CN114114743A

CN114114743A - LCOS display device and manufacturing method thereof

Info

Publication number: CN114114743A
Application number: CN202111439044.0A
Authority: CN
Inventors: 许冠军; 柳冬冬
Original assignee: Omnivision Semiconductor Shanghai Co Ltd
Current assignee: Omnivision Semiconductor Shanghai Co Ltd
Priority date: 2021-11-26
Filing date: 2021-11-26
Publication date: 2022-03-01

Abstract

The invention provides an LCOS display device and a manufacturing method thereof, wherein the LCOS display device comprises a substrate, a metal reflecting layer, a passivation layer, a liquid crystal layer and a transparent cover plate which are sequentially stacked, wherein the passivation layer comprises at least three medium layers which are sequentially stacked; the invention also provides a manufacturing method of the LCOS, and the invention can greatly improve the reflectivity of the LCOS display device and simultaneously improve the light efficiency utilization rate and the optical performance of the LCOS product through the brand new multilayer stack design of the passivation layer.

Description

LCOS display device and manufacturing method thereof

Technical Field

The invention relates to the field of liquid crystal display, in particular to a Liquid Crystal On Silicon (LCOS) display device and a manufacturing method thereof.

Background

The LCOS (Liquid Crystal on Silicon) structure is a new reflective projection display device, which uses semiconductor Silicon technology to control the Liquid Crystal and "project" color pictures. Compared with the transmissive LCD (Liquid Crystal Display and dlp (digital Light processing) structure, the LCOS structure has the characteristics of high Light utilization efficiency, small volume, high aperture ratio, mature manufacturing technology and the like, and can easily realize high resolution and sufficient color expression.

Referring to fig. 1, an exemplary LCOS display includes: a substrate 10, and a metal reflective layer 11 (i.e., a pixel electrode layer), a passivation layer 13, a first alignment layer 12, a liquid crystal layer 30, a second alignment layer 22, a transparent conductive layer 21, and a transparent cover 20 sequentially disposed on the substrate 10. In this configuration, an external strong light source is transmitted through the liquid crystal layer 30, irradiated onto the metal reflective layer 11, and reflected into human eyes through the metal reflective layer 11, so that an image can be viewed.

However, the reflectivity of the LCOS product manufactured by the above structure is not high, about 80% to 85%, and the light efficiency utilization rate is low, resulting in poor optical performance. Therefore, how to improve the reflectivity of the LCOS display is a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide an LCOS display device and a manufacturing method thereof.

To achieve the above object, the present invention provides an LCOS display device, including: the liquid crystal display panel comprises a substrate, a metal reflecting layer, a passivation layer, a liquid crystal layer and a transparent cover plate which are sequentially stacked; the passivation layer comprises at least three dielectric layers which are stacked in sequence.

Optionally, in the LCOS display device, the passivation layer includes three dielectric layers, namely a first dielectric layer, a second dielectric layer and a third dielectric layer, which are stacked in sequence; the refractive index of the second medium layer is higher than that of the first medium layer, and the refractive index of the second medium layer is higher than that of the third medium layer.

Optionally, in the LCOS display device, the refractive index of the first dielectric layer is equal to the refractive index of the third dielectric layer, and the material of the first dielectric layer is the same as the material of the third dielectric layer.

Optionally, in the LCOS display device, the first dielectric layer, the second dielectric layer, and the third dielectric layer are made of silicon oxide, silicon nitride, and silicon oxide in sequence.

Optionally, in the LCOS display device, the passivation layer includes four dielectric layers stacked in sequence, namely a first dielectric layer, a second dielectric layer, a third dielectric layer and a fourth dielectric layer stacked in sequence;

the refractive index of the second medium layer is higher than that of the first medium layer, the refractive index of the second medium layer is higher than that of the third medium layer, the refractive index of the fourth medium layer is higher than that of the third medium layer, and the refractive index of the fourth medium layer is higher than that of the first medium layer.

Optionally, in the LCOS display device, the refractive index of the first dielectric layer is equal to the refractive index of the third dielectric layer, the refractive index of the second dielectric layer is equal to the refractive index of the fourth dielectric layer, the material of the first dielectric layer is the same as the material of the third dielectric layer, and the material of the second dielectric layer is the same as the material of the fourth dielectric layer.

