JPH0445338Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a lens placed in front of a projection tube for projecting an image onto a screen in a projection television.

[Conventional technology]

The projection device in projection television is
The image from the projection tube is enlarged through a lens and projected onto a screen (Fresnel lens) through several mirrors. placed on a horizontal plane.

[Problem that the invention attempts to solve]

By the way, since three of the above-mentioned projection devices are arranged on the same horizontal plane as mentioned above, when the distance between each projection device increases, the amount of light from the projection devices on both sides becomes smaller than the amount of light from the central projection device. As a result, an image with good color tone cannot be obtained.

However, the lens that faces the projection tube built into conventional projection devices is round, and the lens used needs to have a large radius of curvature. A lens must be used, and therefore, there is a problem in that the lens protrudes far beyond the projection tube, making it impossible to arrange the respective projection devices close to each other.

Therefore, it is conceivable to make the lens shape square, but as mentioned above, the lens used here must have a large radius of curvature. For this reason, if a rectangular lens is used, a vertical wall portion will be formed, which may cause a problem in that light from the projection tube will be reflected and cause interference.

[Purpose of invention]

The present invention was developed in view of the above points, and the lens mounting plate for fixing the lens to the frame is provided with a light-shielding plate portion that is treated with anti-reflection treatment to cover the vertical wall portion of the lens. To provide a projection device for a projection television that can prevent reflection on a lens by fixing the lens to a frame with a mounting plate.

[Summary of the idea]

In order to achieve the above-mentioned object, the present invention forms a light-shielding plate part that covers the vertical wall part of the lens on the lens mounting plate for attaching the lens to the frame, and also applies anti-reflection treatment to this part. This is the summary.

〔Example〕

Hereinafter, embodiments will be described with reference to the drawings. The illustrated embodiment shows one of three monochromatic projection tubes constituting a projection television.

In the figure, 1 is a projection tube, and a metal band 1a for blocking the emission of X-rays is fixed to the outer periphery of the side edge close to the fluorescent surface. Reference numeral 2 is a frame made of die-cast aluminum or the like, and a large number of fins 2a are formed on the upper outer peripheral surface. Further, a stepped portion 2b is formed in the center of the frame 2, and the large diameter chamber side separated by the stepped portion 2b is connected to the projection tube 1.
A projection tube chamber 2c into which is inserted is formed, and a cooling chamber 2d in which a cooling liquid A, which will be described later, is sealed is formed on the small diameter chamber side. Projections 2e are formed at the four corners of the inner surface of the side wall constituting the projection tube chamber 2c to abut against the outer periphery of the side edge of the projection tube 1 and to position the projection tube 1 relative to the frame 2. On the other hand, lenses 11 (described later) are provided at the four corners of the side wall constituting the cooling chamber 2d.
A projection 2f for positioning the lens 11 with respect to the frame 2 is formed so as to come into contact with the small projection 11d. Therefore, since the projection tube 1 and the lens 11 are positioned with respect to the frame 2, the center lines of the projection tube 1 and the lens 11 coincide. Further, the frame 2 is formed with a communication hole 2h, which has one end opened on the inner side of the lower surface of the side wall constituting the cooling chamber 2d, and the other end opened to the pressure regulation chamber 2g formed on the outer wall of the projection tube chamber 2c. . Furthermore, cooling chamber 2
The upper surface of the side wall configuring d is tapered toward the center, and a coolant injection hole 2i is provided in the center.
is formed, and the lower surface of the injection hole 2i is tapered toward the injection hole 2i. Therefore, the upper wall surface has a two-step tapered surface. The upper surface of the injection hole 2i is a large diameter hole 2k, into which the gasket 3 is fitted.

Reference numeral 4 denotes a thin plate-like rectangular packing having an enlarged portion 4a having a columnar cross section formed on the inner peripheral edge, and the frame 2
The enlarged portion 4a is disposed in a groove _2b1 formed on the inner surface of the cutout 2b.

Reference numeral 5 designates a metal holding plate inserted from the back side of the projection tube 1 to fix the projection tube 1 to the frame 2.

