TWI569075B - Reflective display apparatus and method of forming the same - Google Patents

Description

Reflective display device and method of forming same

The present invention refers to a display device, and particularly to a reflective display device and a method of forming the reflective display device.

Various projection display devices, such as liquid crystal display devices, digital light processing (DLP) display devices, and germanium-based liquid crystal display devices, are commercially available. In such projection display devices, the liquid crystal display device operates in a transmissive manner, and the digital light processing display device operates in a reflective manner. Liquid crystal display devices are the oldest and most popular, and have advantages such as high color accuracy and low production cost. However, liquid crystal display devices have disadvantages such as dead pixels and screen door effects, which reduce the performance of display. Digital light processing display devices have advantages such as high contrast ratio and color decay. However, digital light processing display devices are relatively expensive. The bismuth-based liquid crystal display device includes a typical liquid crystal display panel and a complementary metal oxide silicon (CMOS) 矽 wafer process.矽-based liquid crystal display devices achieve high resolution, high color resolution and accuracy Reliability, and can be produced by semiconductor manufacturing. Because of these advantages, the 矽-based liquid crystal display device is used in electronic devices such as a micro-projector, a monitor, or a head mounted display.

The present invention provides a reflective display device that improves high contrast performance and a method of forming the reflective display device.

A mode of the present invention is to provide a reflective display device comprising a liquid-crystal-on-silicon (LCOS) display module and a compensation layer. The germanium-based liquid crystal display module has a liquid crystal layer. The liquid crystal layer contains a plurality of liquid crystal molecules, and each liquid crystal molecule has a beta angle ranging from 9 degrees to 11 degrees and a twist angle having a relative beta angle ranging from 84 degrees to 88 degrees. The compensation layer is located on the 矽-based liquid crystal display module to compensate for the delay of the liquid crystal layer.

In one or more embodiments, the compensation layer includes a plurality of compensation films stacked on each other.

In one or more embodiments, the number of such compensation films is two. One of the compensation films has a slow axis between 0 and 30 degrees, and the other of the compensation films has a slow axis between 90 and 120 degrees.

In one or more embodiments, the compensation layer described above includes a single compensation film.

In one or more embodiments, the compensation layer includes a black matrix.

In one or more embodiments, the compensation layer has a compensation layer having a retardation between 25 nm and 140 nm.

In one or more embodiments, the retardation of the liquid crystal layer is between 240 nm and 250 nm.

In one or more embodiments, the liquid crystal molecules described above are mixed-mode twisted nematic (MTN) liquid crystal molecules.

In one or more embodiments, the reflective display device further includes an anti-reflection layer on the compensation layer.

In one or more embodiments, the reflective display device further includes a transparent substrate between the anti-reflective layer and the compensation layer.

In one or more embodiments, the transparent substrate comprises a black matrix.

Another aspect of the present invention is to provide a method of forming a reflective display device, the method comprising providing a germanium-based liquid crystal display module having a liquid crystal layer, wherein the liquid crystal layer has a plurality of liquid crystal molecules, and each liquid crystal molecule has a range It is a beta angle of 9 degrees to 11 degrees and a twist angle having a relative beta angle and ranging from 84 degrees to 88 degrees. The method further includes setting a compensation layer on the germanium-based liquid crystal display module to compensate for delay of the liquid crystal layer.

In one or more embodiments, the compensation layer includes a plurality of compensation films stacked on each other.

In one or more embodiments, the number of such compensation films is two. One of the compensation films has a slow axis between 0 and 30 degrees, and the other of the compensation films has a slow axis between 90 and 120 degrees.

In one or more embodiments, the compensation layer described above includes a single compensation film.

In one or more embodiments, the compensation layer is disposed on the germanium-based liquid crystal display module via an adhesive layer, and the adhesive layer is disposed between the compensation layer and the germanium-based liquid crystal display module.

In one or more embodiments, the compensation layer described above includes a black matrix.

In one or more embodiments, the above method further includes disposing an anti-reflective layer on the compensation layer. The anti-reflection layer is disposed on the compensation layer via the adhesive layer, and the adhesive layer is disposed between the anti-reflection layer and the compensation layer.

In one or more embodiments, the method further includes sequentially disposing the transparent substrate and the anti-reflective layer on the compensation layer. The transparent substrate is disposed on the compensation layer via an adhesive layer, and the adhesive layer is disposed between the transparent substrate and the compensation layer.

