JP2007094069A - Transmission projection screen - Google Patents

Abstract

An assembly effective for maintaining a suitable initial state when a transmission screen comprising a combination of a flexible (non-self-supporting) lens sheet and a rigid (self-supporting) lens sheet is attached to a TV body. Propose structure.
SOLUTION: A lenticular sheet and a Fresnel lens sheet having substantially the same size are faced to each other with their surfaces facing each other and the periphery is sealed with an adhesive tape so that the cross section becomes a U-shape. A space between the sheets is sucked with a vacuum pump to be in a reduced pressure state, and both sheets are brought into close contact with each other, and then supported and fixed to the frame.
[Selection] Figure 4

Description

The present invention relates to an improvement in a screen used for a display represented by a transmissive projection TV (there are various names such as a transmissive TV, a rear projection TV, and a rear projection TV, which are all synonymous).
In particular, when one of the screens formed by superposing a Fresnel lens sheet and a lenticular sheet is composed of a flexible base material that is not self-supporting (has flexibility), it is mounted on the display screen. The present invention relates to a method for fixing a screen that can be stably mounted with a relatively simple structure without requiring a significant change in a housing (frame) and a fixing jig used for the purpose.

In a transmission type projection screen in which both the Fresnel lens sheet and the lenticular sheet have a self-supporting structure, both lens sheets are inserted in a concave portion on the inside of the casing and fixed using a jig as a separate member.
Here, being self-supporting means having a rigidity that can be raised while maintaining the shape.
FIG. 1 shows an example of a conventional fixing method. A lenticular sheet 1 and a Fresnel lens sheet 2 are placed in a recess (housing frame) of a housing (frame) 3 and screws 5 are used via a holding member 4. And fix.
In the figure, the left side is the viewer side, and the right side is the TV cabinet side provided with a projector.

  In FIG. 1, there is a relationship between the material of the Fresnel lens sheet 2 and the lenticular sheet 1 and the material of the housing (frame) 3, but the Fresnel lens sheet 2 and the lenticular sheet 1 have large differences in thermal expansion coefficients. If the thickness is the same, the Fresnel lens sheet 2 and the lenticular sheet 1 are overlapped and fixed with an adhesive tape (not shown), and then fixed to the housing (frame) 3 to change the temperature. Even if the Fresnel lens sheet and the lenticular sheet float or warp in accordance with changes in humidity or humidity, they will return to their original state when left in a room temperature environment.

On the other hand, transmissive projection screens using lenticular sheets and Fresnel lens sheets are being made thinner in order to improve optical characteristics.
As for the lenticular sheet, it is necessary to reduce the fine pitch with the higher definition of the image source, and with the fine pitch, the optical characteristics will inevitably become thinner.
As for the Fresnel lens sheet, if the plate thickness is large, a double image is generated due to stray light.
As this thinning progresses, with only the two-lens lens sheet and Fresnel lens sheet configuration, when an external force is applied from the outside of the screen, the screen may be easily detached from the frame due to insufficient rigidity, or the screen may be damaged. Invite problems such as.
Recently, a screen using a Fresnel lens sheet or a lenticular sheet made of a flexible base material having no self-supporting property (having flexibility) has been developed, and when at least one lens sheet has flexibility, When assembling to a TV, in addition to the above, an attachment method (fixing method) that eliminates the following adverse effects is required.

  In a projection screen in which one lens sheet is a non-supporting base material and the other lens sheet is a self-supporting base material, if two or four sides are fixed with adhesive or adhesive, the temperature Due to expansion and contraction due to changes and humidity changes, the lens sheet that is not self-supporting wrinkles and floats, and when incorporated in a transmissive projection TV, the focus blurs and color shifts over time. Therefore, there is a problem that image deterioration is caused.

