Lcos panel in which liquid crystal is pre-aligned at predetermined angle, and manufacturing method therefor

Abstract

An LCoS panel in which liquid crystal is pre-aligned at a predetermined angle, and a manufacturing method therefor are disclosed. According to one aspect of an embodiment, the LCoS panel is provided, the LCoS panel comprising: a silicon substrate having an alignment film disposed on one surface thereof; an upper substrate having a transparent electrode and an alignment film disposed on one surface thereof, and forming a space into which liquid crystal is to be injected; a seal line printed or drawn between the two substrates so that respective substrates can maintain an interval and form a liquid crystal accommodation space therebetween; the liquid crystal which include a predetermined amount of photoreactive mesogens and which is injected into the liquid crystal accommodation space; and an encapsulant for preventing the liquid crystal from being discharged from the liquid crystal accommodation space by encapsulating a liquid crystal injection port of the seal line, wherein the alignment film undergoes rubbing and, even if the rubbing is performed, a pattern caused by the rubbing is not included in an image output from the LCoS panel.

Description

LCOS panel with liquid crystals oriented at a predetermined angle in advance and its manufacturing method

[0001] The present embodiment relates to an LCoS panel in which liquid crystals are oriented at a preset angle in advance and a method for manufacturing the same.

[0002]

[0003] This patent is the result of research conducted with the support of the Korea Institute of Industrial Technology Planning and Evaluation with funding from the government of the Republic of Korea (Ministry of Trade, Industry and Energy) (Detailed Project Number: 20026453, Project Name: Development of Materials and Components Technology, Project Name: Development of 10000 PPI LCoS Panel Technology Supporting 480 Frame Rate for Ultra-small XR Glasses).

[0004] The content described in this section merely provides background information for the present embodiment and does not constitute prior art.

[0005] LCoS (Liquid Crystal on Silicon) is an ultra-small display device used in augmented reality devices. It shares both structural similarities and differences with conventional LCDs. The two devices share a common structure: they contain liquid crystals sandwiched between two substrates, with an alignment layer on the surface of the substrates to align the liquid crystals. Furthermore, both devices include a pixel electrode that applies an electric field to control the liquid crystal alignment for each pixel, and a driving circuit that includes multiple TFT elements connected to the pixel electrode.

[0006] LCoS differs from conventional LCDs in the following ways: Because its backplane uses a silicon wafer, it can only be used as a reflective display, not a transmissive one. LCoS displays have very small pixels. Furthermore, a significant portion of LCoS's TFT circuitry, wiring, and display driving circuitry are embedded within or beneath the silicon wafer. LCoS displays are also very small, typically less than 1 inch diagonal.

[0007] Meanwhile, when voltage is applied to the liquid crystal, the liquid crystal aligns in a specific direction, determining its light transmittance. However, liquid crystals can be oriented in any direction. If liquid crystals are used as-is without undergoing any adjustment, display devices containing liquid crystals will have difficulty outputting images or videos in the desired format.

[0008] For this reason, LCDs generally form micropatterns on electrodes (mainly transparent electrodes) for aligning liquid crystals so that the liquid crystals align in a preset direction, and use photoreactive liquid crystals (RM: Reactive Mesogen) to fix the liquid crystals at a preset angle. Accordingly, when voltage is applied, the liquid crystals in the LCD can all align in a uniform direction, thereby controlling the light transmittance. However, as mentioned above, since LCoS has considerably small pixels, it is virtually impossible to form micropatterns on the electrodes like in LCDs.

[0009] Due to these problems, after the alignment layer is formed, conventional LCoS physically fixes the liquid crystals at a certain angle by going through a rubbing process on the alignment layer. Accordingly, when voltage is applied, the liquid crystals in the LCoS all align in a uniform direction, thereby controlling the light transmittance. However, in the conventional LCoS manufacturing process, in order to physically fix the liquid crystals at a preset angle, the alignment layer had to be rubbed with a predetermined intensity or higher. However, when the alignment layer is rubbed in this way, a problem occurs in which (unwanted) patterns due to the rubbing are included in the video or image output from the LCoS. This problem is particularly prominent in low-grayscale videos or images. Conventional LCoS had to rub the alignment layer with a predetermined intensity or higher in order to align the liquid crystals in a preset direction, but when rubbing was performed in this way, there was a problem in which the quality of the output video or image was degraded.

[0010] One embodiment of the present invention aims to provide an LCoS panel and a method for manufacturing the same that can maintain the quality of an image or video to be output while aligning liquid crystals at a preset angle in advance.

[0011] One embodiment of the present invention aims to provide an LCoS panel and a method for manufacturing the same, which structurally significantly reduces the possibility of occurrence of a short circuit.

[0012] In addition, one embodiment of the present invention aims to provide an LCoS display device with a significantly improved contrast ratio structurally.

[0013] According to one aspect of the present embodiment, an LCoS panel is provided, comprising: a silicon substrate having an alignment film disposed on one surface; an upper substrate having a transparent electrode and an alignment film disposed on one surface, and forming a space into which a liquid crystal is injected; a seal line printed or drawn between the two substrates so that each substrate can maintain a gap and form a space for accommodating a liquid crystal; and a sealing material including a preset amount of a photo-reactive liquid crystal (Reactive Mesogen), and sealing the liquid crystal injected into the space for accommodating the liquid crystal and the liquid crystal injection port of the seal line to prevent discharge from the space for accommodating the liquid crystal; and rubbing is performed with the alignment film, and even if rubbing is performed, an image output from the LCoS panel does not include a pattern caused by the rubbing.

[0014] According to one aspect of the present embodiment, the lower substrate is characterized in that it is implemented with silicon.

