JPH04195031A - Transmission type screen and its molding method and device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of bubbles and to reduce warpage deformation by filling a cavity with radiation curing resin, radiating radiant rays so that the thickness of the cavity at the time of curing may be thinner than that at the time of filling the cavity with the resin and setting the thickness of the curing resin equal to or under specified thickness. CONSTITUTION:The cavity 3 is formed by a base substance thin plate 2 which transmits the radiant rays and a cavity surface 1a of a metallic mold engraved in a specified shape. Next, the cavity 3 is filled with the radiation curing resin, and the thickness of the radiant ray curing resin layer is set equal to or under 1/3 of the thickness of the base substance thin plate layer, for example, in a Fresnel lens. Then, the valve 10 of a resin discharge port 15 is closed after finishing discharging the resin. Continuously, the radiant rays are radiated by a radiant ray irradiating device 13 so as to cure the resin of the cavity 3. After the mold is opened in succession, it is released by an ejector pin 12. Thus, the warpage deformation is reduced, and the cavity 3 is made so thick that the occurrence of the bubbles is prevented, then high speed filling is accomplished.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thin base plate, a molded product (such as a Fresnel lens) using a radiation-cured resin, such as an ultraviolet-cured resin, and a method and apparatus for molding the same. In particular, when filling the resin, it can be filled at high speed without creating bubbles,
The present invention relates to a radiation-curable resin molded product, a molding method, and an apparatus that improve the transfer accuracy of the cavity surface to the molded product, reduce the amount of ultraviolet-curable resin used, and reduce warpage.

[Conventional technology]

Conventionally, the following three methods are known as methods for forming a Fresnel lens using this type of radiation-curable resin, such as an ultraviolet-curable resin.

Part 1. FIG. 11, which is described in Japanese Patent Application Laid-Open No. 177215/1982, is a schematic diagram showing a first example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

The cavity 37 is formed by an upper mold 35 equipped with a substrate 36 made of a transparent resin plate such as clear resin, and a lower mold 31 in which the cavity surface 32 is engraved in the opposite shape to the Fresnel lens surface.
form. Then, while the inside of the cavity 37 is evacuated from the exhaust port 34 with a vacuum pump, the cavity 37 is filled with ultraviolet curing resin through the injection port 33, and this resin is irradiated with ultraviolet rays from the ultraviolet curing device 38 and cured. The cured prism portion is polymerized and adhered to the substrate 36 to form a Fresnel lens.

Part 2. FIG. 12, which is described in Japanese Unexamined Patent Publication No. 61-248708, is a schematic diagram showing a second example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

This is done by creating a gap of several millimeters between the mold 39a (the upper surface of which is carved in the opposite shape to the Fresnel lens surface) inside the mold body 39 and the acrylic resin substrate 36. Set it in the mold body 39. and,
The valve 40 is opened and the gap is filled with ultraviolet curing resin. When the valve 40 is closed and the valve 41 is opened to suck the resin with the suction force of the vacuum pump 42, a part of it is discharged into the trap 43, and the substrate 36 is moved into the mold 39 by its elasticity.
Approach the Fresnel lens molding surface in a. In this state, the mold 39a is pushed up toward the cavity portion 44, the substrate 36 is returned to a flat surface, and the resin is irradiated with ultraviolet rays to be cured and bonded to the substrate 36 by polymerization.

If this molded product is released from the mold 39a, a desired Fresnel lens can be obtained.

Part 3. FIG. 13, which is described in Japanese Unexamined Patent Publication No. 61-248707, is a schematic view showing a third example of a conventional molding apparatus for molding a Fresnel lens using an ultraviolet curable resin.

This is done by providing a gap between the plastic substrate 36 and a mold 39A having a molding surface having a shape opposite to the Fresnel lens surface on one surface, supporting the back surface of the base Fj, 36 with a reinforcing plate 45, and filling the gap. into a vacuum state. When this vacuum pressure is lower than that of the vacuum tank 46, the ultraviolet curing resin 47 in the vacuum tank 46 is filled into the gap. In this state, if the resin is cured by irradiating ultraviolet rays from the ultraviolet irradiation device 38, a desired Fresnel lens is formed.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into consideration the warping deformation that is affected by the thickness of the radiation-cured resin layer of the molded product.

In addition, all of the above conventional technologies have a structure in which the cavity, which is the gap between the substrate and the mold, is evacuated and the resin is sucked as a measure to prevent air bubbles from entering when filling the resin.
This had the following problems.

