JP2004191429A - Transmission screen, its manufacturing method, and back projection type projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission screen with which display can be performed sharply with high high contrast even in the case of a high definition picture, and a method of manufacturing the screen in a comparatively simple process, and a back projection type projector on which the screen is mounted. <P>SOLUTION: The manufacturing method of the transmission screen which comprises a lens sheet 1 on whose one surface a plurality of lenses 2 are arranged and a light shielding layer 3 which is formed on another surface 1a of the lens sheet, on which lenses are not formed and in which non-light shielding areas 3a each of which is formed centering the optical axis of each lens in the light shielding layer, has at least of a process of forming the light shielding layer on the another surface of the lens sheet and a process of forming the non-light shielding areas at parts of the light shielding layer corresponding to optical axes of respective lenses by irradiating the lens sheet on which the light shielding layer is formed with pulsed laser light from the side of the lens formation surface. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a transmission screen used for a rear projection type projection apparatus and a method of manufacturing the same.
[0002]
[Prior art]
The rear projection type projection apparatus is configured so that an observer can observe an image on a screen by emitting light emitted from a light source disposed on a rear side of a transmission screen from an observation side surface on a front side.
The rear projection type projection device is often used in a bright environment such as outdoors or under indoor lighting. In order to enable use in such a bright environment, the screen has a structure that suppresses the reflection of illumination light from the front observer side and the wraparound of light, and efficiently transmits image light from the back. There is a need to. In addition, a region on the screen surface that is not involved in transmission of image light from the back surface needs to have a black light shielding structure to prevent a decrease in contrast.
From such a situation, it is necessary to arrange a plurality of lenses such as lenticular lenses on the side of the light source to converge and diverge the light from the light source, and to form a light-shielding portion such as a light absorbing film in a light invalid portion between the lenses on the emission side. Has proposed a transmission screen having improved contrast of an image observed by an observer.
In order to realize such a light-shielding structure, a method of forming a light-shielding portion by a method such as screen printing or gravure printing has been practically used. However, in recent years, an image has been formed due to a demand for high-definition image display. The density of scanning lines and pixels has been increasing, and in order to cope with such a high density, it is necessary to further miniaturize the size and pitch of lenses constituting a screen. With such miniaturization, a high level of alignment accuracy is required between the printing plate and the screen during printing, and the opening size formed in the printing plate is also reduced, making it very difficult to manufacture the printing plate. It has become to.
As a conventional example for addressing such a problem, for example, Japanese Patent Laid-Open No. 05-034829 discloses that the shape of a region of a screen surface not involved in image light transmission is formed in a convex shape with respect to an image light transmitting region. There is disclosed a screen forming technique in which a light-shielding structure is formed by transferring a black light-shielding member to an end face of the convex portion by heating and pressing. However, even in this method, when the lens pitch is further refined, the unevenness of the screen surface becomes finer with the pitch height, so that the miniaturization of the light shielding structure is limited, and such a screen is formed. It is difficult to do.
[0003]
Japanese Patent Application Laid-Open No. Sho 59-121033 discloses that a positive photosensitive adhesive layer 101 is provided on the observation surface side of a lens sheet 100 as shown in FIGS. As shown in (d), the photosensitive pressure-sensitive adhesive layer 101 is exposed by irradiating ultraviolet rays from the side opposite to the observation surface to lose the tackiness of the exposed portion, and then, as shown in (e), the surface of the pressure-sensitive adhesive layer The toner 102 is sprayed to adhere to a portion where the tackiness is not lost (unexposed portion), and the toner in the portion where the tackiness is lost by the exposure as shown in FIG. A method for manufacturing a screen having a light-shielding layer 101 in which only an opening 101a is formed is disclosed.
However, the production method described in the publication requires a pressure-sensitive adhesive layer forming step, an exposure step, a light-blocking agent spraying step, and a surplus light-blocking agent removing step, which complicates the steps. Further, it is difficult to make the dispersed toner cover the adhesive portion without any gap. In addition, as shown in FIG. P2, when the lens is miniaturized, the toner located at the boundary between the light-shielding portion 101 and the opening 101a enters the opening and changes the opening shape. This change in the opening shape can be ignored. Gone.
