# US 9,039,192 B2 · Projection display device comprising a light source > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,192 B2 - Document ID: US9039192B2 - Status: Granted - Kind: B2 - Application number: 13/508,979 - Filed: 2009-11-24 - Published: 2012-09-13 - Granted: 2015-05-26 - Earliest claimed: 2009-11-24 - Assignees: NEC Display Solutions, Ltd. - Applicants: Shunsuke Okazawa; Takayuki Okada - Inventors: Shunsuke Okazawa; Takayuki Okada - Web page: https://patentgrep.com/patent/US9039192B2 ## CPC - G03B 21/16: Cooling; Preventing overheating - G09G 3/3406: {Control of illumination source (illumination devices structurally associated with liquid crystal cells G02F1/1336)} - H04N 9/3144: {Cooling systems (cooling of liquid crystal cells in general G02F1/133382; cooling of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/16)} - H04N 9/3155: {for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406)} - 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) - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A projection display device projects light modulated based on a video signal. The projection display device includes a light source, a first fan for cooling the light source, and a second fan different from the first fan. The number of revolutions of the first fan is increased or decreased with the increase or decrease of the output of the light source. The number of revolutions of the second fan is decreased when the number of revolutions of the first fan is increased, and increased when the number of revolutions of the first fan is decreased. ## Claims ### Claim 1 A projection display device that projects light modulated based on a video signal, comprising: a light source; a first fan for cooling the light source; a second fan different from the first fan; and a third fan different from the first fan and the second fan, wherein: a number of revolutions of the first fan is increased or decreased with an increase or decrease of an output of the light source; a number of revolutions of the third fan is decreased when the number of revolutions of the first fan is increased, and increased when the number of revolutions of the first fan is decreased; and a number of revolutions of the second fan is always maintained constant. ### Claim 2 (depends on 1) The projection display device according to claim 1, wherein: the second fan discharges air out of a case; and the third fan cools a power source unit. ### Claim 3 (depends on 2) The projection display device according to claim 2, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan. ### Claim 4 (depends on 1) The projection display device according to claim 1, further comprising a dimming level calculation unit that calculates a dimming level of the light source based on the video signal, wherein the output of the light source is increased or decreased based on the dimming level calculated by the dimming level calculation unit. ### Claim 5 (depends on 4) The projection display device according to claim 4, further comprising: a storage unit that stores data relating to a relationship among a plurality of dimming levels calculated by the dimming level calculation unit, the output of the light source, the number of revolutions of the first fan, and the number of revolutions of the second fan; a light source control unit that controls the output of the light source based on said data; a first fan control unit that controls the number of revolutions of the first fan based on said data; and a second fan control unit that controls the number of revolutions of the second fan based on said data. ### Claim 6 (depends on 5) The projection display device according to claim 5, further comprising a third control unit that controls the number of revolutions of the third fan based on said data stored by the storage unit. ### Claim 7 (depends on 6) The projection display device according to claim 6, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan. ### Claim 8 (depends on 5) The projection display device according to claim 5, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan. ### Claim 9 (depends on 4) The projection display device according to claim 4, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan. ### Claim 10 (depends on 1) The projection display device according to claim 1, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan. ### Claim 11 (depends on 1) The projection display device according to claim 1, wherein the first fan comprises a sirocco fan, and the second fan comprises an axial fan. ### Claim 12 A projection display device that projects light modulated based on a video signal, comprising: a light source; a first fan for cooling the light source; a second fan different from the first fan; and a third fan different from the first fan and the second fan, wherein: a number of revolutions of the first fan is increased or decreased with an increase or decrease of an output of the light source; and a number of revolutions of the second fan and a number of revolutions of the third fan are decreased when the number of revolutions of the first fan is increased, and increased when the number of revolutions of the first fan is decreased. ### Claim 13 (depends on 12) The projection display device according to claim 12, wherein: the second fan discharges air out of a case; and the third fan cools a power source unit. ### Claim 14 (depends on 12) The projection display device according to claim 12, further comprising a dimming level calculation unit that calculates a dimming level of the light source based on the video signal, wherein the output of the light source is increased or decreased based on the dimming level calculated by the dimming level calculation unit. ### Claim 15 (depends on 12) The projection display device according to claim 12, wherein the first fan comprises a sirocco fan, and the second fan comprises an axial fan. ### Claim 16 (depends on 12) The projection display device according to claim 12, wherein the first fan comprises a sirocco fan, and the third fan comprises a sirocco fan similar in shape and size to the first fan.