(a) When the air bubbles contained in the resin are evacuated, their volume expands, and instead they remain as air bubbles.

(b) When the pressure is returned to normal, the volume of the bubbles in the vacuum shrinks, and the film pressure of the resin layer becomes uneven.

(c) When a vacuum is created inside the cavity, for example, if the surface is large, such as a Fresnel lens for a projection television receiver, a force of 5,000 kg or more will be applied to the substrate, causing the transparent reinforcing plate on the back to bend. Producing without
This is either difficult in practice or requires very large equipment even if it is possible.

(d) It is extremely difficult in practice to seal a large-area cavity as described above, and if air leaks from the gap between the mold and the substrate, bubbles will form.

(e) No consideration is given to the dimension in the thickness direction of the cavity during resin injection; if it is too thick, the cost will increase, and if it is too thin, the filling time and manufacturing time will increase.

(f) The thickness of the radiation-cured resin layer of the molded product is not considered, and if the ratio of the thickness of the radiation-cured resin layer increases, the molded product will warp due to the difference in thermal expansion coefficient with the thin base plate. Live.

In addition, the above-mentioned conventional technology did not take into consideration the fact that 1' sinkage occurs in the molded product due to curing shrinkage when the radiation-cured resin is cured, resulting in poor transfer accuracy of the cavity surface to the molded product. In optical components such as Fresnel lenses, this has caused deterioration in the optical performance of the optical components.

The present invention solves the problems of the prior art described above, has a simple structure, does not contain air bubbles, can be filled in a short time, and can obtain a molded product that uses a small amount of radiation-cured resin. The structure and molding method of a radiation-cured resin molded product that can prevent "sink marks" caused by curing shrinkage when cured, and have excellent transfer accuracy and less warping deformation, and this method The object is to provide a molding device that can be used directly.

[Means to solve the problem]

In order to solve the above object, the radiation-curable resin molding method according to the present invention has a structure including a thin base plate that transmits radiation;
By filling the cavity formed by the cavity surface of the mold with the cavity surface carved into a predetermined shape and the cavity surface formed by the mold, and curing the resin by irradiating the resin with radiation from the thin base plate side, In the method of molding a desired molded product, the thickness of the cavity during curing is made thinner than the thickness of the cavity during filling. Further, the thickness of the radiation-cured resin portion of the molded product is set to 1/3 or less of the thickness of the base thin plate portion.

Further, the configuration of the radiation-curable resin molding apparatus according to the present invention is shown below.

(1) A radiation-curing resin is filled into the cavity formed by a radiation-transmitting thin base plate and the cavity surface of a mold whose cavity surface is engraved into a predetermined shape through a gate provided in the mold. A molding device which molds a desired molded product by irradiating radiation from the thin substrate side to harden the resin, and releases the molded product by an ejector bin attached to the mold. A radiation-transmitting transparent plate is provided on the side opposite to the cavity of the base thin plate, and a molding auxiliary device capable of vacuum suction is installed to bring the transparent plate and the base thin plate into close contact. It has a holding member that faces the thin plate and holds the transparent plate, and an exhaust port that can perform vacuum suction to bring the base thin plate and the transparent plate into close contact, and has a predetermined shape. An elastic seal was attached around the entire circumference of the mold that was engraved.

(2) In the molding apparatus of (1), the mold engraved into a predetermined shape is moved in the thickness direction of the cavity by a plate member equipped with a drive unit and a pressure detection unit attached to the side opposite to the engraved surface.

(3) In the molding apparatus of (1), a plurality of discharge ports each equipped with an independently controllable valve for discharging excess resin were provided around the mold engraved into a predetermined shape.

[Effect]

Generally, it is known that molded products obtained by adhesive polymerization of two types of materials are warped due to differences in shrinkage rates and coefficients of thermal expansion. In the present invention, warping deformation is reduced by considering the ratio between the thickness of the radiation-cured resin layer and the thickness of the base thin plate.

The effects of each of means (1) to (3) mentioned in the previous section are as follows:
The corresponding items are as follows.

(1) A transparent plate material that transmits radiation is provided on the side opposite to the cavity of the thin base plate, and with this transparent plate material and the thin base plate in close contact, the elastic seal is compressed to eliminate unevenness in the thickness of the thin base plate. Taking this into account, the cavity size is filled to be thicker than the final product size. In general, if the cavity is filled with the same dimension as the uneven thickness of the board, if there is a thick part of the board, the cavity thickness in that part will be thinner, and the flow velocity in that part will be slower than in the normal part. This results in the formation of bubbles and increases the filling time. However, if you set the cavity thickness to be one liquid larger than the uneven board thickness,
The difference in flow velocity is reduced, and the bubbles can be filled at high speed without forming sea-island-like bubbles. However, increasing the cavity thickness increases the amount of resin used, leading to an increase in price.

