CN106526979A - Reflective display device and method of forming the same - Google Patents

Abstract

The present invention discloses a reflective display device and a method for forming the same. The reflective display device comprises a silicon-based liquid crystal display module and a compensation layer. The silicon-based liquid crystal display module comprises a liquid crystal layer. The liquid crystal layer comprises 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 silicon-based liquid crystal display module and is used to compensate for the delay of the liquid crystal layer.

Description

Reflective display device and method for forming the same

technical field

The present invention relates to a display device, and more particularly to a reflective display device and a method for forming the reflective display device.

Background technique

Various projection display devices, such as liquid crystal display devices, digital light processing (DLP) display devices, and liquid crystal on silicon display devices, are commercially available today. Among these projection display devices, the liquid crystal display device operates in transmissive mode, while the digital light processing display device operates in reflective mode. Liquid crystal display devices are the oldest and most common, and have advantages such as high color accuracy and low production costs. However, liquid crystal display devices have disadvantages such as dead pixels and screen door effects, which reduce display performance. Digital light processing display devices have advantages such as high contrast ratio and freedom from color decay. However, digital light processing display devices are relatively expensive. The liquid crystal on silicon display device includes a typical liquid crystal display panel and a complementary metal oxide half field effect transistor (complementary metal oxide silicon; CMOS) silicon wafer manufacturing process and other technologies. Liquid crystal on silicon display devices can achieve high resolution, high color resolution and accuracy, and can be produced through semiconductor manufacturing processes. Because of these advantages, the liquid crystal on silicon display device is applied in electronic devices such as micro-projectors, monitors, or head mounted displays.

Contents of the invention

The object of the present invention is to provide a reflective display device with improved high contrast performance and a method for forming the reflective display device.

To achieve the above object, the present invention provides a reflective display device, which includes a liquid-crystal-on-silicon (LCOS) display module and a compensation layer. A liquid crystal on silicon display module has a liquid crystal layer. The liquid crystal layer includes 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 ranging from 84 degrees to 88 degrees with a relative beta angle. The compensation layer is located on the liquid crystal on silicon display module, and is used for compensating the retardation of the liquid crystal layer.

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

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

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

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

In one or more embodiments, the aforementioned compensation layer has a compensation layer with 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 aforementioned liquid crystal molecules are mixed-mode twisted nematic (MTN) liquid crystal molecules.

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

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

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

The present invention further provides a method for forming a reflective display device, the method includes providing a liquid crystal on silicon 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 temperature ranging from 9 degrees to 11 degrees. degrees and a twist angle with a relative beta ranging from 84 to 88 degrees. The method also includes setting a compensation layer on the liquid crystal on silicon display module to compensate the retardation of the liquid crystal layer.

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

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

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

In one or more embodiments, the compensation layer is disposed on the LCD module through an adhesive layer, and the adhesive layer is disposed between the compensation layer and the LCD module.

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

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

In one or more embodiments, the above method further includes sequentially disposing a transparent substrate and an anti-reflection 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 includes a black matrix.

Description of drawings

FIG. 1 is a schematic diagram of a reflective display device according to some embodiments of the present invention;

Fig. 2 is the graph of embodiment to the white spectral response of comparative example;

Fig. 3 is the graph of embodiment to the black spectral response of comparative example;

Fig. 4 is the histogram of the contrast value of embodiment to comparative example;

5 is a schematic diagram of a reflective display device according to some embodiments of the present invention;

FIG. 6 is a flowchart of a method of forming a reflective display device according to some embodiments of the present invention.

Symbol Description

100, 500 reflective display device

110, 510 liquid crystal on silicon 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 layers

123 top transparent substrate

124, 125, 523, 524 Adhesive layer

130, 530 anti-reflection layer

521 transparent substrate

600 methods

610, 620 steps

X, Y, Z axis

detailed description

The content of the present invention will be explained below by way of examples. However, these examples are not intended to limit the invention to any specific environment, application or particular implementation described in these examples. Therefore, the descriptions of these embodiments are only for the purpose of illustration rather than limiting the present invention. In the following embodiments and drawings, elements that are not directly related to the present invention are omitted and not shown, and the dimensional relationship between the elements in the drawings is only for understanding, and is not intended to be limited to the actual ratio.