[0015] According to one aspect of the present embodiment, the liquid crystal is characterized in that it has a state in which it is oriented at a preset angle in a preset direction.

[0016] According to one aspect of the present embodiment, the preset angle is characterized by being 80 to 88°.

[0017] According to one aspect of the present embodiment, a method for manufacturing an LCoS panel is provided, comprising: a forming process of forming a groove at each interval between unit cells in a silicon substrate; a second forming process of forming an alignment film on one surface of the silicon substrate and an alignment film and a transparent electrode on one surface of an upper substrate; a rubbing process of rubbing the alignment film; a printing process of printing or drawing a seal line with the upper substrate; a bonding process of bonding the silicon substrate and the upper substrate; a cutting process of cutting the silicon substrate and the upper substrate at each interval between LCoS unit cells; an injection process of injecting a liquid crystal containing a preset amount of a photoreactive liquid crystal (Reactive Mesogen) between the silicon substrate and the upper substrate of each cut LCoS unit cell; a sealing process of sealing an injection hole using a sealing material; and an irradiation process of applying a voltage to the transparent electrode and the silicon substrate and irradiating light to the liquid crystal.

[0018] According to one aspect of the present embodiment, the liquid crystal is characterized in that it has a state in which it is oriented at a preset angle in a preset direction.

[0019] According to one aspect of the present embodiment, the rubbing process is characterized in that each alignment film is arranged in the same direction within each substrate, with the plane facing the same direction.

[0020] According to one aspect of the present embodiment, the preset amount is characterized by being 0.1 to 3% based on the amount of liquid crystal injected.

[0021] As described above, according to one aspect of the present embodiment, there is an advantage in that the quality of an image or video to be output can be maintained while aligning the liquid crystal at a preset angle in advance.

[0022] According to one aspect of this embodiment, there is an advantage in that the possibility of occurrence of a short circuit is structurally significantly reduced.

[0023] In addition, according to one aspect of the present embodiment, there is an advantage in that it can have a significantly superior contrast ratio compared to conventional LCoS structurally.

[0024] FIG. 1 is a plan view of an LCoS panel according to one embodiment of the present invention.

[0025] FIG. 2 is a cross-sectional view of an LCoS panel according to one embodiment of the present invention.

[0026] Figures 3 to 12 are drawings illustrating a process for manufacturing an LCoS panel according to one embodiment of the present invention.

[0027] FIG. 13 is a flowchart illustrating a method for manufacturing an LCoS panel according to one embodiment of the present invention.

[0028] FIG. 14 is a flowchart illustrating a method for aligning liquid crystals in an LCoS panel at a preset angle according to one embodiment of the present invention.

[0029] FIG. 15 is a diagram illustrating the configuration of an LCoS display device according to one embodiment of the present invention.

[0030] FIG. 16 is a diagram illustrating signals transmitted when an LCoS display device according to one embodiment of the present invention operates.

[0031] Fig. 17 is a drawing showing the configuration of a transmittance control unit according to one embodiment of the present invention.

[0032] FIG. 18 is a diagram illustrating a gamma curve for controlling a transmittance control unit and a light source of an LCoS display device according to one embodiment of the present invention.

[0033] FIGS. 19 and 20 are diagrams illustrating examples of images output from an LCoS display device according to one embodiment of the present invention.

[0034] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0035] Terms such as first, second, A, and B may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term "and / or" includes a combination of multiple related items described herein or any of multiple related items described herein.

[0036] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0037] The terminology used in this application is solely for the purpose of describing specific embodiments and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. It should be understood that terms such as "comprise" or "have" in this application do not preclude the presence or possibility of addition of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification.

[0038] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0039] Terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0040] In addition, each configuration, process, procedure or method included in each embodiment of the present invention may be shared within a scope that is not technically inconsistent with each other.

[0041] FIG. 1 is a plan view of an LCoS panel according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an LCoS panel according to an embodiment of the present invention.

[0042] Referring to FIGS. 1 and 2, an LCoS panel (100) according to one embodiment of the present invention includes a lower substrate (110), an alignment film (115, 124), an upper substrate (120), a transparent electrode (128), a liquid crystal (130), a seal line (140), and a sealant (150).

[0043] The lower substrate (110) supports other components within the LCoS panel (100). The lower substrate (110) may be implemented as a silicon substrate and may be implemented in a wafer form. Accordingly, the lower substrate (110) can receive power from the outside to generate an electric field, and reflect incident light, thereby allowing the LCoS panel (100) to operate as a reflective display.

[0044] The lower substrate (110) may be connected to an external driving circuit (not shown) or may include a driving circuit (not shown) internally. The lower substrate (110) may control whether an electric field is generated in the transparent electrode (not shown) and the intensity of the electric field to be generated, depending on the control of the driving circuit (not shown). The lower substrate (110) may be equipped with a TFT circuit and wiring, etc. to control the operation of the LCoS panel (100), on a surface of the lower substrate (110) that is internal or far from the upper substrate (120).

[0045] The alignment film (115) is disposed on one surface of the lower substrate (110) facing the upper substrate (120). In particular, the alignment film (115) is disposed (on the aforementioned surface of the lower substrate (110)) within a space formed by the lower substrate (110), the upper substrate (120), and the seal line (140), into which the liquid crystal (130) is to be injected. The alignment film (115) is disposed at the aforementioned position and is formed so as not to extend beyond the seal line (140). When an electric field is formed by a driving circuit (not shown), the arrangement direction of the liquid crystal (130) changes in a direction different from the initial arrangement direction due to the electric field. At this time, the alignment film (115) maintains the liquid crystal (130) (adjacent to itself) in the initial arrangement direction. The alignment film (115) is implemented as a main chain and a plurality of side chains protruding outward from the main chain. The alignment film (115) can be implemented with polyimide or polyimide acid. Accordingly, the side chain can control the alignment of the liquid crystal (130) depending on the protruding direction.