The following cases are well-known as applications related to the mounting method (fixing method) assuming a screen composed of the above lens sheet combination (when one is not self-supporting and the other is self-supporting). I write.
JP-A-10-246918 Japanese Patent Laid-Open No. 11-271883 JP 2004-94147 A JP 2004-118166 A JP-A-4-249235

<Patent Document 1>
In a transmission screen that combines a Fresnel lens sheet and a lenticular lens sheet,
The lenticular lens sheet is formed on a transparent substrate film with insufficient rigidity, and a lens portion made of a cured product of a photocurable resin or a radiation curable resin is formed.
A screen for image projection, characterized in that a side edge portion of the lenticular lens sheet and a holding frame of the screen are joined and fixed via a synthetic resin film having heat shrinkability. (Claim 1)

<Patent Document 2>
In a transmissive screen composed of a plurality of screens that expands and contracts due to changes in temperature and humidity, on which image light emitted from an image generation source is projected,
A first screen and a second screen having a rigidity relatively lower than that of the first screen, and the second screen in a state of being extended in high temperature and / or high humidity on the first screen. A transmission screen characterized by being fixed. (Claim 1)

<Patent Document 3>
A method of fixing a screen configured by superposing a Fresnel lens and a lenticular lens to a housing frame of a transmissive reaction screen television,
By sticking a single-sided adhesive tape around the superimposed Fresnel lens and lenticular lens in a U shape, the Fresnel lens and lenticular lens are integrated and fixed as a screen,
A method for fixing a screen, wherein the screen is fixed to a housing frame without applying pressure. (Claim 1)

<Patent Document 4>
In a transmissive rear projection screen in which a Fresnel lens sheet and a lenticular lens sheet are overlapped and the periphery is supported and fixed by a housing frame and a holder,
Either the Fresnel lens sheet or the lenticular lens sheet is composed of a lens sheet (2) made of a base material having self-supporting property, and the lens sheet (1) made of a base material having no self-supporting property. The lens sheet (2) made of a base material having no self-supporting property and the lens sheet (1) made of a base material having self-supporting property are fixed with an elastic adhesive layer (31) at a lower edge thereof. The upper edge of the lens sheet (1) made of a non-base material and one end of the holding tape (30) are fixed by the adhesive layer (41), and the other end of the holding tape (30) is the housing. Connected and fixed to the body frame (11a) via the adhesive layer (42) with the holder (12a) and the screw (13),
The lens sheet (2) made of the non-self-supporting base material is suspended between the housing frame (11a) and the holder (12a) and at one end of the lens sheet (2) by the holding tape (3). ) And the holder (12b). A transmissive rear projection screen characterized by being held between the holder and the holder (12b). (Claim 1: see FIG. 2)

<Patent Document 5>
In the screen mounting method of attaching the rigid sheet and the flexible sheet to the mounted structure,
The rigid sheet is supported by the mounted structure so as to be movable up and down, and tension is applied to a portion near the lower end of the flexible sheet by applying gravity of the rigid sheet, so that the flexible sheet is closely attached to the rigid sheet. A screen mounting method characterized in that it is made to cause.
(Claim 1)

  In the technique disclosed in Patent Document 1, a heat-shrinkable synthetic resin film is formed on the four sides of the upper and lower side edges and the left and right side edges of a mounting part (holding frame) to which a film-like lenticular lens sheet having insufficient rigidity is attached. When the synthetic resin film is shrunk by heat treatment, a uniform tensile stress is applied to the film-like lenticular sheet in two vertical and horizontal directions, and there is no wrinkle or deflection. A lenticular lens sheet is attached in a good condition.

  In the method disclosed in Patent Document 2, a lens sheet that is not self-supporting is stretched in advance at a high temperature and / or high humidity, and then bonded to the lens sheet having self-supporting property. A lens sheet that is not self-supporting is always tensioned in the direction of contraction after being mounted on a TV set, so that the lens sheet is kept stretched without wrinkles or sagging. A process of stretching in the humidity is required.

  In the technique disclosed in Patent Document 3, a self-supporting lens sheet and a non-self-supporting lens sheet are formed in a U-shape using a single-sided adhesive tape having a support elongation of 200% or more. It is described that if it is integrated and fixed by sticking on, it can be prevented from generating wrinkles around the surface and lifting of the entire surface according to expansion and contraction due to temperature change and humidity change and shrinkage temperature humidity However, there is no description about the tension applying means for preventing the wrinkling and bending of the lens sheet that is not self-supporting. “Evaluation by leaving the lens sheet in a 60 ° C. environment for 1 hour and inspecting the appearance in a 23 ° C. environment” From the result (0032), it is understood that a process of stretching at high temperature and / or high humidity is required as in Patent Document 2.

