# US 10,503,061 B2 · Focusing method of optical machine of projector, focusing device and optical machine

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- Number: US 10,503,061 B2
- Document ID: US10503061B2
- Status: Granted
- Kind: B2
- Application number: 15/993,994
- Filed: 2018-05-31
- Published: 2019-01-24
- Granted: 2019-12-10
- Earliest claimed: 2017-07-21
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Hongtao Guan; Wenchu Dong; Junwei Yan; Ying Zhang; Tailiang Li
- Web page: https://patentgrep.com/patent/US10503061B2

## CPC

- G03B 21/53: Means for automatic focusing, e.g. to compensate thermal effects
- G02B 7/028: {with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation}
- G02B 7/08: adapted to co-operate with a remote control mechanism
- G02B 7/28: Systems for automatic generation of focusing signals
- 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)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

The disclosure provides a focusing method of optical machine of projector, a focusing device and an optical machine. The focusing method comprises steps of: detecting deformation amount of lens of an optical machine; and controlling and adjusting a focal length of the lens of the optical machine according to the deformation amount of the lens of the optical machine. In the he focusing method, by detecting the deformation amount of the lens of the optical machine in real time and controlling to adjust the focal length of the lens of the optical machine in real time according to the deformation amount of the lens of the optical machine, the adjustment precision of the focal length of the lens of the optical machine can be greatly improved.

## Claims

### Claim 1

A focusing method of an optical machine of a projector,
comprising steps of:
attaching a deformation sensor on a light exit surface of a lens of the optical machine to detect a deformation amount of the lens of the optical machine; and
controlling and adjusting a focal length of the lens of the optical machine according to the deformation amount of the lens of the optical machine, wherein
the step of attaching the deformation sensor on the light exit surface of the lens of the optical machine to detect the deformation amount of the lens of the optical machine comprises:
detecting, by the deformation sensor, a first deformation amount of the lens of the optical machine as a function of temperature;
detecting a second deformation amount of the deformation sensor as a function of temperature; and
calculating the deformation amount of the lens of the optical machine according to the first deformation amount and the second deformation amount, wherein the deformation amount of the lens of the optical machine is equal to the first deformation amount minus the second deformation amount, and wherein
the step of detecting a second deformation amount of the deformation sensor as a function of temperature comprises:
mounting a temperature sensor on the lens of the optical machine;
detecting, by the temperature sensor, a temperature change of the deformation sensor; and
determining the second deformation amount of the deformation sensor based on the temperature change.

### Claim 2 (depends on 1)

The focusing method according to claim 1, wherein the deformation sensor includes a piezoelectric film sensor and the temperature sensor includes a thermocouple sensor.

### Claim 3

A focusing device of an optical machine, comprising a detection circuit, a control circuit, and a focusing circuit, wherein
the detection circuit comprises a deformation sensor which is attached on a light exit surface of a lens of the optical machine and which is configured to detect a deformation amount of the lens of the optical machine;
the control circuit is configured to control the focusing circuit to adjust a focal length of the lens of the optical machine according to the deformation amount of the lens of the optical machine; and
the focusing circuit is configured to adjust the focal length of the lens of the optical machine,
the detection circuit further comprises a first detection sub-circuit disposed on the lens of the optical machine, and a calculation sub-circuit, wherein
the deformation sensor is configured to detect a first deformation amount of the lens of the optical machine as a function of temperature:
the first detection sub-circuit includes a temperature sensor and is configured to detect a second deformation amount of the deformation sensor as a function of temperature; and
the calculation sub-circuit is configured to calculate the deformation amount of the lens of the optical machine according to the first deformation amount and the second deformation amount, wherein the deformation amount of the lens of the optical machine is equal to the first deformation amount minus the second deformation amount.

### Claim 4 (depends on 3)

The focusing device according to claim 3, wherein the deformation sensor includes a piezoelectric film sensor; the temperature sensor includes a thermocouple sensor; and the focusing circuit includes a focusing motor that adjusts the focal length of the lens of the optical machine by adjusting a rotational direction and a rotational speed of the focusing motor.

### Claim 5 (depends on 3)

An optical machine, comprising the focusing device according to claim 3.

### Claim 6 (depends on 5)

The optical machine according to claim 5, wherein the deformation sensor is configured to detect the deformation amount of the lens of the optical machine as a function of temperature.

### Claim 7 (depends on 5)

The optical machine according to claim 5, wherein the deformation sensor includes a piezoelectric film sensor; the temperature sensor includes a thermocouple sensor; and the focusing circuit includes a focusing motor that adjusts the focal length of the lens of the optical machine by adjusting a rotational direction and a rotational speed of the focusing motor.