Optionally, in the LCOS display device, the first dielectric layer, the second dielectric layer, the third dielectric layer, and the fourth dielectric layer are made of silicon oxide, silicon nitride, silicon oxide, and silicon nitride in sequence.

Optionally, in the LCOS display device, the LCOS display device further includes a first alignment layer, a second alignment layer, and a transparent conductive layer;

the first alignment layer is located between the passivation layer and the liquid crystal layer, the second alignment layer is located between the liquid crystal layer and the transparent cover plate, and the transparent conducting layer is located between the second alignment layer and the transparent cover plate.

Correspondingly, the invention also provides a manufacturing method of the LCOS display device, which comprises the following steps:

providing a substrate and a transparent cover plate;

sequentially stacking a metal reflecting layer and a passivation layer on the substrate, wherein the passivation layer comprises at least three dielectric layers which are sequentially stacked; and

and a liquid crystal layer is arranged on one side of the passivation layer, which is far away from the substrate, and the metal reflection layer, the passivation layer and the liquid crystal layer are sequentially stacked, and the substrate is attached to the transparent cover plate.

Optionally, in the manufacturing method of the LCOS display device, the dielectric layer is formed by a chemical vapor deposition method.

Compared with the prior art, in the LCOS display device and the manufacturing method thereof provided by the invention, the LCOS display device comprises the substrate, the metal reflecting layer, the passivation layer, the liquid crystal layer and the transparent cover plate which are sequentially stacked, and the passivation layer comprises at least three dielectric layers which are sequentially stacked. According to the invention, through the brand new multilayer stack design of the passivation layer, the reflectivity of the LCOS display device can be greatly improved, and meanwhile, the light efficiency utilization rate and the optical performance of the LCOS product can also be improved.

Drawings

Fig. 1 is a schematic diagram of an LCOS display structure.

Fig. 2 is a schematic structural diagram of an LCOS display according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an LCOS display according to another embodiment of the present invention.

Fig. 4 is a schematic diagram illustrating a comparison of the reflectivity before and after the improvement of the passivation layer according to an embodiment of the invention.

Fig. 5 is a flowchart illustrating a method for fabricating an LCOS display according to an embodiment of the present invention.

Detailed Description

Referring to fig. 1, the passivation layer 11 is generally made of silicon oxide, and mainly plays a role of circuit protection and dielectric layer. In view of the problems in the background art, the inventors have found through research that the passivation layer is redesigned to have the function of an antireflection film, so that the reflectivity of the LCOS display device can be greatly improved.

In this regard, the inventors provide an LCOS display device comprising: the liquid crystal display panel comprises a substrate, a metal reflecting layer, a passivation layer, a liquid crystal layer and a transparent cover plate which are sequentially stacked; the passivation layer comprises at least three dielectric layers which are stacked in sequence.

providing a substrate and a transparent cover plate;

In the LCOS display device and the manufacturing method thereof provided by the invention, the LCOS display device comprises a substrate, a metal reflecting layer, a passivation layer, a liquid crystal layer and a transparent cover plate which are sequentially stacked, wherein the passivation layer comprises at least three dielectric layers which are sequentially stacked. According to the invention, through the brand new multilayer stack design of the passivation layer, the reflectivity of the LCOS display device can be greatly improved, and meanwhile, the light efficiency utilization rate and the optical performance of the LCOS product can also be improved.

In order to make the contents of the present invention more clearly understood, the contents of the present invention will be further described with reference to the accompanying drawings. The invention is of course not limited to this particular embodiment, and general alternatives known to those skilled in the art are also covered by the scope of the invention.

It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The present invention is described in detail with reference to the drawings, and for convenience of explanation, the drawings are not enlarged partially according to the general scale, and should not be construed as limiting the present invention.

Fig. 2 is a schematic structural diagram of an LCOS display device according to an embodiment of the present invention. As shown in fig. 2, the LCOS display device includes: a substrate 100, a metal reflective layer 110, a passivation layer 130, a liquid crystal layer 300, and a transparent cover plate 200 sequentially stacked; the passivation layer 130 includes at least three dielectric layers stacked in sequence.