It can be understood that although terms such as "first" and "second" may be used herein to describe various elements, parts, regions, layers and/or sections, these terms should not limit the , Region, Layer and/or Section. These terms are only used to distinguish one element, component, region, layer and/or section from another element, component, region, layer and/or section.

FIG. 1 is a schematic diagram illustrating a reflective display device 100 according to some embodiments of the present invention. The reflective display device 100 is a liquid crystal on silicon display device, which can be realized by wafer-level production, and includes a liquid crystal on silicon display module 110 and a compensation structure 120 . The anti-reflection layer 130 is disposed on the compensation structure 120 to reduce light reflection.

The LCD module 110 includes a backplane 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 include red pixels, blue pixels, and green pixels. These red pixels, blue pixels and green pixels are sometimes referred to as sub-pixels. The three sub-pixels (ie red pixel, blue pixel and green pixel) form a complete pixel for emitting light, which includes red, blue and green parts with individual gray scales. For example, the backplane structure 111 further includes a reflective layer to reflect light incident on the LCD module 110 , and the backplane structure 111 also includes pixel electrodes to provide pixel voltages to all pixels.

The alignment layer 112 is disposed on the backplane structure 111 , the alignment layer 113 is 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 aligned by the alignment layers 112 and 113 and twisted according to the electric field generated between the pixel electrodes in the backplane structure 111 and the electrode layer 115 disposed 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 and is configured to provide a common voltage so that the pixels display individual gray scales based on individual pixel voltages. The electrode layer 115 includes 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 LCD module 110 . In some embodiments, the bottom transparent substrate 121 includes a transparent material, such as glass, silicon dioxide, or the like.

The compensation layer 122 is disposed between the bottom transparent substrate 121 and the top transparent substrate 123 to compensate 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, the optical axes of which are parallel to the planar direction of the LCD module 110 , and may have different optical characteristics as will be described below. Alternatively, the compensation layer 122 may include 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 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 transparent materials such as glass, resin or the like. The adhesive layers 124, 125 may include transparent and adhesive materials, such as optical glue, double-sided tape, or the like. In some embodiments, the top transparent substrate 123 includes a black matrix disposed thereon to shield light. Alternatively, the black matrix can be disposed on the compensation layer 122 .

Table 1

Table 1 lists the optical characteristics of the compensation layer 122 according to some embodiments, wherein the compensation film 1 represents the first compensation film stacked on the adhesive layer 124, and the compensation film 2 represents the second compensation film stacked on the first compensation film. . According to Table 1, the slow axis angle of the first compensation film relative to the X axis is between 0 degrees and 30 degrees, and the slow axis angle of the second compensation film relative to the X axis is between 90 degrees and 120 degrees between. In addition, the phase retardation of the first compensation film and the second compensation film is between 25nm and 140nm. In other words, the phase retardation of the compensation layer 144 is in the retardation 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 relative to the X-axis are also correspondingly determined. In this embodiment, the phase retardation of the first compensation film and the second compensation film are substantially the same, and the slow axis angle of the first compensation film relative to the X axis is the same as the slow axis angle of the second compensation film relative to the X axis. The difference between them is essentially 90 degrees.

Table 2

Table 2 lists the optical properties of the liquid crystal layer 114 according to some embodiments. According to Table 2, the phase retardation of the liquid crystal layer 114 is in the 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 the range between -11 degrees and -9 degrees, And the twist angle of the liquid crystal layer 114 relative to the beta angle is in a range between 84 degrees and 88 degrees. In this embodiment, when the phase retardation of the liquid crystal layer 114 is selected, the corresponding beta angle and twist angle of the liquid crystal layer 114 are determined.