[Patent Document 1] Japanese Patent Application Laid-Open No. H05-034829 [Patent Document 2] Japanese Patent Application Laid-Open No. 59-121033
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems of the related art, and a transmissive screen capable of displaying a clear image with high contrast even for a high-definition image, and using a relatively simple process. It is an object of the invention to provide a manufacturing method and a rear projection type projection apparatus equipped with the screen.
[0005]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 includes a lens sheet in which a plurality of lenses are arranged on one surface, and a light shielding layer provided on the other surface of the lens sheet where the lenses are not formed, In the method of manufacturing a transmissive screen in which a non-light-shielding region centered on the optical axis of each lens is formed in the light-shielding layer, at least a step of forming a light-shielding layer on the other surface of the lens sheet; Irradiating the formed lens sheet with a pulsed laser beam from the lens forming surface side to form a non-light-shielded region in a local portion of the light-shielding layer corresponding to the optical axis of each lens. .
According to the present invention, since the opening as the non-light-shielding region provided in the light-shielding layer is formed by condensing the corresponding lens itself, the center of the optical axis of the lens and the center of the opening regardless of the size, pitch, and arrangement of the lens. Are accurately matched, and a transmission screen having an opening of a minimum required size can be manufactured.
According to a second aspect of the present invention, in the first aspect, the wavelength of the pulsed laser light is a wavelength having a transmitting property to the lens sheet material and an absorbing property to the light shielding layer material. It is characterized.
According to the present invention, while the laser light used for processing is transmitted through the transparent lens sheet and is absorbed by the light shielding layer material, the lens sheet is not affected and only the light shielding layer can be removed by heating. .
According to a third aspect of the present invention, in the first or second aspect, the lens sheet material is made of a single material such that the thermal conductivity of the lens sheet material is smaller than the thermal conductivity of the light shielding layer material. Or a combination of a plurality of materials.
According to the present invention, since the thermal conductivity of the lens sheet material is smaller than the thermal conductivity of the light shielding layer material, the energy of the laser beam absorbed by the light shielding layer material is prevented from diffusing from near the interface with the lens sheet. Therefore, the light-shielding layer material can be efficiently heated, and the opening can be formed with a small input energy.
[0006]
According to a fourth aspect of the present invention, in the first, second or third aspect, a laser beam having a pulse width of 100 μs or less is used as the pulsed laser beam.
According to the present invention, since the pulse width of the laser beam used for processing is short, only a very close area of the region irradiated with the laser beam is heated, and a minute opening can be formed.
According to a fifth aspect of the present invention, in any one of the first to third aspects, the thickness of the light shielding layer is 1 μm or less.
According to the present invention, since the thickness of the light shielding layer is as thin as 1 μm or less, processing with one pulse is possible, and damage to the lens sheet material can be suppressed.
According to a sixth aspect of the present invention, in any one of the first, second, third, fourth, and fifth aspects, the output of the pulsed laser beam is equal to or less than a processing threshold value for the light shielding layer material.
According to the present invention, since the output of the laser beam used for processing is equal to or less than the processing threshold value of the material of the light shielding layer, the light shielding layer is damaged by light transmitted without being collected by the lens portion of the lens array sheet. There is no.
A transmission screen according to a seventh aspect of the present invention is manufactured by the manufacturing method according to any one of the first to sixth aspects.
According to this invention, the center of the optical axis of each lens element on the lens array sheet constituting the screen coincides with the center of the opening provided in the light shielding layer, and the diameter of the opening is equal to the light incident on the lens. Is almost equal to the size of the light that is condensed and emitted, so that the image light incident on the screen can be emitted toward the observer without being attenuated. Further, since the size of the opening formed in the light-shielding layer is the minimum required, an image with high contrast can be displayed.
[0007]
The invention of claim 8 is characterized in that a member having a light diffusion effect is provided on the light-shielding layer forming surface side of the transmission screen according to claim 7.
According to the present invention, since the member having the light diffusion effect is provided on the screen surface, the light emitted from the screen can be spread over a wide range and can be displayed with a wide viewing angle.
