WO2010067892A1

WO2010067892A1 - Light modulating pattern forming method

Info

Publication number: WO2010067892A1
Application number: PCT/JP2009/070938
Authority: WO
Inventors: 川口裕次郎
Original assignee: 住友化学株式会社
Priority date: 2008-12-10
Filing date: 2009-12-09
Publication date: 2010-06-17
Also published as: JP2010140721A; TW201111839A

Abstract

Disclosed is a light modulating pattern forming method for forming a light modulating pattern for modulating the amount of light emitted from a light source (31). The light modulating pattern is provided on the side of a light diffusion plate (40) that faces the light source (31). The light diffusion plate (40) is a component of a surface light source device (20) provided with at least one light source (31) and the light diffusion plate (40) which diffuses light emitted from the light source (31). In the forming method, a photoreceptor (F1) is disposed on the side of the light diffusion plate (40) that faces the light source (31), and a film (F2) having a contact screen is disposed on the photoreceptor. A plate making light source (31A) is disposed at the position of the light source (31). The plate making light source (31A) emits light having the direction distribution and the intensity distribution substantially identical to those of light emitted from the light source (31), to expose the photoreceptor (F1). Thus, a halftone pattern is formed on the photoreceptor (F1) in accordance with the light intensity distribution on the surface of the light diffusion plate, and a light modulating pattern is formed on the basis of the halftone pattern.

Description

Method for forming dimming pattern

The present invention relates to a method for forming a light control pattern, a method for manufacturing a light diffusion plate, a light diffusion plate, a light control film, a surface light source device, and a transmissive image display device.

As a transmissive image display device, for example, a device in which a direct type surface light source device is disposed on the back side of a transmissive liquid crystal cell or the like is known. In this type of surface light source device, a plurality of light sources are arranged at intervals in a plane, and light from these light sources is diffused over one surface and emitted to the front side of the plurality of light sources. The thing in which the light diffusing plate is arrange | positioned is known. In this type of surface light source device, the intensity of light is high directly above each light source, and the intensity of light gradually decreases as the distance from the light source increases, causing a problem of periodic luminance unevenness.
With regard to this problem, in the surface light source device (backlight device) described in Japanese Patent Application Laid-Open No. 2005-117023 (Patent Document 1), a dot-like shape for adjusting the amount of light shielded from the light source (cold cathode tube) is used. A dimming pattern is printed on the light diffusion plate corresponding to the arrangement of the light source, or a transparent film on which the dimming pattern is deposited is arranged between the light source and the light diffusion plate. This light control dot pattern has a total light transmittance of 62% to 71% and a haze value of 90% to 99% in the light projecting direction of the light source. Further, each dot of this light control dot pattern is arranged at a position where the interval between the light sources is divided by 24-48, and the diameter of each dot is 0.16 mm to 0.7 mm depending on the distance from the light source. is there. According to this configuration, the surface light source device can secure a sufficient luminance value and make the luminance of the planar light emitted uniform without increasing the power consumption of the light source.

