JP2010140721A - Method of forming light modulation pattern, method of manufacturing light diffusion plate, light diffusion plate, light modulation film, surface light source device, and transmission type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming a light modulation pattern, in which luminance unevenness can be suppressed more stably. <P>SOLUTION: The method of forming the light modulation pattern is used for modulating a shielding amount of light from a light source 31, and the light modulation pattern is provided on the light source 31 side of a light diffusion plate 40 in a surface light source device 20 equipped with at least one light source 31 and the light diffusion plate 40 which diffuses light from the light source 31. In the method of forming the light modulation pattern, a photoreceptor F1 and a film F2 having a halftone screen are disposed on the light source 31 side of the light diffusion plate 40 in this order from the light diffusion plate 40 side, a halftone pattern is formed on the photoreceptor F1 in accordance with the light amount distribution on the surface of the light diffusion plate by using a plate making light source 31A disposed on a position corresponding to the light source 31 and having the light distribution and the intensity distribution substantially identical to the light source 31 and exposing the photoreceptor F1, and the light modulation pattern is formed on the basis of the halftone pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a dimming pattern generation method, a light diffusing plate manufacturing method, a light diffusing plate, a dimming 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.

Regarding this problem, in the surface light source device (backlight device) described in Patent Document 1, a dot-shaped dimming pattern for adjusting the amount of light blocked from the light source (cold cathode tube) corresponds to the arrangement of the light sources. Then, printing is performed on the light diffusion plate, or a transparent film on which the light control pattern is deposited is disposed 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. In addition, each dot of the dimming dot pattern is arranged at a position where the interval between the light sources is divided by 24 to 48, and each dot system is 0.16 mm to 0.7 mm depending on the distance from the light source. . With this configuration, a sufficient luminance value can be ensured without increasing the power consumption of the light source, and the luminance of the planar light emission can be made uniform.
Japanese Laid-Open Patent Publication No. 2005-117023

  However, it is difficult to design 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.

  Accordingly, the present invention provides a light control pattern generation method, a light diffusing plate manufacturing method, a light diffusing plate, a light control 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 light modulation pattern generation method of the present invention is provided on the light source side of a light diffusion plate in a surface light source device including at least one light source and a light diffusion plate for diffusing light from the light source, and blocks light from the light source. It is a method of generating a light control pattern for adjusting the amount, arranged on the light source side of the light diffusion plate in order from the light diffusion plate side, the photoreceptor and the halftone screen screen, arranged at a position corresponding to the light source, A halftone pattern corresponding to the light amount distribution on the surface of the light diffusing plate is formed on the photoconductor by exposing the photoconductor using a plate-making light source that has substantially the same light distribution and intensity distribution as the light source. Then, a dimming pattern is generated based on the halftone pattern.

  The light diffusing plate manufacturing method of the present invention is a light diffusing plate in a surface light source device including at least one light source and a light diffusing plate for diffusing light from the light source, and blocks light from the light source. Is a light diffusing plate manufacturing method provided with a light control pattern on the light source side, and arranged on the light source side of the light diffusing plate in order from the light diffusing plate side, and a screen screen screen. Light distribution on the surface of the light diffusion plate on the photoconductor by exposing the photoconductor using a plate making light source that is disposed at a position corresponding to the light source and has substantially the same light distribution and intensity distribution with respect to the light source A halftone pattern corresponding to the halftone screen screen is formed, and a light control pattern is formed on the light source side surface of the light diffusion plate based on the halftone pattern.

  In the halftone printing method, a larger halftone pattern is generated as the light amount is larger, and a smaller halftone pattern is generated as the light amount is smaller.

  According to this invention, since the light control pattern is generated based on the screen pattern generated using the screen printing method, a large light control pattern is generated directly above the plate making light source, and is moved away from the plate making light source. As a result, a small dimming pattern is generated. 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.

  Further, according to the present invention, the plate-making light source is disposed at the position of the actual light source on the photoconductor on which the halftone pattern is formed, and the light distribution and intensity distribution of the plate-making light source are arranged according to the actual light source arrangement. Since it is substantially the same as the light and intensity distribution, a halftone pattern corresponding to the light amount distribution on the surface of the light diffusion plate can be generated, and a light control pattern capable of suppressing luminance unevenness more stably. Can be generated.