Therefore, after filling, the elastic seal is further compressed to thin the cavity to the final product size, and the resin is discharged and hardened. The discharged resin can be used for filling again, so a product can be obtained without increasing manufacturing costs.

Of the final product dimensions, the thickness of the cured resin part can be made as thin as possible and a thick base plate can be used, but the thickness variation of the base plate (±0.1 mm) and the simplification of the discharge process, Damage during molding.

Considering the difference in thermal expansion coefficient between the radiation-cured resin layer after molding and the thin base plate, the thickness of the radiation-cured resin layer is set to 1/3 or less of the thickness of the thin base plate to reduce warpage of the molded product, Reduce the rise in manufacturing costs.

(2) In (1), with the elastic seal completely compressed, the cavity is filled to a size that is thicker than the final product size, taking into account the thickness unevenness of the base thin plate. Then (
Similar to 1), seabird-like bubbles are not generated. After filling, the mold engraved into a predetermined shape is moved in the thickness direction of the cavity by a plate member equipped with a drive source attached to the side opposite to the engraved surface, the cavity is thinned to the final product size, and the resin is discharged. and harden. Then, as in (1), the manufacturing cost does not increase.

Furthermore, when the mold is moved in the thickness direction of the cavity and positive force (pressure greater than atmospheric pressure) is applied to reduce the cavity space, the pressure of the filled resin increases.

If radiation such as ultraviolet rays is irradiated in this state, the resin will shrink toward the center of the cavity in the radial direction. Therefore, it is possible to eliminate "one stick" of the resin to the unevenness of the cavity surface due to curing shrinkage toward the center in the radial direction, and the molded product (especially in the case of a Fresnel lens) can be easily released from the mold. There will be no transfer defects or "sink marks" on the cavity surface to the molded product.

(3) A plate member equipped with a drive source equipped with a pressure detection section is used when applying positive force (pressure greater than atmospheric pressure) to move the mold in the cavity thickness direction and reduce the cavity space. The pressure in the cavity space due to resin contraction can be detected and optimal pressure control can be performed, without causing transfer defects or "sink marks" to the molded product.

(4) Multiple outlets for discharging excess resin are provided around the mold engraved into a predetermined shape, so that the cavity can be thinned to the final product size and the resin can be discharged uniformly and at high speed. I can do it.

A plurality of surplus resin discharge ports, each equipped with a valve that can be independently controlled, opens the valve of the discharge port only in the final filling section when filling the resin, eliminating errors in the cavity and preventing air bubbles from entering. By closing the valve at the discharge port, resin is not discharged during filling and can be injected at high speed.

〔Example〕

The present invention will be explained below with reference to an example in which a Fresnel lens used as a screen for a rear projection television is molded.

FIG. 1 is a structural diagram of a Fresnel lens molded product using the radiation-curable resin of the present invention, and FIGS. 2 and 3 show the molding apparatus used to carry out the method of molding the radiation-curable resin of the present invention. A sectional view showing an example, FIG. 4, is a top view of the outlet in FIGS. 2 and 3, and a sectional view of the outlet provided with an independent on-off valve.

First, an outline of this molding apparatus will be explained using FIGS. 2 and 4.

This molding device has a thin base plate that transmits ultraviolet rays and a cavity surface 1a having a predetermined shape (opposite shape to the Fresnel lens surface).
The cavity surface 1a of the Fresnel mold insert piece 1 engraved in
formed by. A resin filling port 14 provided in the lower mold 8 into which the Fresnel mold inserting piece 1 is attached is inserted into the cavity 3.
Then, an ultraviolet curable resin or resin is filled from the gate 9 through the valve 30, and the resin is cured by irradiating ultraviolet rays from the base thin plate side, so that the cured prism portion and the base thin plate are integrally polymerized. A desired molded product is formed by bonding, and this molded product is released from the mold by an ejector pin 12 attached to the lower mold 8 to obtain a Fresnel lens. A transparent plate material 4 that transmits radiation is provided on the cavity side, and an upper mold 7 related to this molding auxiliary device that can perform vacuum suction to bring the transparent plate material 4 (details will be described later) into close contact with the base thin plate is attached. Reference numeral 7 denotes the transparent plate material, a holding member 7a that holds the transparent plate material 4, and the vacuum suction exhaust port 5.
Furthermore, this exhaust port also serves as an air supply port through which air can be sent to release the vacuum state. The molding piece 1 is assembled to a plate member 21 that is assembled on the side opposite to the engraving surface. A plurality of resin discharge ports 15 are provided around the front end mold via valves 10 in the middle, and an elastic seal 6 is attached to the outside thereof over the entire circumference.