In one or more embodiments, the transparent substrate comprises a black matrix.

100,500‧‧‧reflective display device

110, 510‧‧‧矽-based liquid crystal display module

111, 511‧‧‧ Backplane structure

112, 113, 512, 513‧‧ ‧ alignment layer

114, 514‧‧‧ liquid crystal layer

115, 515‧‧‧ electrode layer

120, 520‧‧‧ Compensation structure

121‧‧‧Bottom transparent substrate

122, 522‧‧ ‧ compensation layer

123‧‧‧Top transparent substrate

124, 125, 523, 524‧‧ ‧ adhesive layer

130, 530‧‧ ‧ anti-reflection layer

521‧‧‧Transparent substrate

600‧‧‧ method

610, 620‧ ‧ steps

X, Y, Z‧‧‧ axial

For a more complete understanding of the embodiments and their advantages, reference is made to the following description in conjunction with the drawings in which: 1 is a schematic view showing a reflective display device according to some embodiments of the present invention; [FIG. 2] is a graph of a white spectrum response of a comparative example to a comparative example; [FIG. 3] is an example of a comparative example. a graph of black spectral response; [Fig. 4] is a histogram of comparative values of the comparative examples of the embodiment; [Fig. 5] is a schematic view showing a reflective display device according to some embodiments of the present invention; and [Fig. 6] A flow chart of a method of forming a reflective display device in accordance with some embodiments of the present invention is shown.

The contents of the present invention will be explained below by way of examples. However, the embodiments are not intended to limit any particular environment, application, or particular embodiment of the invention described in the embodiments. Therefore, the description of the embodiments is for illustrative purposes only and is not intended to limit the invention. In the following embodiments and the drawings, the components that are not directly related to the present invention are omitted, and the dimensional relationships between the components in the drawings are only for ease of understanding, and are not intended to be limited to actual ratios.

It will be understood that, although the terms "first" and "second" may be used herein to describe various elements, parts, regions, layers and/or portions, such terms are not intended to limit such elements, parts, Area, layer and/or part. The terms are only used to distinguish one element, part, region, layer, and/or portion from another element, part, region, layer and/or portion.

1 is a schematic diagram of a reflective display device 100 in accordance with some embodiments of the present invention. The reflective display device 100 is a 矽-based liquid crystal display The device is implemented by wafer-level production and includes a germanium-based liquid crystal display module 110 and a compensation structure 120. The anti-reflective layer 130 is disposed on the compensation structure 120 to reduce light reflection.

The NMOS-based liquid crystal display module 110 includes a back plate structure 111, alignment layers 112, 113, a liquid crystal layer 114, and an electrode layer 115. The backplane structure 111 has a plurality of pixels arranged in a matrix, and each pixel can correspond to a specific color. In some embodiments, such pixels comprise a red pixel, a blue pixel, and a green pixel. These red, blue, and green pixels are sometimes referred to as sub-pixels. The three sub-pixels (ie, red, blue, and green pixels) form a complete pixel for emitting light, including red, blue, and individual gray scales. Green part. For example, the backplane structure 111 further includes a reflective layer to reflect light incident on the NMOS-based liquid crystal display module 110, and the backplane structure 111 further includes a pixel electrode to provide a pixel voltage to all pixels.

The alignment layer 112 is disposed on the backplane structure 111, the alignment layer 113 is disposed opposite to the alignment layer 112, and the liquid crystal layer 114 is disposed between the alignment layer 112 and the alignment layer 113. The liquid crystal layer 114 has liquid crystal molecules which are aligned by the alignment layers 112 and 113 and which are twisted in accordance with an electric field generated between the pixel electrodes in the back plate structure 111 and the electrode layers 115 provided on the alignment layer 113. The liquid crystal molecules of the liquid crystal layer 114 are mixed-mode twisted nematic (MTN) liquid crystal molecules. In some embodiments, the retardation of the liquid crystal layer 114 is between about 240 nm and about 250 nm. The alignment layers 112, 113 may be formed to have respective rubbing directions. The electrode layer 115 is disposed on the alignment layer 113 It is configured to provide a common voltage such that the pixels display individual gray levels based on individual pixel voltages. The electrode layer 115 comprises a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO) or other suitable materials.

