JPH0522935Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a screen mounting device for a rear projector that allows a large television screen to be obtained.

[Summary of the idea]

The present invention relates to a screen mounting device for a rear projector that can obtain a large TV screen. In Ekta's screen mounting device, the locking tool is semi-transparent and at least one side has a satin surface to reduce the shadow of the locking tool on the screen.

[Conventional technology]

Various types of conventional video projection systems have been proposed, including a separate type in which a projector and a screen are separated, and an integrated type in which they are integrated, depending on the projection form.

FIGS. 4 and 5 show an integrated type rear projector that uses a conventional transmissive screen and projects light from the back of the screen.
A transmission screen 2 is arranged on the front surface of the cabinet 1, and is held by a screen frame 3 and locking devices (not shown in FIG. 4). The inside of cabinet 1 is R as shown in Figure 5.
(red), G (green), and B (blue) cathode ray tubes (CRT)
) 4R, 4G, 4B, and these CRT
The light is reflected by the first and second reflectors 6a and 6b via the lens system 5, and the image light transmitted from the back side of the transmissive screen 2 is viewed from the front side of the screen. has been done. As shown in FIG. 6, the transmission screen 2 includes a Fresnel lens 7 for mitigating the hot spot phenomenon,
The lenticular lens 8, which mainly determines the horizontal directivity, is formed from a synthetic resin plate, and then the lenticular lens forming surface and the Fresnel lens forming surface are stacked against each other, and the lenticular lens is transparent. A plurality of semicylindrical lenses are formed in the vertical direction of the mold screen. In order to overlap such a transparent screen 2, as shown in FIG.
holds the four sides of Figure 7 is A-A of Figure 4.
This figure shows a side cross section of a cross section along the direction viewed from B-B, and the screen frame 3 includes a frame 3a with a substantially F-shaped cross section made of wood, metal, synthetic resin, etc., and a reinforcing frame of this frame 3a. A screen holding member 3c is fixed on the screen holding member 3b, and the screen frame 3 including the screen holding member 3c is arranged so as to surround the four sides of the transmission screen 2, and the cross section is L-shaped from the back side of the transmission screen 2. Approximately Z with the end of the member extending downward
The transparent screen 2 is clamped with a letter-shaped locking tool 4,
It is configured to be fixed to a frame 3a or a reinforcing frame 3b with screws or the like, and the screen frame 3 and locking tools 4 are attached to the cabinet 1. This locking tool 4 is made of an opaque material such as wood or metal.
A locking tool using such an opaque member is shown as a holding tool in, for example, Japanese Utility Model Application No. 62-4744.

[Problem that the invention attempts to solve]

In the above-mentioned screen mounting device for a rear projector, the incident light 10 incident on the back surface 7c of the Fresnel lens 7 of the transmissive screen 2 from the CRT 4R, 4G, 4B is directed to the inclined surface of the Fresnel lens as shown in FIG. The original light 1 is emitted from 7a.
0a, the light reflected on this inclined surface 7a is emitted from the flat portion 7d, enters the upper inclined surface 7b again, is reflected on the back surface 7c of the Fresnel lens 7, and is reflected light emitted outside the Fresnel lens 7. 11, if an opaque fastener 4 is used as shown in FIG. 7, shadows 9 will be produced on the upper and lower surfaces of the transmissive screen 2, as shown in FIG. Of course, shadows are generated on the left and right sides of the transmissive screen 2, but these are not very noticeable. The cause of such shadows will be explained with reference to FIG. FIG. 9 shows a screen mounting device similar to that shown in FIG. The light 10 passes through the inclined surface 7a of the Fresnel lens and the lenticular lens 8 and is emitted as original light 10a. On the other hand, the incident light 10b is transmitted to the inclined surface 7 of the Fresnel lens 7.
a, 7b, the back surface 7c of the Fresnel lens 7, and the flat part 7d of the Fresnel lens, the light is repeatedly entered and reflected and is emitted from the point A as reflected light 11b. Therefore, the light diffused at the point A of the lenticular lens 8 is different from the original one. The light is the sum of the light 10a and the reflected light 11b. On the other hand, the light diffused at point B of the lenticular lens 8 is only the original light 10a due to the incident light 10, and the incident light 10b shown by the broken line is blocked by the opaque stopper 4, so the optical path shown by the broken line is The reflected light 11b that passes through and exits from point B disappears. For this reason, there is a drawback that the light shines strongly at point A, but does not shine at point B, producing a shadow 9.

The present invention has been developed in view of the above-mentioned drawbacks, and its purpose is to provide a screen mounting device that can reduce shadows generated on at least the upper and lower surfaces of a transmission screen.

[Means for solving problems]

The present invention uses a screen frame 3 and a locking tool 4 to hold at least the upper and lower two pieces of a transmissive screen 2, and to lock the screen in a screen mounting device for a rear projector that projects light from the back of the transmissive screen 2. Ingredients 4
is translucent, and at least one side has a pear finish 12.

[Effect]

According to the rear projector screen mounting device of the present invention, the locking tool 4 is semitransparent and at least one side has a matte surface 12, so that the incident light 10b transmitted through the locking tool 4 is added to the original light 10a. Therefore, it is possible to reduce the occurrence of shadows 9 on the upper and lower lines of the screen.

〔Example〕

Hereinafter, an embodiment of the screen mounting device for a rear projector according to the present invention will be described with reference to FIG. FIG. 1 is a side sectional view similar to FIG. 7, and corresponding parts to those in FIG. 7 are designated by the same reference numerals and redundant explanation will be omitted.