  In the above-described method for generating the light control pattern, it is preferable that the photosensitive member and the halftone screen screen are arranged apart from each other. Thereby, gradation can be provided to the light that exposes the photoconductor through the screen printing screen, and a light control pattern that can suppress luminance unevenness when viewed from an oblique direction can be generated.

  In the above-described method for generating the light control pattern, it is preferable that the gap between the photoconductor and the halftone screen screen is 0.1 to 10 times the halftone dot size of the halftone screen screen. By setting the gap between the photoconductor and the halftone screen screen to 0.1 times or more the halftone dot size of the halftone screen screen, it is possible to obtain an appropriate gradation by the light that exposes the photoconductor through the halftone screen screen. Therefore, it is possible to generate a light control pattern that can more appropriately suppress luminance unevenness when viewed from an oblique direction. On the other hand, by setting the gap between the photoconductor and the halftone screen screen to 10 times or less the halftone dot size of the halftone screen screen, the exposure light to the photoconductor is not excessively blurred, resulting in more uneven brightness. A dimming pattern that can be appropriately suppressed can be generated.

  Furthermore, in the above-described method for generating 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 halftone dot size of the halftone screen screen. By making the gap between the photosensitive member and the halftone screen screen at least 0.5 times the size of the halftone screen screen, it is even more suitable for light that exposes the photosensitive member through the halftone screen screen. Therefore, it is possible to generate a dimming pattern that can more appropriately suppress luminance unevenness when viewed from an oblique direction. On the other hand, by setting the gap between the photoconductor and the halftone screen screen to be twice or less the halftone dot size of the halftone screen screen, the light that exposes the photoconductor is not excessively blurred and brightness unevenness is further improved. Therefore, it is possible to generate a dimming pattern that can be appropriately suppressed.

  In the above-described method for generating the light control pattern, it is preferable that the number of lines of the screen printing screen be 60 lines or more and 400 lines or less. By setting the number of lines of the halftone screen screen to 60 lines or more, the interval of the luminance fringes 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 increasing the number of lines of the screen printing screen to 400 lines or less, it is possible to suppress an increase in price due to manufacturing accuracy.

  Furthermore, it is preferable that the number of lines of the halftone screen screen is 100 lines or more and 200 lines or less. By setting the number of lines of the halftone screen screen to 100 lines or more, the interval of the luminance fringes resulting from the dimming pattern can be made finer, and the luminance fringes resulting from the dimming pattern cannot be further identified. Can do. On the other hand, by setting the number of lines of the screen printing screen to 200 lines or less, it is possible to further suppress an increase in price due to manufacturing accuracy.

  In the light diffusing plate of the present invention, the dimming pattern generated by the above-described dimming pattern generation method is formed. Moreover, the light control pattern produced | generated by the production | generation method of an above-mentioned light control pattern is formed in the light control film of this invention. Moreover, the above-mentioned light control film is affixed to another light-diffusion 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.

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 to 5 mm.

  The light diffusion plate 40 is made of a transparent material such as a transparent resin or transparent glass. Transparent resins include polycarbonate resin, ABS resin (acrylonitrile-styrene-butadiene copolymer resin), methacrylic 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. 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 directly above the light source 31 having a high intensity, and the amount of light shielding can be gradually decreased as the intensity of the light decreases as the distance from the light source 31 decreases, thereby suppressing luminance unevenness.

Next, the manufacturing method of the light diffusing plate 40 of 1st Embodiment and the production | generation 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 generating the light control pattern according to the present invention, and FIG. 4 is a diagram showing the states in the respective processing steps 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.

  As shown in FIG. 5, for example, as shown in FIG. 5, a contact screen (screen screen screen) used in the halftone printing method, in which a contact screen is formed in which the surroundings are blurred. ing. 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 generated.