The compensation structure 120 includes a bottom transparent substrate 121, a compensation layer 122, a top transparent substrate 123, and adhesive layers 124, 125. The bottom transparent substrate 121 is disposed on the electrode layer 115 for receiving incident light and protecting components in the NMOS-based liquid crystal display module 110. In some embodiments, the bottom transparent substrate 121 comprises a transparent material such as glass, ceria or the like.

The compensation layer 122 is disposed between the bottom transparent substrate 121 and the top transparent substrate 123 to compensate for the retardation of the liquid crystal layer 114 and improve the viewing angle of the reflective display device 100. In some embodiments, the compensation layer 122 includes two compensation films. The compensation films may be two A-plates whose optical axis direction is parallel to the planar direction of the NMOS-based liquid crystal display module 110 and may have different optical characteristics as will be described below. Alternatively, the compensation layer 122 may comprise a single compensation film or more than two compensation films stacked on each other. The adhesive layer 124 is disposed between the bottom transparent substrate 121 and the compensation layer 122, and the adhesive layer 125 is disposed between the compensation layer 122 and the top transparent substrate 123 for adhering the compensation layer 122. The bottom transparent substrate 121 and the top transparent substrate 123 may have the same refractive index and may be formed of the same material. For example, the bottom transparent substrate 121 and the top transparent substrate 123 may have a refractive index of 1.51 and may be formed of a transparent material such as glass, resin, or the like. Adhesive layers 124, 125 may comprise a transparent and adhesive material such as optical glue, double sided tape or the like. in In some embodiments, the top transparent substrate 123 includes a black matrix disposed thereon to shield light. Alternatively, a black matrix may be disposed on the compensation layer 122.

Table 1 lists the optical properties of the compensation layer 122 in accordance with some embodiments, wherein the compensation film 1 represents a first compensation film stacked on the adhesion layer 124, and the compensation film 2 represents a second compensation film stacked on the first compensation film. . According to Table 1, the slow axis angle of the first compensation film with respect to the X axis is between 0 and 30 degrees, and the slow axis angle of the second compensation film with respect to the X axis is between 90 degrees and 120 degrees. between. Further, the phase delay of the first compensation film and the second compensation film is between 25 nm and 140 nm. In other words, the phase retardation of the compensation layer 144 is in the range of 25 nm to 140 nm.

When the phase delays of the first compensation film and the second compensation film are selected, their slow axis angles with respect to the X-axis are also determined. In this embodiment, the phase delays of the first compensation film and the second compensation film are substantially the same, the slow axis angle of the first compensation film with respect to the X axis and the slow axis angle of the second compensation film with respect to the X axis. The difference between the two is essentially 90 degrees.

Table 2 lists the optical characteristics of the liquid crystal layer 114 in accordance with some embodiments. According to Table 2, the phase retardation of the liquid crystal layer 114 is in a range between 240 nm and 250 nm, and the beta angle of the liquid crystal layer 114 with respect to the X-axis is in a range between -11 degrees and -9 degrees, And the liquid crystal layer 114 is opposite to The torsion angle of the beta angle is in the range between 84 and 88 degrees. In the present embodiment, when the phase retardation of the liquid crystal layer 114 is selected, the beta angle and the twist angle of the liquid crystal layer 114 are determined.

2 and 3 are graphs of white and black spectral responses of the comparative examples of the comparative examples. The embodiment represents a reflective display device 100 having two compensation films, the optical characteristics of which are shown in Table 1, and the comparative example represents an MTN-90 reflective display device without a compensation layer. In Figs. 2 and 3, the horizontal axis represents the wavelength of the incident light, and the vertical axis represents the reflectance of the reflective display device of the embodiment and the comparative example. In the examples and comparative examples, the operating voltage was 6.5 volts.

As shown in Fig. 2, in the white spectral response, the reflectance of the example was 16.5%, and the reflectance of the comparative example was 16%. The reflectance of the examples was nearly equal to the reflectance of the comparative example. That is, the reflectance of the embodiment was kept at approximately 16%. On the other hand, as shown in FIG. 3, the reflectance of the example was 0.047% in the black spectral response, and the reflectance of the comparative example was 0.078%. The reflectance of the examples was nearly equal to the reflectance of the comparative example. The reflectance of the examples was 40% lower than that of the comparative example. As can be seen from the above, the white frequency of the embodiment The ratio of the rate response to the black frequency response (i.e., the contrast value) was approximately 1.71 times that of the comparative example. Therefore, the contrast value of the embodiment is effectively improved.