  In Patent Documents 4 and 5, a structure that suspends the sheet by applying the gravity of a rigid body (self-supporting) sheet as tension applying means for preventing wrinkling and bending of a flexible (non-self-supporting) lens sheet. Is adopted. (Hereinafter, this method may be referred to as a “hanging method”.)

Patent Document 5 describes that the problems listed below are solved as a reason (purpose) of adopting the suspension method.
(1) The jig becomes large according to the use of an elastic material, a spring or the like.
(2) Handling is difficult due to the provision of the pressure-sensitive adhesive layer between the lens sheets, resulting in poor workability.
(3) Once attached, the tension may change due to the expansion and contraction of the lens sheet, and the adhesion effect may be lost.
(4) Providing an adhesive layer between lens sheets is difficult to handle, and not only the workability is deteriorated, but also the image may be deteriorated.

As described above, the suspension method that is superior to various other methods is exemplified below as a structural problem inherent to the suspension method.
(1) The structure for suspending both lens sheets is complicated.
(2) Since the weight is determined according to the plate thickness and size of the rigid lens sheet, there is a limit to the tension applied to the flexible lens sheet.
(3) Since both lens sheets are suspended, they are vulnerable to vibration.
(4) The adhesion between both lens sheets is weak.
(5) Although it is easy to apply tension to the flexible lens sheet in the vertical direction where gravity is applied, the application of tension to the lens sheet in the horizontal direction where gravity does not work tends to be insufficient, When a horizontal external force is applied, wrinkles and deflection are likely to occur.

The above (1) shows that it is required to adopt a structure that is suspended from the upper part of the frame and a structure that is different between the upper part and the lower part, such as fixing the flexible lens sheet to the lower part of the frame.
In the above (3), since the movement of the rigid lens sheet is further free, for example, in order to solve the problem (4), the lens sheet is previously “warped (convex to the other lens sheet side). If the shape is changed after being attached, the adhesion with the other lens sheet is deteriorated.
In order to eliminate the above (5), it is conceivable that a reinforcing member for preventing wrinkles and deflections occurring in the horizontal direction of the flexible lens sheet is applied to the lens sheet (stacked and integrated). Flexibility is such that the linearity and rigidity of the frame and the reinforcing member excessively affect the surface state, and it is difficult to realize a stable holding structure. (In other words, it will lack mass productivity.)

Also, as a mechanism for realizing the suspension method, double-sided adhesive tape, reinforcing plate (if necessary), screws and other members are required, but their cost is not cheap, double-sided adhesive tape Alternatively, fixing with screws does not guarantee strength, and particularly double-sided adhesive tape has a problem that it lacks environmental resistance (high temperature and high humidity) in terms of material.

  In the present invention, the above problem is solved and a good initial state is achieved when a transmissive screen comprising a combination of a flexible (non-self-supporting) lens sheet and a rigid (self-supporting) lens sheet is attached to the TV body. The purpose is to propose a new assembly structure that can realize the above.

The transmission screen according to the present invention is
In a transmissive screen that is mounted on the display screen of a transmissive projection display by superposing a Fresnel lens sheet and a lenticular sheet and supporting and fixing the periphery to the frame,
In the lenticular sheet, a lens part composed of a cylindrical lens group is formed on the surface of the translucent substrate film with a cured product of a radiation curable resin, and the entire structure is flexible.
In the Fresnel lens sheet, the lens part is formed of a cured product of radiation curable resin on the surface of a translucent base material having a light diffusion function, and it is not flexible as a whole, compared with a lenticular sheet. It is a structure with large rigidity and thickness,
The gap between the two sheets of lenticular sheet and Fresnel lens sheet, which are approximately equal in size, are sealed with adhesive tape so that the lens side faces each other and the cross section is U-shaped. It is characterized in that the pressure is reduced by sucking with a vacuum pump, the two sheets are brought into close contact, and then supported and fixed to the frame.