[0046] The upper substrate (120) is mounted on the lower substrate (110) and, together with the lower substrate (110) and the seal line (140), forms a space into which liquid crystal (130) is injected. The upper substrate (120) is made of glass, thereby allowing light incident from the outside to pass through.

[0047] The transparent electrode (128) is formed on one side of the upper substrate (120) facing the lower substrate (110), and similarly generates an electric field. The transparent electrode (128) is arranged, receives power from the outside, generates an electric field, and aligns the liquid crystal (130). Similarly to the lower substrate (110), the upper substrate (120) has a seal line (140) printed or drawn so as to be biased at one end, and the liquid crystal (130) is injected into the space formed by the seal line (140). Accordingly, a sufficient space is formed at the other end on the corresponding surface of the upper substrate (120) to apply power from the outside to the transparent electrode (128). The transparent electrode (128) formed at the other end of the upper substrate (120) receives power from the outside and generates an electric field.

[0048] The transparent electrode (128) can structurally minimize short circuits by being patterned into a structure described later with reference to FIG. 4. The transparent electrode (128) can structurally prevent the occurrence of short circuits that frequently occur between the substrate and the transparent electrode or between each unit cell arranged on the transparent electrode through patterning.

[0049] The alignment film (124) is disposed on the transparent electrode (128) of the upper substrate (120). In particular, similar to the alignment film (115), the alignment film (124) is also disposed (on the aforementioned surface of the lower substrate (110)) within the space formed by the lower substrate (110), the upper substrate (120), and the seal line (140) into which the liquid crystal (130) is to be injected, and performs the same operation. The alignment film (124) is also implemented as a main chain and a side chain, and can control the alignment of the liquid crystal (130).

[0050] The upper substrate (120) may be implemented with a material having a thermal expansion coefficient within a preset error range, similar to the lower substrate (110), which may be implemented with a silicon wafer. For example, when the lower substrate (110) is implemented with a silicon wafer, the upper substrate (120) may be implemented with borosilicate glass, etc., whose thermal expansion coefficient is within a preset error range. As described below, the seal line (140) is implemented with a polymer sealant having thermosetting characteristics. Accordingly, it is essential that each substrate (110, 120) be exposed to at least a temperature at which the seal line (140) must be cured. At this time, if the thermal expansion coefficients of the two are different, a problem may arise in which the two warp to different degrees during the aforementioned heat process. If the two materials bend to different degrees due to differences in their coefficients of thermal expansion (by a margin of error), this complicates the manufacturing process of LCoS and reduces the reliability of accommodating (sealing) the liquid crystal (130). To prevent such problems, the upper substrate (120) is made of the aforementioned material, thereby preventing the aforementioned problems.

[0051] Meanwhile, an anti-reflection coating (not shown) may be applied to the surface opposite to the surface on which the alignment film (124) and transparent electrode (128) of the upper substrate (120) are formed. As the anti-reflection coating (not shown) is applied to the corresponding surface of the upper substrate (120), light incident from the outside or reflected after being incident can be prevented from being reflected on the surface of the upper substrate (120).

[0052] The liquid crystal (130) changes its orientation when an electric field is applied from the outside. By changing its orientation, the liquid crystal (130) controls the amount of light that passes through it. The liquid crystal (130) goes through a process described below with reference to FIGS. 10 to 12 and has a state in which it is oriented at a preset angle. Here, the preset angle may be 80 to 88°, and more preferably 84 to 86°. In this way, since the liquid crystal (130) has a state in which it is oriented at a preset angle in advance, when an electric field is applied from the outside, all the liquid crystals (130) can be oriented in a uniform direction and can be oriented at a desired angle more quickly. In addition, since the liquid crystal (130) goes through a process described below with reference to FIGS. 10 to 12 and has a state in which it is oriented at a preset angle in advance, it is possible to resolve the problem of including (unwanted) patterns due to rubbing in the final output video or image, as in the prior art.

[0053] When the liquid crystal (130) is injected, a photoreactive liquid crystal (135, RM: Reactive Mesogen, described later with reference to FIG. 10) is injected together with the liquid crystal (130) in a preset amount. The photoreactive liquid crystal (135) may be included in an amount of about 0.1 to 3% relative to the amount of the liquid crystal (130) injected. The photoreactive liquid crystal (135) is polymerized when irradiated with light from the outside, particularly, light in the ultraviolet wavelength range. When the photoreactive liquid crystal (135) is polymerized when irradiated with light from the outside, the angle of the liquid crystal (130) can be physically fixed. As described above, the orientation of the liquid crystal (130) changes only when an electric field is applied from the outside. At this time, the photoreactive liquid crystal (135) is polymerized, and the angle of the liquid crystal (130) can be physically / structurally fixed. Accordingly, the liquid crystal (130) can maintain a state of being aligned at a pre-set angle even if the electric field is stopped from outside.

[0054] The seal line (140) is printed or drawn between each substrate (110, 120) to form a space (144) for accommodating the liquid crystal (130) together with each substrate (110, 120). The seal line (140) may be implemented with a polymer sealant having thermosetting characteristics and may be printed or drawn between each substrate (110, 120). The seal line (140) may also be implemented with a polymer sealant having photocurable characteristics, but the photocurable polymer sealant may have relatively weak adhesive strength and may be unstable in accommodating the liquid crystal (130). Therefore, the seal line (140) is implemented with a polymer sealant having thermosetting characteristics.