Figure 4 is a histogram of comparative values of various focal lengths (F-number) of the comparative examples of the examples. The focal length is the amount given by the ratio of the focal length in the optical system to the diameter (i.e., the opening) of the entrance pupil. As shown in Fig. 4, the comparative values of the examples were at least 60% higher than the comparative values of the comparative examples in terms of the number of focal points of 3.85, 2.50, 1.67 and 1.11.

From the comparison between the examples shown in Figures 2 to 4 and the comparative examples, it is known that the examples significantly improve the contrast performance and maintain the reflectance of the white spectral response. Therefore, the reflective display device of the present invention improves display quality.

FIG. 5 is a schematic diagram of a reflective display device 500 in accordance with some embodiments of the present invention. The reflective display device 500 is a germanium-based liquid crystal display device that can be realized by wafer level production, and includes a germanium-based liquid crystal display module 510 and a compensation structure 520. The NMOS-based liquid crystal display module 510 includes a back plate structure 511, alignment layers 512, 513, a liquid crystal layer 514, and an electrode layer 515. The compensation structure 520 includes a transparent substrate 521, a compensation layer 522, and adhesion layers 523, 524. The anti-reflective layer 530 is disposed on the compensation structure 520 to reduce reflection of light. The 矽-based liquid crystal display module 510 and the anti-reflection layer 530 are the same as the 矽-based liquid crystal display module 110 and the anti-reflection layer 130 shown in FIG. 1 respectively, so the details of the 矽-based liquid crystal display module 510 and the anti-reflection layer 530 are here. Do not repeat the narrative. Compared to the compensation structure 120 shown in FIG. 1, the compensation structure 520 does not include a top transparent substrate, so that the reflective display device 500 can be thinned. Similarly, the transparent substrate 521, the compensation layer 522, and the adhesive layers 523, 524 are the same as the transparent substrate 121, the compensation layer 122, and the adhesive layers 124, 125 shown in FIG. 1, respectively, so that the transparent substrate The details of the 521, the compensation layer 522 and the adhesive layers 523, 524 are not repeated here. In some embodiments, the compensation layer 522 includes a black matrix thereon to shield the light.

6 is a flow chart of a method of forming a reflective display device in accordance with some embodiments of the present invention. The method 600 begins at step 610, which provides a germanium based liquid crystal display module. The germanium-based liquid crystal display module has a liquid crystal layer, and the liquid crystal layer contains liquid crystal molecules. Each of the liquid crystal molecules is a mixed mode twisted nematic liquid crystal molecule and has a beta angle ranging from about 9 degrees to about 11 degrees and a twist angle having a relative beta angle and ranging from about 84 degrees to about 88 degrees. In some embodiments, the retardation of the liquid crystal layer is between about 240 nm and about 250 nm.

In step 620, the compensation layer is disposed on the germanium-based liquid crystal display module to compensate for the retardation of the liquid crystal layer. In some embodiments, the compensation layer comprises two compensation films. The compensation films may be two A-plates whose optical axis direction is parallel to the planar direction of the 矽-based liquid crystal display module and may have different optical characteristics. For example, one of the compensation films can have a slow axis between 0 degrees and about 30 degrees, and another compensation film can have a slow axis between 90 degrees and about 120 degrees. In some embodiments, the compensation layer has a retardation between about 25 nm and about 140 nm. Alternatively, the compensation layer may comprise a single compensation film or more than two compensation films stacked on each other. In some embodiments, the compensation layer includes a black matrix disposed thereon to shield the light.

In some embodiments, before step 620, the adhesive layer is disposed on the germanium-based liquid crystal display module such that the compensation layer is disposed on the adhesive layer via the adhesive layer. On the 矽-based LCD module. The adhesive layer may comprise a transparent and adhesive material such as an optical glue, a double-sided tape or the like.

In some embodiments, after step 620, the transparent substrate is disposed on the compensation layer. The adhesive layer may be disposed on the compensation layer such that the transparent substrate is disposed on the compensation layer via the adhesive layer. The transparent substrate may have a black matrix disposed thereon to shield light. In addition, an anti-reflection layer may be disposed on the compensation layer to reduce light reflection.