Thus, the projection tube 1 is placed in the projection tube chamber 2c of the frame 2.
It is inserted with the projection surface side facing the side. At this time, since the packing 4 is disposed in the groove _2b1 of the stepped portion 2b of the frame 2, the projection surface of the projection tube 1 comes into contact with the packing 4. Next, the holding plate 5 is inserted from the back side of the projection tube 1, and the screws 6 are inserted through the holes 5a of the holding plate 5 and screwed onto the mounting pillars 2l of the frame 2 to fix it. Here, an elastic material 7 is attached to the support portion 1b formed protruding from the rear surface 2 of the projection tube 1.
Since the holding plate 5 comes into contact with the projection tube 1 by tightening the screws 6 (at the four corners), the projection tube 1 is attached with the gasket 4 crushed.

By the way, in this installation, if the pressing force against the packing 4 of the projection tube 1 is not applied uniformly over the whole area, a small gap may be formed in some parts, which may cause leakage of the cooling liquid as described below. Therefore, it is necessary to uniformly apply the tightening force of the presser plate 5 to the frame 1, so in this embodiment, one end of the presser plate 5 is made to abut against the pillar portion 2l of the frame 2 through the hole 5a. color 8
At the same time, a spring 9 is inserted around the outer periphery of the collar 8 so that one end is in contact with the presser plate 5.
Furthermore, the screw 6 inserted through the washer 10 is screwed into the pillar portion 2l of the frame 2 via the collar 8,
Tighten until the washer 10 contacts the other end of the collar 8, and the spring 9 is deflected. This results in
Since the holding plate 5 presses the projection tube 1 at four locations with the spring force of the spring 9, the projection tube 1 is pressed against the gasket 4 with a uniform pressing force, and the frame 2
There is no gap between the stepped portion 2b and the projection surface of the projection tube 1.

Reference numeral 11 denotes a lens made of acrylic resin or the like, and has a curved surface 11a curved with a constant radius of curvature formed on only one surface, and has four sides cut off at right angles to form a rectangular planar shape. Then, each cut-off side has a vertical wall section 1
1b is formed, and a flange 11c is formed around the entire circumference.
are integrally formed. In this embodiment, the four corners of the curved surface 11a are formed with a radius, but this is to prevent cracks from forming at the corners when pressure is applied to the curved surface 11a, and the radius is not necessarily formed. There is no need to add. Also,
A small protrusion 11d is formed at the corner of the flange 11c, and this abuts against the protrusion 2f of the frame 2.

12 is a gasket with a round cross section, and the lens 11
It is fitted onto the flange portion 11c of.

Reference numeral 13 denotes a metal lens mounting plate, which is formed in a shape to surround the flange portion 11c of the lens 11, and has a light shielding plate portion 13a overlapping with the inner surface of the vertical wall portion 11b of the lens 11 integrally formed therein. has been done. Further, a stepped portion 13b is formed in a portion of the lens 11 that overlaps with the flange portion 11c.

The lens 11 is placed on the end face of the side wall of the frame 2 constituting the cooling chamber 2d with the curved surface 11a facing inside. At this time, the flange 1 of the lens 11
A packing 12 is interposed between 1c and the end surface of the side wall. Further, since the small protrusion 11d of the lens 11 comes into contact with the side surface of the protrusion 2f of the frame 2, the lens 11 is positioned relative to the frame 2.

Next, the lens mounting plate 13 is arranged to cover the flange 11c of the lens 11, and the screws 14 are inserted through the holes 13c formed at the four corners of the lens mounting plate 13. The lens 11 is fixed to the frame ₂ by screwing it into the screw hole 2f1 and tightening it. At this time, the step part 13b of the lens mounting plate 13 and the seal 1
Since the flange 11c of the lens 11 is sandwiched between the lenses 2 and 2 from both sides, no bending stress is applied to the flange 11c, and only compressive stress is applied to the flange 11c.

In addition, in this embodiment, the lens mounting plate 13
Although a stepped portion 13b is shown in FIG. 1, instead of the stepped portion 13b, a protrusion may be provided on the contact surface side of the flange portion 11c of the lens 11 with the lens mounting plate 13.