However, it is difficult to design and form a dimming pattern so as to be placed at an optimum position, size, and interval according to the light source arrangement of the actual machine.
Therefore, the present invention provides a light modulation pattern forming method, a light diffusing plate manufacturing method, a light diffusing plate, a light modulating film, a surface light source device, and a transmissive image display device capable of suppressing luminance unevenness more stably. It is intended to provide.
The dimming pattern forming method of the present invention is a dimming pattern forming method for adjusting a light shielding amount of light from a light source, the dimming pattern is provided on the light source side of the light diffusion plate, and the light diffusion plate is at least A component in a surface light source device including one light source and a light diffusing plate for diffusing light from the light source. The forming method includes a photoconductor and a mesh in order from the light diffusing plate side to the light source side of the light diffusing plate. By arranging a plate screen, placing a plate making light source at the position of the light source, irradiating light from the plate making light source with light having substantially the same light source and light emission direction distribution and intensity distribution, A halftone pattern corresponding to the light amount distribution on the surface of the light diffusion plate is formed on the photoconductor, and the light control pattern is formed based on the halftone pattern.
Moreover, the manufacturing method of the light diffusing plate of the present invention is a manufacturing method of a light diffusing plate provided with a dimming pattern for adjusting the amount of light blocked from the light source, and the dimming pattern is provided on the light source side of the light diffusing plate. The light diffusing plate is a component in a surface light source device including at least one light source and a light diffusing plate that diffuses light from the light source, and the manufacturing method is arranged on the light diffusing plate side on the light source side of the light diffusing plate. A photoconductor and a screen printing screen are arranged in order, a plate making light source is arranged at the position of the light source, and light having substantially the same light source and light emission direction distribution and intensity distribution is irradiated from the plate making light source. To form a halftone pattern corresponding to the light amount distribution on the surface of the light diffusing plate, and to form a dimming pattern on the light source side surface of the light diffusing plate based on the halftone pattern .
In the halftone printing method, a larger halftone pattern is formed as the exposure light quantity is larger, and a smaller halftone pattern is formed as the exposure light quantity is smaller.
According to the present invention, the dimming pattern is formed based on the halftone pattern formed by using the halftone printing method. Therefore, a large dimming pattern is formed immediately above the platemaking light source, and is moved away from the platemaking light source. A small dimming pattern is formed gradually. Therefore, when this light control pattern is provided on the light source side of the light diffusing plate in the surface light source device, the amount of light shielding can be increased directly above the light source having a high light intensity, and the light shielding distance increases as the light intensity decreases away from the light source. Since the amount can be gradually reduced, luminance unevenness can be suppressed.
According to the present invention, the plate-making light source is disposed at the position of the actual light source with respect to the photoconductor on which the halftone pattern is formed, and the light emission direction distribution and the intensity distribution of the plate-making light source are actual. Since the light emission direction distribution and intensity distribution of the light source are substantially the same, a halftone pattern corresponding to the light amount distribution on the surface of the light diffusion plate can be formed, and luminance unevenness can be suppressed more stably. Possible dimming patterns can be formed.
In the above-described method for forming a light control pattern, it is preferable that the photosensitive member and the halftone screen screen are spaced apart from each other. Thus, gradation can be provided to the light that exposes the photoreceptor through the halftone screen, and a light control pattern that can suppress luminance unevenness when viewed obliquely can be formed.
In the above-described method for forming a light control pattern, it is preferable that the gap between the photosensitive member and the halftone screen screen be 0.1 to 10 times the mesh size of the halftone screen screen. By setting the gap between the photosensitive member and the halftone screen screen to be 0.1 times or more the size of the halftone screen screen, an appropriate gradation can be obtained by the light that exposes the photosensitive member through the halftone screen screen. The light control pattern which can be provided and can suppress the brightness nonuniformity at the time of seeing from diagonally more appropriately can be formed. On the other hand, by setting the gap between the photoconductor and the halftone screen screen to be 10 times or less than the size of the halftone screen screen, the exposure of the photoconductor is not excessively blurred and uneven brightness is more appropriate. It is possible to form a light control pattern that can be suppressed to a low level.
Further, in the above-described method for forming a light control pattern, it is preferable that the gap between the photosensitive member and the halftone screen screen be 0.5 to 2 times the mesh size of the halftone screen screen. By making the gap between the photoreceptor and the halftone screen screen at least 0.5 times the mesh size of the halftone screen screen, it is even more suitable for light that exposes the photoreceptor through the halftone screen screen. A gradation can be provided, and a dimming pattern that can more appropriately suppress luminance unevenness when viewed from an oblique direction can be formed. On the other hand, by setting the gap between the photoconductor and the halftone screen screen to be twice or less the size of the halftone screen screen, the exposure of light on the photoconductor is not excessively blurred, resulting in even more uneven brightness. The light control pattern which can be suppressed appropriately can be formed.
In the above-described method for forming a light control pattern, the number of lines of the halftone screen screen is preferably 60 LPI or more and 400 LPI or less. LPI is a unit representing the number of lines, and is an abbreviation for Line Per Inch. By setting the number of lines of the halftone screen screen to 60 LPI or more, it is possible to reduce the interval between the luminance stripes resulting from the dimming pattern, and to prevent the luminance fringes resulting from the dimming pattern from being identified. On the other hand, by making the number of lines of the screen printing screen 400 LPI or less, it is possible to suppress an increase in price due to manufacturing accuracy.
Furthermore, in the above-described method of forming a light control pattern, it is preferable that the number of lines of the halftone screen screen is 100 LPI or more and 200 LPI or less. By setting the number of lines of the halftone screen screen to 100 LPI or more, it is possible to make the interval of the luminance fringes caused by the dimming pattern finer and make the luminance fringes resulting from the dimming pattern more indistinguishable. it can. On the other hand, by setting the number of lines of the halftone screen screen to 200 LPI or less, it is possible to further suppress an increase in price due to manufacturing accuracy.
The light diffusing plate of this invention is equipped with the light control pattern formed by the formation method of an above-described light control pattern. Moreover, the light control film of this invention is equipped with the light control pattern formed by the formation method of an above-described light control pattern. Moreover, the above-mentioned light control film is affixed on the other light diffusing plate of this invention. The surface light source device of the present invention includes at least one light source and a light diffusing plate that diffuses light from the light source, and includes the above-described light diffusing plate. A transmissive image display device of the present invention includes a transmissive image display cell and a surface light source device that supplies light to the transmissive image display cell, and includes the surface light source device described above. According to the present invention, as described above, since the dimming pattern corresponding to the amount of light on the surface of the light diffusion plate is formed, it is possible to suppress luminance unevenness more stably.
According to the present invention, the luminance unevenness of the output light of the surface light source device in the transmissive image display device can be more stably suppressed.

