Display substrate for projector, preparation method of display substrate and projector

Abstract

The embodiment of the invention provides a display substrate for a projector, a preparation method of the display substrate and the projector, the display substrate comprises an array substrate, a liquid crystal layer and a color film substrate, and the array substrate comprises a substrate, a switch tube structure layer and a transparent electrode layer arranged on the side, away from the substrate, of the switch tube structure layer; the display substrate further comprises a flat layer, the flat layer is arranged on the side, away from the substrate, of the transparent electrode layer, the surface of the side, away from the substrate, of the flat layer is flush, and the surface of the side, close to the substrate, of the liquid crystal layer in the same sub-pixel area is flush. By applying the embodiment of the invention, the light utilization rate of the projector can be improved, and the brightness and contrast of the projected image can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of display devices, and in particular to a display substrate for a projector, a preparation method thereof, and a projector. Background Art

[0002] Currently, the common projectors on the market mainly include LCD (Liquid Crystal Display), LCOS (Liquid Crystal on Silicon) and DLP (Digital Light Processing). Among them, LCD is still the mainstream technology in the low-end and mid-range projector market due to its low cost and mature manufacturing process.

[0003] LCD projectors are different from conventional LCD display products. During the use of projector products, users do not directly view the display panel, but need to illuminate the LCD projector through an external light source, so that the light emitted by the external light source is transmitted (or reflected) by the display panel of the LCD projector and then projected onto the screen. The observer views the projected image through the reflection of the screen. However, during the transmission and reflection process of the light incident on the LCD projector display panel, it is easy for light to be strayed, resulting in insufficient brightness, poor contrast and other image quality problems in the projected pattern. Summary of the invention

[0004] The purpose of this application is to provide a display substrate for a projector and a preparation method thereof, and a projector, so as to improve the light utilization rate of the projector and improve the brightness and contrast of the projected image. The specific technical solution is as follows:

[0005] In a first aspect, the present application provides a display substrate for a projector, comprising: an array substrate, a liquid crystal layer and a color film substrate, wherein the array substrate comprises a substrate, a switch tube structure layer, and a transparent electrode layer arranged on a side of the switch tube structure layer away from the substrate; the display substrate further comprises:

[0006] The flat layer is arranged on a side of the transparent electrode layer away from the substrate, the surface of the flat layer away from the substrate is flush, and the surface of the liquid crystal layer in the same sub-pixel area close to the substrate is flush.

[0007] Optionally, the display substrate further includes:

[0008] A metal electrode layer, wherein the metal electrode layer is disposed on a side of the transparent electrode layer away from the substrate;

[0009] The planar layer is disposed between the metal electrode layer and the liquid crystal layer.

[0010] Optionally, the display substrate further includes:

[0011] A metal electrode layer, wherein the metal electrode layer is disposed on a side of the transparent electrode layer away from the substrate;

[0012] The planar layer is disposed between the transparent electrode layer and the metal electrode layer.

[0013] Optionally, the transparent electrode layer has a first protrusion, which is the part of the transparent electrode layer with the largest distance from the substrate; the surface of the flat layer away from the substrate is flush with the surface of the first protrusion away from the substrate, and the metal electrode layer is in contact with the first protrusion.

[0014] Optionally, the display substrate includes a switching circuit area and a non-switching circuit area, and the first protruding portion of the transparent electrode layer is located in the switching circuit area.

[0015] Optionally, the display substrate further includes:

[0016] A reflection enhancement layer is arranged between the metal electrode layer and the liquid crystal layer.

[0017] Optionally, the reflection enhancing layer includes a plurality of insulating layers, and the refractive index of each insulating layer is different.

[0018] Optionally, the display substrate includes a plurality of sub-pixel regions, each of the sub-pixel regions includes a switch circuit region and a non-switch circuit region; the switch tube structure layer includes:

[0019] The gate metal layer comprises a first flat portion arranged in the switch circuit area and a second flat portion arranged in the non-switch circuit area; the first flat portion is disconnected from the second flat portion;

[0020] A first insulating layer is disposed on a side of the gate metal layer away from the substrate;

[0021] An active layer, comprising a third flat portion disposed in the switch circuit region and located on a side of the first insulating layer away from the substrate;

[0022] A source-drain metal layer, arranged on a side of the active layer and the first insulating layer away from the substrate;

[0023] A second insulating layer is provided on a side of the source-drain metal layer away from the substrate; the second insulating layer has a first via hole located in the non-switching circuit area, and the transparent electrode layer is connected to the source-drain metal layer through the first via hole;

[0024] Optionally, the area ratio of the second flat portion of the gate metal layer in the non-switching circuit area and the area ratio of the source and drain metal layer in the non-switching circuit area are both not less than 80%.

[0025] Optionally, the active layer further has a fourth tiled portion disposed in the non-switching circuit area and located between the first insulating layer and the source and drain metal layer; a projection of the first via on the substrate is located within the projection range of the fourth tiled portion on the substrate.

[0026] In a second aspect, the present application provides a method for preparing a display substrate for a projector, comprising:

[0027] A switch tube structure layer, a transparent electrode layer and a flat layer are sequentially formed on the substrate; the surface of the flat layer away from the substrate is flush;

[0028] Depositing a first metal electrode layer on the flat layer, and patterning the first metal electrode layer through a first photomask to obtain a semi-patterned array substrate; the first metal electrode layer pattern of a first pixel position set is provided on the first photomask;

[0029] A second metal electrode layer is deposited on the semi-patterned array substrate, and the second metal electrode layer is patterned by a second photomask to obtain a patterned array substrate; a second metal electrode layer pattern of a second pixel position set is provided on the second photomask; wherein the first pixel position set includes pixel positions whose sum of row and column numbers is an odd number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an even number, or the first pixel position set includes pixel positions whose sum of row and column numbers is an even number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an odd number;

[0030] A liquid crystal layer and a color filter substrate are sequentially formed on the array substrate; wherein a surface of the liquid crystal layer in the same sub-pixel region close to the substrate is flush.

[0031] Optionally, before depositing the second metal electrode layer on the semi-patterned array substrate, the method further includes:

[0032] Depositing a third insulating layer on the semi-patterned array substrate; and depositing the second metal electrode layer on the third insulating layer;

[0033] After patterning the second metal electrode layer by using the second photomask, the method further includes:

[0034] The third insulating layer covering the patterned first metal electrode layer is removed.

[0035] Optionally, before depositing the second metal electrode layer on the semi-patterned array substrate, the method further includes:

[0036] Depositing a third insulating layer on the semi-patterned array substrate; and depositing the second metal electrode layer on the third insulating layer;

[0037] After patterning the second metal electrode layer by using the second photomask, the method further includes:

[0038] For the first metal electrode layer at each first pixel position, the third insulating layer covering the non-edge region of the first metal electrode layer is removed, and the third insulating layer covering the edge region of the first metal electrode layer is retained.

[0039] In a third aspect, the present application provides a projector, comprising a display substrate for a projector according to any one of the first aspects.

[0040] Beneficial effects of this application:

[0041] The display substrate for a projector provided by the present application, its preparation method, and the projector are provided with a flat layer on the side of the transparent electrode layer in the display substrate away from the substrate, and the surface of the flat layer away from the substrate is flush, so that the surface of the liquid crystal layer in the same sub-pixel area close to the substrate is flush, which helps to achieve uniformity of the thickness of the liquid crystal box and avoid the liquid crystal disorder problem caused by the uneven thickness of the liquid crystal box. Therefore, when the display substrate for a projector provided by the present application is applied to the projector, it can avoid the scattering of the light incident on the inside of the display substrate during the transmission or reflection process due to the uneven thickness of the liquid crystal box and the liquid crystal disorder problem, which helps to improve the light utilization rate and thus improve the brightness of the projected image. At the same time, the reduction of scattered light in the display substrate also helps to improve the dark state light leakage problem of the display substrate, thereby also being able to improve the contrast of the projected image to a certain extent.

