Optical: systems and elements – Lens – With support
Reexamination Certificate
2001-09-27
2003-10-28
Mack, Ricky (Department: 2873)
Optical: systems and elements
Lens
With support
C359S512000, C359S636000
Reexamination Certificate
active
06639743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cooling mechanism of an optical modulator attached to a light-incident end of a prism, an optical modulator attachment unit for attaching the optical modulator on a light-incident end of the prism and a projector having the same.
2. Description of Related Art
Conventionally, a projector including three optical modulators for modulating a plurality of colors of light in accordance with image information, a cross dichroic prism for combining the color light modulated by the three optical modulator, and a projection lens for enlarging and projecting the light combined by the prism has been used.
Such projectors have been widely used for multimedia presentation in a meeting, scientific society, exhibition etc., and size reduction thereof has been strongly desired since such projectors are brought to other locations as necessary and is brought to other places for storing.
In recent years, in order to reduce size and simplify structure thereof, an arrangement for attaching the optical modulator to a light-incident end of the prism has come to be used. For instance, according to an arrangement shown in Japanese Patent Laid-Open Publication No. Hei 2000-221588, three optical modulators are respectively held by a holding frame and a stick member is inserted to four comers of the holding frame with a distal end thereof being fixed to the light-incident end of the cross dichroic prism by an adhesive, thereby attaching the optical modulator to the cross dichroic prism.
According to another arrangement shown in International Publication No. WO98/27453, an optical modulator held by a holding frame is attached to a light-incident end of the prism through a frame body and a wedge-shaped spacer. A guide for guiding the wedge-shaped spacer is formed on the holding frame.
A polarizer for polarizing the light modulated by the optical modulator is provided between the optical modulator and the light-incident end of the prism. The polarizer is directly adhered to the light-incident end of the prism by an adhesive etc.
The polarizer is formed by attaching a polarizing film to a glass substrate. The polarizing film can be deteriorated on account of heat generated by the light passing the prism and the optical modulator after long use and projected image quality can be deteriorated in accordance therewith. On the other hand, since the optical modulator is also weak in heat, the optical modulator has to be cooled by cooling air. Accordingly, in order to efficiently cool the polarizer and the optical modulator, there is an idea for feeding the cooling air between the light-incident end of the prism and the optical modulator.
However, only a narrow gap is formed between the prism and the optical modulator in accordance with size reduction, even when cooling air is sent from lower side of the prism by, for instance, a suction fan etc., only a little air enters between the prism and the optical modulator, so that efficient cooling of the polarizer and the optical modulator is difficult.
Further, an axial fan is used as a suction fan disposed on the lower side of the prism. Since the cooling air exhausted from the axial fan flows in spiral, the cooling air is blown to the surface of the optical modulator obliquely upward, so that it is difficult to uniformly cool the surface of the optical modulator.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a cooling mechanism of an optical modulator capable of efficiently cooling a polarizer, an optical modulator etc., an optical modulator attachment unit and a projector having the cooling mechanism.
A cooling mechanism of optical modulator according to the present invention is for an optical modulator plurally attached to a light-incident end of a prism for modulating a plurality of color lights in accordance with image information and for emitting the modulated light to the light-incident end of the prism, the cooling mechanism including: a base member attached to the light-incident end of the prism; and a support member attached to the base member for supporting the optical modulator, the support member including a pair of components disposed parallel to a cooling air flow channel formed between the light-incident end of the prism and the optical modulator and for supporting a neighborhood of an end of the optical modulator.
The plurality of optical modulators may be, for instance, three optical modulators for modulating red, green and blue light beams, which may be attached to the light-incident end of the prism by, for instance, an arrangement where the gap between the light-incident end of the prism and the optical modulator is likely to become small such as attaching the optical modulator to the light-incident end of the prism by a screw or a spacer.
According to the present invention, since the support member for supporting the optical modulator is formed by a pair of components disposed parallel to the cooling air flow channel formed between the light-incident end of the prism and the optical modulator for supporting the neighborhood of the end of the optical modulator, the gap between the light-incident end of the prism and the optical modulator facing the cooling air flow channel can be enlarged, so that cooling air sufficient for cooling the polarizer and the optical modulator can be flowed in the direction of the cooling air flow channel. Accordingly, the polarizer and the optical modulator can be efficiently cooled.
In the cooling mechanism according to the present invention, a polarizer may preferably be provided on a light-emitting side of the optical modulator, a polarizer fixing plate for holding and fixing the polarizer may preferably interposed between the base member and the fixing plate; and the polarizer fixing plate may preferably hold and fix the polarizer being spaced apart from the light-incident end of the prism with a predetermined gap therebetween.
Accordingly, sufficient cooling air can be flowed not only between the polarizer and the optical modulator but also between the polarizer and the light-incident end of the prism, so that both sides of the polarizer can be efficiently cooled.
In the cooling mechanism according to the present invention, the support member may preferably include a fixing plate attached to the base member, an optical modulator fixing plate attached to the optical modulator and a spacer interposed between the fixing plate and the optical modulator fixing plate, the fixing plate, the optical modulator fixing plate and the spacer being disposed around the end of the optical modulator approximately in parallel.
Accordingly, since the gap between the light-incident end of the prism and the optical modulator facing the cooling air flow channel can be enlarged as mentioned above, the cooling efficiency can be enhanced, and the focus and alignment of the optical modulator can be adjusted only by changing the insertion amount of the pair of spacers inserted to the end.
In the cooling mechanism according to the present invention, a slanted surface for guiding the spacer may preferably be formed on the optical modulator fixing plate.
Accordingly, since the insertion amount of the spacer can be adjusted along the slanted surface, the focus and alignment adjustment of the optical modulator can be facilitated.
In the cooling mechanism according to the present invention, a cooling fan for cooling the optical modulator and a wind guide provided between the cooling fan and the optical modulator for introducing the cooling air from the cooling fan in a predetermined direction may preferably be provided, the wind guide including a first guide plate for directing the cooling air toward between the light-incident end of the prism and the optical modulator.
By introducing the cooling air from the cooling fan toward between the light-incident end of the prism and the optical modulator by the first guide plate, the cooling air from the cooling fan can be securely guided to the gap between the light-incident end of the pris
Mack Ricky
Oliff & Berridg,e PLC
Seiko Epson Corporation
Thomas Brandi N
LandOfFree
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