When mounting a transmissive screen consisting of a flexible (non-self-supporting) lens sheet and a rigid (self-supporting) lens sheet to the TV body, both lens sheets are supported by the frame (joined to the TV body) -When fixing, the lens parts side of both lens sheets face each other in close contact with each other, so that it is possible to realize a structure that does not use double-sided adhesive tape or screws to improve the adhesion of both lens sheets. Since it is possible to omit the use of double-sided pressure-sensitive adhesive tapes that have problems with environmental resistance, a stable mounting structure can be realized over time.
In addition, between the flexible lens sheet and the rigid lens sheet, compared to the case where both have the same flexibility, rigidity, and thickness, the adhesiveness is excellent, and the state in which no wrinkles or deflection occur is observed over time. Adhering stably maintained can be realized by a relatively inexpensive method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
3 and 4 are explanatory views showing the main part of the screen (two lens sheets) mounting structure according to this embodiment.
A self-supporting and flexible film-like (thin) lenticular sheet 1 has a greater rigidity and thickness than the lenticular sheet 1 and has no flexibility as a whole. The surface on the side (the illustration of the lens portion is omitted) is made to face, and the periphery is sealed with an adhesive tape 7 so that the cross section becomes a U-shape, so that the initial state of contact is obtained. (Figure 3)
As shown in FIG. 3, the surrounding sealing with the adhesive tape 7 may be a pair of opposite sides instead of all four sides as long as the pressure-reduced state in the surface on the lens part side is maintained.
As the adhesive tape, an elastomeric tape can be used.
Alternatively, when sealing around both lens sheets, an adhesive tape may not be used, and bonding using an adhesive or an adhesive may be performed outside the effective area of the surface on the lens part side.

A gap between both sheets is sucked with a vacuum pump to form a reduced pressure state. (Fig. 4)
In FIG. 4, the illustration of the adhesive tape 7 whose periphery is sealed is omitted for convenience of explanation.
In the suction, suction is performed by a vacuum pump from a small hole (a joint portion that can be pulled by a pump) 8 formed in the peripheral portion of the Fresnel lens sheet 2.
In the figure, the small hole 8 is formed only in the lower left of the Fresnel lens sheet 2 on the front side, but even if the small hole 8 is formed at a plurality of locations outside the effective area of the lens portion (outside the display screen of the TV). good.

  Adhering over time, such as “fixing the screen to the frame”, “attaching to the TV body”, “transporting and storing the TV”, “use of the TV by the user” etc. It is preferable to maintain the reduced pressure state (initial state) between the two sheets with the small holes 8 closed by the caps 9 or the like so as not to cause a decrease in the above.

As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, this invention is not limited to this structure.
Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications. The technical scope of the present invention is also applicable to these changes and modifications. It is understood that it belongs to.

Explanatory drawing which shows an example of the transmission type screen (attachment method) which concerns on a prior art. Explanatory drawing which shows an example of the transmission type screen (attachment method) which concerns on a prior art. Explanatory drawing which shows an example of the transmission type screen (attachment method) by this invention. Explanatory drawing which shows an example of the transmission type screen (attachment method) by this invention.

Explanation of symbols

1 Lenticular sheet 2 Fresnel lens sheet 3 Frame (housing)
7 Adhesive tape 8 Small hole 9 Cap

Claims (3)

In a transmissive screen that is mounted on the display screen of a transmissive projection display by superposing a Fresnel lens sheet and a lenticular sheet and supporting and fixing the periphery to the frame,
In the lenticular sheet, a lens part composed of a cylindrical lens group is formed on the surface of the translucent substrate film with a cured product of a radiation curable resin, and the entire structure is flexible.
In the Fresnel lens sheet, the lens part is formed of a cured product of radiation curable resin on the surface of a translucent base material having a light diffusion function, and it is not flexible as a whole, compared with a lenticular sheet. It is a structure with large rigidity and thickness,
The gap between the two sheets of lenticular sheet and Fresnel lens sheet, which are approximately equal in size, are sealed with adhesive tape so that the lens side faces each other and the cross section is U-shaped. A transmissive screen characterized by having a structure in which a sheet is sucked with a vacuum pump to be in a reduced pressure state, both sheets are brought into close contact, and then supported and fixed to a frame.   2. The transmission type according to claim 1, wherein an adhesive tape is not used for sealing the periphery of both lens sheets, and bonding is performed using an adhesive or an adhesive outside the effective area of the surfaces of the lens portions. screen.   The vacuum hole is sucked with a vacuum pump from a small hole formed in the peripheral portion of the Fresnel lens sheet to reduce the pressure between the two sheets, and then the small hole is closed. Transmissive screen.

Images