FIG. 1 is a cross-sectional view schematically showing a configuration of a first embodiment of a transmissive image display device, a surface light source device, and a light diffusing plate according to the present invention.
FIG. 2 is an enlarged view showing a light control pattern formed on the light source side surface of the light diffusion plate shown in FIG.
FIG. 3 is a flowchart of the first embodiment of the method for manufacturing a light diffusing plate and the method for forming a light control pattern according to the present invention.
FIG. 4 is a diagram showing a state in each processing step shown in FIG.
FIG. 5 is an enlarged view showing contact screens in the screen printing screen film shown in FIG.
FIG. 6 is a partially enlarged view of FIG.
FIG. 7 is a cross-sectional view schematically showing the configuration of the second embodiment of the transmissive image display device, the surface light source device, and the light diffusing plate according to the present invention.
FIG. 8 is a flowchart of the second embodiment of the method for manufacturing a light diffusing plate and the method for forming a light control pattern according to the present invention.
FIG. 9 is a flowchart of a modification of the light diffusing plate manufacturing method and the dimming pattern forming method according to the present invention.

DESCRIPTION OF SYMBOLS 1,1A ... Transmission type image display apparatus, 10 ... Transmission type image display part, 11 ... Liquid crystal cell, 12, 13 ... Polarizing plate, 20, 20A ... Surface light source device, 30 ... Light source part, 31 ... Light source, 31A ... Plate making Light source for 32, lamp box, 40, 40A ... light diffusion plate, 50 ... light control film, 51 ... light diffusion plate, 61 ... contact screen (screen screen screen), F1 ... photosensitive film (photoconductor), F2 ... Screen printing screen film

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals.
[First Embodiment]
FIG. 1 is a cross-sectional view schematically showing a configuration of a first embodiment of a transmissive image display apparatus according to the present invention. The transmissive image display device 1 is a liquid crystal display device, and a direct surface light source on the back side (lower side) of the transmissive image display unit 10 in which polarizing plates 12 and 13 are laminated on both upper and lower surfaces of a liquid crystal cell 11. An apparatus 20 is provided and configured.
As the liquid crystal cell 11 and the polarizing plates 12 and 13, those used in a transmissive image display device such as a conventional liquid crystal display device can be used. Examples of the liquid crystal cell 11 include known liquid crystal cells such as a TFT type and an STN type.
The surface light source device 20 is a so-called direct type surface light source device and includes a light source unit 30 including a plurality of light sources 31 arranged in parallel. Each light source 31 is a linear light source extending in a direction orthogonal to the arrangement direction of the plurality of light sources 31, and is exemplified by a straight tube like a fluorescent lamp (cold cathode ray lamp). The plurality of light sources 31 are arranged at intervals so that the central axes of the light sources 31 are located in the same plane P1, and when the distance between the central axes of the two adjacent