This will be explained in detail below.

In the lower mold 8, a Fresnel mold insert piece 1 formed with a shape opposite to the Fresnel lens surface of a predetermined shape is attached to a vacuum exhaust port 1 for mold adsorption.
It is vacuum-adsorbed by vacuum suction from 1. Lower mold 8
is provided with a resin injection port 14 for injecting an ultraviolet curable resin, and communicates from the gate 9 to the cavity 3 via a valve 10 in the middle.

The transparent plate material 4 is attached to the upper mold 7, and this transparent plate material is made of glass (quartz, blue plate glass, or acrylic resin plate) that transmits ultraviolet rays. Further, above the transparent plate material 4 of the upper mold 7, an ultraviolet irradiation device 1 is provided.
3 is attached to the drive device 51 so that the entire area of the cavity 3 can be irradiated.

Further, as shown in FIG. 4, this molding device is held horizontally by a press device 25.

By using the molding apparatus configured as described above, the present invention
A first example of a method for molding a radiation-cured resin will be described.

6 to 10 are for explaining an embodiment of the molding method using the second molding apparatus, FIG. 6 is a cross-sectional view showing the state during curing, and FIG. 7 is a cross-sectional view.

Figure 8 is a characteristic diagram showing the relationship between cavity thickness and filling time, Figure 8 is a characteristic diagram showing the relationship between cavity thickness during curing, adhesion failure during mold release, and resin ejection time, and Figure 9 is a characteristic diagram showing the relationship between molded product warpage. FIG. 10 is a schematic diagram showing a Fresnel lens which is a molded product. In each episode, the same numbers as in FIG. 1 indicate the same parts.

This molding device is held by a press device 25 as shown in FIG.

By evacuation from the exhaust port 5 using a vacuum pump (not shown) in advance, the base thin plate 2 is brought into close contact with the transparent plate material 4 and filled with resin. The cavity thickness was determined from FIG. 7 to be 0.5 mm in order to shorten the filling time. (However, the characteristics of this cavity thickness vary depending on the viscosity of the resin, etc.) Of the valves 10 of the resin discharge port 15, 10a and 10
Only ports b and 10c are opened, and resin is filled from the valve 30 of the resin injection port 14. After filling the entire cavity, the valve 30 of the resin injection port 14 is closed. After that, resin discharge port 1
After the valve 10 of No. 5 is opened, the upper mold 7 is tightened while compressing the elastic seal 6. As a result, a portion of the resin is discharged, but this discharged resin can be reused. As shown in Fig. 8, the resin thickness after discharge is determined from the curve deformation characteristics diagram of the molded product. Experiments have shown that warpage occurs due to the difference in shrinkage and thermal expansion coefficients of the resin and the resin cannot be used as a product.

Therefore, in the Fresnel lens 59 shown in FIG.
The following shall apply. After the resin discharge is completed, all valves 10 of the resin discharge port 15 are closed. The ultraviolet rays are irradiated by the ultraviolet irradiation device 13 to harden the resin in the cavity 3.

After opening the mold, the molded product is released by the ejector pin 12.

The Fresnel lens 27 formed in this way and having unnecessary parts cut off around it is shown in detail in FIG.
) is a plan view, (b) is a side view], size is approximately 670 m
It has a size of 880 mm x 880 mm and a thickness of about 3 mIn, and is made by integrally polymerizing and bonding the thin base plate 2 and the prism part 18 (details will be described later). Surface 1 of the prism portion 18
7 has a prism with a height h of about 0, 2 ram at the outer periphery and 0 mm at the center, and a prism with a pitch of about 0, l n+l] l
The prism angle is approximately 60° at the outer periphery and Oo at the center.

According to the embodiment described above, there are the following effects.

■The thickness of the ultraviolet curable resin layer of the molded product is 1/3 that of the thin base plate.
By doing the following, warpage and deformation can be reduced.

(2) Since the cavity thickness is set to be sufficiently larger than the thickness unevenness of the thin base plate 2, the difference in flow velocity is reduced, and the cavity can be filled at high speed without forming seabird-like bubbles.