Figures 2 and 3 are graphs of white and black spectral responses of Examples versus Comparative Examples. The embodiment represents a reflective display device 100 with two compensation films, the optical characteristics of which are listed in Table 1, and the comparative example represents a MTN-90 reflective display device without a compensation layer. In FIGS. 2 and 3 , the horizontal axis represents the wavelength of incident light, and the vertical axis represents the reflectance of the reflective display devices of Examples and Comparative Examples. In Examples and Comparative Examples, the operating voltage was 6.5 volts.

As shown in FIG. 2 , on the white spectral response, the reflectance of the embodiment is 16.5%, while the reflectance of the comparative example is 16%. The reflectance of the example is nearly equal to that of the comparative example. That is, the reflectance of the embodiment is maintained at about 16%. On the other hand, as shown in FIG. 3 , in the black spectral response, the reflectance of the example is 0.047%, while the reflectance of the comparative example is 0.078%. The reflectance of the example is nearly equal to that of the comparative example. The reflectance of the example is 40% lower than that of the comparative example. From the above, it can be seen that the ratio of the white frequency response to the black frequency response (ie the contrast value) of the embodiment is about 1.71 times that of the comparative example. Therefore, the contrast value of the example is effectively enhanced.

Fig. 4 is a histogram of contrast values of various focal numbers (F-number) of the embodiment versus the comparative example. The focal power is a quantity given by the ratio of the focal length to the diameter of the entrance pupil (ie, opening) in an optical system. As shown in FIG. 4 , for focal numbers of 3.85, 2.50, 1.67, and 1.11, the contrast values of the Examples are at least 60% higher than those of the Comparative Examples.

From the comparison between the embodiment and the comparative example as shown in FIGS. 2 to 4 , it can be seen that the embodiment significantly improves the contrast value performance and maintains the reflectivity of the white spectral response. Therefore, the reflective display device of the present invention improves display quality.

FIG. 5 is a schematic diagram illustrating a reflective display device 500 according to some embodiments of the present invention. The reflective display device 500 is a liquid crystal on silicon display device, which can be realized through wafer-level production, and includes a liquid crystal on silicon display module 510 and a compensation structure 520 . The LCD module 510 includes a backplane 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 adhesive layers 523 , 524 . The anti-reflection layer 530 is disposed on the compensation structure 520 to reduce light reflection. The liquid crystal on silicon display module 510 and the anti-reflection layer 530 are respectively the same as the liquid crystal on silicon display module 110 and the anti-reflection layer 130 shown in FIG. . Compared with 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, compensation layer 522, and adhesive layers 523, 524 are the same as the transparent substrate 121, compensation layer 122, and adhesive layers 124, 125 shown in FIG. The details of , 524 are not repeated here. In some embodiments, the compensation layer 522 includes a black matrix thereon to shield light.

FIG. 6 is a flowchart of a method of forming a reflective display device according to some embodiments of the invention. Method 600 begins at step 610, which provides a liquid crystal on silicon display module. The liquid crystal on silicon display module has a liquid crystal layer, and the liquid crystal layer contains liquid crystal molecules. Each liquid crystal molecule 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 ranging from about 84 degrees to about 88 degrees with a relative beta angle. In some embodiments, the retardation of the liquid crystal layer is between about 240 nm and about 250 nm.

In step 620, a compensation layer is disposed on the LCD module to compensate the retardation of the liquid crystal layer. In some embodiments, the compensation layer includes two compensation films. These compensation films can be two A-plates, the optical axis direction of which is parallel to the plane direction of the liquid crystal on silicon display module, and can have different optical properties. For example, one of the compensation films may have a slow axis between 0 degrees and about 30 degrees, and the other compensation film may 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 light.

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

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

In another embodiment, after step 620, an anti-reflection layer is disposed on the compensation layer to reduce light reflection. An adhesive layer may be disposed on the compensation layer such that the antireflection layer is disposed on the compensation layer via the adhesive layer.