As shown in FIG. 4, the rear projector screen mounting device of this example has a transparent screen 2 disposed on the front of a cabinet 1, and holds the transparent screen 2 with a screen frame 3 and locking tools 4. The transmission screen 2 is fixed to the cabinet 1 by the screen frame 3 and the locking members 4. Inside cabinet 1 are CRT4R, 4G, 4B for R, G, B.
The light from the CRT is transmitted from the back of the transmissive screen 2 through the lens system and reflector.
The image light can be viewed from the front of the screen. In such a rear projector, in this example, the above-mentioned locking member 4 is made of synthetic resin, and the light transmittance is controlled to make it translucent. Optimal light transmission is approximately 50%. Furthermore, CRT4R, 4G, 4 are attached to the L-shaped part of the locking tool 4.
At least one side on which the incident light 10b from B enters is roughened to form a satin surface 12 and diffuse the light. Furthermore, in this example, a tapered surface 13 is provided on the upper surface of the locking tool 4.
form. This tapered surface 13 is selected at an angle that is substantially parallel to the incident light 10.

With this configuration, the shadows 9 appearing on the upper and lower edges of the transmissive screen 2 can be greatly reduced.

Even if a light-transmitting synthetic resin is used as the above-mentioned locking device 4 instead of a translucent one, the incident light 10b shown by the broken line explained in FIG. 9 will be blocked by this locking device. Therefore, even at point B of the lenticular lens 8, the incident light 10b shown by the broken line
Since the shadow 9 comes and is emitted, it is basically possible to eliminate the shadow 9. However, if this light-transmitting synthetic resin is used, the end surfaces 14 of the four sides of the Fresnel lens 7
(Fig. 1) Incident light 1 transmitted through the locking tool 4
0b is reflected, and this light passes through the lenticular lens 8
The light is emitted from one point on a predetermined surface, and a speckled shadow 9 is generated. This spot shadow is caused by scratches, irregularities, or non-uniformity when forming the fastening tool 4. Therefore, the fastening tool 4 should be semitransparent, and at least one side of the fastening tool should be pear-shaped. It was confirmed that setting it as the ground is the most suitable for reducing shadows.

Furthermore, the reason why the tapered surface 13 is formed on the upper surface of the locking tool 4 in this example will be explained with reference to FIG.
Although FIG. 2 shows an enlarged view of portion C in FIG. 1, the upper surface of the locking tool 4 is flat and has no tapered surface 13. Considering the case where the locking tool 4 is semitransparent and at least one side of the locking tool 4 has a matte surface 12, the incident light 10b from the CRTs 4R, 4G, and 4B
If the path length of the light that enters from the L-shaped side surface 4a of the locking tool 4 and passes through the translucent locking tool 4 is l, then the light that enters from the L-shaped top surface 4c The path lengths of the incident light 10c passing through the semi-transparent locking tool 4 are l ₁ and l ₂ , and since the relationship of l>l ₂ >l ₁ naturally holds, the outgoing light of the portion that has passed through the top surface 4c and the side surface 4a The intensity of the light will vary between the emitted light that has passed through it, causing unevenness. This locking tool 4
Since the thickness of the upper surface 4b of the screen was extremely thin compared to the overall size of the transmissive screen 2, the influence of shadows caused by spots was negligible. However, in order to completely eliminate the shadow of this spot, the upper surface 4c of the locking tool 4 should be adjusted to the tapered surface 1.
It is preferable to set it to 3. FIG. 3 is for explaining the angle of the tapered surface.
If the angle is acute as shown by a, or obtuse as shown by the broken line 13b, the optical path length l of the incident light entering the locking tool 4 will change, so the tapered surface 13
It can be seen that it is preferable to make the angle substantially parallel to the incident light 10.

In addition, a device was manufactured in which the locking tool 4 and transparent synthetic resin were used, and at least one side had a satin surface and a tapered surface 13 was formed, but in this case, the shadow of the spots was uniform, but on the other hand, the shadow was The areas marked 9 tended to shine. Therefore, if the locking tool 4 made of a transparent material is made opaque and the light transmittance is selected to be about 50%, when viewing the screen 2, the screen has a uniform brightness in which the shadow 9 and the shadows of the spots are hardly recognizable. I was able to obtain

In this example, the four sides of the transmissive screen are held by the screen frame 3 and the locking tools 4, but translucent locking tools 4 are attached only to the top and bottom sides of the transparent screen 3.
It goes without saying that the present invention is not limited to the above-described embodiments, and that various other configurations can be taken without departing from the gist of the present invention.

[Effect of idea]

Since the present invention is configured as described above, it is possible to obtain a screen mounting device for a rear projector that can reduce shadows caused by the opaque fasteners 4 when projecting light onto a transmissive screen from the back. has.

[Brief explanation of the drawing]

Fig. 1 is a partial side cross-sectional view of a screen frame showing an embodiment of the screen mounting device for a rear projector of the present invention, and Fig. 2 is a top surface of a locking device with the tapered portion of section C in Fig. 1 made flat. Figure 3 is an explanatory diagram of the optical path of
4 is a perspective view of a conventional rear projector; FIG. 5 is an explanatory diagram of the optical path system of the rear projector shown in FIG. 4; The figure is a perspective view showing a part of the screen used in Figure 4, and Figure 7 is A-A in Figure 4.
A side sectional view of the screen frame as viewed from the B-B direction, Figure 8 is an illustration of the optical path incident on the Fresnel lens, and Figure 9 is an illustration of the optical path created by the locking tool attached to the screen. It is a diagram. 1 is the cabinet, 2 is the transparent screen, 3
is a screen frame, and 4 is a locking tool.

Claims (1)

[Claims for Utility Model Registration] In a screen mounting device for a rear projector that holds at least the upper and lower sides of a transmissive screen using a screen frame and locking tools and projects light from the back of the transmissive screen, the above-mentioned A screen mounting device for a rear projector, characterized in that the locking tool is semi-transparent and at least one side has a matte finish.