light sources

31, 31 is L, The distance L is, for example, 15 mm to 150 mm. Here, the light source 31 is linear, but it is also possible to use a point light source such as an LED. Note that the plane P1 shown in FIG. 1 is a virtual plane for convenience of explanation.
As shown in FIG. 1, the plurality of light sources 31 are preferably disposed in a lamp box 32, and the inner surface 32a of the lamp box 32 is preferably formed as a light scattering reflection surface. This is because the light output from each light source 31 is reliably output to the transmissive image display unit 10 side, so that the light from each light source 31 can be used efficiently. In the present embodiment, the light source unit 30 will be described as including the lamp box 32 having the above-described preferable configuration.
The surface light source device 20 includes a light diffusing plate 40 that is disposed away from the light source 31 on the front surface side (the upper side in FIG. 1) of the light source unit 30, that is, on the transmissive image display unit 10 side. . When the distance between the light diffusion plate 40 and the plurality of light sources 31 is D, the distance D is, for example, 5 mm to 50 mm. In the surface light source device 20, in order to reduce the thickness, the distance L between two adjacent

light sources

31 and 31 is set so that L / D is 1.5 or more, and preferably L / D is 2.5 or more. And the separation distance D is selected.
The light diffusing plate 40 does not project the image of each light source 31 onto the transmissive image display unit 10, and is reflected by the light from the light source unit 30, that is, the direct light from each light source 31 and the inner surface 32 a of the lamp box 32. This is for diffusing the reflected light toward the transmissive image display unit 10. The thickness _{d 1} of the light diffusing plate 40 is about 0.8 mm ~ 5 mm.
The light diffusion plate 40 is made of a transparent material such as a transparent resin or transparent glass. As transparent resin, polycarbonate resin, ABS resin (acrylonitrile-styrene-butadiene copolymer resin), methacryl resin, MS resin (methyl methacrylate-styrene copolymer resin), polystyrene resin, AS resin (acrylonitrile-styrene copolymer) Examples thereof include polyolefin resins such as coalesced resin), polyethylene, and polypropylene. In the light diffusing plate 40, a diffusing agent similar to the diffusing agent for diffusing light contained in a light diffusing plate used in a transmissive image display device such as a liquid crystal display device is appropriately added.
On the light source 31 side of the light diffusing plate 40, a dimming pattern for adjusting the light shielding amount of the light from the light source 31 is formed. For example, the dimming pattern is formed of ink, and the amount of light blocked from the light source 31 is adjusted by light reflection, light diffusion, light absorption, or the like. In the dimming pattern with white ink, the amount of light blocked from the light source 31 can be adjusted also by the effect of diffuse reflection.
This light control pattern is formed by, for example, halftone dots used for halftone printing. A halftone plate is a relief plate that expresses the gradation of a photograph or the like by the size of halftone dots, and is one of the relief plates for printing. In this case, the dimming pattern has a large halftone dot at a place where the light intensity on the light diffusing plate 40 is high, and gradually has a small halftone dot as the light intensity decreases. In general, the light intensity directly above the light source is the strongest, and the light intensity decreases as the distance from the light source increases. Therefore, as shown in FIG. Gradually has smaller halftone dots.
Here, for example, the intensity of light is high directly above each light source 31, and the intensity of light gradually decreases as the distance from the light source 31 increases. Can occur periodically. As a result, periodic luminance unevenness may occur in the output light from the surface light source device 20. However, according to this dimming pattern, the light shielding amount can be increased at a place where the light intensity on the light diffusion plate 40 is high, and the light shielding amount can be gradually decreased as the light intensity decreases. The amount of light shielding can be increased immediately above the light source 31 having a high intensity, and the amount of light shielding can be gradually decreased as the light intensity decreases as the distance from the light source 31 decreases, and uneven brightness can be suppressed.
Next, the manufacturing method of the light diffusing plate 40 of 1st Embodiment and the formation method of the light control pattern with which the light diffusing plate 40 is provided are demonstrated. FIG. 3 is a flowchart of the first embodiment of the method of manufacturing the light diffusing plate 40 and the method of forming the light control pattern according to the present invention, and FIG. 4 is a diagram showing the state in each processing step shown in FIG. It is.
(Placement processing)
First, as shown in FIG. 4, the photosensitive film F1 and the screen printing screen film F2 are arranged in this order from the light diffusion plate 40 side on the surface of the light diffusion plate 40 on the light source 31 side (S01).