In a further embodiment, after step 620, an anti-reflective layer is disposed on the compensation layer to reduce light reflection. The adhesive layer may be disposed on the compensation layer such that the anti-reflection layer is disposed on the compensation layer via the adhesive layer.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

100‧‧‧Reflective display device

110‧‧‧矽-based LCD module

111‧‧‧Backplane structure

112, 113‧‧‧ Alignment layer

114‧‧‧Liquid layer

115‧‧‧electrode layer

120‧‧‧Compensation structure

121‧‧‧Bottom transparent substrate

122‧‧‧Compensation layer

123‧‧‧Top transparent substrate

124, 125‧‧‧ adhesive layer

130‧‧‧Anti-reflective layer

X, Y, Z‧‧‧ axial

Claims (19)

A reflective display device comprising: a liquid crystal on silicon (LCoS) display module having a liquid crystal layer, wherein the liquid crystal layer has a plurality of liquid crystal molecules, each of the liquid crystal molecules having a relative axial direction One of the beta angles, the beta angle ranges from -11 degrees to -9 degrees, and each of the liquid crystal molecules has a twist angle relative to the beta angle and ranging from 84 degrees to 88 degrees (twist angle) And the retardation of the liquid crystal layer is between 240 nm and 250 nm; and a compensation layer is disposed on the germanium-based liquid crystal display module, the compensation layer is used to compensate for the delay of the liquid crystal layer. The reflective display device of claim 1, wherein the compensation layer comprises a plurality of compensation films stacked on each other. The reflective display device of claim 2, wherein the number of the compensation films is two, wherein one of the compensation films has a first slow axis angle with respect to the one of the axial directions The first slow axis angle is between 0 degrees and 30 degrees, and the other of the compensation films has a second slow axis angle with respect to one of the axial directions, and the second slow axis angle is between 90 degrees Between 120 degrees. The reflective display device of claim 1, wherein the compensation layer comprises a single compensation film. The reflective display device of claim 1, wherein the compensation layer comprises a black matrix. The reflective display device of claim 1, wherein the compensation layer has a retardation between 25 nm and 140 nm. The reflective display device of claim 1, wherein the liquid crystal molecules are mixed-mode twisted nematic (MTN) liquid crystal molecules. The reflective display device of claim 1, further comprising: an anti-reflection layer on the compensation layer. The reflective display device of claim 8, further comprising: a transparent substrate between the anti-reflection layer and the compensation layer. The reflective display device of claim 9, wherein the transparent substrate comprises a black matrix. A method of forming a reflective display device, comprising: providing a liquid crystal display module having a liquid crystal layer, wherein the liquid crystal layer has a plurality of liquid crystal molecules, each of the liquid crystal molecules having a relative One of the axial beta angles, the beta angle ranges from -11 degrees to -9 degrees, and each of the liquid crystal molecules has a twist angle with respect to the beta angle and ranging from 84 degrees to 88 degrees, and the liquid crystal layer The delay is between 240 nm and 250 nm; and a compensation layer is disposed on the germanium-based liquid crystal display module to compensate for the retardation of the liquid crystal layer. The method of claim 11, wherein the compensation layer comprises a plurality of compensation films stacked on each other. The method of claim 12, wherein the number of the compensation films is 2, wherein one of the compensation films has a first slow axis angle with respect to one of the axial directions, the first slow axis angle Between 0 degrees and 30 degrees, and the other of the compensation films has a second slow axis angle with respect to one of the axial directions, the second slow axis angle being between 90 degrees and 120 degrees. The method of claim 11, wherein the compensation layer comprises a single compensation film. The method of claim 11, wherein the compensation layer is disposed on the 矽-based liquid crystal display module via an adhesive layer, and the adhesive layer is disposed on the compensation layer and the 矽-based liquid crystal display module between. The method of claim 11, wherein the compensation layer comprises a black matrix. The method of claim 11, further comprising: providing an anti-reflection layer on the compensation layer, wherein the anti-reflection layer is disposed on the compensation layer via an adhesive layer, wherein the adhesive layer is disposed on the compensation layer Between the antireflection layer and the compensation layer. The method of claim 11, further comprising sequentially providing a transparent substrate and an anti-reflection layer on the compensation layer, wherein the transparent substrate is disposed on the compensation layer via an adhesive layer, the adhesion A layer is disposed between the transparent substrate and the compensation layer. The method of claim 18, wherein the transparent substrate comprises a black matrix.