■After filling, the elastic seal 6 is further compressed, the cavity is thinned to the final product size, the resin is discharged and hardened, and the discharged resin is used again for filling, reducing the actual amount used in manufacturing. Products can be obtained without increasing costs.

(◇Since a plurality of discharge ports 15 for discharging surplus resin are provided, when the cavity is thinned to the final product size and the resin is discharged, the resin can be discharged uniformly and at high speed.

(2) The plurality of surplus resin discharge ports 15 are each equipped with a valve 1o that can be independently controlled, so that air can be removed from the cavity, preventing air bubbles from being mixed in, and resin can be injected at high speed without being discharged during filling.

Next, an outline of the second molding apparatus will be explained using FIGS. 3 to 6.

FIG. 4 is a sectional view showing the state at the time of filling.

FIG. 6 is a sectional view showing the state at the time of curing.

In the second molding device, a mold inserting piece 1 engraved into a predetermined shape placed on a lower mold is moved in the thickness direction of the cavity by a plate member 21 of a genuine drive source attached to the side opposite to the engraved surface. be. Also.

One member 21 of the above-mentioned moving part equipment was equipped with a pressure detection part 24. The other parts are the same as the first molding apparatus.

Next, a second embodiment of the method for molding a radiation-cured resin according to the present invention will be described with reference to FIG. 1o.

FIG. 10 is a schematic diagram showing the resin flow within the cavity for explaining a second embodiment of the molding method using the molding apparatus according to FIG. 3. FIG.

In the first embodiment, the cavity thickness at the time of filling and the cavity thickness at the time of curing were varied by the amount of clamping of the upper mold. The placed mold insert piece 1 engraved into a predetermined shape is moved in the thickness direction of the cavity by a plate member 21 equipped with a drive source 50, which is attached to the side opposite to the engraved surface. The thickness of the cavity during curing is changed. Furthermore, in this embodiment, when the cavity thickness becomes thicker than the desired resin layer thickness by the amount of shrinkage during resin curing, the valve 1 of the resin discharge port 15 is opened.
All 0's are closed.

During curing, the mold inserting piece 1 is pressed in the direction of the cavity 3, and this is maintained until the resin is completely cured. Further, a pressure checking section 24 is provided to detect the pressure during curing.

The system detects the pressure fluctuations that occur when the product is stored, so that a constant positive pressure can be applied at all times.

This will be explained using FIG. 10. FIG. 10 shows that, as in the first embodiment, after filling, the elastic seal is further compressed to thin the cavity to the final product size and the resin is removed. In this case, no pressure is applied to the inside of the cavity 3. In contrast, the same figure (b).

The figure (c) shows the case of this embodiment in which the mold inserting piece 1 is pressed in the direction of the cavity 3 to create a positive pressure inside the cavity, and in both cases the molten resin 23 inside the cavity 3 is pressed.

Looking at this in detail, in the case shown in Fig. (a), when the molten resin 23 hardens, it contracts toward the radial center of the cavity. The shape of the minute irregularities on the cavity surface 1a is
Since the resin is inclined toward the outer periphery at the rising portion, the resin moving toward the center in the radial direction increases the mold release force required to release the molded product excessively toward the rising portion. . On the other hand, in the case of figures (b) and (C), the positive pressure inside the cavity 3 causes the molten resin 23 to move toward the outer periphery in the radial direction of the cavity and in the thickness direction, and toward the cavity surface. It is possible to prevent "sticking" of the mold and, as a result, to reduce the mold release force.

According to the second embodiment described above, in addition to the curing of the first embodiment described above, positive pressure is applied to the inside of the cavity 3 (
(or adjust its size), the direction in which the resin hardens and shrinks is in the thickness direction and outer circumferential direction of the Fresnel lens, reducing mold release force and further improving transferability. This has the advantage that deformation of the shape of minute irregularities in the mold can be prevented.

In addition, although each of the above-mentioned embodiments has been described with respect to molding a Fresnel lens, the present invention is also applicable to a lenticular lens,
It can be applied to the molding of optical discs, gratings, and other molded products made by integrally polymerizing and bonding a radiation-curable resin onto a thin base plate.

Furthermore, in each of the above Examples, a transparent acrylic plate was used as the thin base plate, but styrene, acrylic styrene polymer,
Any material may be used as long as it is made of transparent and elastic plastic, such as polycarbonate and polymethylbenzene.