The photosensitive film F1 is preferably in close contact with the surface of the light diffusion plate 40 on the light source 31 side, and the thickness of the photosensitive film F1 is preferably as thin as possible. Thus, the photosensitive film F1 is disposed at a position where the actual light control pattern is formed on the light diffusion plate 40.
For example, as shown in FIG. 5, a contact screen (screen screen screen) used in a halftone printing method is formed on the halftone screen film F <b> 2. Has been. Various halftone screen screens such as halftone screen screens can be applied to the halftone screen screen formed on the halftone screen film F2.
The screen printing screen film F2 is preferably separated from the photosensitive film F1 (proximity exposure). As a result, gradation can be provided to the light that exposes the photosensitive film F1 through the contact screen in the screen printing screen film F2, and luminance unevenness when the transmissive image display device 1 is viewed from an oblique direction can be suppressed. A dimming pattern can be formed.
The gap between the screen printing screen film F2 and the photosensitive film F1 is preferably 0.1 to 10 times the mesh size of the contact screen. By setting the gap between the screen printing screen film F2 and the photosensitive film F1 to be not less than 0.1 times the mesh size of the contact screen, an appropriate gradation is provided by the light that exposes the photosensitive film F1 through the contact screen. Therefore, it is possible to form a dimming pattern that can more appropriately suppress luminance unevenness when the transmissive image display device 1 is viewed obliquely.
On the other hand, by setting the gap between the screen printing screen film F2 and the photosensitive film F1 to be not more than 10 times the mesh size of the contact screen, the light for exposing the photosensitive film F1 is not excessively blurred, and the surface light source device 20 It is possible to form a light control pattern that can more appropriately suppress the luminance unevenness.
Further, the gap between the halftone screen film F2 and the photosensitive film F1 is preferably 0.5 to 2 times the mesh size of the contact screen. By setting the gap between the screen printing screen film F2 and the photosensitive film F1 to be 0.5 times or more of the mesh size of the contact screen, a more appropriate gradation can be obtained by light exposing the photosensitive film F1 through the contact screen. Thus, it is possible to form a light control pattern that can more appropriately suppress luminance unevenness when the transmissive image display device 1 is viewed obliquely.
On the other hand, by setting the gap between the screen printing screen film F2 and the photosensitive film F1 to be not more than twice the size of the contact screen screen, the surface light source device does not excessively blur the light that exposes the photosensitive film F1. It is possible to form a light control pattern that can more appropriately suppress the luminance unevenness of 20.
When a gap is provided between the halftone screen film F2 and the photosensitive film F1, as shown in FIG. 6A, the photosensitive surface of the photosensitive film F1 and the contact screen 61 of the halftone screen film F2 are formed. It is preferable that the above-described gap is provided between the contact screen 61 and the photosensitive film F1 by making use of the thickness d of its own. According to this, a uniform gap can be provided over the entire surface.
The screen printing screen film F2 may be in close contact with the photosensitive film F1 (contact exposure). In this case, as shown in FIG. 6B, the photosensitive surface of the photosensitive film F1 and the surface on which the contact screen 61 of the halftone screen film F2 is formed are brought into close contact with each other.
It is preferable that the number of contact screen lines (number per line of lines in which square meshes are arranged) in the screen printing screen film F2 is 60 LPI or more and 400 LPI or less. By setting the number of contact screen lines to 60 LPI or more, the interval between the luminance stripes resulting from the dimming pattern can be reduced, and the luminance fringes resulting from the dimming pattern cannot be identified. On the other hand, by setting the number of contact screen lines to 400 LPI or less, it is possible to suppress an increase in price due to manufacturing accuracy.
Furthermore, the number of contact screen lines in the halftone screen film F2 is more preferably 100 LPI or more and 200 LPI or less. By setting the number of contact screen lines to 100 LPI or more, the interval between the luminance stripes resulting from the dimming pattern can be made finer, and the luminance fringes resulting from the dimming pattern can be made more indistinguishable. On the other hand, by setting the number of contact screen lines to 200 LPI or less, it is possible to further suppress an increase in price due to manufacturing accuracy.
Next, the plate-making light source 31A is arranged at the actual configuration position of the light source 31 in the lamp box 32, and the light diffusing plate 40 is arranged at the actual configuration position together with the photosensitive film F1 and the halftone screen film F2 (S02).