[0055] The seal line (140) has a preset shape, for example, a square shape, and forms a receiving space inside. The seal line (140) includes an injection port (148) at one portion, so that liquid crystal (130) can be injected into the receiving space (144) from the outside.

[0056] The sealing material (150) seals the injection port (148) of the seal line (140) to prevent the liquid crystal (130) from being discharged from the receiving space (144). The sealing material (150) is partially injected into the receiving space (144) formed by the seal line (140), particularly, the injection port (148), and is cured, thereby sealing the injection port (148). The sealing material (150) seals the injection port (148) of the seal line (140) and prevents the liquid crystal (130) from being discharged to the outside from the receiving space (144).

[0057] LCoS (100) can have the above-described configuration and characteristics by being manufactured according to the process described below.

[0058] Figures 3 to 12 are drawings illustrating a process for manufacturing an LCoS panel according to one embodiment of the present invention.

[0059] Referring to FIG. 3, a first cut is performed at each interval between LCoS unit cells (320) to be formed on a silicon substrate (110). As described above, the silicon substrate (110) may be implemented in a wafer form. The first cut is performed at each interval between LCoS unit cells (320) on the silicon substrate (110), particularly on the surface facing the glass substrate (420) to be mounted according to the process described below.

[0060] The first cutting into the silicon substrate (110) is performed only to the following extent. The width of the first cutting is performed to be less than 50㎛, and the depth can be performed only to 10 to 60% of the thickness of the silicon substrate (110).

[0061] If the width of the first cut is longer than the aforementioned length, the probability of scratch defects occurring on the back side of the silicon substrate (110) (the side opposite to the side where the first cut was performed) during the rubbing process of the alignment film (115) described later increases significantly. Therefore, the width of the first cut is limited to 50 ㎛ or less.

[0062] In addition, the depth of the first cutting is only 10 to 60%. In particular, when cutting the silicon substrate (110) by the process (scribing process) illustrated in FIG. 8 as described below, the depth of the first cutting can only be 10 to 30% of the thickness of the silicon substrate (110). If the silicon substrate (110) is first cut below the aforementioned level, there is a possibility that the silicon substrate (110) may not be cut smoothly when cut at unit cell intervals through the process illustrated in FIG. 8. Conversely, if the silicon substrate (110) is first cut above the aforementioned level, a situation in which the silicon substrate (110) is separated before the cutting process may occur.

[0063] Referring to Fig. 4a, an alignment film (115) is coated on one surface of the first cut silicon substrate (110).

[0064] Referring to Fig. 4b, a transparent electrode (128) is deposited on one surface of the upper substrate (120).

[0065] Referring to FIG. 4C, patterning is performed on the deposited transparent electrode (128). The transparent electrode (128) is patterned so that the unit cells adjacent to each other in the vertical direction are separated and the upper substrate (120) is exposed, and the transparent electrode (128) is patterned so that the transparent electrode (128) remains in some areas in the form of a bridge (410) and is connected between the unit cells adjacent to each other in the left and right directions. Accordingly, the transparent electrode (128) is patterned, and each unit cell and the unit cells adjacent to each other in the left and right directions remain connected in the form of a bridge, but the unit cells adjacent to each other in the vertical direction are separated. The transparent electrode (128) is patterned in this manner, and a short circuit that may occur between the substrate and the transparent electrode or between each unit cell arranged on the transparent electrode can be minimized.

[0066] Referring to FIG. 4d, an alignment film (124) is coated on the patterned transparent electrode (128). The alignment film (124) can be coated on the upper substrate (120) at intervals between LCoS unit cells (320) to be formed.

[0067] Referring to FIGS. 5A and 5B, rubbing is performed on each alignment film (115, 124) coated on the silicon substrate (110) and the upper substrate (120). The rubbing may be performed so that each alignment film (115, 124), particularly, side chains within the alignment film, are inclined in one direction. As this rubbing is performed on each alignment film (115, 124), the liquid crystal may be oriented in a pre-set direction (e.g., a direction of φ = 45 degrees and θ = 84 to 86 degrees based on the spherical coordinate system).

[0068] In addition, the depth of the rubbing performed on each alignment film (115, 124) may be 0.08 to 0.15 mm. Conventionally, rubbing has been performed on the alignment film to a depth of 0.2 mm or more. As a result, a problem has occurred in which (unwanted) patterns due to the rubbing are included in the image or video output from the LCoS. On the other hand, since the rubbing is performed on each alignment film (115, 124) to a depth of 0.08 to 0.15 mm, patterns due to the rubbing may not be included in the image output from the LCoS panel (100).

[0069] The depth of the love can be calculated as follows:

[0070]

[0071] Here, l represents the depth of rubbing, R represents the radius of the rubbing roll for performing the rubbing, and W represents the width of the rubbing marks created on the alignment film by rotating the rubbing roll while fixing the substrate. As the rubbing on each alignment film (115, 124) progresses to the depth described above according to the formula described above, a pattern caused by the rubbing may not be included in the image output from the LCoS panel (100).

[0072] Rubbing proceeds in the same direction while each alignment film (115, 124) is positioned facing the same direction within each substrate (110, 120). Accordingly, when the two substrates (110, 120) are bonded according to the process described below, each alignment film (115, 124) is rubbed in opposite directions, and the liquid crystals are uniformly aligned in a pre-set direction.

[0073] Referring to FIGS. 6A and 6B, a seal line (140) is printed or drawn at every LCoS unit cell interval on one surface (coated with an alignment film) of a glass substrate (120) to form an accommodation space within the LCoS unit cell. The seal line (140) is printed or drawn on a transparent electrode (128), and is printed or drawn at every LCoS unit cell interval in an area where the alignment film (124) is not coated. However, the present invention is not limited thereto, and the seal line (140) may also be printed or drawn on a silicon substrate (110).