[0042] Of course, implementing any product or method of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0044] Figure 1 A schematic diagram of a projection light path when a projector device in the related art is used for projection;

[0045] Figure 2A first structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0046] Figure 3 A second structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0047] Figure 4 A third structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0048] Figure 5 A fourth structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0049] Figure 6 A fifth structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0050] Figure 7 A sixth structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0051] Figure 8 A seventh structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0052] Fig. 9 (a) is a top view of a display substrate in the related art. Fig. 9 (b) is Figure 8 A top view of the substrate is shown in FIG.

[0053] Fig.10 An eighth structural diagram of a display substrate for a projector provided in an embodiment of the present application;

[0054] Fig.11 A schematic flow chart of a method for preparing a display substrate for a projector provided in an embodiment of the present application;

[0055] Fig.12 A schematic diagram of a first photomask and a second photomask provided in an embodiment of the present application;

[0056] Fig.13 This is a ninth structural diagram of a display substrate for a projector provided in an embodiment of the present application.

[0057] Reference numerals:

[0058] 1-array substrate, 2-liquid crystal layer, 3-color film substrate, 4-PBS device, 5-curtain, 6-light source, 7-flat layer, 8-reflection enhancement layer, 9-third insulating layer;

[0059] 10-substrate, 11-gate metal layer, 12-gate metal insulating layer, 13-active layer, 14-source and drain metal layer, 15-source and drain metal insulating layer, 16-metal shielding layer, 17-pixel insulating layer, 18-metal electrode layer, 19-transparent electrode layer, 20-common electrode; 111-first tile portion, 112-second tile portion, 131-third tile portion, 132-fourth tile portion, 151-first via hole. DETAILED DESCRIPTION

[0060] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field based on the present application belong to the scope of protection of the present application.

[0061] At present, the common projectors on the market mainly include LCD, LCOS and DLP. Among them, LCOS (Complementary Metal Oxide Semiconductor) replaces the polycrystalline silicon or amorphous silicon TFT (Thin Film Transistor) dot matrix of LCD with CMOS (Complementary Metal Oxide Semiconductor) dot matrix on a single crystal silicon substrate, which has higher precision and more delicate image quality, but because its manufacturing process involves single-chip chip technology, the cost is very high. DLP sets a precise DMD (Digtial Micromirror Devices) array on the chip, and controls the projection display of reflected light by powering on the angle of the micromirror, but because of its high manufacturing precision requirements and complex optical system, the cost of DLP is also very high. Therefore, LCD is still the mainstream technology in the low-end and mid-range projector market due to its low cost and mature manufacturing process.

[0062] LCD projectors can be divided into two types according to the optical path: transmissive projectors and reflective projectors. In a transmissive projector, the light emitted by the light source needs to penetrate the display panel of the projector for display. However, due to the increasing requirements for PPI (pixels per inch, a unit of pixel density) in recent years, the metal traces in each pixel of the LCD projector display panel are wider and the size of the TFT device is larger, which will block the transmitted light, making the display panel's penetration rate very low, generally less than 5%. In a reflective projector, the light emitted by the light source does not need to pass through the display panel of the LCD projector, but is reflected by the display panel and projected onto the screen. Since the reflectivity of the LCD projector display panel (generally greater than 50%) is usually much higher than the transmittance, the light utilization rate in the reflective projector can be greatly improved compared to the transmissive projector. In addition, in a reflective projector, a heat dissipation module can be directly set on the back of the display panel without affecting the display optical path, reducing the risk of deterioration of image quality and life at high temperatures.

[0063] LCD projectors are different from conventional LCD display products. During the use of projector products, users do not directly view the display panel, but need to illuminate the LCD projector through an external light source, so that the light emitted by the external light source is transmitted (or reflected) through the display panel of the LCD projector and then projected onto the screen. The observer views the projected image through the reflection of the screen. This special application mode requires that the light path has good collimation when it enters the display panel for transmission (or reflection) to reduce the loss of light during the propagation process and ensure the projection brightness. However, in existing LCD projectors, the light incident on the display panel is prone to stray light during the transmission (or reflection) process, resulting in insufficient brightness, poor contrast and other image quality problems in the projection pattern.

[0064] The following is an exemplary description using a reflective projector. Figure 1 The optical system based on the reflective projector includes a display panel, a PBS (Polarization Beam Splitter) device 4, a screen 5 and a light source 1. The display panel includes an array substrate 1 and a color filter substrate 3 that are arranged opposite to each other, and a liquid crystal layer 2 that is arranged between the array substrate 1 and the color filter substrate 3. The array substrate 1 includes a substrate, a gate metal layer 11, a gate metal insulating layer 12, an active layer 13, a source and drain metal layer 14, a source and drain metal insulating layer 15, a pixel insulating layer 17, a metal shielding layer 16 and a metal electrode layer 18. In the reflective projector, the metal electrode layer 18 is made of a reflective metal layer, and there is also a transparent electrode layer between the metal electrode layer 18 and the metal shielding layer 16. The pattern of the transparent electrode layer is exactly the same as that of the metal electrode layer 18. Figure 1 Not shown for simplicity. Figure 1 In the illustrated display panel, the gate metal layer 11, the gate metal insulating layer 12, the active layer 13 and the source-drain metal layer 14 constitute a TFT switch structure (the TFT switch structure is specifically shown as part A in the figure). In the source-drain metal layer 14, the drain is connected to the data signal line, and the source is connected to the transparent electrode layer through the vias on the source-drain metal insulating layer 15 and the pixel insulating layer 17, so that precise control of pixel charging and discharging can be achieved. Specifically, each pixel area of ​​the display substrate has a TFT switch structure, and the TFT switch structure in each pixel area can be independently controlled. When the transparent electrode layer in a pixel area is not charged through the TFT switch structure, the liquid crystal molecules of the liquid crystal layer 2 in the pixel area are arranged in a disordered manner, and light is not easy to penetrate the liquid crystal layer 2 in the pixel area; when the transparent electrode layer in a pixel area is charged through the TFT switch structure, a voltage that penetrates the liquid crystal layer 2 can be formed in the pixel area, and the liquid crystal molecules in the liquid crystal layer 2 are deflected under the action of the voltage, and the arrangement of the liquid crystal molecules becomes orderly, so that light can penetrate the liquid crystal layer 2 in the pixel area. Therefore, by controlling the TFT switch structure in each pixel area of ​​the display panel, the light transmission state of the liquid crystal layer 2 in each pixel area of ​​the display panel can be controlled.

[0065] In use Figure 1 When the illustrated system is projecting, the polarized light emitted by the light source 1 is incident on the PBS device 4, and is divided by the PBS device 4 into two perpendicular linear polarized light beams, namely, P light and S light. Among them, the P light completely passes through the PBS device 4, and the S light is reflected at an angle of 45 degrees, and the emission direction of the S light forms an angle of 90 degrees with the P light. The light emitted from the PBS device 4 is vertically irradiated to the metal electrode layer 18 in the display panel, and is reflected on the metal electrode layer 18 and then projected onto the screen 5. In actual applications, the light transmittance state of the liquid crystal layer 2 in each pixel area of ​​the display panel can be controlled by the TFT switch structure, so that the S light incident on the display panel is reflected through the liquid crystal layer 2 in a specific pixel area and blocked by the liquid crystal layer 2 in other pixel areas, so that a specific pattern can be presented on the screen 5. However, based on Figure 1 It can be seen that the surface of the metal electrode layer 18 as a reflective surface has unevenness, and the arrangement of the liquid crystal molecules in the liquid crystal layer 2 above the metal electrode layer 18 is also affected by the unevenness, resulting in liquid crystal disorder, which makes it easy for the light irradiated to the metal electrode layer 18 to be scattered, and the light utilization rate is lost, resulting in insufficient brightness of the projection pattern. At the same time, the scattered light in the display panel may also be emitted in the pixel area where the liquid crystal layer 2 is not turned on by the TFT switch structure, resulting in dark state light leakage in the display panel, making the projection pattern also prone to poor contrast.

