JPH0815773A - Projection type display device - Google Patents

Abstract

PURPOSE:To prevent dust attached to the inside of a transmission type screen from entering without wrinkling and swelling a front sheet constituting the transmission type screen. CONSTITUTION:The dust entering the inside of the transmission type screen is sucked and attached to a gap between the front sheet 6 and a Fresnel sheet 5 by air sucked in a housing from a gap between the periphery of the transmission type screen and a screen frame 2 by a spraying principle. Then, the gap between the sheet 5 and the frame 2 or the housing is sealed by an adhesive tape and the entering of the air being the foundamental cause of the suction of the dust is cut so as to prevent the dust from being attached. Thus, the air is interrupted to enter from the periphery of the sheet 6 and the dust is prevented from being attached to the inside of the transmission type screen without wrinkling and swelling the sheet 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device, and more particularly to a mounting structure means for preventing dust from entering a transmissive screen mounted on the front surface of the display device.

[0002]

2. Description of the Related Art FIG. 1 shows a front view of a projection display device. Reference numeral 1 denotes a housing of the display device. Reference numeral 2 denotes a screen frame attached to the housing 1, and 3 denotes a transmissive screen attached to the screen frame 2. Reference numeral 4 denotes dust adhering to the inside of the transmissive screen 3.

FIG. 2 is a sectional view taken along line XX of FIG. 1 and shows a structural example of a conventional screen frame 2. Reference numeral 5 denotes a Fresnel sheet that is a second sheet that constitutes the transmissive screen 3, and 6 denotes a first sheet that constitutes the transmissive screen 3.
The front seat which is a seat of is shown. 12 is the case 1
Shows a fan for cooling the inside of the fan, 13 shows air blown by the fan 12, and 7 shows a part of air sucked by the fan 12.

FIG. 3 is a partially enlarged view of the screen frame 2 shown in FIG. Conventionally, since there is a gap between the screen frame 2 and the peripheral portions of the Fresnel sheet 5 and the front sheet 6 which form the transmissive screen 3, a part of the air 7 sucked by the cooling fan 12 passes through the gap. It had flowed into the inside of the housing 1. A part of the air 7 passing through the gap of the screen frame 2 also flows into between the front seat 6 and the Fresnel seat 5 on the principle of atomization. When dust is brought between the front sheet 6 and the Fresnel sheet 5 together with the air, the dust 4 adheres to the inside of the transmissive screen 3 as shown in FIG. 1 and the image quality is significantly deteriorated.

If the above-mentioned air is prevented from entering between the front sheet 6 and the Fresnel sheet 5, the dust 4 will not adhere, so that in the conventional transmissive screen 3 for a television receiver, As shown in the example of No. 4, the front sheet 6 and the Fresnel sheet 5 were surrounded by dust-proof tape to prevent the above dust from entering. Since the conventional front seat 6 is as thick as about 1.5 mm, there is no problem that the front seat 6 is wrinkled even if it is wrapped with tape as described above.

Actual opening 60-77173 and actual opening 60-1
In 867664, the attachment means of the transmissive screen 3 is described, but the dust intrusion prevention means is not considered.

[0007]

In the transmissive screen 3 of a high-definition projection display, the front sheet 6 is generally formed as an extremely thin sheet of 1 mm or less (usually about 0.7 mm). When the dustproof tape is applied as shown in FIG. 5, when only the front sheet 6 expands due to environmental changes such as moisture absorption, the expansion is suppressed by the dustproof tape. As a result, the observer of the transmission screen 3 as shown in FIG. The front seat 6 disposed on the side has a drawback that it buckles and wrinkles 9 occur. The wrinkles 9 have a problem that they impair the appearance of the screen and deteriorate the focus of the image. Solving this problem has been an important issue in high-definition projection displays.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a projection type display device which overcomes the above-mentioned problems and prevents dust from adhering due to invasion of air and is resistant to environmental changes.

[0009]

As described above, in order to prevent air from entering between the front sheet 6 which is the first sheet and the Fresnel sheet 5 which is the second sheet, which constitutes the transmissive screen 3. If the space between the front sheet 6 and the Fresnel sheet 5 is directly surrounded by dustproof tape, the expansion and contraction of the front sheet 6 is hindered and wrinkles 9 occur.