Furthermore, by making at least the light shielding plate portion 13a of the lens mounting plate 13 non-reflective with black or the like,
The light transmitted through the lens 11 will not be reflected by the lens mounting plate 13.

Reference numeral 15 designates a diaphragm that covers the pressure regulating chamber 2g of the frame 2, and a fastening ring 16 is fitted to the peripheral edge 15a of the diaphragm, and is fixed to the frame 2 with screws. Therefore, the diaphragm 15 is fixed to the opening of the pressure regulating chamber 2g of the frame 2 by the fastening ring 16. In addition, 17 is a fastening ring 16
It is a cap that is placed over the opening of the

Next, the operation will be explained based on the above configuration.

First, the projection tube 1 is attached to the projection tube chamber 2c of the frame 2 having the fins 2a.At this time, the seal 4 is placed in the groove _2b1 of the stepped portion 2b, and the projection surface of the projection tube 1 is placed in the seal 4. bring it into contact. In this state, the four corners of the projection tube 1 come into contact with the protrusions 2e projecting from the inner surface of the four corners of the projection tube chamber 2C of the frame 2, so that the projection tube 1 is positioned relative to the frame 2. Next, the presser plate 5 is inserted from the back surface of the projection tube 1 and placed on the support portion 1b formed on the back surface of the projection tube 1 via the elastic material 7. here,
When the washer 10, spring 9, and spacer 8 are inserted in order into the screw 6 through the hole 5a of the holding plate 5 and the screw 6 is tightened, the screw 6 is attached to the frame 2.
It is screwed into the mounting pillar part 2l. Then, when the screws 6 are tightened until the washer 10 comes into contact with the spacer 8, the holding plate 5 and the frame 2 are fixed by the force of the spring 9. That is, the four corners of the projection tube 1 are pressed by the spring force of the spring 9 via the gasket 4.
Therefore, the projection tube 1 is fixed to the stepped portion 2b of the frame 2 in a sealed state with uniform force. Further, since the enlarged part 4a of the seal 4 is placed in the groove _2b1 of the stepped part 2b of the frame 2, the seal 4 can be easily positioned with respect to the frame 2, and the enlarged part 4a and the flat part 4b are connected to the projection tube. 1, the contact area between the two becomes large, and when the enlarged portion 4a is pressed against the projection tube 1, this portion is mainly crushed, so that the gap between the projection tube 1 and the stepped portion 2b of the frame 2 increases. This has the effect of keeping watertight.

Next, the lens 11 is attached to the frame 2. First, fit the gasket 12 onto the flange 11c of the lens 11, put the gasket 12 side into the opening of the frame 2, and place the curved side of the lens 11 into the lens. Place it in the chamber 2d. At this time, the small protrusions 11d formed at the four corners of the lens 11 come into contact with the protrusions 2f of the frame 2, so the lens 11 is positioned with respect to the frame 2, and the projection tube 1 is positioned with respect to the frame 2. and lens 11 are always maintained in a constant positional relationship.

Next, the lens 11 is attached to the frame 2 by placing the lens attachment plate 13 over the lens 11 and tightening the screw 14 onto the protrusion 2f of the frame 2. Lens 11 with this lens mounting plate 13
When attaching the lens 11, the seal 12 and the stepped portion 13b of the lens mounting plate 13 face each other at corresponding positions on both sides of the flange 11c of the lens 11, and are sandwiched from both sides in this state.
1c is compressed with uniform force as a whole, so the flange 1
No bending stress is applied to 1c and it will not break. Furthermore, by making the lens 11 into a rectangular planar shape with the four sides of the circle cut off at right angles, it is possible to reduce the size of the lens even if it has a large radius of curvature. This has the effect of making the optical axis length of each projection tube close to the same length and making the intensity of color tone uniform.