[0066] In view of this, the present application provides a display substrate for a projector, see Figure 2 The display substrate includes an array substrate 1, a liquid crystal layer 2 and a color filter substrate 3. The liquid crystal layer 2 is specifically arranged between the array substrate 1 and the color filter substrate 3.

[0067] The array substrate 1 includes a substrate 10, a switch tube structure layer, and a transparent electrode layer 19 arranged on a side of the switch tube structure layer away from the substrate 10. The switch tube structure layer is used to provide a voltage to the transparent electrode layer 19, thereby forming an electric field that penetrates the liquid crystal layer 2 in the display substrate, and the liquid crystal molecules in the liquid crystal layer 2 can be deflected under the action of the electric field, so that the transmittance of the liquid crystal layer 2 will change. By controlling the magnitude of the voltage difference in the electric field, the deflection angle of the liquid crystal molecules in the liquid crystal layer 2 can be controlled, thereby controlling the magnitude of the transmittance of the liquid crystal layer 2. In practical applications, the conduction state of the switch tube structure layer in each pixel of the display substrate can be independently controlled.

[0068] In a conventional display substrate structure, the structure of the switch tube structure layer is usually complex, so its surface away from the substrate 10 is generally uneven, resulting in the array substrate 1 in the display substrate having an uneven surface away from the substrate 10. Figure 1 It is easy to understand that if the liquid crystal layer 2 and the color film substrate 3 are prepared directly on the array substrate 1 with an uneven surface, the surface of the liquid crystal layer 2 close to the substrate 10 will also be uneven, resulting in uneven thickness of the liquid crystal boxes at different positions in the display substrate, which is prone to liquid crystal disorder problems, and will lead to obvious light scattering in the display substrate.

[0069] Considering this phenomenon, the embodiment of the present application further provides a flat layer 7 in the display substrate to achieve uniform thickness of the liquid crystal cell. Specifically, the flat layer 7 is provided on the side of the transparent electrode layer 19 away from the substrate 10, and the surface of the flat layer 7 away from the substrate 10 is flush, so that the surface of the liquid crystal layer 2 close to the substrate 10 in the same sub-pixel area is flush.

[0070] In one example, the planar layer 7 can be made of an organic material with good fluidity, such as an organic resin.

[0071] Those skilled in the art will appreciate that the entire display substrate generally includes a plurality of sub-pixels. Figure 2 A sub-pixel in a display substrate is shown. Figure 2 Schematically, in the display substrate provided in the embodiment of the present application, the surface of the planarization layer in each sub-pixel away from the substrate 10 is flat. Specifically, the surface of the planarization layer 7 away from the substrate 10 is flat, which can be understood as the surface of the planarization layer 7 away from the substrate 10 is a plane or approximately a plane.

[0072] In the display substrate provided in the embodiment of the present application, the liquid crystal layer 2 is specifically arranged between the flat layer 7 and the color filter substrate 3. Since the surface of the flattening layer away from the substrate 10 is flush, the surface of the liquid crystal layer 2 in the same sub-pixel region close to the substrate 10 is flush. In practical applications, the surface of the liquid crystal layer 2 in each sub-pixel close to the substrate 10 can be set to be flush, and the surface of the liquid crystal layer 2 in each sub-pixel of the entire display substrate close to the substrate 10 is a flat surface, or the surface of the liquid crystal layer 2 in adjacent pixels close to the substrate 10 may also have a certain height difference, and the surface of the liquid crystal layer 2 in a single sub-pixel close to the substrate 10 is a flat surface.

[0073] Based on the planarization of the surface of the liquid crystal layer 2 close to the substrate 10 in the embodiment of the present application, since the surface of the color film substrate 3 close to the color film substrate 3 is also generally flat, the upper and lower surfaces of the liquid crystal layer 2 are flat in each sub-pixel of the display substrate provided in the embodiment of the present application, which helps to achieve uniformity of the thickness of the liquid crystal box and avoid liquid crystal disorder caused by uneven thickness of the liquid crystal box.

[0074] In practical applications, the display substrate provided in the embodiment of the present application can be used in both a transmission projector and a reflection projector, depending on actual needs. Since the thickness of the liquid crystal box is uniformed in the display substrate provided in the embodiment of the present application, when the display substrate is actually applied to a projector, it can avoid scattering of light incident on the inside of the display substrate due to uneven thickness of the liquid crystal box and liquid crystal disorder during transmission or reflection, which helps to improve light utilization and thus improve the brightness of the projected image. At the same time, the reduction of scattered light in the display substrate also helps to improve the dark state light leakage problem of the display substrate, thereby also being able to improve the contrast of the projected image to a certain extent.

[0075] In some embodiments of the present application, Figure 3 and Figure 4As shown, the display substrate also includes a metal electrode layer 18, which is arranged on the side of the transparent electrode layer 19 away from the substrate 10, and the liquid crystal layer 2 is arranged between the metal electrode layer 18 and the color film substrate 3. Generally speaking, the pattern of the transparent electrode layer 19 is consistent with the pattern of the metal electrode layer 18. For this display substrate structure, when it is applied to a reflective projector, the metal electrode layer 18 needs to be prepared by a reflective metal material, and the surface of the metal electrode layer 18 away from the substrate 10 constitutes a reflection surface of the light incident on the display substrate; when it is applied to a transmissive projector, the metal electrode layer 18 needs to be prepared by a transparent material. In the case where the display substrate includes the transparent electrode layer 19 and the metal electrode layer 18, the flat layer 7 can be arranged between the metal electrode layer 18 and the liquid crystal layer 2, or between the transparent electrode layer 19 and the metal electrode layer 18. Both design ideas can achieve the flattening of the liquid crystal layer 2. The two design ideas are described separately below.

[0076] exist Figure 3 In the illustrated display substrate, the metal electrode layer 18 is disposed on the side of the transparent electrode layer 19 away from the substrate 10 , the planar layer 7 is disposed on the side of the metal electrode layer 18 away from the substrate 10 , and the liquid crystal layer 2 is disposed on the side of the planar layer 7 away from the substrate 10 .

[0077] Combined with the previous description, it can be seen that Figure 1 Based on the structure of the display substrate in the related art, it is only necessary to prepare an additional flat layer 7 on the metal electrode layer 18 after the metal electrode layer 18 is prepared, and the Figure 3 The schematic diagram shows the structure of the substrate. That is, in the application Figure 3 The technical solution provided only requires adding a small number of steps on the basis of the traditional display substrate preparation process, which can achieve the flattening of the liquid crystal layer 2 to reduce the scattering of light incident on the display substrate due to the thickness and unevenness of the liquid crystal box and the disorder of the liquid crystal, thereby improving the brightness and contrast of the projected image. The solution is easy to implement and the cost is low.