Therefore, it is necessary to provide a means for stopping the invasion of air while leaving the front seat 6 free. Therefore, in the present invention, the idea is changed so that the invasion of air between the front sheet 6 and the Fresnel sheet 5 is not stopped by a direct means, and the display device is passed through the gap around the transmissive screen 3. The means for cutting off the root cause of the invasion of air between the front seat 6 and the Fresnel seat 5 by cutting off the flow of the air 7 sucked into the housing 1 to eliminate the atomization phenomenon is adopted. The first means of the present invention is to provide an L-shaped groove inside the screen frame 2 and insert the front sheet 6 and the Fresnel sheet 5 in this order into the L-shaped groove of the screen frame 2 to form the Fresnel sheet. Around the entrance surface of the sheet 5 and the screen frame 2
The gap between the L-shaped groove and the bank portion is sealed with a dust-proof adhesive tape to block the air flow 7.
The second means of the present invention is to provide an L-shaped groove on the front surface of the housing 1 of the display device, and first insert the Fresnel sheet 5 into the L-shaped groove so that the Fresnel sheet 5 has an emission surface side. The space between the bank of the L-shaped groove of the housing is sealed with adhesive tape, the air flow 7 is blocked, and the front sheet 6 is sandwiched by the screen frame on the observer side of the Fresnel sheet 5. To configure. The third means of the present invention is to seal the space between the housing 1 of the display device and the Fresnel sheet 5 with a double-sided adhesive tape to block the air flow 7 and to attach the front sheet to the observer side of the Fresnel sheet 5. 6 is sandwiched by the screen frame 2.

[0011]

According to the above-mentioned means of the present invention, the air sucked into the housing 1 of the display device from the gap between the periphery of the front sheet 6 and the Fresnel sheet 5 and the screen frame 2 is blocked. As a result, it is possible to prevent the root cause of the invasion of air between the front sheet 6 and the Fresnel sheet 5 according to the atomization principle, and to eliminate the adhesion of dust inside the transmissive screen 3.

Since the Fresnel sheet 5 is twice as thick as the front sheet 6 or more, even if the Fresnel sheet 5 is adhered to the periphery of the Fresnel sheet 5 with adhesive tape, expansion and contraction due to environmental changes is hardly impeded, and wrinkles and blisters are generated. Since the above does not occur, the above-mentioned means according to the present invention can provide a very effective and practical dust intrusion prevention measure.

[0013]

EXAMPLES Specific examples of the present invention are shown in FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. Of the numbers in the figure,
1, 2, 5, 6, and 8 indicate the same names as described above.

A first embodiment of the present invention is shown in FIGS. FIG. 6 is a top sectional view of the projection display device. An L-shaped groove is provided inside the screen frame 2, and the front sheet 6 and the Fresnel sheet 5 are inserted into the groove in this order. The space between the incident surface side of the Fresnel sheet 5 and the bank portion of the L-shaped groove of the screen frame 2 is sealed with an adhesive tape.

FIG. 7 is a partially enlarged view of the screen frame 2 shown in FIG. In the figure, the Fresnel sheet 5
Place the metal fitting 10 on the front surface of the dust-proof adhesive tape 8 around and fix the front sheet 6 and the Fresnel sheet 5 with the fixing screw 11 so as not to fall. Front seat 6 at this time
A slight gap is provided between the screen frame 2 and the screen frame 2 so as not to hinder the expansion and contraction of the front seat 6.

A second practical example of the present invention is shown in FIGS. FIG. 8 is a top sectional view of the projection display device. An L-shaped groove is provided on the front surface of the housing 1 of the display device, and the Fresnel sheet 5 is inserted into the L-shaped groove,
A space between the emission surface side of the Fresnel sheet 5 and the bank portion of the L-shaped groove of the housing 1 is sealed with an adhesive tape. The front sheet 6 is attached to the Fresnel sheet 5 on the viewer side with the screen frame 2 interposed therebetween. FIG. 9 shows a partially enlarged view of the screen frame 2 of FIG. In the figure, the screen frame 2 is provided with an L-shaped groove,
Only the front seat 6 can be inserted, and a slight gap is provided between the front seat 6 and the screen frame 2 so as not to hinder the expansion and contraction of the front seat 6. Further, as shown in FIG. 10, the Fresnel sheet 5 is made longer than the front sheet 6, and the long portion and the bank portion of the L-shaped groove on the front surface of the housing 1 are sealed with an adhesive tape. The front sheet 6 is placed on the observer side of the Fresnel sheet 5 so as not to hit the adhesive tape, and the Fresnel sheet 5 is attached by being sandwiched by the screen frame 2. At this time, a slight gap is provided between the front seat 6 and the screen frame 2 so as not to hinder the expansion and contraction of the front seat 6.

A third embodiment of the present invention is shown in FIG. In the figure, a double-sided tape is inserted between the periphery of the Fresnel sheet 5 and the front surface of the housing 1 of the display device for sealing.
Place the front seat 6 on the front surface of the Fresnel sheet 5, and further hold the metal fittings 10 around the front seat 6,
Fix the front seat 6 and Fresnel seat 5 with the fixing screw 11 so that they will not fall. Further, the screen frame 2 is attached to the front surface of the holding metal fitting. At this time, a slight gap is provided between the front seat 6 and the holding metal fitting 10 so as not to hinder the expansion and contraction of the front seat 6.