Furthermore, by forming the lens 11 into a rectangular shape as described above, the vertical wall portion 11b is formed on the lens 11, and there is a possibility that the projection light from the projection tube 1 will be reflected and interfere with the projection tube 1. Therefore, in this embodiment, a light shielding plate part 13a having approximately the same size as the vertical wall part 11b and subjected to anti-reflection treatment is formed on the lens mounting plate 13, and this light shielding plate part 13a is attached to the vertical wall of the lens 11. The projection light is overlapped with the inner surface of the portion 11b to prevent the projection light from being reflected and to prevent light interference.

Next, by fitting the diaphragm 15 into the pressure regulating chamber 2g of the frame 2 and screwing the fastening ring 16 to the frame 2, the diaphragm 15
, and then attach the cap 17 to the opening of the fastening ring 16.

Next, coolant A is introduced from the injection port 2i of the frame 2.
is injected to fill the space formed between the diaphragm 15 and the projection surface of the projection tube 1 and the curved surface of the lens 11. When the cooling liquid A is filled in this filling, there is a possibility that air remains on the upper surface of the space. Therefore, in this embodiment, a tapered surface 2j is formed on the lower surface of the injection port 2i, so that the air is discharged from the injection port 2i along the tapered surface 2j. As a result, no air remains in the space, and the space is filled with the cooling liquid A. Then, the gasket 3 is inserted into the injection hole 2i with the screw 3.
Since it is attached by a, the coolant A is enclosed.

In this embodiment, the injection port 2i is sealed using a gasket 3 and a screw 3a.
As another sealing means, a hollow rubber member with a flange may be inserted into the injection port 2i, and a shaft-shaped stopper made of stainless steel, aluminum alloy, brass, etc. may be fitted into the hollow portion of the hollow rubber member.
In this case, if a bulge is formed on the inner periphery of the portion of the hollow rubber member that protrudes from the lower surface of the injection port 2i, the bulge will expand outward when the shaft-shaped stopper is inserted into the hollow portion. The lower surface of the injection port 2i is sealed to further improve the sealing state.

When a signal is applied to the projection tube 1 and the projection tube 1 is heated with this coolant A sealed in it, the coolant A expands, but the expanded amount is sucked by the diaphragm 15. , projection tube 1 and lens 1
No extra pressure is applied to the cooling liquid A, and the cooling liquid A circulates within the space and is cooled by the frame 2, so that the temperature does not rise above a certain level.

In addition, as the temperature of the coolant A increases, the lens 11
The lens 11 is also heated and expands, and its four corners come into contact with the protruding piece 2f of the frame 2, which applies stress to the lens 11 and may cause it to break.
Small projections 11d are formed at the four corners of the
By crushing d, stress on the lens 11 is released and damage is prevented.

[Effect of idea]

As described above, in the present invention, a lens having a vertical wall portion on the other side of a frame having a projection tube attached to one side is mounted, and the vertical wall portion is attached to a lens mounting plate for fixing the lens to the frame. By forming a covering light-shielding plate part with anti-reflection treatment, the light passing through the lens will not be reflected by the light-shielding plate part, which has the effect of preventing image disturbance due to light interference. It is.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of the whole, Fig. 2 is a sectional view of the same as above in an assembled state, Fig. 3 is a sectional perspective view of the frame portion, Fig. 4 is a front view of the lens attached to the frame, and Fig. 5 FIG. 6 is an enlarged sectional view of a portion of FIG. 2. 1... Projection tube, 2... Frame, 3, 4, 12
...Packskin, 5...Press plate, 9...Spring, 11...Lens, 13...Lens mounting plate.

Claims (1)

[Scope of utility model registration request] a frame made of a material with good thermal conductivity; a projection tube fixed to one side of the frame;
a lens in which a flange is placed via a gasket in an opening on the opposite side of the frame to the side on which the projection tube is fixed, and vertical walls are formed on four sides;
a lens mounting plate overlaid on the flange of the lens and screwed to the frame; the lens mounting plate has a light-shielding plate that is substantially the same size as the vertical wall of the lens and is subjected to anti-reflection treatment; forming a plate part;
A projection device for a projection television, characterized in that the light passing through the lens is prevented from being reflected by the vertical wall by the light shielding plate.