Optics: image projectors – Temperature control – Blower
Reexamination Certificate
2000-04-20
2003-05-27
Adams, Russell (Department: 2851)
Optics: image projectors
Temperature control
Blower
C353S058000, C353S060000, C353S061000, C353S100000, C353S119000
Reexamination Certificate
active
06568813
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a projector including an electro-optical device for forming optical images according to image information.
2. Description of Related Art
There are conventionally-known projectors including a light source, a electro-optical device for forming optical images of light flux emitted from the light source according to image information, a projecting lens for performing enlarged projection of the image formed with this electro-optical device, and an external case for storing these components.
Such projectors are widely used for multimedia presentations at conferences, academic meetings, exhibitions, etc., and reduction in size is being promoted since the projectors may be brought in a necessary or moved to another location for storage after usage.
Also, high luminance of light source lamps serving as the light source is being promoted, in order to make the projected images from the projector clear.
With such projectors having high luminance and reduced size, the temperature within the device tends to rise, so there is the need to efficiently cool the electro-optical device which is weak to heat.
Accordingly, an air intake is formed at the lower plane of the exterior case, and a cooling fan for introducing external air as cooling air from the air intake is provided below the electro-optical device, thereby cooling the electro-optical device.
However, with the above conventional projector, there is the need to have the center of gravity at a low position in order to secure stability at the time of being set up, so the height-wise dimensions from the desktop, or the like, on which the projector is set to the lower plane of the exterior case is made to be small. Accordingly, even in the event that introduction of great amounts of cooling air from the lower plane of the projector using the cooling fan is attempted, there is a limit to the amount of air which can be introduced through the gap portion, and particularly, with projectors having high luminance and reduced size, there is the problem that cooling of the electro-optical device cannot be performed sufficiently.
SUMMARY OF THE INVENTION
The present invention provides a projector that includes a cooling structure which effectively cools the electro-optical device and which can deal with high luminance of light source lamps and reduction in size of the apparatuses. The projector may include an electro-optical device for forming optical images according to image information and an exterior case for covering a main unit containing the electro-optical device, wherein an air intake opening for intake of external air as cooling air is formed at the upper plane of the exterior case, and a cooling fan for introducing the cooling air from the air intake opening and cooling the electro-optical device is provided above the electro-optical device.
According to the present invention, the upper plane of the exterior case is usually opened upwards, so an air intake is provided on this upper plane, and a cooling fan for introducing cooling air from this air intake to the inside of the apparatus is provided above the electro-optical device, whereby cooling air sufficient for cooling the electro-optical device can be easily blown onto the electro-optical device. Thus, the electro-optical device can be cooled efficiently, and a cooling structure capable of dealing with high luminance of light source lamps and reduction in size of the apparatuses can be obtained.
In the above, it is preferable for the projector to have a projecting lens for enlarged projection of images formed by the electro-optical device, and the projecting lens to have a plurality of lenses positioned following a predetermined axis, with the lens of the plurality of lenses positioned at the base edge closest to the projecting direction at least notched at the upper edge side thereof.
The electro-optical device may be provided near the base edge of the projection lens, so arranging for the center of the image forming area of the electro-optical device to be positioned lower than the intersection of an extended line from the axis of the projection lens and the electro-optical device causes the optical image from the electro-optical device to be cast in from the lower side of the axis, and to be projected by passing through the projecting lens and expanding above the axis. Accordingly, even in the event that the upper edge side of the lens positioned at the side closest to the base edge is notched, there is no problem, and an optical image is enlarged and projected into a projecting plane.
Accordingly, with the upper edge of the lens in a notched form, the cooling fan provided above the electro-optical device can be positioned closer to the electro-optical device by an degree equivalent to the degree of the notching of the upper edge. Thus, cooling air with great force can be introduced to the electro-optical device, so cooling of the electro-optical device can be performed even more efficiently. Also, positioning the cooling fan closer to the electro-optical device reduces the height-wise dimensions of the projector, so the projector can be made smaller and thinner.
Also, a light shielding structure for preventing light from leaking from the air intake opening is preferably provided above the cooling fan.
Thus, light can be prevented from leaking from the air intake, thus improving the visual recognition of the image by observers which generally observe the image from behind the apparatus.
Further, the light shielding structure is preferably formed in a louver-like configuration wherein a plurality of plate-shaped members positioned in a parallel manner across the air intake opening so as to assume a predetermined angle with the planes thereof as to the opening plane of the air intake opening. Specifically, inclining the plate-shaped members so as to descend toward the rear side of the apparatus or inclining so as to descend toward the front side of the apparatus changes the direction of the gaps between the plate-shaped members, so the direction of emission of leaking light can be restricted. Now, inclining the plate-shaped members so as to descend toward the rear side of the apparatus causes leaking light to be emitted forwards from the apparatus, so leaking light is not cast into the eyes of the observers, and the visual recognition of the image by observers observing the image from behind or beside the apparatus can be further improved. That is, with an arrangement wherein the multiple plate-shaped members assume a predetermined angle with the planes thereof as to the opening plane of the air intake opening, there is hardly any light leaking out. Moreover, cooling air can be introduced to the cooling fan from the gaps between the plate-shaped members. Accordingly, employing a louver-like configuration of plurality of plate-shaped members as the light shielding structure allows prevention of leaking light and introduction of cooling air to be performed with a single light-shielding structure, so there is no increase in the number of parts for the projector, and the projector can be reduced in size from this perspective, as well.
Also, an exhaust opening for exhausting air within the projector externally is preferably provided to the front plane of the exterior case.
Thus, the air taken inside the apparatus with the cooling fan can be exhausted forward from the apparatus, so the exhausted air does not blow on observers observing the image from behind or beside the apparatus, so the observers do not feel discomfort from this perspective as well.
Also, the exhaust is formed at the front plane of the exterior case, so light leaking from the exhaust is not recognized by observers observing the image from behind or beside the apparatus, so visual recognition of the image by the observers can be improved. Incidentally, providing the exhaust with a light-shielding structure for preventing leaking of light from the exhaust can prevent light from leaking from the exhaust.
Further, the aforementioned projector
Fujimori Motoyuki
Haba Shinji
Kuroda Akitoshi
Adams Russell
Koval Melissa J
Oliff & Berridge PLC.
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