Furthermore, in each of the above embodiments, molding is performed using acrylic resin, but not only ultraviolet curable resin such as acrylic resin, but also radiation curable resin such as γ-ray curable resin and X-ray curable resin may be used. Needless to say, it can also be applied to molding.

〔Effect of the invention〕

As explained in detail above, according to the present invention, it is possible to obtain a molded product that has a simple structure, can be filled in a short time without the inclusion of air bubbles, has little warping deformation, uses a small amount of radiation-cured resin, and A method for molding radiation-cured resin, which prevents "whiskers" caused by curing shrinkage when the cured resin is cured, and can mold molded products with excellent transfer accuracy and less warping deformation, and this method. A molding device that can be used directly can be provided.

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of a Fresnel lens molded product according to the present invention, and FIGS. 2 and 3 are cross-sectional views showing an example of a molding apparatus used for carrying out the method for molding a radiation-cured resin according to the present invention. , FIG. 4 is a top view of the discharge port in FIGS. 2 and 3, and a sectional view of the discharge port equipped with an independent Kansai valve. FIG. 5 is a top view of the discharge port in FIGS. 2 and 3, and FIG. A schematic diagram showing the installed state; FIG. 6 is a sectional view showing the state when hardened;
Fig. 7 is a characteristic diagram showing the relationship between cavity thickness and filling time, Fig. 8 is a characteristic diagram of warping deformation of a molded product, Fig. 9 is a schematic diagram showing a Fresnel lens as a molded product, and Fig. 10. teeth,
FIG. 3 is a schematic diagram showing the flow of resin in the cavity for explaining the second embodiment of the molding method using the molding apparatus, and FIGS. The first molding device for molding a Fresnel lens using
It is a schematic diagram showing a third example. 1... Fresnel mold insert piece, 1 a-cavity surface, 2... thin base plate, 3...
Cavity, 4.Transparent plate material 5.Exhaust port
6. Elastic seal, 7. Upper mold,
8...Lower mold, 9...Gate, 10...
・Valve, 12... Release pin, 13... Ultraviolet irradiation device, 14... Resin filling port, 15...
Resin discharge port 24...pressure detection unit, 25...press device, 30...valve, 50...drive source,
59...Fresnel lens, 60...Radiation curing resin layer, 61...Substrate thin plate layer. Trap 1 η I ~ (3h'IN 4th field 5 To 1 N 2 theory interpretation E kE K E Trigger 9 Z /σ (Re Cb) East II Close / 21D Trigger / 3 (fJ tU Coni 67

Claims (1)

[Claims] 1. In a transmission type screen in which a Fresnel lens or lenticular lens made of a radiation-cured resin layer is laminated on one side of a thin base plate, the thickness of the radiation-cured resin layer is set to 1/th of the thickness of the thin base plate. A transparent screen characterized by having a light intensity of 3 or less. 2. A radiation-cured resin is filled into the cavity formed by a thin base plate that transmits radiation and the cavity surface of a mold whose cavity surface is engraved into a predetermined shape, and this resin is irradiated with radiation from the thin base plate side. A method of molding a radiation-cured resin to form a desired molded article by curing the resin, the method comprising: making the thickness of the cavity at the time of curing thinner than the thickness of the cavity at the time of filling. 3. Fill the cavity formed by the radiation-transmitting thin base plate and the cavity surface of the mold with the cavity surface engraved into a predetermined shape with radiation-curable resin through the gate provided in the mold, and fill this resin with radiation-curable resin. A molding apparatus in which a desired molded product is molded by curing the resin by irradiating radiation from the thin base plate side, and the molded product is released from the mold by an ejector pin attached to the mold, A transparent plate material that transmits radiation is provided on the side opposite to the cavity of the thin base plate, and a molding auxiliary device capable of vacuum suction is installed to bring the transparent plate material into close contact with the thin base plate. facing the transparent plate material, a holding member for holding the transparent plate material, and an exhaust port capable of vacuum suction for bringing the base thin plate and the transparent plate material into close contact; A radiation-curing resin molding device characterized by having an elastic seal attached to the entire circumference of the engraved mold. 4. The radiation curing method according to claim 3, wherein the mold engraved into a predetermined shape is movable in the thickness direction of the cavity by a plate member equipped with a pressure detection section and a drive source attached to the side opposite to the engraved surface. Resin molding equipment. 5. The radiation-cured resin molding apparatus according to claim 3, wherein a plurality of discharge ports for discharging surplus resin, each having an independent valve, are provided around the mold engraved in a predetermined shape. 6. A rear projection television and an overhead projector using the transmission screen according to claim 1.