[0074] Referring to Fig. 7, a silicon substrate (110) is bonded onto a seal line (140). At this time, the silicon substrate (110) is bonded so that the alignment film (115) faces the glass substrate (120) or the seal line (140). After the silicon substrate (110) is bonded, the seal line (140) is heat-cured.

[0075] Referring to FIG. 8, cutting is performed at intervals between LCoS unit cells on the silicon substrate (110) and the upper substrate (120). The upper substrate (120) is scribed at intervals between LCoS unit cells. Meanwhile, the silicon substrate (110) is scribed at intervals between LCoS unit cells on the opposite side of the first cut surface. Since the silicon substrate (110) is in a state of being first cut, cutting can be performed in a relatively straight shape, and the possibility of damage to the upper substrate (120) occurring during the cutting (scribing) process is also significantly reduced. If the silicon substrate is completely scribed without first cutting, there is a high possibility of damage to the upper substrate (120) occurring during the scribing process. However, since the silicon substrate (110) is first cut, the above-mentioned problem can be prevented.

[0076] Referring to FIGS. 9a and 9b, liquid crystals (130) are injected into the injection ports (148) of each cut LCoS unit cell. As described above, a preset amount of photoreactive liquid crystals (135) are injected together with the liquid crystals (130). After the liquid crystals (130) are injected, the injection ports (148) are sealed by a sealant (150).

[0077] Referring to Fig. 10, when the alignment film (115, 124) is present, the liquid crystal (130) and the photo-reactive liquid crystal (135) are naturally aligned in the vertical direction. Thereafter, voltage is applied to the transparent electrode (128) and the silicon substrate (110) to adjust the alignment direction of the liquid crystal (130) and the photo-reactive liquid crystal (135). When voltage is applied to both components (110, 128), an electric field is generated.

[0078] At this time, an AC voltage can be applied to both components (110, 128). If a DC voltage is applied to both components (110, 128), an imbalance in the ion concentration in the liquid crystal may occur, causing afterimages or uneven brightness. Conventionally, a DC voltage has been used to orient the liquid crystal due to its structural characteristics, but since the silicon substrate (110) and the transparent electrode (128) can be used to generate an electric field, an AC voltage is applied to generate an electric field.

[0079] Referring to FIGS. 11 and 12, a voltage is applied to the two components (110, 128), an electric field is generated, and accordingly, the angles of the liquid crystal and the photoreactive liquid crystal (135) (e.g., the direction of the other of φ and θ based on the spherical coordinate system) are adjusted. Through the above-described process, since rubbing has occurred on each alignment film (115, 124), the liquid crystal (130) and the photoreactive liquid crystal (135) are both aligned in the same direction. The liquid crystal (130) and the photoreactive liquid crystal (135) are aligned at a certain angle according to the distance or gap with the alignment film (115, 124) by the applied electric field.

[0080] While the liquid crystal (130) and the photoreactive liquid crystal (135) are aligned by an electric field, light in the ultraviolet wavelength range is irradiated from the outside. The light in the ultraviolet wavelength range is irradiated, and the photoreactive liquid crystal (135) is polymerized (1010). Here, the irradiated light (in the ultraviolet wavelength range) can be irradiated in a preset pattern. The preset pattern may be a pattern in which light with an intensity of several to several tens of J is repeatedly irradiated at preset intervals. As the light in the ultraviolet wavelength range is repeatedly irradiated at regular intervals, additional time can be provided for the photoreactive liquid crystal (135) to be polymerized and for the liquid crystal (130) to be oriented at a preset angle. Additionally, the irradiation with light in the ultraviolet wavelength range can continue even after the provision of the electric field (voltage application) is stopped. The light in the ultraviolet wavelength range can be continuously irradiated at a relatively lower intensity than when provided in the aforementioned process.

[0081] The photo-reactive liquid crystal (135) is polymerized, and structurally / physically maintains the liquid crystals (130) at a preset angle. After the photo-reactive liquid crystal (130) is polymerized (1010), the supply of the electric field is stopped. When the supply of the electric field is stopped, the liquid crystals (130) return to their original position (vertical direction). At this time, since the photo-reactive liquid crystal (130) is in a polymerized state (1010), the liquid crystals (130) can all be aligned at a preset angle by the photo-reactive liquid crystal (135). Through this process, the liquid crystal (130) can have a state in which it is aligned at a preset angle in a preset direction in advance. That is, the LCoS panel (100) can include the liquid crystal (130) in the above-described state without the need to form a micropattern on the electrode as in a conventional LCD. In addition, the LCoS panel (100) can prevent a pattern caused by rubbing from being included in the final output image or video, unlike conventional LCoS.

[0082] Meanwhile, although FIGS. 9 to 12 illustrate that the encapsulation of the injection port (148) and the polymerization of the photo-reactive liquid crystal are performed as separate processes, this is not necessarily limited. The processes of FIGS. 9 to 12 may be performed sequentially, but both processes may be performed simultaneously. The encapsulation of the encapsulant may also be performed by irradiation with light in the ultraviolet wavelength range, and the ultraviolet wavelength range light may be irradiated to the entire LCoS panel, and the encapsulation and polymerization may be performed simultaneously (in parallel). When both processes are performed simultaneously in this way, the following advantages may be obtained. If the encapsulation of the injection port (148) is performed first and the polymerization of the photo-reactive liquid crystal is performed later, the liquid crystal near the injection port (148) may be relatively excessively irradiated with light in the ultraviolet wavelength range during both processes. The liquid crystal may be relatively excessively irradiated with light in the ultraviolet wavelength range, and there is also a possibility that the liquid crystal may pretilt in an unintended direction (or angle). Accordingly, the bagging of the injection port (148) illustrated in FIG. 9 and the polymerization of the photo-reactive liquid crystal illustrated in FIGS. 10 to 12 can be performed simultaneously (once) while light in the ultraviolet wavelength band is irradiated across the entire LCoS panel, thereby preventing pretilt of the liquid crystal and simplifying the manufacturing process.