[0078] exist Figure 4 In the illustrated display substrate, the planar layer 7 is disposed on the side of the transparent electrode layer 19 away from the substrate 10 , the metal electrode layer 18 is disposed on the side of the planar layer 7 away from the substrate 10 , and the liquid crystal layer 2 is disposed on the side of the metal electrode layer 18 away from the substrate 10 .

[0079] Since the surface of the planarization layer away from the substrate 10 is flush, and the metal electrode layer 18 is arranged on the side of the planarization layer 7 away from the substrate 10, Figure 4Schematically, in each sub-pixel region in the display substrate, the surface of the metal electrode layer 18 close to the substrate 10 and the surface of the metal electrode layer 18 away from the substrate 10 are both flush, thereby making the surface of the liquid crystal layer 2 close to the substrate 10 also flush.

[0080] In the Figure 4 When the illustrated display substrate is applied to a reflective projector, the light emitted by the light source enters the display substrate from one side of the color filter substrate 3, and the surface of the metal electrode layer 18 on the side away from the substrate 10 constitutes a reflection surface for the light entering the display substrate. Since the surface of the metal electrode layer 18 on the side away from the substrate 10 is flat in each sub-pixel region of the display substrate, when the light incident into the display substrate reaches the metal electrode layer 18, it can achieve excellent lens reflection on the flat surface of the metal electrode layer 18, and the light scattering phenomenon in the display substrate is greatly reduced, which helps to further improve the light utilization rate and improve the brightness and contrast of the projected image.

[0081] And, because in Figure 4 In the illustrated structure, the surface of the flat layer 7 away from the substrate 10 is flush, so that in the preparation process of the metal electrode layer 18, the film formation uniformity of the metal electrode layer 18 will be better, so that the mura (unevenness) type defects in the display substrate can be effectively improved. At the same time, the uniformity of the photoresist in the photolithography process of the metal electrode layer 18 will also be improved, so that the photolithography accuracy can be improved and the product yield can also be improved.

[0082] also, Figure 4 Schematic display substrate and Figure 3 Compared with the structure in FIG. 1 , the transparent electrode layer 19 and the metal electrode layer 18 are separated, and the planarization layer is arranged between the transparent electrode layer 19 and the metal electrode layer 18. Therefore, there are certain differences in the driving principles of the two display substrate structures.

[0083] In practical applications, the color filter substrate 3 generally includes a common electrode layer, a color filter layer disposed on a side of the common electrode layer away from the array substrate 1, and a glass backplane disposed on a side of the color filter layer away from the array substrate 1. Figure 3 As for the schematic structure, the metal electrode layer 18 and the transparent electrode layer 19 in the array substrate 1 are electrically connected to the switch tube structure layer by contact. During the use of the display substrate, a certain electric signal is applied to the metal electrode layer 18 through the switch tube structure layer in the array substrate 1, and a certain electric signal is applied to the common electrode layer of the color film substrate 3 through the driving structure configured for the color film substrate 3, so that an electric field is formed between the metal electrode layer 18 and the common electrode layer, and the liquid crystal molecules in the liquid crystal layer 2 are deflected under the action of the electric field, thereby realizing the control of the transmittance of the liquid crystal layer 2.

[0084] And in Figure 4In the structure, since no through hole is provided on the flat layer 7, the metal electrode layer 18 is not in direct contact with the transparent electrode layer 19, and the metal electrode layer 18 constitutes a floating electrode. In this structure, the transparent electrode layer 19 and the metal electrode layer 18 constitute a parallel plate capacitor, and the metal electrode layer 18 and the common electrode layer constitute another parallel plate capacitor. During the use of the display substrate, after the transparent electrode layer 19 is charged, the voltage of the metal electrode layer 18 will also change by inducing an electric field between the parallel plate capacitors. Finally, a vertical electric field is formed between the metal electrode layer 18 and the common electrode layer of the color film substrate 3, and the liquid crystal molecules of the liquid crystal layer 2 are deflected under the action of the electric field, thereby adjusting the transmittance of the liquid crystal layer 2.

[0085] Those skilled in the art will understand that when the flat layer 7 is disposed between the metal electrode layer 18 and the transparent electrode layer 19, if the liquid crystal layer 2 is still to be driven by electrical contact, it is necessary to open a through hole in the flat layer 7 so that the metal electrode layer 18 can contact the transparent electrode layer 19 through the through hole. In practical applications, since the surface of the transparent electrode layer 19 has obvious unevenness, in order to ensure that the flat layer 7 can smooth out the unevenness on the surface of the transparent electrode layer 19 and flatten the surface of the metal electrode layer 18 away from the substrate 10, the flat layer 7 needs to be prepared thicker, which may be 1-3μm (micrometers) thick. The thickness of the flat layer 7 can be specifically understood as: the vertical distance between the flat surface of the flat layer 7 away from the substrate and the most concave point on the surface of the flat layer 7 close to the substrate, with Figure 4 For example, the thickness of the flat layer 7 is specifically d as shown in the figure.

[0086] Since the planar layer 7 is relatively thick, the size of the via hole is usually large (>10μm) when it is opened. For ultra-high PPI projector products (PPI>1500), the sub-pixel size is limited (<15μm), so it is difficult to leave space in the sub-pixel for placing the planar layer via hole. Figure 4 The structure of the display substrate provided in the invention realizes driving of the liquid crystal layer by means of an induced electric field, eliminates the via holes of the flat layer, avoids the problem of no space for placement of via holes of the flat layer in ultra-high PPI projector products, and simplifies the via process in the display substrate preparation project, thereby reducing the product preparation cost of the display substrate and improving the product yield.

[0087] However, in practical applications, Figure 4The structure of the display substrate provided may also have certain disadvantages. Specifically, in the actual application of the display substrate, a constant DC voltage is usually applied to the common electrode layer of the color filter substrate 3, and an AC voltage is applied to the transparent electrode layer 19, so that a voltage difference is formed between the common electrode layer and the transparent electrode layer 19 to drive the liquid crystal in the liquid crystal layer 2. Figure 4 In terms of the schematic structure, the flat layer 7 is equivalent to a dielectric layer inserted between the common electrode layer and the transparent electrode layer 19, which has the side effect of voltage division, resulting in a decrease in the voltage difference that can be applied to the liquid crystal layer 2. Figure 1 In the structure shown in FIG. 1 , it is necessary to increase the voltage difference between the common electrode layer and the transparent electrode layer 19 to ensure that the voltage difference applied to the liquid crystal layer 2 meets the driving requirements.

[0088] Specifically, after a voltage difference is formed between the common electrode layer and the transparent electrode layer 19, the magnitude of the voltage difference divided by the flat layer 7 is positively correlated with the thickness of the flat layer 7. In other words, the thicker the flat layer 7 is, the greater the voltage difference divided by the flat layer 7. Therefore, in order to ensure that the voltage difference applied to the liquid crystal layer 2 is not reduced, the voltage difference between the common electrode layer and the transparent electrode layer 19 needs to be greater, which will put higher requirements on the driver chip that can be used for the display substrate, affect the selection of the driver chip, and may lead to an increase in the cost of the projector equipment. Demo (which can be understood as testing and verification of product samples) tests found that when the flat layer 7 is made of organic resin, the thickness of the flat layer 7 is about 1.6-2.5μm, and the thickness of the liquid crystal layer 2 is about 2μm, compared with Figure 1 In the schematic structure, the voltage difference required to achieve the driving voltage between the common electrode layer and the transparent electrode layer 19 increases from 5V (volts) to 10V, which is doubled.