According to a ninth aspect of the present invention, an anti-reflection layer is formed on the outermost surface on the other side of the transmission screen according to the seventh or eighth aspect.
According to the present invention, since the antireflection layer is provided on the outermost surface of the screen, it is possible to reliably prevent a decrease in contrast due to reflection or reflection of illumination light.
A tenth aspect of the present invention is characterized in that, in the seventh, eighth or ninth aspect, the pitch of the lens is set to 150 μm or less.
According to the present invention, since the lens pitch constituting the screen is 150 μm or less, which is sufficiently small with respect to the pixel size of the image projected on the screen, a high-definition image can be displayed.
An eleventh aspect of the present invention is characterized in that, in the tenth aspect, the pitch of the lens is irregular and not constant.
According to the present invention, since the pitch of the lenses constituting the screen is not irregularly constant, a high-quality image free from moire can be formed.
According to a twelfth aspect of the present invention, there is provided a rear projection type projection apparatus including the transmission screen according to any one of the seventh to eleventh aspects.
According to the present invention, the light of the light source can be used for image display without being attenuated, so that a clear image can be displayed even in a bright environment.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 is an explanatory diagram of a method of manufacturing a transmission screen according to one embodiment of the present invention.
First, as shown in FIG. 1A, a lens sheet 1 in which a plurality of lenses 2 are formed close to each other on a front surface (observation surface) side is prepared. This lens sheet 1 was prepared by preparing a mold having an inverted shape of the lens shape to be formed, applying and filling an ultraviolet curing resin on the mold, and placing a light-transmitting flat plate on the ultraviolet curing resin layer. After the resin on the mold was cured by irradiating ultraviolet light from the translucent flat plate side in this state, the resin was peeled off from the mold, which was a so-called 2P method. As a manufacturing method of the lens sheet 1, besides the 2P method, a known duplication technique such as a hot press method or a casting method using a mold having the above-described inverted concavo-convex shape can be used. The above-described 2P method is suitable as a molding method for obtaining high transferability when the pitch becomes fine, and the material is also suitable for applying this method because of its excellent light transmission.
Next, a light-shielding layer (light-shielding material layer) 3 is formed on the flat surface 1a of the lens sheet 1 on which the lenses 2 are not formed (FIG. 1B). As the light shielding material, a chromium oxide layer made of a single material is used, or a plurality of materials, for example, chromium, chromium oxide or chromium oxide, chromium, and chromium oxide are sequentially laminated from the flat surface 1a side of the lens sheet. The structure is formed as a film so as to have a total thickness of 1 μm or less. These light-shielding materials are also used as light-shielding portions of an exposure mask for photolithography, and have a sufficient light-shielding function at a thickness of about 1 μm, and have a black appearance.
As described above, since the thickness of the light-shielding layer 3 is reduced to 1 μm or less, processing with one pulse is possible, and damage to the lens sheet material can be suppressed.
[0009]
Next, pulse laser light is irradiated from the lens forming surface side of the lens sheet 1 so as to be parallel to each lens optical axis (FIG. 1C). The laser light is condensed by each lens 2 and condensed around the optical axis of the lens, and irradiates the light shielding layer 3. The laser beam is absorbed by the light-shielding layer 3 and heated, so that the light-shielding layer portion corresponding to the irradiated portion is locally removed, and an opening 3a as a non-light-shielding region is formed there. Through the above steps, the screen 10 is manufactured.
Examples of the shape of the lens sheet 1 (screen 10) in which the openings (non-light-shielding regions) 3a are formed in the light-shielding layer 3 by the processing method as described above include a lenticular lens array as shown in FIG. 2 and FIGS. There is a two-dimensional lens array shown. With this processing method, an opening 3a having a pitch of 50 μm and a diameter of 15 μm could be formed.
As described above, in the method for manufacturing a transmission screen according to the present invention, since the openings 3a provided in the light shielding layer 3 are formed by condensing the corresponding lenses 2 themselves, regardless of the size, pitch, and arrangement of the lenses 2. The center position between the lens 2 and the opening 3a always coincides with high accuracy, and the transmission screen 10 having the minimum required size of the opening 3a can be manufactured.
