# US 8,465,156 B2 · Image projection apparatus having cleaning function of air filter

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- Number: US 8,465,156 B2
- Document ID: US8465156B2
- Status: Granted
- Kind: B2
- Application number: 13/005,889
- Filed: 2011-01-13
- Published: 2011-07-28
- Granted: 2013-06-18
- Earliest claimed: 2010-01-25
- Assignees: Canon Kabushiki Kaisha
- Applicants: Daisuke Nakashita
- Inventors: Daisuke Nakashita
- Web page: https://patentgrep.com/patent/US8465156B2

## CPC

- G03B 21/16: Cooling; Preventing overheating
- 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)

## Abstract

An image projection apparatus includes cooling fans 10, 12, and 16 provided inside a chassis 17 and configured to take in cooling air from a cooling inlet port 17a formed in the chassis, an air filter 22 that covers the cooling inlet port, an exhaust port 19a formed in the chassis and configured to exhaust the cooling air from an inside to an outside of the chassis, and a cleaning fan 25 provided inside the chassis and configured to take in cleaning air from a cleaning inlet port 17b formed in the chassis separately from the exhaust port. The image projection apparatus exhausts the cleaning air discharged from the cleaning fan, from the inside to the outside of the chassis via the cooling inlet port and the air filter.

## Claims

### Claim 1

An image projection apparatus that projects light modulated by an optical modulation element onto a projection surface to display an image, the image projection apparatus comprising:
a cooling fan provided inside a chassis of the image projection apparatus and configured to take in cooling air from a cooling inlet port formed in the chassis;
an air filter that covers the cooling inlet port;
an exhaust port formed in the chassis and configured to exhaust the cooling air from an inside to an outside of the chassis; and
a cleaning fan provided inside the chassis and configured to take in cleaning air from a cleaning inlet port formed in the chassis separately from the exhaust port,
wherein the image projection apparatus exhausts the cleaning air discharged from the cleaning fan, from the inside to the outside of the chassis via the cooling inlet port and the air filter.

### Claim 2 (depends on 1)

The image projection apparatus according to claim 1,
wherein the image projection apparatus has a structure that guides the cleaning air discharged from the cleaning fan to an area of the cooling inlet port and the air filter in which the cooling air cooling the optical modulation element passes.

### Claim 3 (depends on 1)

The image projection apparatus according to claim 1, further comprising:
an opening that passes the cooling air flowing from the cooling inlet port to the cooling fan; and
an air guide member configured to guide to the cleaning air discharged from the cleaning fan to the cooling inlet port.

### Claim 4 (depends on 1)

The image projection apparatus according to claim 1,
wherein a part of the air filter covers the cleaning inlet port.

### Claim 5 (depends on 1)

The image projection apparatus according to claim 1, further comprising:
a sensor configured to detect a clogging of the air filter; and
a controller configured to operate the cleaning fan in accordance with an output from the sensor.