  The gap between the halftone screen film F2 and the photosensitive film F1 is preferably not less than 0.1 times and not more than 10 times the dot size of the contact screen. By setting the gap between the screen printing screen film F2 and the photosensitive film F1 to be 0.1 times or more the size of the contact screen screen dot, an appropriate gradation can be obtained by the light that exposes the photosensitive film F1 through the contact screen. The light control pattern which can be provided and can suppress the brightness nonuniformity at the time of seeing the transmissive image display apparatus 1 from diagonally can be produced | generated.

  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 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 generate a dimming pattern that can more appropriately suppress the 20 luminance unevenness.

  Further, the gap between the halftone screen film F2 and the photosensitive film F1 is preferably 0.5 to 2 times the size of the halftone dot of the contact screen. By setting the gap between the halftone screen screen film F2 and the photosensitive film F1 to 0.5 times or more the size of the halftone dot of the contact screen, it is even more appropriate for the light that exposes the photosensitive film F1 through the contact screen. A gradation can be provided, and a dimming pattern that can more appropriately suppress luminance unevenness when the transmissive image display device 1 is viewed obliquely can be generated.

  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 screen dot of the contact screen, the light that exposes the photosensitive film F1 is not excessively blurred. It is possible to generate a light control pattern that can more appropriately suppress the luminance unevenness of the device 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.

  The number of contact screen lines in the halftone screen film F2 is preferably 60 lines or more and 400 lines or less. By setting the number of contact screen lines to 60 or more, it is possible to reduce the interval between the luminance fringes resulting from the dimming pattern and to prevent the luminance fringes resulting from the dimming pattern from being identified. On the other hand, by setting the number of contact screen lines to 400 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 lines or more and 200 lines or less. By setting the number of contact screen lines to 100 lines or more, it is possible to make the intervals between the luminance stripes caused by the dimming pattern finer and make the luminance fringes caused by the dimming pattern more indistinguishable. . On the other hand, by making the number of contact screen lines 200 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 position of the light source 31 in the lamp box 32, and the light diffusion plate 40 together with the photosensitive film F1 and the halftone screen film F2 is placed with respect to the plate-making light source 31A and the lamp box 32. It arrange | positions in an actual structure position (S02).

  The light source 31A for plate making may be an actual light source 31 or a light source having a wavelength suitable for the photosensitive wavelength of the photosensitive film F1 (for example, often ultraviolet rays). In that case, the light distribution and intensity distribution of the light source 31A for plate making are preferably substantially the same as the light distribution and intensity distribution of the light source 31.

The light diffusing 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 diffusing 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 generated at a position where the light intensity is directly above the plate making light source 31A, and a small halftone dot can be generated at a position where the intensity of light moving 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 generate a dimming pattern having a halftone dot corresponding to the actual amount of light on the light diffusing 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 generated as the light amount is larger, and a smaller halftone pattern is generated as the light amount is smaller.

  According to the light control pattern generation method and the light diffusing plate manufacturing method of the first embodiment, the light control pattern is generated based on the screen pattern generated using the screen printing method. A large dimming pattern is generated immediately above, and gradually smaller dimming patterns are generated 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.

  Further, according to the method of generating a light control pattern and the method of manufacturing a light diffusion plate of the first embodiment, the plate-making light source 31A is placed at the position of the actual light source 31 with respect to the photosensitive film F1 on which the halftone pattern is formed. Since the light distribution and intensity distribution of the light source 31A for plate making are substantially the same as the light distribution and intensity distribution of the actual light source 31, a halftone pattern corresponding to the light amount distribution on the surface of the light diffusion plate 40 is generated. Therefore, it is possible to generate a dimming pattern that can suppress luminance unevenness more stably.

Further, according to the light control pattern generation method and the light diffusion plate manufacturing method of the first embodiment, as described above, a halftone pattern corresponding to the light amount distribution on the surface of the light diffusion plate 40 is generated. Since the dimming pattern is generated from the halftone pattern, it is easy to design the dimming pattern so as to be placed at the optimum position, size, and interval according to the light source arrangement of the actual machine. Moreover, according to the light control pattern generation method and the light diffusing plate manufacturing method of the first embodiment, for example, an optimal light control pattern is generated without foreseeing knowledge such as “the light intensity is high directly above the light source”. can do. In addition, it is possible to generate a dimming pattern that reflects the total 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 apparatus 1A of the second embodiment is different from the first embodiment in that the transmissive image display apparatus 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 20 </ b> A are the same as those of the surface light source device 20.