In addition, the laser beam used for processing passes through the transparent lens sheet 1 and is absorbed by the light shielding layer material 3, so that the laser light has no effect on the lens sheet 1 and only the light shielding layer 3 is locally heated and removed. can do.
The lens sheet 1 of the screen 10 shown in FIG. 1 has lenses that are continuously adjacent to each other, but FIG. 5 includes a flat portion 4 that is not in contact with another lens 2 in at least a part of the lens 2. 3 shows a lens sheet structure. In the light shielding layer 3 formed on the flat surface 1a (back surface), an opening 3a centering on the optical axis of each lens 2 is formed.
[0010]
FIG. 6 shows an example of a method of manufacturing the screen of FIG. The manufacturing process is exactly the same as in FIG. That is, after the light shielding layer 3 is formed on the flat surface 1a of the lens sheet 1 ((a) and (b)), when the lens forming surface side of the lens sheet 1 is irradiated with pulsed laser light ((c)), The light applied to the portion having the lens shape is condensed similarly to the case of FIG. 1, and contributes to the partial removal processing of the light shielding layer 3 ((d)).
On the other hand, the light applied to the flat portion 4 located between the lenses 2 travels straight through the lens sheet in the thickness direction without being collected, and irradiates the light shielding layer 3. The straight light entering from the flat portion 4 has a smaller energy density than the light collected by the lens 2. Therefore, there is a difference in the degree of heating when the light is irradiated to the light shielding layer. In order for the light-shielding layer corresponding to the light-collecting portion to be removed by heating, a laser energy density higher than a certain threshold value is required. Accordingly, the energy density of the light (not condensed) incident from the flat portion 4 on the light-shielding layer 3 is lower than the threshold, and only the energy density of the light condensed by the lens 2 on the light-shielding layer 3 is higher than the threshold. By setting the output of the laser light so as to satisfy the condition, the light-shielding layer region irradiated with the unfocused laser light is not processed, and only the light-shielding layer in the region focused by the lens 2 is removed. It is also possible to form a local opening 3a only in the target portion of the light shielding layer 3 in the lens sheet 1 as shown in FIG.
In each of the manufacturing steps shown in FIGS. 1 and 6, the third harmonic of a YAG laser having a wavelength of 355 nm was used as the laser light, but the laser light only needs to be transmitted through the lens material and absorbed by the light shielding layer material 3. Therefore, a wavelength other than the above, for example, a second harmonic having a wavelength of 532 nm or a fundamental wave having a wavelength of 1064 nm may be used.
Further, by setting the thermal conductivity of the constituent material of the lens sheet 1 to be smaller than the thermal conductivity of the constituent material of the light shielding layer 3, the transfer of heat from the light shielding layer 3 to the lens sheet side can be suppressed. When forming the opening 3a as a non-light-shielding region, thermal damage to the lens sheet can be suppressed.
That is, since the thermal conductivity of the material of the lens sheet 1 is smaller than the thermal conductivity of the material of the light shielding layer 3, the energy of the laser beam absorbed by the material of the light shielding layer can be prevented from diffusing from the vicinity of the interface with the lens sheet. Since the light-shielding layer material can be efficiently heated, the opening 3a can be formed with a small input energy.
In addition, when the pulse width of the laser light is long, the time required for heat to move from the light shielding layer 3 to the lens sheet 1 becomes long. Therefore, thermal damage to the lens sheet occurs. This effect can be suppressed by shortening the pulse width of the laser light. As described above, according to the present invention, since the pulse width of the laser light used for processing is short, only the vicinity of the region irradiated with the laser light is heated, and a minute opening is formed in the light shielding layer 3. Will be possible.