[0089] Therefore, in order to avoid the increase in equipment cost caused by the increase in the required voltage difference between the common electrode layer and the transparent electrode layer 19 as much as possible, the thickness of the planar layer 7 should not be too thick. In one example, if an organic resin is used to prepare the planar layer 7, considering that the dielectric constant of the organic resin is close to that of the commonly used liquid crystal layer material, the thickness ratio between the liquid crystal layer 2 and the planar layer 7 can basically reflect the voltage division ratio of the two for the voltage difference between the common electrode layer and the transparent electrode layer 19, so that the thickness of the planar layer 7 can be set based on this to ensure that the voltage difference applied to the liquid crystal layer 2 meets the driving requirements. Preferably, the thickness of the planar layer 7 does not exceed 2μm.

[0090] To avoid Figure 4 The structure in the embodiment may cause the cost of the projector device to increase. In some embodiments of the present application, Figure 4 The structure of the display substrate shown in the figure is further improved. Figure 5As shown in the figure, in these embodiments, the transparent electrode layer 19 has a first protrusion, which refers to the portion of the transparent electrode layer 19 with the largest distance from the substrate 10; the surface of the flat layer 7 away from the substrate 10 is flush with the surface of the first protrusion away from the substrate 10, and the metal electrode layer 18 is in contact with the first protrusion.

[0091] In practical applications, the first protrusion on the transparent electrode layer 19 is generally a portion of the transparent electrode layer 19 located directly above the TFT switch structure.

[0092] Figure 5 The schematic structure of the display substrate is equivalent to Figure 4 Based on the structure of the above, the preparation process was further improved. Figure 5 In the illustrated structure, after the preparation of the switch tube structure layer in the array substrate 1 is completed, and the transparent electrode layer 19 and the flat layer 7 are sequentially prepared on the switch tube structure layer, the flat layer 7 is thinned so that the convex position at the highest point on the transparent electrode layer 19 is just exposed, and then the metal electrode layer 18 is deposited. In an example, after the preparation of the transparent electrode layer 19 is completed, the flat layer 7 can be prepared by coating or deposition, and then the flat layer 7 can be thinned by a dry etching process.

[0093] After the thinning process of the flat layer 7 is completed, since the concave portion of the transparent electrode layer 19 is still filled with the flat layer 7, and the surface of the thinned flat layer 7 on the side away from the substrate 10 is flush with the highest point of the transparent electrode layer 19, it is still possible to ensure that the surface of the metal electrode layer 18 close to the substrate 10 and the surface of the metal electrode layer 18 on the side away from the substrate 10 are flat as a whole. In other words, the reflective surface in the display substrate is still flat as a whole, which can achieve a good optical effect and avoid light scattering in the display substrate.

[0094] for Figure 5 For the structure of the display substrate shown in the figure, the metal electrode layer 18 can be in electrical contact with the switch tube structure layer through the transparent electrode layer 19, and the metal electrode layer 18 can receive the electrical signal applied by the switch tube structure layer through the electrical contact. Figure 5 The driving method of the liquid crystal layer 2 in the display substrate is shown in FIG. Figure 1 The driving method of the liquid crystal layer 2 in the structure is the same. Therefore, in practical applications Figure 5 When the structure of the display substrate is provided, the magnitude of the driving voltage required to drive the liquid crystal layer 2 is similar to that of conventional LCD products (eg Figure 1 The size of the driving voltage required in the display substrate shown in FIG. 1 is the same, so that the optical performance of the display substrate can be ensured while avoiding Figure 4The problem of increased product costs caused by changes in the driving mode of the structure.

[0095] In some embodiments of the present application, Figure 6 As shown, the display substrate further includes a reflection enhancing layer 8 , and the reflection enhancing layer 8 is arranged between the metal electrode layer 18 and the liquid crystal layer 2 .

[0096] Figure 6 The structure of the display substrate provided can be specifically applied in a reflective projector. The reflection enhancement layer 8 may include one or more insulating layers. The thickness of each insulating layer is reasonably set using the interference enhancement principle, which can effectively increase the utilization rate of the reflected light in the display substrate, thereby improving the brightness of the projected image. Among them, the interference enhancement principle means that when the thickness of the film layer (insulating layer) is an even multiple of the half wavelength of the light, the light reflected from the upper surface of the film layer and the light reflected from the lower surface of the film layer will experience interference enhancement.

[0097] In one example, the reflection-enhancing layer 8 may be composed of multiple insulating layers, and the refractive index of each insulating layer is different. In this example, when the light incident into the display substrate passes through each insulating layer in turn, interference enhancement can be achieved on the surface of each insulating layer, thereby greatly improving the utilization rate of the reflected light in the display substrate. In practical applications, the number of insulating layers in the reflection-enhancing layer 8, the refractive index and thickness of each insulating layer, and the arrangement of each insulating layer can be set according to actual needs, and the embodiments of the present application do not specifically limit this. For example, the setting method of the reflection-enhancing layer 8 can be determined in combination with the relevant theories of optical thin film calculations to achieve a higher utilization rate of reflected light.

[0098] for Figure 6 For the display substrate shown in the figure, since the reflection enhancement layer 8 also causes the voltage difference that can be applied to the liquid crystal layer 2 to decrease, compared with Figure 4 The schematic structure may require further increasing the voltage difference between the common electrode layer and the transparent electrode layer 19 in order to normally drive the liquid crystal layer 2. Therefore, in practical applications, in order to reduce the driving voltage required for the display substrate, the thickness of the reflection enhancement layer 8 should not be too thick. In one example, four insulating layers can be set as the reflection enhancement layer 8, and the thickness of each insulating layer is set between 1000 and 1500 Å (angstroms), and the refractive index of each insulating layer is set between 1.0 and 2.0.

[0099] Based on the same principle, Figure 5 Based on the structure of the schematic display substrate, a reflection enhancement layer 8 is further deposited on the metal electrode layer 18 to obtain Figure 7 Schematic diagram showing the structure of the substrate.

[0100] In some embodiments of the present application, Figure 4The problem of the required driving voltage in the structure is too large. Figure 5 The solution provided by thinning the planar layer 7 to change the driving mode for the liquid crystal layer 2 also provides another solution. Figure 8 and Fig. 9 To explain this solution:

[0101] As mentioned above, the display substrate includes a plurality of sub-pixel regions. Specifically, each sub-pixel region includes a switch circuit region and a non-switch circuit region, wherein the switch circuit region is a region for setting a TFT switch structure, such as Figure 8 and Fig. 9 The area B shown in the figure, the area other than the switching circuit area in the sub-pixel area is called the non-switching circuit area. Figure 8 , the switch tube structure layer specifically includes:

[0102] The gate metal layer 11 includes a first flat portion 111 disposed in the switch circuit area and a second flat portion 112 disposed in the non-switch circuit area; the first flat portion 111 is disconnected from the second flat portion 112;

[0103] The gate metal insulating layer 12 (first insulating layer) is disposed on a side of the gate metal layer 11 away from the substrate 10;

[0104] The active layer 13 includes a third flat portion 131 disposed in the switch circuit region and located on a side of the gate metal insulating layer 12 away from the substrate 10;

[0105] The source and drain metal layer 14 is arranged on a side of the active layer 13 and the gate metal insulating layer 12 away from the substrate 10;

[0106] The second insulating layer is arranged on the side of the source-drain metal layer 14 away from the substrate 10 ; the second insulating layer has a first via hole 151 located in the non-switching circuit area, and the transparent electrode layer 19 is connected to the source-drain metal layer 14 through the first via hole 151 .

[0107] In an actual display substrate structure, the second insulating layer generally includes a source-drain metal insulating layer 15 disposed on a side of the source-drain metal layer 14 away from the substrate 10, and a pixel insulating layer 17 disposed on a side of the source-drain metal insulating layer 15 away from the substrate 10. In addition, a metal shielding layer 16 is generally disposed between the source-drain metal insulating layer 15 and the pixel insulating layer 17 in the switch circuit region.