[0018]

According to the embodiment of the present invention described above,
The periphery of the Fresnel sheet 5, which is the second sheet that constitutes the transmissive screen 3, and the screen frame 2 or housing 1.
The air 7 that is sucked into the housing 1 of the display device from the gap between and is blocked. As a result, front seat 6
It is possible to cut off the root cause that causes the flow of air between the Fresnel sheet 5 and the Fresnel sheet 5, and to prevent dust from entering the transmissive screen without causing wrinkles 9 or blisters on the front sheet 6. Can be prevented.

When the projection display apparatus is installed for several years, dust 4 adheres to the inside of the transmissive screen 3 as shown in FIG. 1 and the image is significantly deteriorated. However, according to the present invention, the appearance is impaired. Without the dust 4 adhering to the inside of the transmissive screen 3, it is possible to maintain a bright and high-performance image for many years.

[Brief description of drawings]

FIG. 1 shows an example of a front view of a projection display device, showing a dust adhesion phenomenon when a transmissive screen is attached by conventional means.

FIG. 2 shows a top sectional view of a conventional example of a projection display device.

FIG. 3 is a partially enlarged view of the conventional screen frame shown in FIG.

FIG. 4 shows an example of dust intrusion prevention means in a conventional transmission screen mounting means.

5 shows an example of wrinkles on the front seat generated by the dust intrusion prevention means shown in FIG.

FIG. 6 is a sectional view showing a first embodiment of the present invention.

FIG. 7 is a sectional view showing a first embodiment of the present invention.

FIG. 8 is a sectional view showing a second embodiment of the present invention.

FIG. 9 is a sectional view showing a second embodiment of the present invention.

FIG. 10 is a sectional view showing a second embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Enclosure of a projection type display apparatus, 2 ... Screen frame, 3 ... Transmission type screen, 4 ... Dust adhering to the transmission type screen, 5 ... Fresnel sheet which is a 2nd sheet, 6 ... Front which is a 1st sheet Sheet, 7 ... Air sucked into the housing, 8 ... Dustproof adhesive tape.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Sakamoto 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Information & Video Media Division, Hitachi, Ltd. (72) Takashi Ito 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock company Hitachi Information & Video Media Division (72) Inventor Masaru Ogino 216 Totsuka-cho, Totsuka-ku, Yokohama-shi Kanagawa Stock Company Hitachi Information & Media Division (72) Makoto Kamiya Totsuka-cho Totsuka-ku, Yokohama-shi, Kanagawa 216 Hitachi, Ltd. Information & Video Media Division

Claims (5)

[Claims] 1. A transmission type screen mounted on the front surface of a housing of a projection display device, wherein a first sheet having a thickness of 1 mm or less arranged on an observer side and a projection source side with respect to the first sheet. It is composed of a second sheet and at least two sheets that are arranged and have a thickness that is at least twice the thickness of the first sheet, and that there is no circulation of air from the periphery of the transmissive screen into the housing. A projection display device, characterized in that a tape is adhesively sealed between the screen frame and the second sheet to prevent dust from entering the transmissive screen. 2. A transmission type screen mounted on the front surface of a housing of a projection display device, wherein a first sheet having a thickness of 1 mm or less, which is arranged on the observer side, and a projection source side with respect to the first sheet. It is composed of a second sheet arranged at least twice as thick as the first sheet and at least two sheets, and there is no air flow from the periphery of the transmissive screen into the housing. A projection display device, characterized in that a tape is adhesively sealed between the housing and the second sheet to prevent dust from entering the transmissive screen. 3. An L-shaped groove is provided inside the screen frame, and a first groove is formed in the L-shaped groove of the screen frame.
Sheet and the second sheet are inserted in this order, and the space between the incident surface side of the second sheet and the bank portion of the L-shaped groove of the screen frame is adhesively sealed with tape to form a transmissive screen. 2. The projection display apparatus according to claim 1, wherein dust is prevented from entering the transmissive screen by blocking the flow of air from the periphery of the screen into the housing. 4. An L-shaped groove is provided on the front surface of the housing of the display device, and a second sheet is inserted into the L-shaped groove, and the exit surface side of the second sheet and the housing are provided. Adhesively seal the gap between the bank of the L-shaped groove and the second
The flow of air from the periphery of the sheet into the housing, and by mounting the first sheet with the screen frame on the observer side of the second sheet, the dust in the transmissive screen is removed. The projection type display device according to claim 2, wherein intrusion is prevented. 5. A flow of air from the periphery of the second sheet into the casing by sealing between the periphery of the front face of the casing of the display device and the incident surface side of the second sheet with a double-sided adhesive tape. And the first sheet is attached to the observer side of the second sheet by sandwiching it with a screen frame to prevent dust from entering the transmissive screen. The described projection display device.