In an embodiment of the present invention, referring to fig. 2, the passivation layer 130 includes three dielectric layers, namely a first dielectric layer 131, a second dielectric layer 132 and a third dielectric layer 133, stacked in sequence, wherein a refractive index of the second dielectric layer 132 is higher than a refractive index of the first dielectric layer 131, and a refractive index of the second dielectric layer 132 is higher than a refractive index of the third dielectric layer 133.

Preferably, the refractive index of the first dielectric layer 131 is equal to the refractive index of the third dielectric layer 133, and the material of the first dielectric layer 131 is the same as the material of the third dielectric layer 133. The material of the first dielectric layer 131 is preferably silicon oxide, the material of the second dielectric layer 132 is preferably silicon nitride, and the material of the third dielectric layer 133 is preferably silicon oxide. Namely, a stacked structure layer of silicon oxide, silicon nitride and silicon oxide is sequentially formed on the metal reflective layer 110.

In another embodiment of the present invention, referring to fig. 3, the passivation layer 130 includes four dielectric layers sequentially stacked, namely a first dielectric layer 131, a second dielectric layer 132, a third dielectric layer 133 and a fourth dielectric layer 134, wherein the refractive index of the second dielectric layer 132 is higher than the refractive index of the first dielectric layer 131, the refractive index of the second dielectric layer 132 is higher than the refractive index of the third dielectric layer 133, the refractive index of the fourth dielectric layer 134 is higher than the refractive index of the third dielectric layer 133, and the refractive index of the fourth dielectric layer 134 is higher than the refractive index of the first dielectric layer 131.

Preferably, the refractive index of the first dielectric layer 131 is equal to the refractive index of the third dielectric layer 133, the refractive index of the second dielectric layer 132 is equal to the refractive index of the fourth dielectric layer 134, the material of the first dielectric layer 131 is the same as the material of the third dielectric layer 133, and the material of the second dielectric layer 132 is the same as the material of the fourth dielectric layer 134. The material of the first dielectric layer 131 is preferably silicon oxide, the material of the second dielectric layer 132 is preferably silicon nitride, the material of the third dielectric layer 133 is preferably silicon oxide, and the material of the fourth dielectric layer 134 is preferably silicon nitride. That is, a stacked structure layer of silicon oxide, silicon nitride, silicon oxide and silicon nitride is sequentially formed on the metal reflective layer 110.

Of course, the passivation layer 130 may also include five dielectric layers or more dielectric layers stacked in sequence, which is not limited in the present invention. However, since the number of the passivation layers 130 is too large, the performance of the LCOS display device may be affected, and therefore, the number of the passivation layers 130 needs to be determined according to the contribution to the reflectivity and the influence on the LCOS display device, for example, the reflectivity is greatly improved, but other influences on the LCOS display device cannot be used, and a balanced selection between the contribution to the reflectivity and the influence on the LCOS display device is needed.

With continued reference to fig. 2 and fig. 3, the LCOS display device further includes a first alignment layer 120, a second alignment layer 220, and a transparent conductive layer 210; wherein the first alignment layer 120 is located between the passivation layer 130 and the liquid crystal layer 300, the second alignment layer 220 is located between the liquid crystal layer 300 and the transparent cover plate 200, and the transparent conductive layer 210 is located between the second alignment layer 220 and the transparent cover plate 200.

Comparing fig. 1, 2 and 3, the passivation layer 13 in fig. 1 has only one layer, mainly functioning as a circuit protection layer and a dielectric layer, and the passivation layer 130 in fig. 2 and 3 is a three-layer stacked structure or a four-layer stacked structure, and not only has the functions of circuit protection and a dielectric layer, but also has the function of increasing reflection, thereby greatly improving the reflectivity of the LCOS display device. Specifically, the comparison is made by the reflectance comparison diagram of fig. 4. As shown in fig. 4, the abscissa indicates the wavelength and the ordinate indicates the reflectivity of the LCOS display device, and it can be seen that the reflectivity of the LCOS display device of the present invention (shown in fig. 2) is significantly better than that of the LCOS display device of the prior art (shown in fig. 1) when comparing the LCOS display device of the prior art (shown in fig. 1) with the LCOS display device of the present invention (shown in fig. 2).