[0083] Fig. 13 is a flowchart illustrating a method for manufacturing an LCoS panel according to one embodiment of the present invention. The method for manufacturing an LCoS panel (100) illustrated in Fig. 13 can be performed by an LCoS panel manufacturing apparatus.

[0084] The first cutting is performed at each interval between unit cells in the silicon substrate (110) (S1310).

[0085] An alignment film (115), a transparent electrode (128), and an alignment film (124) are printed on one surface of a silicon substrate (110) and an upper substrate (120) (S1320). At this time, the transparent electrode (128) is first deposited on the upper substrate (120), and the transparent electrode (128) is patterned so that the upper substrate (120) is exposed by separating the unit cells adjacent in the vertical direction. Meanwhile, the transparent electrode (128) is patterned so that the transparent electrode (128) remains in some areas in the form of a bridge and is connected between the unit cells adjacent in the left and right directions. Thereafter, the alignment film (124) is printed on the patterned transparent electrode (128).

[0086] Rubbing is performed at a preset depth on each alignment film of the silicon substrate (110) and the upper substrate (120) (S1330). Rubbing is performed in the same direction while each alignment film (115, 124) is positioned facing the same direction surface within each substrate (110, 120).

[0087] A seal line (140) is printed on the upper substrate (210) (S1340).

[0088] The silicon substrate (110) and the upper substrate (120) are bonded (S1350).

[0089] The silicon substrate (110) and the upper substrate (120) are cut at each LCoS unit cell interval (S1360).

[0090] Liquid crystal (130) is injected between the silicon substrate (110) and the upper substrate (120) (S1370).

[0091] The injection port (148) is sealed using a sealing material (150) (S1380).

[0092] Voltage is applied to the transparent electrode (128) and the silicon substrate (110), and light is irradiated to the liquid crystal (130) (S1390). However, as mentioned above, the S1380 and S1390 processes can be performed simultaneously.

[0093] FIG. 14 is a flowchart illustrating a method for aligning liquid crystals in an LCoS panel at a preset angle according to one embodiment of the present invention.

[0094] An alternating voltage is applied to the transparent electrode (128) and the silicon substrate (110) (S1410).

[0095] Light in the ultraviolet wavelength range is irradiated to the liquid crystal (130) in a preset pattern (S1420). Accordingly, the photoreactive liquid crystal (135) is polymerized.

[0096] The application of the AC voltage is stopped (S1430). Since the photoreactive liquid crystal (135) is in a polymerized state, when the application of the AC voltage is stopped, the liquid crystal (130) is freed from the state of being aligned by the electric field and returns to its original state. However, since the photoreactive liquid crystal (135) is in a polymerized state according to the process described above, the liquid crystals (130) are aligned at a preset angle.

[0097] FIG. 15 is a diagram illustrating the configuration of an LCoS display device according to one embodiment of the present invention.

[0098] Referring to FIG. 15, an LCoS display device (1500) according to one embodiment of the present invention includes a driving circuit (1510), a light source (1520), a polarizer (1530, 1535), a transmittance control unit (1540), a polarizing beam splitter (1550), and an LCoS panel (100).

[0099] The LCoS display device (1500) outputs an image or video including an LCoS panel (100), and solves the problem of low contrast ratio, which is a problem of a display device including an LCoS panel, by including a transmittance control unit (1540).

[0100] The driving circuit (1510) controls the operations of the light source (1520), the transmittance control unit (1540), and the LCoS panel (100), which will be described later. The driving circuit (1510) controls each component (1520, 1540, 100) as illustrated in FIG. 16.

[0101] FIG. 16 is a diagram illustrating signals transmitted when an LCoS display device according to one embodiment of the present invention operates.

[0102] Referring to Fig. 16(a), the driving circuit (1510) controls each light source (1520) to emit light sequentially.

[0103] At this time, referring to FIGS. 16(b) and (c), the driving circuit (1510) sequentially receives image or video data to be output from the outside by sub-frame, and controls the operation of the LCoS panel (100) after receiving data corresponding to one sub-frame. The driving circuit (1510) transmits the brightness (gray level) of the signal to be output through the LCoS panel (100) for each pixel, but rather than driving (outputting light) each line individually, transmits the brightness of the signal to all lines and then drives each frame. That is, rather than driving each line like an LCD, the driving circuit (1510) transmits the brightness of the signal to all lines of the LCoS panel (100) and then drives so that one entire frame is output. The signal output and displayed to the pixel is maintained until the next frame signal is output.

[0104] Referring to Fig. 16(d), the driving circuit (1510) controls the operation of the transmittance control unit (1540). When controlling the transmittance control unit (1540), the driving circuit (1510) does not sequentially control each pixel or line (as in controlling each light source (1520)), but controls all areas to operate appropriately in unison.

[0105] In this way, the driving circuit (1510) controls the light source (1520) and the LCoS panel (100) to control the image or video to be output, and individually controls the transmittance of each area within the transmittance control unit (1540) for each frame to improve the contrast ratio of the image or video to be output. This will be described later with reference to FIGS. 18 to 20.