[0108] The second flat portion 112 of the gate metal layer 11 is located in the non-switching circuit area, which can play a role in raising the height of the transparent electrode layer 19 in the non-switching circuit area, thereby smoothing out the unevenness on the surface of the transparent electrode layer 19 to a certain extent, and improving the overall flatness of the transparent electrode layer 19. In this case, the unevenness on the surface of the transparent electrode layer 19 can be completely smoothed out by depositing a thinner flat layer 7, thereby ensuring that the surface of the liquid crystal layer 2 facing the substrate 10 is flat, which helps to reduce the display substrate's requirements for the driving voltage (that is, the voltage difference between the common electrode layer and the transparent electrode layer 19).

[0109] In an example, Figure 8 As shown, in order to make the surface of the transparent electrode layer 19 as flat as possible, the gate metal layer 11 and the source-drain metal layer 14 are tiled over a large area in the non-switching circuit area, so that the area ratio of the second tiled portion 112 of the gate metal layer 11 in the non-switching circuit area and the area ratio of the source-drain metal layer 14 in the non-switching circuit area are not less than 80%. The area ratio of a film layer in the non-switching circuit area can be understood as: the ratio of the projection area of ​​the film layer on the substrate 10 in the non-switching circuit area to the total projection area of ​​the non-switching circuit area.

[0110] Fig. 9 The specific graphics of the second flat portion 112 of the gate metal layer 11 and the source and drain metal layer 14 in the top view direction are shown, wherein: Fig. 9 (a) is a top view of a conventional LCD display substrate in the related art. Fig. 9 (b) is Figure 8 A top view of the substrate is shown in FIG. Fig. 9 (a) and (b) of FIG. 1 respectively show two sub-pixels in the display substrate, the switch circuit area B in the sub-pixel, the gate metal layer 11, the source-drain metal layer 14, the first via hole 151 exposing the source-drain metal layer 14 on the source-drain metal insulating layer 15, the transparent electrode layer 19, and the common electrode 20 in the top view direction. It can be seen that Fig. 9 In (b), the second flat portion 112 of the gate metal layer 11 and the source-drain metal layer 14 are flattened over a large area in the non-switching circuit region.

[0111] In a conventional display substrate structure, since the TFT switch structure is arranged in the switch circuit area, the switch tube structure layer is generally higher in the switch circuit area and lower in the non-switch circuit area, so that the transparent electrode layer 19 arranged on the side of the light-opening tube structure layer away from the substrate 10 is also higher in the switch circuit area and lower in the non-switch circuit area. Figure 8In the illustrated structure, since the gate metal layer 11 and the source and drain metal layer 14 of the switch tube structure layer are flattened over a large area in the non-switching circuit area, the transparent electrode layer 19 in the non-switching circuit area can be raised to a certain extent, thereby improving the overall flatness of the transparent electrode layer 19.

[0112] Combination Figure 4 Easy to understand, because Figure 8 The flatness of the transparent electrode layer 19 in the display substrate is significantly improved. Figure 4 The preparation of the substrate is shown in the figure. Figure 8 In the process of realizing the substrate shown in the figure, by depositing a thinner flat layer 7, the unevenness on the surface of the transparent electrode layer 19 can be completely smoothed out, so as to realize the flattening of the metal electrode layer 18 to be prepared later. On the basis of reducing the thickness of the flat layer 7, the requirement of the display substrate for the driving voltage can also be reduced, thereby solving the problem mentioned above. Figure 4 The problem of rising projector equipment costs due to the influence of the structure on the selection of driver chips.

[0113] And, for Figure 4 The structure has a high requirement for driving voltage. Figure 8 The solutions provided are Figure 5 Compared with the solution provided, it can save a dry etching process for the flat layer 7, thereby helping to reduce the production cost of the product and improve the product yield. Fig. 9 It is easy to understand that, since the gate metal layer 11 and the source-drain metal layer 14 are substantially opaque to light, this solution is only applicable to reflective projector products, and cannot be applied to transmissive projector products.

[0114] In some embodiments of the present application, see Fig.10 As shown in the figure, the active layer 13 also has a fourth tiled portion 132 arranged in the non-switching circuit area and located between the gate metal insulating layer 12 and the source and drain metal layer 14; the projection of the first via 151 on the substrate 10 is located within the projection range of the fourth tiled portion 132 on the substrate 10.

[0115] Because in Fig.10 In the schematic structure, an active layer 13 is further provided at the bottom of the source-drain metal layer 14 below the first via hole 151, so that Fig. 9 Compared with the structure shown in the figure, the depression of the first via hole 151 can be improved without adding an additional exposure process, and the overall flatness of the transparent electrode layer 19 is better, which helps to further reduce the requirements of the display substrate for the driving voltage. In addition, it also helps to simplify the via process, thereby reducing the product preparation cost of the display substrate and improving the product yield.

[0116] Corresponding to the above-mentioned embodiment of the display substrate for a projector, the present application also provides a method for preparing the display substrate for a projector, see Fig.11 , the method comprising:

[0117] Step 1: forming a switch tube structure layer, a transparent electrode layer and a planar layer in sequence on a substrate; the surface of the planar layer away from the substrate is flush.

[0118] Step 2: depositing a first metal electrode layer on the flat layer, and patterning the first metal electrode layer through a first photomask to obtain a semi-patterned array substrate; the first photomask is provided with a first metal electrode layer pattern of a first pixel position set.

[0119] Step 3: depositing a second metal electrode layer on the semi-patterned array substrate, and patterning the second metal electrode layer through a second mask to obtain a patterned array substrate; the second mask is provided with a second metal electrode layer pattern of a second pixel position set.

[0120] Step 4: forming a liquid crystal layer and a color filter substrate in sequence on the array substrate; the surface of the liquid crystal layer close to the substrate in the same sub-pixel area is flush.

[0121] Among them, the flat layer arranged in the display substrate is used to realize the flatness of the liquid crystal layer to enhance the display effect of the projector product. The relevant specific contents and beneficial effects can be referred to the embodiment of the display substrate for the projector mentioned above, which will not be repeated here.

[0122] The process flow of the above-mentioned preparation method provided in the embodiment of the present application is different from the conventional process flow of preparing LCD devices in that the preparation process of the metal electrode layer is improved.

[0123] Those skilled in the art will understand that each sub-pixel of the display substrate has its own independent metal electrode layer pattern, and the metal electrode layer of each sub-pixel is generally formed by a photomask process. Specifically, the photomask is a circular motherboard used in the electronic manufacturing process, on which a pre-designed pattern is arranged (in the preparation process of the metal electrode layer, specifically the metal electrode layer pattern), and the pattern on the photomask can be subsequently transferred to the display substrate through processes such as exposure and etching.

[0124] According to the conventional LCD device manufacturing process, the metal electrode layer pattern of each sub-pixel in the display substrate is formed through a photomask process. In this process, the minimum spacing between adjacent sub-pixels depends on the resolution of the exposure machine. The resolution of different models of exposure machines varies to a certain extent, but is usually between 2.5 and 4μm. In other words, the minimum spacing that can be achieved between adjacent sub-pixels is also basically between 2.5 and 4μm.

[0125] In actual products, the smaller the spacing between adjacent sub-pixels, the larger the reflection (or transmission) area in the display substrate, the higher the aperture ratio, and the higher the product PPI. Therefore, the minimum achievable spacing between sub-pixels has an important impact on the maximum achievable PPI. For projector products, the projected image projected onto the screen is magnified many times compared to the original image on the display substrate, and the PPI of the projected image will drop significantly. Therefore, in order to ensure fine pixels, the requirements for PPI of projector products are increasing year by year (>1200), and conventional metal electrode layer exposure processes are difficult to meet ultra-high PPI requirements.

