# US 2020/0401024 A1 · Active optical rotator and optical system for LCD projector

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- Number: US 2020/0401024 A1
- Document ID: US20200401024A1
- Status: Published application
- Kind: A1
- Application number: 16/997,959
- Filed: 2020-08-20
- Published: 2020-12-24
- Earliest claimed: 2020-04-27
- Assignees: Nanhua Intelligent Precision Machine (Shenzhen) Co., Ltd.
- Applicants: Nanhua Intelligent Precision Machine (Shenzhen) Co., Ltd.
- Inventors: Hanwen Guo
- Web page: https://patentgrep.com/patent/US20200401024A1

## CPC

- G03B 21/006: {using LCD's}
- G02F 1/0136: {for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence)}
- G02F 1/13306: {Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence)}
- G02F 1/1337: Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G03B 21/14: Details
- G03B 21/2073: {Polarisers in the lamp house (peculiar to electronic spatial light modulators H04N9/3197)}
- G02F 1/13: based on liquid crystals, e.g. single liquid crystal display cells
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- 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

An active optical rotator is provided, which includes a first glass substrate, a liquid crystal cell, a liner frame, a second glass substrate, a first connection line and a second connection line. The external driving device drives the liquid crystal cell to rotate the light, so that the illuminating light of the projector optical system with the polarization conversion device is capable of achieving polarization conversion with more efficient and wider wavelength range. Compared with the passive optical rotator, the active optical rotator has a lower price, better performance, better innovation, cost performance and application. An optical system for the LCD projector is further provided, including an LED light source, a transflective plate, a square cone condenser, collimating lens, an active rotator, a brightness-increasing polarizer, an LCD light valve, field lens, reflector and projection lens which are arranged in sequence according to the direction of light travel.

## Claims

### Claim at position 1

1-7. (canceled)

### Claim at position 2

8: An active optical rotator, comprising a first glass substrate (1), a liner frame (2), a liquid crystal cell (3), a second glass substrate (4), and a first connecting wire (5) and a second connecting wire (6);
wherein at least one light-transmitting window is provided on the liner frame (2);
the liner frame (2) is interposed between an exit surface of the first glass substrate (1) and an incident surface of the second glass substrate (4), and are mounted by surface, and then the liquid crystal cell (3) is provided in the light-transmitting window;
a first transparent conductive film (101) is provided on the exit surface of the first glass substrate (1), and a first alignment film (102) is provided on the first transparent conductive film (101); the first connecting wire (5) is connected with the first transparent conductive film (101);
a second transparent conductive film (401) is provided on the incident surface of the second glass substrate (4), and a second alignment film (402) is provided on the second transparent conductive film (401); the second connecting wire (6) is connected with the second transparent conductive film (401); and
the first transparent conductive film (101), the first alignment film (102), the liquid crystal cell (3), the second alignment film (402) and the second transparent conductive film (401) are sequentially arranged according to a light traveling direction.

### Claim at position 3 (depends on 8)

9: The active optical rotator, as recited in claim 8, wherein the liner frame (2) is directly provided on an edge of the exit surface of the first glass substrate (1).

### Claim at position 4 (depends on 8)

10: The active optical rotator, as recited in claim 8, wherein the liner frame (2) is directly provided on an edge of the incident surface of the second glass substrate (4).

### Claim at position 5 (depends on 8)

11: The active optical rotator, as recited in claim 8, further comprising a driving device (7), wherein the driving device (7) comprises a voltage source; the first connecting wire (5) and the second connecting wire (6) are connected to the voltage source.

### Claim at position 6 (depends on 11)

12: The active optical rotator, as recited in claim 11, wherein the driving device (7) further comprising a temperature compensation circuit for controlling an output voltage of the voltage source.

### Claim at position 7 (depends on 8)

13: An optical system for an LCD projector, comprising an LED light source (11), a transflective plate (12), a square cone condenser (13), a collimating lens (14), the active optical rotator (15) as recited in claim 8, a brightness enhancement polarizer (16), an LCD light valve (17), field lens (18), a reflector (19) and projection lens (20);
wherein a light-transmitting portion (121) that allows light to pass through is provided on the transflective plate (12); a size and an area of the light-transmitting portion (121) are greater than or equal to that of a light-emitting surface (1101) of the LEI) light source (11); a reflection part (122) that reflects light is provided on the exit surface of the transflective plate (12);
the light emitting surface (1101) of the LED light source (1) faces the light transmitting portion (121);
an external dimension of the reflecting portion (122) is greater than or equal to the dimension of the light-passing hole at the incident end of the square cone-shaped condenser (13).

### Claim at position 8 (depends on 13)

14: The optical system for an LCD projector, as recited in claim 13, wherein the exit surface of the transflective plate (12) and the incident end of the square cone-shaped condenser (13) are attached to each other;

### Claim at position 9 (depends on 13)

15: The optical system for an LCD projector, as recited in claim 13, wherein the light-transmitting part (121) and the reflecting part (122) of the transflective plate (12) are provided on the incident end of the square conical condenser (13).

### Claim at position 10 (depends on 13)

16: The optical system for an LCD projector, as recited in claim 13, wherein the incident surface of the transflective plate (12) and the substrate (1102) of the LED light source (11) are attached to each other.

### Claim at position 11 (depends on 13)

17: The optical system for an LCD projector, as recited in claim 13, wherein a brightness-enhancing polarizer (16) and the exit surface of the active optical rotator (15) are attached to each other.