[0106] Referring again to FIG. 15, the light source (1520) irradiates light to be output to the outside of the device (1500) through a polarizer (1530, 1535), a transmittance control unit (1540), a polarizing beam splitter (1550), and an LCoS panel (100).

[0107] Polarizers (1530, 1535) are placed at both ends of the transmittance control unit (1540) to adjust the polarization direction of light incident on them.

[0108] The polarizer (1530) is placed between the light source (1520) and the transmittance control unit (1540) on the optical path, and transmits only the light of the second polarization direction perpendicular to the first polarization direction reflected from the polarizing beam splitter (1550) among the light incident on it.

[0109] The polarizer (1535) is placed between the transmittance control unit (1540) and the polarizing beam splitter (1550) on the optical path, and transmits only the light of the first polarization direction reflected from the beam splitter (1550) among the light incident on it.

[0110] The transmittance control unit (1540) adjusts the transmittance of each region within the frame by adjusting the polarization direction of the light incident on it. The transmittance control unit (1540) adjusts the transmittance of each region within the frame in this way to adjust the brightness. The transmittance control unit (1540) is implemented as illustrated in Fig. 17.

[0111] Fig. 17 is a drawing showing the configuration of a transmittance control unit according to one embodiment of the present invention.

[0112] Referring to Fig. 17, the transmittance control unit (1540) is implemented as a configuration for controlling the transmittance, and can be implemented as, for example, an LCD. The transmittance control unit (1540) is implemented as an LCD, and can divide a plurality of regions (1710) and control the transmittance for each region. The transmittance control unit (1540) can control the polarization direction of light incident on it, thereby controlling the amount of light passing through the polarizer (1535). The transmittance control unit (1540) adjusts the polarization direction according to the control of the driving circuit (1510), thereby controlling the transmittance for each region according to the video or image to be output. The transmittance for each region of the transmittance control unit (1540) is not adjusted line by line, but each region is individually controlled, and like the LCoS panel (100), all regions are controlled collectively for each frame.

[0113] The transmittance control unit (1540) can be divided into m*n regions (1710), and each (m, n) may preferably be smaller than 10. According to the control of the driving circuit (1510), the transmittance at the boundary of each region changes in a gradient manner, thereby preventing the brightness of an image or video to be output from being noticeably different from region to region.

[0114] Referring again to FIG. 15, the polarizing beam splitter (1550) reflects light in the first polarization direction, but transmits light in the second polarization direction. The polarizing beam splitter (1550) has a reflective surface facing the light source (1520) and the LCoS panel (100), so that the light in the first polarization direction that is irradiated from the light source (1520) and ultimately passes through the polarizer (1535) is reflected onto the LCoS panel (100), and the light that is reflected after entering the LCoS panel (100) is reflected or transmitted depending on the polarization state.

[0115] The LCoS panel (100) is controlled by the driving circuit (1510) to adjust the polarization state of the light incident on each pixel according to the image or video to be output. The LCoS panel (100) adjusts the light incident on each pixel so that a portion of the image or video to be output that should be relatively bright has a relatively high proportion of light in the first polarization direction, and a portion of the image or video to be output that should be relatively dark has a relatively high proportion of light in the second polarization direction. Accordingly, the light reflected after being incident on the LCoS panel (100) is output as light in the first polarization direction with an appropriate proportion for each pixel, so that the light in the first polarization direction is output to the outside (viewer) by transmitting through the polarizing beam splitter (1550), and the light in the second polarization direction is reflected from the polarizing beam splitter (1550) and not output. The LCoS panel (100) can adjust the gamma of an image or video to be output by adjusting the proportion of light in the first polarization direction for each pixel according to the control of the driving circuit (1510).

[0116] At this time, the device (1500) includes a transmittance control unit (1540) and can improve the contrast ratio as illustrated in FIGS. 19 and 20 by controlling it as illustrated in FIG. 18.

[0117] FIG. 18 is a drawing showing a gamma curve for controlling a transmittance control unit and a light source of an LCoS display device according to an embodiment of the present invention, and FIGS. 19 and 20 are drawings showing examples of images output from an LCoS display device according to an embodiment of the present invention.

[0118] In order to output an image or video to be output, the driving circuit (1510) controls the ratio of the polarization state of light to be reflected from the LCoS panel (100) for each pixel of the LCoS panel (100). Meanwhile, the driving circuit (1510) adjusts the transmittance for each area of ​​the transmittance control unit (1540) in conjunction therewith.

[0119] Referring to Fig. 18a, when the transmittance is 100%, the pixel value (Gray Level) can be the largest 256, and at this time, the brightest light is output. At this time, for example, in order to output light with a pixel value of 192 from the pixel, the pixel value itself can be reduced to 192 and output. However, in this case, in order to output light with a low pixel value, the pixel value itself is reduced by the corresponding value and output. At this time, the problem of unintentionally including light in the second polarization direction cannot be prevented, and thus the problem of a low contrast ratio has occurred.

[0120] Accordingly, the driving circuit (1510) can control each configuration as follows. The pixel value of 192 in the corresponding pixel corresponds to the pixel value when the transmittance is 50% based on the maximum transmittance (100%). Accordingly, the driving circuit (1510) can control the transmittance control unit (1540) to reduce the transmittance to 50% instead of reducing and outputting the pixel value itself in the corresponding pixel, and can control the light source (1520) and the LCoS panel (100) to output light in the first polarization direction with the maximum pixel value. Accordingly, the device (1500) can output light having a specific pixel value while preventing the problem of unintentionally including light in the second polarization direction.

