# US 11,308,902 B2 · Spatial light modulator

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- Number: US 11,308,902 B2
- Document ID: US11308902B2
- Status: Granted
- Kind: B2
- Application number: 17/079,556
- Filed: 2020-10-26
- Published: 2021-07-08
- Granted: 2022-04-19
- Earliest claimed: 2020-01-07
- Assignees: National Yang Ming Chiao Tung University
- Applicants: National Chiao Tung University
- Inventors: Huang-Ming Chen; Jhou-Pu Yang
- Web page: https://patentgrep.com/patent/US11308902B2

## CPC

- G09G 3/3611: {Control of matrices with row and column drivers}
- C09K 19/00: Liquid crystal materials
- G02F 1/133723: {Polyimide, polyamide-imide}
- G02F 1/136277: {formed on a semiconductor substrate, e.g. of silicon}
- G09G 2320/0247: Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
- G09G 2340/0435: Change or adaptation of the frame rate of the video stream
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

A spatial light modulator includes a panel and a driver board. The panel includes an ultra-high pixel density backplane and a liquid crystal layer. The ultra-high pixel density backplane includes a pixel array with at least 4000 PPI. The liquid crystal layer includes an ultra-high figure-of-merit liquid crystal material with a first figure-of-merit value. The driver board is connected to the panel for driving the panel by executing a fast panel driving procedure design to achieve low phase error.

## Claims

### Claim 1

A spatial light modulator comprises:
a panel including:
a backplane having a pixel array, wherein the pixel array is provided with a pixel density of at least 4000 PPI (pixels per inch); and
a liquid crystal layer having a liquid crystal material, wherein the liquid crystal material is provided with a first figure-of-merit; and
a panel driver electrically connected to the panel for driving the panel according to a fast panel driving procedure design;
wherein the first figure-of-merit satisfies condition:
FoM
⁢
-
⁢
1
=
Δ
⁢
⁢
n
2
(
γ
1
k
11
)
>
15
⁢
⁢
µm
2
⁢
/
⁢
s
,
where FoM-1 represents the first figure-of-merit, Δn represents a birefringence of the liquid crystal material, γ1 represents a rotational viscosity coefficient of the liquid crystal material, and k11 represents a splay elastic constant of the liquid crystal material.

### Claim 2 (depends on 1)

The spatial light modulator of claim 1, wherein the liquid crystal material is further provided with a second figure-of-merit, and the second figure-of-merit satisfies condition:
FoM
⁢
-
⁢
2
=
Δ
⁢
⁢
ϵ
*
Δ
⁢
⁢
n
2
(
γ
1
k
11
)
>
230
⁢
⁢
µm
2
⁢
/
⁢
s
,
where FoM-2 represents the second figure-of-merit, and Δϵ represents a dielectric anisotropy of the liquid crystal material.

### Claim 3 (depends on 1)

The spatial light modulator of claim 1, wherein the fast panel driving procedure design is provided to enable an input frame rate of the panel to conform to condition:
Input Frame Rate=[Tclks]×Repeat,
where “Input Frame Rate” represents an actual input frame rate, which corresponds to an actual display period of a same frame; Tclks represents an addressing frequency of a sub-frame, which corresponds to a driving period of the sub-frame; “Repeat” represents a number of repeated driving of the sub-frame during the actual display period of the frame.

### Claim 4 (depends on 3)

The spatial light modulator of claim 3, wherein the addressing frequency is further set to conform to condition:
Tclks
=
mclksperrow
mclkfreq
×
swp
×
twgt
,
where mclksperrow represents a number of memory clocks allocated to a row-writing of the pixel array, mclkfreq represents a memory clocks frequency, swp represents a division amount for all rows of the pixel array, and twgt represents a data input weight for corresponding to an allocation situation when an image data is inputted to the pixel array.

### Claim 5 (depends on 4)

The spatial light modulator of claim 4, wherein the data input weight is set to have a positive relationship with the pixel density of the pixel array.

### Claim 6 (depends on 1)

The spatial light modulator of claim 1, wherein the panel further includes an alignment layer and a glass cover plate, the alignment layer is disposed above the liquid crystal layer, the glass cover plate is disposed above the alignment layer, the driving logic circuit includes a field programmable gate array or an application specific integrated circuit, and the alignment layer includes a polyimide layer.

### Claim 7 (depends on 1)

The spatial light modulator of claim 1, wherein the panel is designed to be driven by a liquid crystal response time while maintaining a phase stability, in which the liquid crystal response time is not greater than 10 ms, the phase stability corresponds to an average peak-to-peak value, and the average peak-to-peak value is not greater than 3 percentages.

### Claim 8 (depends on 1)

The spatial light modulator of claim 1, wherein the panel 20 of the spatial light modulator 1 is designed to be driven by a full-phase operating voltage while maintaining a phase stability, in which the full-phase operating voltage includes a high-voltage frame (Vw) and a low-voltage frame (Vb), the high-voltage frame is between 2V to 8V, the low-voltage frame is between 0.1V to 3V, the phase stability corresponds to an average peak-to-peak value, and the average peak-to-peak value is not greater than 3 percentages (3%).

### Claim 9 (depends on 8)

The spatial light modulator of claim 8, wherein the panel is further designed to be driven in a digital driving manner, wherein the high-voltage frame corresponds to a digital logic state 1 and the low-voltage frame corresponds to a digital logic state 0.

### Claim 10 (depends on 1)

The spatial light modulator of claim 1, wherein the panel is designed to be driven by a liquid crystal response time while maintaining a phase linearity and a phase precision, in which the liquid crystal response time is not greater than 10 ms, the phase linearity corresponds to an APAE (average peak to peak) value, the APAE value is not greater than 1.5 percentages, the phase precision corresponds to an mSTD (mean standard deviation) value, and the mSTD value is not greater than 0.04π.