[0126] In order to reduce the spacing between adjacent sub-pixels in the display substrate, the embodiment of the present application disassembles the exposure process for the metal electrode layer into two mask processes, and the masks used in these two mask processes are referred to as the first mask and the second mask respectively in the following text. Specifically, the preparation method provided in the embodiment of the present application sets the metal electrode layer patterns of adjacent pixel positions on the first mask and the second mask, respectively, and uses two mask processes to form the metal electrode layer patterns of adjacent pixel positions. In the following text, the pixel positions to which the metal electrode layer pattern set on the first mask belongs are referred to as the first pixel position set, and the pixel positions to which the metal electrode layer pattern set on the second mask belongs are referred to as the second pixel position set. Among them, each pixel position can be specifically understood as the position of a sub-pixel area.

[0127] In order to disperse the metal electrode layer patterns of adjacent pixel positions on different masks, the patterns on the first mask and the second mask can be set in the following manner: the first pixel position set includes pixel positions whose sum of row and column numbers is an odd number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an even number, or the first pixel position set includes pixel positions whose sum of row and column numbers is an even number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an odd number.

[0128] When the patterns on the first mask and the second mask are set in the above manner, if the metal electrode layer pattern at the pixel position of the first row and the first column is set on the first mask, the metal electrode layer pattern at the pixel position of the first row and the second column needs to be set on the second mask, and the metal electrode layer pattern at the pixel position of the first row and the third column needs to be set on the first mask. It is easy to see that only the metal electrode layer patterns at the pixel positions that are spaced apart from each other will be set on the same mask.

[0129] by Figure 4Taking the preparation process of the display substrate illustrated in the figure as an example, after completing the preparation of the flat layer 7, a metal electrode layer (first metal electrode layer) can be deposited on the flat layer 7 for the first time, and then the deposited metal electrode layer is patterned through a first mask to complete the patterning of the metal electrode layer in the first pixel position set in the display substrate.

[0130] In practical applications, the process of the patterning treatment is usually: using a first photomask to expose the deposited metal electrode layer, and then performing subsequent processes such as stripping and etching.

[0131] After the patterning process is performed by the first photomask, the metal electrode layer of the first pixel position set in the display substrate is prepared, and the metal electrode layer is not covered on the flat layer 7 of the second pixel position set. At this time, the metal electrode layer (the second metal electrode layer) can be deposited again, and then the deposited metal electrode layer is patterned by the second photomask. After the patterning process is completed by the second photomask, the metal electrode layer of the second pixel position set is also prepared, that is, the metal electrode layer of each pixel position in the display substrate has been prepared, and the subsequent preparation of the liquid crystal layer 2 and the color filter substrate 3 can be carried out.

[0132] Combine the following Fig.12 An exemplary description is given. Fig.12 An example of a first mask and a second mask is given. The first mask is provided with a metal electrode layer pattern at pixel positions P1 to P5, and the second mask is provided with a metal electrode layer pattern at pixel positions P6 to P9. It can be seen that the metal electrode layer patterns on each mask are spaced apart from each other, and the sum of the metal electrode layer patterns on the two masks is the metal electrode layer pattern at all pixel positions in the display substrate. Fig.12 When the first mask and the second mask are used to pattern the metal electrode layer, after the preparation of the flat layer 7 is completed, a metal electrode layer is first deposited, and the first mask is used to perform patterning to complete the preparation of the metal electrode layer at pixel positions P1 to P5; then the metal electrode layer is deposited again, and the second mask is used to perform patterning, so that the metal electrode layer at pixel positions P6 to P9 is also prepared.

[0133] When preparing the display substrate based on the preparation method of the display substrate for the projector provided in the embodiment of the present application, since the patterns of the metal electrode layers at adjacent pixel positions are dispersed on different masks, and the patterning of the metal electrode layers at two adjacent pixel positions will be completed separately in two different mask processes, the minimum spacing between adjacent pixels no longer depends on the resolution of the exposure machine, but only depends on the alignment accuracy between the two exposure processes. After testing, by controlling the alignment accuracy, the spacing between the metal electrode layers at adjacent pixel positions can be controlled within 2μm. Compared with the minimum spacing of 2.5 to 4μm that can be achieved in the conventional LCD process flow, the minimum spacing between adjacent pixels in the display substrate has been significantly reduced. In practical applications, the above-mentioned preparation method can be applied to the preparation process of products with ultra-high PPI requirements to improve the aperture ratio of the display substrate, thereby achieving a higher PPI.

[0134] In some embodiments of the present application, after the first metal electrode layer is patterned by the first photomask and before the second metal electrode layer is deposited, a third insulating layer may be deposited to cover the first metal electrode layer of the first pixel position set. Then, the second metal electrode layer is deposited on the third insulating layer and patterned by the second photomask.

[0135] In this process flow, since the first metal electrode layer of the first pixel position set is covered by the third insulating layer when the second metal electrode layer is deposited, the deposition of the second metal electrode layer can avoid the problem of short circuit between adjacent pixels, which helps to improve the product yield. However, it should be noted that after the second metal electrode layer is patterned by the second mask, the third insulating layer covering the metal electrode layer of the first pixel position set needs to be removed (that is, the third insulating layer covering the patterned first metal electrode layer needs to be removed), the metal electrode layer of the first pixel position set needs to be exposed, and then the subsequent preparation of the liquid crystal layer and the color filter substrate can be carried out.

[0136] Combination Fig.13 An exemplary description is given, in which a cross-sectional view of two adjacent pixels in a display substrate is specifically shown, assuming that the left pixel corresponds to Fig.12 The pixel position P1 in the right corresponds to Fig.12The pixel position P6 in the image is obtained. After the flat layer 7 is prepared, the metal electrode layer of the pixel position P1 is first deposited on the flat layer 7, and the first mask is used for exposure. The subsequent stripping, etching and other processes are completed to achieve patterning of the metal electrode layer of the pixel position P1. At this time, there is no metal electrode layer at the pixel position P6. The third insulating layer 9 is then deposited to cover the metal electrode layer of the pixel position P1 to avoid a short circuit between the subsequent pixel position P1 and the pixel position P6. The metal electrode layer of the pixel position P6 is then deposited, and the second mask is used for exposure. The subsequent stripping, etching and other processes are completed to achieve patterning of the metal electrode layer of the pixel position P6. The third insulating layer covering the surface of the metal electrode layer at the pixel position P1 is then removed. Finally, the subsequent liquid crystal layer 2 and the color film substrate 3 are prepared to obtain the image. Fig.13 Schematic structure.

[0137] In order to further reduce the spacing between adjacent pixels and maximize the aperture ratio, in one embodiment of the present application, after the third insulating layer 9 is deposited to avoid short circuits between adjacent pixels, after the patterning of the second metal electrode layer for the second set of pixel positions is completed, the third insulating layer 9 covering the edge area of ​​each first pixel position can be retained (that is, the third insulating layer of the edge area of ​​the first metal electrode layer is retained), and only the third insulating layer 9 covering the non-edge area of ​​each first pixel position is removed (that is, the third insulating layer 9 covering the non-edge area of ​​the first metal electrode layer is removed).