The plate-making light source 31A may be an actual light source 31 or a light source having a wavelength suitable for the photosensitive wavelength of the photosensitive film F1 (often ultraviolet rays). The light emission direction distribution and the intensity distribution of the light source 31A for plate making are substantially the same as the light emission direction distribution and the intensity distribution of the light source 31.
The light diffusion plate 40 is used for alignment of the photosensitive film F1, and any means may be used as long as the photosensitive film F1 can be held at a position equivalent to the surface of the light diffusion plate 40. Further, when the surface light source device 20 does not include the lamp box 32, the lamp box 32 is omitted.
(Exposure processing)
Next, by exposing the photosensitive film F1 using the plate-making light source 31A, a halftone pattern having halftone dots corresponding to the amount of light is formed on the photosensitive film F1 (S03). Thereby, the size of the halftone dot can be determined according to the exposure surface of the light diffusion plate 40, that is, the light intensity at the actual exposure position. That is, a large halftone dot can be formed at a position where the light intensity is directly above the plate making light source 31A, and a small halftone dot can be formed at a position where the light intensity away from the plate making light source 31A is small.
(Printing process)
Next, the photosensitive film F1 is developed to prepare a halftone pattern original (S04). Then, a printing plate having a halftone pattern is created from this original plate (S05). Next, by using this printing plate, a halftone pattern is printed on the light source 31 side of the light diffusing plate 40, thereby forming a light control pattern on the light source 31 side of the light diffusing plate 40 (S06). In this way, it is possible to form a dimming pattern having a halftone dot corresponding to the actual amount of light on the light diffusion plate 40.
Note that a general printing process such as screen printing, offset printing, flexographic printing, or the like can be applied to steps S04 to S06.
Here, in the halftone printing method, a larger halftone pattern is formed as the amount of light is larger, and a smaller halftone pattern is formed as the amount of light is smaller.
According to the light control pattern forming method and the light diffusing plate manufacturing method of the first embodiment, the light control pattern is formed based on the halftone pattern formed using the halftone printing method. A large dimming pattern is formed immediately above, and gradually smaller dimming patterns are formed as the distance from the plate-making light source 31A increases. Therefore, when this light control pattern is provided on the light source 31 side of the light diffusing plate 40 in the surface light source device 20, it is possible to increase the amount of light shielding directly above the light source 31 with high light intensity. Since the light shielding amount can be gradually reduced as the intensity decreases, luminance unevenness can be suppressed.
In addition, according to the method for forming a light control pattern and the method for manufacturing a light diffusing plate according to the first embodiment, the light source 31A for plate making is located at the position of the actual light source 31 with respect to the photosensitive film F1 on which the halftone pattern is formed. In addition, the light emission direction distribution and the intensity distribution of the light source 31A for plate making are substantially the same as the light emission direction distribution and the intensity distribution of the actual light source 31, so that it corresponds to the light quantity distribution on the surface of the light diffusion plate 40. A halftone pattern can be formed, and a light control pattern capable of suppressing luminance unevenness more stably can be formed.
Further, according to the method for forming a light control pattern and the method for manufacturing a light diffusing plate according to the first embodiment, as described above, a halftone pattern corresponding to the light amount distribution on the surface of the light diffusing plate 40 is formed. Since the light control pattern is formed from the halftone pattern, it is easy to design the light control pattern so as to be placed at an optimum position, size, and interval according to the light source arrangement of the actual machine. Further, according to the method for forming a light control pattern and the method for manufacturing a light diffusing plate according to the first embodiment, for example, an optimal light control pattern can be formed without a priori knowledge such as “the light intensity is high directly above the light source”. can do. In addition, it is possible to form a dimming pattern that reflects the overall light intensity including not only the direct light from the light source but also the reflection of the lamp box and the like. Accordingly, it is possible to obtain a light diffusing plate having a dimming pattern more suitable for a real machine, and it is possible to obtain a surface light source device with less unevenness in light quantity. As a result, a transmissive image display device with higher image quality can be obtained.
[Second Embodiment]