[0011]
Next, an embodiment of the operation of the transmission screen manufactured as described above will be described. On the front side of the screen 10 according to the embodiment shown in FIG. 7, a Fresnel lens 20 is arranged at a predetermined distance. On the front side of the Fresnel lens 20, an image forming unit including a light source, a liquid crystal, a driving unit, and the like, not shown, and an optical system for enlarging and projecting an image formed in the image forming unit are arranged. The light is incident on the Fresnel lens 20 and becomes substantially parallel light, and is incident on the screen 10. Since the screen 10 has the surface on which the lens 2 of the lens sheet 1 is formed as an incident surface, incident light is condensed by each lens 2 and the condensed light reaches the light shielding layer 3. . Since the aperture 3a is formed at the position on the light-shielding layer 3 where the condensed image light reaches, the laser light passes through the opening 3a as it is, becomes divergent light after the focal point, and reaches the divergent light. The range is recognized as an image by the observer.
[0012]
Further, as shown in FIGS. 8A and 8B, by providing a member having a light diffusion effect such as a so-called diffusion plate 15 behind the light shielding layer 3, light can reach a wider area. And enables observation from a wider range.
At this time, since the opening 3a is processed by laser light having the same optical path as the image light at the time of its formation, the centers of the respective lenses 2 and the opening 3a coincide with each other, and the image light surely reaches the observer side. Is emitted. The opening 3a formed in the light-shielding layer 3 has a very small opening diameter of about several tens to 200 μm, and cannot be recognized by an observer at a distance from the screen 10, so that a screen on which no image is formed is formed. As a whole, one surface is recognized as substantially black, so that a high-contrast image can be displayed during image formation.
Further, as shown in FIGS. 8B and 9, by performing an antireflection treatment on the outermost surface of the screen 10 to form an antireflection layer 16, light from the observer side is reflected on the screen 10. Thus, a decrease in contrast due to returning to the observer side can be reduced, and the contrast can be further improved.
In the screen according to each of the above embodiments, by setting the pitch of the lens 2 to 150 μm or less, the lens pitch can be sufficiently reduced with respect to the pixel size of an image projected on the screen, and high definition Images can be displayed.
In addition, by forming the lens pitch irregularly and non-constantly, a high-quality image free from moire can be formed.
Further, by constructing the rear projection type projection device using the transmission screen according to each of the above embodiments, it is possible to use the image display without attenuating the light of the light source, and it is possible to sharpen even in a bright environment. Images can be displayed.
[0013]
【The invention's effect】
As described above, according to the present invention, a transmissive screen capable of displaying a clear image with high contrast even for a high-definition image, a method of manufacturing the same in a relatively simple process, and the screen A mounted rear projection type projection device can be provided.
That is, according to the first aspect of the present invention, since the opening as the non-light-shielding region provided in the light-shielding layer is formed by condensing the corresponding lens itself, the center of the optical axis of the lens regardless of the size, pitch, and arrangement of the lens. And the center of the opening accurately match, and a transmission screen having an opening of a minimum required size can be manufactured.
According to the second aspect of the present invention, the laser light used for processing is transmitted through the transparent lens sheet and is absorbed by the light-shielding layer material, so that there is no influence on the lens sheet and only the light-shielding layer is removed by heating. be able to.
According to the third aspect of the present invention, since the thermal conductivity of the lens sheet material is smaller than the thermal conductivity of the light shielding layer material, the energy of the laser beam absorbed by the light shielding layer material is diffused from near the interface with the lens sheet. In order to prevent this, the material of the light shielding layer can be efficiently heated, and the opening can be formed with a small input energy.
According to the fourth aspect of the present invention, since the pulse width of the laser beam used for processing is short, only a very close area of the region irradiated with the laser beam is heated, and a minute opening can be formed.
According to the invention of claim 5, since the thickness of the light shielding layer is as thin as 1 μm or less, processing with one pulse is possible, and damage to the lens sheet material can be suppressed.
According to the invention of claim 6, since the output of the laser beam used for processing is equal to or less than the processing threshold value of the material of the light shielding layer, the light shielding layer is damaged by light transmitted without being condensed by the lens portion of the lens array sheet. I do not receive.
[0014]
According to the seventh aspect of the present invention, the center of the optical axis of each lens element on the lens array sheet constituting the screen coincides with the center of the opening provided in the light shielding layer, and the diameter of the opening corresponds to the lens. Since the size of the incident light is approximately equal to the size of the collected light, the image light incident on the screen can be emitted toward the observer without being attenuated. Further, since the size of the opening formed in the light-shielding layer is the minimum required, an image with high contrast can be displayed.