[0138] By retaining a certain width of the third insulating layer 9 at the edge area of ​​each first pixel position, the metal electrode layer 18 at the adjacent pixel position can be blocked by the retained third insulating layer 9 to avoid short circuits between adjacent pixels, thereby helping to further improve the product aperture ratio. Fig.13 Taking an example for illustrative explanation, it can be seen that a third insulating layer 9 with a width of d is retained on the side of pixel position P1 close to pixel position P6. At this time, due to the obstruction of the third insulating layer 9, even if the interval between adjacent sub-pixels is designed to be 0μm (that is, the interval between the metal electrode layer patterns at pixel positions P1 and P2 is designed to be 0μm), there will be no short circuit between adjacent sub-pixels. Therefore, the spacing between adjacent sub-pixels can be further reduced to maximize the aperture ratio. Specifically, if the influence of the alignment deviation between the two exposure processes is not considered, the aperture ratio can reach 100%.

[0139] In practical applications, the width of the third insulating layer 9 retained in the edge region of each pixel position, that is, Fig.13 The size of d shown in the figure can be set according to actual needs, for example, it can be set to about 2 μm.

[0140] for Fig.13 As for the structure of the display substrate shown in the diagram, since the third insulating layer 9 is retained under the metal electrode layer 18 at the second pixel position, the overall flatness of the reflective surface and the liquid crystal layer 2 will be affected to a certain extent. And in the actual process flow, if the spacing between adjacent sub-pixels is set too small, the adjacent sub-pixels inside the display substrate actually prepared may overlap, and the flatness of the reflective surface and the liquid crystal layer 2 at the edge of the pixel position will be slightly affected. And because parasitic capacitance will be generated between the sub-pixels, slight crosstalk may also occur, causing a slight decrease in the contrast of the projected image. However, compared with the conventional LCD product structure, in addition to the significant improvement in the PPI of the product, the overall flatness of the reflective surface and the liquid crystal layer 2 is still significantly improved, so the brightness and contrast of the projected image can still be significantly improved.

[0141] Corresponding to the embodiments of the display substrate for a projector described above, the present application further provides a projector, which includes the display substrate for a projector provided by any of the embodiments described above.

[0142] Specifically, the projector device may also include components such as PBS and light source, depending on actual needs.

[0143] In the display substrate in the projector provided in the embodiment of the present application, since a flat layer is arranged on the side of the transparent electrode layer away from the substrate, the surface of the liquid crystal layer close to the substrate in the same sub-pixel area is flush, thereby achieving flattening of the liquid crystal layer, thereby improving the brightness and contrast of the projected image and improving its display effect.

[0144] The relevant specific contents and beneficial effects can be referred to the embodiment of the display substrate for the projector mentioned above, which will not be described in detail here.

[0145] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0146] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0147] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A display substrate for a projector, characterized in that: include: An array substrate, a liquid crystal layer and a color film substrate, wherein the array substrate comprises a substrate, a switch tube structure layer, and a transparent electrode layer arranged on a side of the switch tube structure layer away from the substrate; the display substrate further comprises: The flat layer is arranged on a side of the transparent electrode layer away from the substrate, the surface of the flat layer away from the substrate is flush, and the surface of the liquid crystal layer in the same sub-pixel area close to the substrate is flush.

2. The display substrate according to claim 1, characterized in that: The display substrate further comprises: A metal electrode layer, wherein the metal electrode layer is disposed on a side of the transparent electrode layer away from the substrate; The planar layer is disposed between the metal electrode layer and the liquid crystal layer.

3. The display substrate according to claim 1, characterized in that: The display substrate further comprises: A metal electrode layer, wherein the metal electrode layer is disposed on a side of the transparent electrode layer away from the substrate; The planar layer is disposed between the transparent electrode layer and the metal electrode layer.

4. The display substrate according to claim 3, characterized in that: The transparent electrode layer has a first protrusion, and the first protrusion is the part of the transparent electrode layer with the largest distance from the substrate; A surface of the flat layer away from the substrate is flush with a surface of the first protrusion away from the substrate, and the metal electrode layer is in contact with the first protrusion.

5. The display substrate according to claim 4, characterized in that: The display substrate includes a switch circuit area and a non-switch circuit area, and the first protruding portion of the transparent electrode layer is located in the switch circuit area.

6. The display substrate according to claim 2 or 3, characterized in that: The display substrate further comprises: A reflection enhancement layer is arranged between the metal electrode layer and the liquid crystal layer.

7. The display substrate according to claim 6, characterized in that: The reflection enhancement layer includes a plurality of insulating layers, and the refractive index of each insulating layer is different.

8. The display substrate according to claim 1, characterized in that: The display substrate includes a plurality of sub-pixel regions, each of which includes a switch circuit region and a non-switch circuit region; the switch tube structure layer includes: The gate metal layer comprises a first flat portion arranged in the switch circuit area and a second flat portion arranged in the non-switch circuit area; the first flat portion is disconnected from the second flat portion; A first insulating layer is disposed on a side of the gate metal layer away from the substrate; An active layer, comprising a third flat portion disposed in the switch circuit region and located on a side of the first insulating layer away from the substrate; A source-drain metal layer, arranged on a side of the active layer and the first insulating layer away from the substrate; The second insulating layer is arranged on a side of the source-drain metal layer away from the substrate; the second insulating layer has a first via hole located in the non-switching circuit area, and the transparent electrode layer is connected to the source-drain metal layer through the first via hole.

9. The display substrate according to claim 8, characterized in that: The area ratio of the second flat portion of the gate metal layer in the non-switching circuit area and the area ratio of the source and drain metal layer in the non-switching circuit area are both not less than 80%.

10. The display substrate according to claim 8, characterized in that: The active layer further comprises a fourth flat portion disposed in the non-switching circuit region and located between the first insulating layer and the source-drain metal layer; a projection of the first via on the substrate is located within the projection range of the fourth flat portion on the substrate.

11. A method for preparing a display substrate for a projector, characterized in that: include: A switch tube structure layer, a transparent electrode layer and a flat layer are sequentially formed on the substrate; the surface of the flat layer away from the substrate is flush; Depositing a first metal electrode layer on the flat layer, and patterning the first metal electrode layer through a first photomask to obtain a semi-patterned array substrate; The first photomask is provided with a first metal electrode layer pattern of a first pixel position set; A second metal electrode layer is deposited on the semi-patterned array substrate, and the second metal electrode layer is patterned by a second photomask to obtain a patterned array substrate; a second metal electrode layer pattern of a second pixel position set is provided on the second photomask; wherein the first pixel position set includes pixel positions whose sum of row and column numbers is an odd number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an even number, or the first pixel position set includes pixel positions whose sum of row and column numbers is an even number, and the second pixel position set includes pixel positions whose sum of row and column numbers is an odd number; A liquid crystal layer and a color filter substrate are sequentially formed on the array substrate; wherein a surface of the liquid crystal layer in the same sub-pixel region close to the substrate is flush.

12. The method according to claim 11, characterized in that Before depositing the second metal electrode layer on the semi-patterned array substrate, the method further includes: Depositing a third insulating layer on the semi-patterned array substrate; and depositing the second metal electrode layer on the third insulating layer; After patterning the second metal electrode layer by using the second photomask, the method further includes: The third insulating layer covering the patterned first metal electrode layer is removed.

13. The method according to claim 11, characterized in that Before depositing the second metal electrode layer on the semi-patterned array substrate, the method further includes: Depositing a third insulating layer on the semi-patterned array substrate; and depositing the second metal electrode layer on the third insulating layer; After patterning the second metal electrode layer by using the second photomask, the method further includes: For the first metal electrode layer at each first pixel position, the third insulating layer covering the non-edge region of the first metal electrode layer is removed, and the third insulating layer covering the edge region of the first metal electrode layer is retained.

14. A projector, characterized in that: It comprises a display substrate for a projector as claimed in any one of claims 1 to 10.

Images