through holes. The thickness of the mask strip in the effective coating area is less than the thickness of the mask strip in the etching buffer area. The etching buffer area is a rectangular non-through hole etching area formed by etching from both sides of the mask strip.

2. The mask bar according to claim 1, characterized in that: The bottom spacing of the etching holes in the rectangular etching area formed by etching from both sides is not less than 2 μm.

3. The mask bar according to claim 1, wherein: The thickness range of the mask strip is 20-100 μm.

4. The mask bar according to claim 1, characterized in that: The mask strip is a mask strip made of INVAR36 material.

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