Therefore, the passivation layer 130 designed by the inventor can greatly improve the reflectivity of the LCOS display device, thereby greatly improving the light efficiency utilization rate of the LCOS product and improving the optical performance of the LCOS product.

Correspondingly, the embodiment of the invention also provides a manufacturing method of the LCOS display device, which is used for manufacturing the LCOS display device. Fig. 5 is a flowchart of a method for manufacturing an LCOS display device according to an embodiment of the present invention, where the method for manufacturing an LCOS display device includes:

in step S1, a substrate 100 and a transparent cover 200 are provided.

The material of the substrate 100 may be any suitable semiconductor material known to those skilled in the art, such as silicon, germanium, silicon carbide, silicon-on-insulator, germanium-on-insulator, gallium arsenide, and the like, or the substrate 100 may be a silicon substrate. In the present embodiment, the substrate 100 is preferably a silicon crystal substrate. The transparent cover plate 200 may be a glass substrate or a substrate of other transparent materials, and when the transparent cover plate 200 is a glass substrate, it may be preferably made of quartz, fused quartz, high temperature glass, or glass having a thermal expansion coefficient similar to that of a silicon substrate.

Step S2, sequentially stacking a metal reflective layer 110 and a passivation layer 130 on the substrate 100, where the passivation layer 130 includes at least three dielectric layers stacked in sequence.

First, a metal reflective layer 110 is formed on the substrate 100, and a material of the metal reflective layer 110 includes at least one of magnesium (Mg), copper (Cu), aluminum (Al), titanium (Ti), tantalum (Ta), gold (Au), zinc (Zn), and silver (Ag), preferably aluminum.

Next, a passivation layer 130 is formed on the metal reflective layer 110. In an embodiment of the present invention, the passivation layer 130 includes three dielectric layers, namely a first dielectric layer 131, a second dielectric layer 132 and a third dielectric layer 133, which are sequentially stacked, a refractive index of the first dielectric layer 131 is equal to a refractive index of the third dielectric layer 133, and a refractive index of the second dielectric layer 132 is greater than the refractive indices of the first dielectric layer 131 and the third dielectric layer 133. Preferably, the material of the first dielectric layer 131 is the same as that of the third dielectric layer 133. More preferably, the first dielectric layer 131, the second dielectric layer 132, and the third dielectric layer 133 are made of silicon oxide, silicon nitride, and silicon oxide in sequence. That is, a stacked structure of silicon oxide, silicon nitride, and silicon oxide is sequentially formed on the metal reflective layer 110, and preferably, each dielectric layer may be formed by a chemical vapor deposition method. The thickness of the three dielectric layers can be determined according to the actual process, so that the reflectivity can be improved, and the LCOS display device cannot be influenced.

Alternatively, in another embodiment of the present invention, referring to fig. 3, the passivation layer 130 includes four dielectric layers, namely a first dielectric layer 131, a second dielectric layer 132, a third dielectric layer 133 and a fourth dielectric layer 134, which are sequentially stacked, wherein a refractive index of the second dielectric layer 132 is higher than a refractive index of the first dielectric layer 131, a refractive index of the second dielectric layer 132 is higher than a refractive index of the third dielectric layer 133, a refractive index of the fourth dielectric layer 134 is higher than a refractive index of the third dielectric layer 133, and a refractive index of the fourth dielectric layer 134 is higher than a refractive index of the first dielectric layer 131.

Preferably, the refractive index of the first dielectric layer 131 is equal to the refractive index of the third dielectric layer 133, the refractive index of the second dielectric layer 132 is equal to the refractive index of the fourth dielectric layer 134, the material of the first dielectric layer 131 is the same as the material of the third dielectric layer 133, and the material of the second dielectric layer 132 is the same as the material of the fourth dielectric layer 134. The material of the first dielectric layer 131 is preferably silicon oxide, the material of the second dielectric layer 132 is preferably silicon nitride, the material of the third dielectric layer 133 is preferably silicon oxide, and the material of the fourth dielectric layer 134 is preferably silicon nitride. That is, a stacked structure layer of silicon oxide, silicon nitride, silicon oxide, and silicon nitride is sequentially formed on the metal reflective layer 110, and preferably, each dielectric layer may be formed by a chemical vapor deposition method. The thickness of the four dielectric layers can be determined according to the actual process, so that the reflectivity can be improved, and the LCOS display device cannot be influenced.