Although the present invention has been disclosed in conjunction with the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be defined by the appended claims.

Claims (20)

1. a kind of reflection display device, comprising：

Liquid crystal on silicon (liquid crystal on silicon；LCoS) display module, with a liquid crystal layer, Wherein the liquid crystal layer has multiple liquid crystal molecules, and each those liquid crystal molecules have scope for 9 degree to 11 The one beta angle (beta angle) of degree and with the relative beta angle and scope be 84 degree to 88 degree one Torsion angle (twist angle)；And

Layer of compensation, on the liquid crystal on silicon display module, the layer of compensation is to compensate prolonging for the liquid crystal layer Late.

2. reflection display device as claimed in claim 1, the wherein layer of compensation include multiple heaps each other Folded compensation film.

3. reflection display device as claimed in claim 2, quantity of wherein those compensation films are 2, Wherein those compensate the one of films with the slow axis (slow axis) between 0 degree and 30 degree, and The another one of those compensation films is with the slow axis between 90 degree and 120 degree.

4. reflection display device as claimed in claim 1, the wherein layer of compensation include single compensation film.

5. reflection display device as claimed in claim 1, the wherein layer of compensation include a black matrix (black matrix)。

6. reflection display device as claimed in claim 1, wherein the layer of compensation is between 25nm A delay between 140nm.

7. reflection display device as claimed in claim 1, the wherein delay of the liquid crystal layer between Between 240nm and 250nm.

8. reflection display device as claimed in claim 1, wherein those liquid crystal molecules are mixed models Stable twisted nematic (mixed-mode twisted nematic；MTN) liquid crystal molecule.

9. reflection display device as claimed in claim 1, also includes：

Anti-reflecting layer, on the layer of compensation.

10. reflection display device as claimed in claim 9, also includes：

Transparency carrier, between the anti-reflecting layer and the layer of compensation.

11. reflection display devices as claimed in claim 10, the wherein transparency carrier include a black square Battle array.

A kind of 12. methods for forming a reflection display device, comprising：

The liquid crystal on silicon display module with a liquid crystal layer is provided, the wherein liquid crystal layer has multiple liquid crystal Molecule, each those liquid crystal molecules have the beta angle that scope is 9 degree to 11 degree and have relative being somebody's turn to do Beta angle and scope are 84 degree to 88 degree of a torsion angle；And

One layer of compensation is set on the liquid crystal on silicon display module, to compensate the delay of the liquid crystal layer.

13. methods as claimed in claim 12, the wherein layer of compensation include multiple compensation for overlieing one another Film.

14. methods as claimed in claim 13, wherein those compensation films quantity be 2, wherein those The one of compensation film is with the slow axis between 0 degree and 30 degree, and the another one of those compensation films With the slow axis between 90 degree and 120 degree.

15. methods as claimed in claim 12, the wherein layer of compensation include single compensation film.

16. methods as claimed in claim 12, the wherein layer of compensation are arranged at via an adhesion coating On the liquid crystal on silicon display module, the adhesion coating is disposed on the layer of compensation and the liquid crystal on silicon display module Between.

17. methods as claimed in claim 12, the wherein layer of compensation include a black matrix.

18. methods as claimed in claim 12, also comprising one anti-reflecting layer of setting on the layer of compensation, Wherein the anti-reflecting layer is arranged on the layer of compensation via an adhesion coating, and the adhesion coating is arranged at the anti-reflective Penetrate between layer and the layer of compensation.

19. methods as claimed in claim 12, also comprising sequentially arranging a transparency carrier and an antireflection On the layer of compensation, wherein the transparency carrier is arranged on the layer of compensation via an adhesion coating to layer, should Adhesion coating is disposed between the transparency carrier and the layer of compensation.

20. methods as claimed in claim 19, the wherein transparency carrier include a black matrix.