According to the eighth aspect of the present invention, since the member having the light diffusion effect is provided on the screen surface, the light emitted from the screen can be spread over a wide range and can be displayed with a wide viewing angle.
According to the ninth aspect of the present invention, since the antireflection layer is provided on the outermost surface of the screen, it is possible to reliably prevent a decrease in contrast due to reflection or reflection of illumination light.
According to the tenth aspect of the present invention, since the lens pitch constituting the screen is 150 μm or less, which is sufficiently smaller than the pixel size of the image projected on the screen, a high-definition image can be displayed.
According to the eleventh aspect, since the pitch of the lenses constituting the screen is not irregularly constant, a high-quality image free from moiré can be formed.
According to the twelfth aspect of the present invention, since the light of the light source can be used for image display without being attenuated, a clear image can be displayed even in a bright environment.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a method for manufacturing a transmission screen according to an embodiment of the present invention.
FIG. 2 is a view showing an example of the shape of a lens sheet (screen).
FIG. 3 is a diagram showing a shape example of a lens sheet (screen).
FIG. 4 is a diagram showing a shape example of a lens sheet (screen).
FIG. 5 is a diagram showing a configuration example of a transmission screen.
FIG. 6 is a diagram showing an example of a method of manufacturing the screen of FIG.
FIG. 7 is a view for explaining the operation of the transmission screen according to the present invention.
FIG. 8 is a diagram illustrating a modification of the transmission screen of the present invention.
FIG. 9 is a diagram illustrating a modification of the transmission screen of the present invention.
FIG. 10 is a view showing a method of manufacturing a screen according to a conventional example.
FIG. 11 is a diagram illustrating a conventional defect.
[Explanation of symbols]
Reference Signs List 1 lens sheet, 1a flat surface, 2 lenses, 3 light-shielding layer (light-shielding material layer), 3a opening (non-light-shielding area), 4 flat portion, 10 transmission screen, 15 diffusion plate, 16 anti-reflection layer.

Claims (12)

The lens sheet includes a lens sheet having a plurality of lenses disposed on one surface and a light shielding layer provided on the other surface of the lens sheet on which no lens is formed. In a method of manufacturing a transmission screen in which a light shielding region is formed,
at least,
Forming a light-shielding layer on the other surface of the lens sheet;
Forming a non-light-blocking region in a local portion of the light-blocking layer corresponding to the optical axis of each lens by irradiating a pulsed laser beam from the lens forming surface side to the lens sheet on which the light-blocking layer is formed;
A method for manufacturing a transmission screen, comprising: 2. The transmission type according to claim 1, wherein the wavelength of the pulsed laser light is a wavelength having a transmissive property with respect to the lens sheet material and an absorptive property with respect to the light shielding layer material. Screen manufacturing method. The lens sheet material is made of a single material or a combination of a plurality of materials so that the heat conductivity of the lens sheet material is smaller than the heat conductivity of the light shielding layer material. The method for producing a transmission screen according to claim 1. 4. The method for manufacturing a transmission screen according to claim 1, wherein a laser beam having a pulse width of 100 μs or less is used as the pulse laser beam. 5. The method according to claim 1, wherein the thickness of the light-shielding layer is 1 μm or less. 6. The method according to claim 1, wherein an output of the pulse laser beam is equal to or less than a processing threshold value for the light shielding layer material. A transmission screen manufactured by the manufacturing method according to claim 1. A transmission screen, wherein a member having a light diffusion effect is provided on the light-shielding layer forming surface side of the transmission screen according to claim 7. A transmission screen, wherein an anti-reflection layer is formed on the outermost surface on the other side of the transmission screen according to claim 7. 10. The transmission screen according to claim 7, wherein the pitch of the lenses is set to 150 μm or less. The transmission screen according to claim 10, wherein the pitch of the lenses is random and not constant. A rear projection type projection apparatus comprising the transmission type screen according to claim 7.

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