Next, a first alignment layer 120 is formed on the passivation layer 130, and the first alignment layer 120 may be a polymer layer, such as polyimide.

Meanwhile, a transparent conductive layer 210 is formed on the cover glass 200, and the transparent conductive layer 210 includes a light-transmissive and conductive material, such as indium tin oxide, indium zinc oxide, or other suitable materials. Next, a second alignment layer 220 is formed on the transparent electrode 210, and the material of the second alignment layer 220 is the same as that of the first alignment layer 120, and may be a polymer layer, such as polyimide.

Step S3, disposing the liquid crystal layer 300 on a side of the passivation layer 130 away from the substrate 100, and attaching the substrate 100, on which the metal reflective layer 110, the passivation layer 130, and the liquid crystal layer 300 are sequentially stacked, to the transparent cover plate 200.

Specifically, a sealant (not shown) may be formed on the first alignment layer 120 of the substrate 100, then a liquid crystal layer 300 is formed on the first alignment layer 120, the sealant surrounds the liquid crystal layer 300, and finally, the surface of the substrate 100 on which the first alignment layer 120 is formed is attached to the surface of the transparent cover plate 200 on which the second alignment layer 220 is formed, and the substrate 100 and the glass cover plate 200 are fixed by the sealant.

It should be noted that, this embodiment provides only one manufacturing method for manufacturing the LCOS display device as described above, the sequence of the sub-steps in each step is not limited to the above, and the LCOS display device is not limited to this manufacturing method.

In summary, in the LCOS display device and the manufacturing method thereof provided by the present invention, the LCOS display device includes a substrate, a metal reflective layer, a passivation layer, a liquid crystal layer, and a transparent cover plate, which are sequentially stacked, and the passivation layer includes at least three dielectric layers that are sequentially stacked. According to the invention, through the brand new multilayer stack design of the passivation layer, the reflectivity of the LCOS display device can be greatly improved, and meanwhile, the light efficiency utilization rate and the optical performance of the LCOS product can also be improved.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. An LCOS display device, comprising: the liquid crystal display panel comprises a substrate, a metal reflecting layer, a passivation layer, a liquid crystal layer and a transparent cover plate which are sequentially stacked; the passivation layer comprises at least three dielectric layers which are stacked in sequence.

2. The LCOS display device of claim 1, wherein the passivation layer comprises three dielectric layers stacked in sequence, a first dielectric layer, a second dielectric layer and a third dielectric layer stacked in sequence;

the refractive index of the second medium layer is higher than that of the first medium layer, and the refractive index of the second medium layer is higher than that of the third medium layer.

3. The LCOS display device of claim 2, wherein the refractive index of the first dielectric layer is equal to the refractive index of the third dielectric layer, and the material of the first dielectric layer is the same as the material of the third dielectric layer.

4. The LCOS display device of claim 3, wherein the first, second and third dielectric layers are made of silicon oxide, silicon nitride, silicon oxide in sequence.

5. The LCOS display device of claim 1, wherein the passivation layer comprises four dielectric layers stacked in sequence, a first dielectric layer, a second dielectric layer, a third dielectric layer and a fourth dielectric layer stacked in sequence, respectively;

6. The LCOS display device of claim 5, wherein the refractive index of the first dielectric layer is equal to the refractive index of the third dielectric layer, the refractive index of the second dielectric layer is equal to the refractive index of the fourth dielectric layer, the material of the first dielectric layer is the same as the material of the third dielectric layer, and the material of the second dielectric layer is the same as the material of the fourth dielectric layer.

7. The LCOS display device of claim 6, wherein the first, second, third and fourth dielectric layers are made of silicon oxide, silicon nitride, silicon oxide, silicon nitride in sequence.

8. The LCOS display device of claim 1, further comprising a first alignment layer, a second alignment layer, and a transparent conductive layer;

9. A method of fabricating an LCOS display device, the method comprising:

providing a substrate and a transparent cover plate;

10. A method of fabricating an LCOS display device as recited in claim 9, wherein said dielectric layer is formed by chemical vapor deposition.