[0121] The driving circuit (1510) can adjust the transmittance for each area of ​​the transmittance control unit (1540) and output as shown in FIGS. 19 and 20.

[0122] As shown in Figure 19a, if the final output image is the Earth, the Earth in the center should have a constant pixel value, while areas other than the Earth should have very dark pixel values. However, as previously mentioned, conventional LCoS has a significantly low contrast ratio due to unintentionally residual polarization components.

[0123] On the other hand, the transmittance control unit (1540) divides into a plurality of regions (1710) as illustrated in FIG. 19b, and the driving circuit (1510) can control the transmittance of each region of the transmittance control unit (1540). The driving circuit (1510) adjusts the region (within the transmittance control unit (1540)) corresponding to the part where the Earth should be placed to have an appropriate transmittance, while adjusting the region (within the transmittance control unit (1540)) corresponding to a part other than the Earth to have the lowest transmittance. Since the region within the transmittance control unit (1540) has the lowest transmittance, even if light is output with the brightest pixel value from the light source (1520) as illustrated in FIG. 18b, the effect of outputting the same light as that with the lowest pixel value can be achieved.

[0124] Accordingly, as illustrated in FIG. 19c, an image or video output through the device (1500) can be output to be considerably dark in areas that should be dark, thereby having an excellent contrast ratio.

[0125] This is also the case in Fig. 20. Regardless of which image or video is output, the driving circuit (1510) can secure an excellent contrast ratio by adjusting the transmittance of each area within the transmittance control unit (1540) to correspond to the pixel value of the image or video to be output.

[0126] Although FIGS. 13 and 14 describe each process as being executed sequentially, this is merely an illustrative description of the technical idea of ​​one embodiment of the present invention. In other words, a person skilled in the art to which one embodiment of the present invention pertains may modify and apply various modifications and variations, such as changing the order described in each drawing and executing it without departing from the essential characteristics of one embodiment of the present invention, or executing one or more of each process in parallel. Therefore, FIGS. 13 and 14 are not limited to a chronological order.

[0127] Meanwhile, the processes illustrated in FIGS. 13 and 14 can be implemented as computer-readable code on a computer-readable recording medium. A computer-readable recording medium includes any type of recording device that stores data readable by a computer system. Specifically, a computer-readable recording medium includes storage media such as magnetic storage media (e.g., ROM, floppy disks, hard disks, etc.) and optical readable media (e.g., CD-ROMs, DVDs, etc.). Furthermore, a computer-readable recording medium can be distributed across network-connected computer systems, allowing the computer-readable code to be stored and executed in a distributed manner.

[0128] The above description is merely an example of the technical idea of ​​the present embodiment, and those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of ​​the present embodiment, but rather to explain it, and the scope of the technical idea of ​​the present embodiment is not limited by these embodiments. The scope of protection of the present embodiment should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of the present embodiment.

[0129]

[0130] CROSS-REFERENCE TO RELATED APPLICATION

[0131] This patent application claims priority under 35 USC § 119(a) to Korean Patent Application No. 10-2024-0106008, filed in Korea on August 8, 2024, the entire contents of which are incorporated by reference herein. Furthermore, this patent application claims priority in countries other than the United States for the same reasons, the entire contents of which are incorporated by reference herein.

Claims

1. In the LCoS panel, A silicon substrate having an alignment film disposed on one side; An upper substrate having a transparent electrode and an alignment film arranged on one side and forming a space into which liquid crystal is injected; A seal line printed or drawn between two substrates to allow each substrate to maintain a gap and form a space to accommodate the liquid crystal; A liquid crystal that contains a preset amount of a photo-reactive liquid crystal (Reactive Mesogen) and is injected into the liquid crystal receiving space; It includes a sealing material that seals the liquid crystal injection port of the above seal line and prevents the liquid crystal from being discharged from the receiving space. An LCoS panel characterized in that rubbing is performed with the above-mentioned alignment film, and even when rubbing is performed, a pattern caused by rubbing is not included in an image output from the LCoS panel.

2. In paragraph 1, The above lower substrate, An LCoS panel characterized by being implemented with silicon.

3. In paragraph 1, The above liquid crystal is, An LCoS panel characterized by having a state oriented at a preset angle in a preset direction.

4. In paragraph 3, The above preset angle is, An LCoS panel characterized by an angle of 80 to 88°.

5. In the LCoS panel manufacturing method, A formation process that forms grooves at intervals between unit cells on a silicon substrate; A second forming process of forming an alignment film on one side of the silicon substrate and an alignment film and a transparent electrode on one side of the upper substrate; A rubbing process for rubbing the above-mentioned alignment film; A printing process for printing or drawing a seal line on the upper substrate; A bonding process for bonding the above silicon substrate and the upper substrate; A cutting process for cutting the silicon substrate and the upper substrate at each LCoS unit cell interval; An injection process of injecting a liquid crystal containing a preset amount of photo-reactive liquid crystal (Reactive Mesogen) between the silicon substrate and the upper substrate of each cut LCoS unit cell; A bagging process of bagging the injection port using bagging material; and An irradiation process of applying voltage to the above transparent electrode and the above silicon substrate and irradiating light to the liquid crystal A method for manufacturing an LCoS panel, characterized by including:

6. In paragraph 5, The above liquid crystal is, A method for manufacturing an LCoS panel, characterized in that the panel is oriented at a preset angle in a preset direction.

7. In paragraph 5, The above loving process is, A method for manufacturing an LCoS panel, characterized in that each alignment film is arranged toward the same direction within each substrate and progresses in the same direction.

8. In paragraph 5, The above preset amount is, A method for manufacturing an LCoS panel, characterized in that the amount of liquid crystal injected is 0.1 to 3%.

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