FIG. 7 is a cross-sectional view schematically showing the configuration of the second embodiment of the transmissive image display apparatus according to the present invention. The transmissive image display device 1A of the second embodiment is different from the first embodiment in that the transmissive image display device 1 includes a surface light source device 20A instead of the surface light source device 20. Other configurations of the transmissive image display device 1A are the same as those of the transmissive image display device 1.
The surface light source device 20A is different from the surface light source device 20 in that the surface light source device 20 includes a light diffusion plate 40A instead of the light diffusion plate 40. Other configurations of the surface light source device 20A are the same as those of the surface light source device 20.
The light diffusing plate 40 </ b> A has a light control film 50 attached to the light source side surface of the light diffusing plate 51. The light diffusing plate 51 is different from the light diffusing plate 40 in that a dimming pattern is not formed on the surface of the light diffusing plate 40 on the light source side. On the light control film 50, the same light control pattern as the light control pattern formed on the light source side surface of the light diffusion plate 40 is formed. That is, the light control film 50 has a large halftone dot in a place where the light intensity on the light diffusion plate 40 is high, and a light control pattern having a gradually small dot as the light intensity decreases, for example, as shown in FIG. A dimming pattern having a large halftone dot immediately above the light source 31 and gradually smaller dot as the distance from the light source 31 is formed.
Next, the manufacturing method of the light diffusing plate 40A of 2nd Embodiment, the manufacturing method of the light control film 50 with which 40 A of light diffusing plates are provided, and the formation method of the light control pattern with which a light control film is provided are demonstrated. FIG. 8 is a flowchart of the second embodiment of the method for manufacturing the light diffusing plate 40A, the method for manufacturing the light control film 50, and the method for forming the light control pattern according to the present invention.
(Arrangement processing and exposure processing)
First, the arrangement process of steps S01 and S02 described above is performed. Thereafter, the exposure processing in step S03 described above is performed.
(Printing process)
Next, the processes in steps S04 and S05 described above are performed to create a halftone pattern printing plate. Next, by using this printing plate, a halftone pattern is printed on the light source 31 side surface of the light control film 50 to form a light control pattern on the light source 31 side surface of the light control film 50 (S16). . Thereafter, the light diffusing plate 40A is obtained by pasting the light control film 50 on the surface of the light diffusing plate 51 on the light source 31 side (S17).
The light control pattern forming method, the light control film manufacturing method, and the light diffusing plate manufacturing method of the second embodiment have the same advantages as the light control pattern forming method and the light diffusing plate manufacturing method of the first embodiment. Obtainable.
The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the first embodiment, the dimming pattern is printed on the light diffusion plate 40 by using a general printing method, but the dimming pattern may be formed by spraying ink with an ink jet printer. Below, the manufacturing method of the light diffusing plate of this modification and the formation method of the light control pattern with which a light diffusing plate is provided are demonstrated. FIG. 9 is a flowchart of a modification of the light diffusing plate manufacturing method and the dimming pattern forming method according to the present invention.
(Arrangement processing and exposure processing)
First, the arrangement process of steps S01 and S02 described above is performed. Thereafter, the exposure processing in step S03 described above is performed.
(Printing process)
Next, the above-described processing in step S04 is performed to create a halftone pattern original. Next, electronic data of a halftone pattern is created from this original by a scanner and a computer (S25). Next, a dimming pattern is formed on the light source 31 side of the light diffusing plate by spraying ink on the light source 31 side of the light diffusing plate 40 based on the halftone pattern of the electronic data by a computer, an ink jet printer, or the like. (S26).
Moreover, also in 2nd Embodiment, the light control pattern of a light control film may be formed using the ink spraying method of this modification.
Even in the method of forming a light control pattern, the method of manufacturing a light control film, and the method of manufacturing a light diffusion plate of this modification, the method of forming the light control pattern, the method of manufacturing the light control film, and the method of manufacturing the light control film of the first and second embodiments Advantages similar to those of the light diffusing plate manufacturing method can be obtained.
In addition, the idea of the present invention is not limited to the surface light source device used in the liquid crystal display device, but when the light control pattern formed on the light diffusion plate in the surface light source device such as a light box or a trace box is formed. Is also applicable.