  The light diffusing plate 40 </ b> A is formed by attaching the light control film 50 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 production | generation 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 generating 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 generation method, the light control film manufacturing method, and the light diffusion plate manufacturing method of the second embodiment have the same advantages as the light control pattern generation method and the light diffusion 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 production | generation 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 generation 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 generating a light control pattern, the method of manufacturing a light control film, and the method of manufacturing a light diffusing plate according to this modification, the method of generating 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.

  Further, the idea of the present invention is not limited to the surface light emitting device used in the liquid crystal display device, and is used when generating a dimming pattern formed on a light diffusion plate in a surface light emitting device such as a light box or a trace box. Is also applicable.

It is sectional drawing which shows typically the structure of 1st Embodiment of the transmissive image display apparatus which concerns on this invention, a surface light source device, and a light diffusing plate. It is an enlarged view which shows the light control pattern formed in the surface at the side of the light source of the light diffusing plate shown in FIG. It is a flowchart of 1st Embodiment of the manufacturing method of the light diffusing plate which concerns on this invention, and the production method of a light control pattern. It is a figure which shows the state in each process step shown in FIG. It is an enlarged view which shows the contact screen in the screen printing screen film shown in FIG. FIG. 5 is a partially enlarged view of FIG. 4. It is sectional drawing which shows typically the structure of 2nd Embodiment of the transmissive image display apparatus which concerns on this invention, a surface light source device, and a light diffusing plate. It is a flowchart of 2nd Embodiment of the manufacturing method of the light diffusing plate which concerns on this invention, and the production | generation method of a light control pattern. It is a flowchart of the modification of the manufacturing method of the light diffusing plate which concerns on this invention, and the production | generation method of a light control pattern.

Explanation of symbols

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

Claims (12)

The light source plate is provided on the light source side of the light diffusing plate in a surface light source device including at least one light source and a light diffusing plate for diffusing light from the light source, and adjusts a light shielding amount of the light from the light source. A method for generating a dimming pattern,
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,
By exposing the photoconductor using a plate-making light source that is disposed at a position corresponding to the light source and has substantially the same light distribution and intensity distribution as the light source, the light diffusion plate is exposed to the photoconductor. Form a halftone pattern according to the light distribution on the surface,
A dimming pattern generation method for generating the dimming pattern based on the halftone pattern. The method for generating a light control pattern according to claim 1, wherein the photoconductor and the screen printing screen are spaced apart from each other. The method of generating a light control pattern according to claim 2, wherein a gap between the photoconductor and the halftone screen screen is 0.1 to 10 times as large as a halftone dot size of the halftone screen screen. The method of generating a light control pattern according to claim 2, wherein a gap between the photoconductor and the halftone screen screen is 0.5 to 2 times a halftone dot size of the halftone screen screen. The method of generating a light control pattern according to claim 1 or 2, wherein the number of lines of the screen printing screen is 60 lines or more and 400 lines or less. The method of generating a light control pattern according to claim 1 or 2, wherein the number of lines of the screen printing screen is 100 lines or more and 200 lines or less. A light diffusing plate in a surface light source device comprising at least one light source and a light diffusing plate for diffusing light from the light source, wherein a dimming pattern for adjusting a light shielding amount of light from the light source It is a manufacturing method of the light diffusing plate provided on the light source side,
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,
By exposing the photoconductor using a plate-making light source that is disposed at a position corresponding to the light source and has substantially the same light distribution and intensity distribution as the light source, the light diffusion plate is exposed to the photoconductor. Form a halftone pattern according to the light distribution on the surface,
The method of manufacturing a light diffusing plate, comprising forming the light control pattern on the light source side surface of the light diffusing plate based on the halftone pattern.   The light diffusing plate in which the light control pattern produced | generated by the production | generation method of the light control pattern of any one of Claims 1-6 was formed.   The light control film in which the light control pattern produced | generated by the production | generation method of the light control pattern of any one of Claims 1-6 was formed.   A light diffusion 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 that supplies light to the transmissive image display cell, comprising the surface light source device according to claim 11.

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