Claims

It is a method of forming a light control pattern that adjusts the amount of light blocked from the light source,
The dimming pattern is provided on the light source side of the light diffusion plate,
The light diffusing plate is a component in a surface light source device including at least one light source and a light diffusing plate for diffusing light from the light source,
The forming method includes:
On the light source side of the light diffusing plate, a photoconductor and a screen printing screen are arranged in order from the light diffusing plate side,
A light source for plate making is arranged at the position of the light source,
By irradiating light from the plate making light source with light having substantially the same light emission direction distribution and intensity distribution as the light source and exposing the photoconductor, the photoconductor is subjected to a light amount distribution on the surface of the light diffusion plate. Forming a halftone pattern,
The method of forming the light control pattern, wherein the light control pattern is formed based on the halftone pattern.
The method for forming a light control pattern according to claim 1, wherein the photosensitive member and the screen printing screen are arranged apart from each other.
The method for forming a light control pattern according to claim 2, wherein a gap between the photoconductor and the screen printing screen is 0.1 to 10 times larger than a screen size of the screen printing screen.
The method for forming a light control pattern according to claim 2, wherein a gap between the photoconductor and the screen printing screen is 0.5 to 2 times as large as a screen size of the screen printing screen.
The method of forming a light control pattern according to claim 1 or 2, wherein the number of lines of the screen printing screen is 60 LPI or more and 400 LPI or less.
The method of forming a light control pattern according to claim 1 or 2, wherein the number of lines of the screen printing screen is 100 LPI or more and 200 LPI or less.
A method of manufacturing a light diffusing plate having a light control pattern for adjusting the amount of light blocked from a light source,
The dimming pattern is provided on the light source side of the light diffusing plate,
The light diffusing plate is a component in a surface light source device including at least one light source and a light diffusing plate for diffusing light from the light source,
The manufacturing method includes:
On the light source side of the light diffusing plate, a photoconductor and a screen printing screen are arranged in order from the light diffusing plate side,
A light source for plate making is arranged at the position of the light source,
By irradiating light from the plate making light source with light having substantially the same light emission direction distribution and intensity distribution as the light source and exposing the photoconductor, the photoconductor is subjected to a light amount distribution on the surface of the light diffusion plate. Forming a halftone pattern,
The manufacturing method of the said light diffusing plate which forms the said light control pattern in the surface at the side of the said light source of the said light diffusing plate based on the said halftone pattern.
A light diffusing plate provided with a light control pattern formed by the method for forming a light control pattern according to any one of claims 1 to 6.
A light control film comprising a light control pattern formed by the method for forming a light control pattern according to any one of claims 1 to 6.
A light diffusing plate to which the light control film according to claim 9 is attached.
At least one light source;
A surface light source device comprising a light diffusing plate for diffusing light from the light source and the light diffusing plate according to claim 8.
A transmissive image display cell;
A transmissive image display device comprising the surface light source device according to claim 11 for supplying light to the transmissive image display cell.