TWI490566B - Light guide plate making method and device - Google Patents

Description

Light guide plate manufacturing method and device

The present invention relates to a method and apparatus for fabricating a light guide plate for a liquid crystal display device or the like.

It has been previously known to print (print) a transparent acrylic plate or the like using an ink jet printer or the like, and to control the pixel density to produce a light guide plate capable of uniform reflection. Further, it has been known to use and set LEDs. A technique such as changing the printing density by the distance from the peripheral portion of the light source (see, for example, Patent Document 1).

Further, it is also known that in screen printing, there is a problem of a corresponding resolution, which causes a phenomenon that a dot pattern, that is, a so-called dot pattern, can be seen. In order to avoid this phenomenon, it has been proposed to use a light-diffusing sheet or the like, or to eliminate this phenomenon as long as it is set as a fine pitch (for example, refer to Patent Document 2).

[Patent Document 1] Japanese Patent Laid-Open No. Hei 9-68614

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-93319

It is a problem to reduce the thickness of a liquid crystal display device such as a liquid crystal television or a liquid crystal screen, and it is required that a light guide plate for the light guide plate is not thinly observed. Moreover, there is a problem in that only the reflection system of the self-guide plate is made uniform. It is impossible to achieve a good visual effect when viewing the liquid crystal screen visually.

Moreover, a light guide plate having a high brightness is also required in terms of brightness.

The object of the present invention is to solve the above problems.

In order to achieve the above problem, the present invention is a method for fabricating a light guide plate, which transports printed data stored in a light reflection pattern of a computer to an inkjet printer, and uses the inkjet printer to pass the light guide plate to the left and right. a method of producing a light guide plate by performing reflective printing on a substantially rectangular printed surface surrounded by an edge portion for diffusing light emitted from a light source into the interior of the light guide plate; and using the reflective print for use The density of the printed material is increased from the edge portion of the square corresponding to the edge portion of the four sides of the light guide plate toward the high concentration set point set before the opposite edge portions, and is performed using white ink containing titanium oxide. The above reflective printing.

Further, in the present invention, one of the edge portions of the four sides of the printed material is disposed as a light source, and when the distance between the edge portion for arranging the light source and the edge portion opposite to the edge portion is set to 1, The high-concentration set point is set to an arbitrary position that is more than 1/2 and less than 1 from the edge portion for light source arrangement, and is set to be substantially the center between the remaining two edge portions.

Moreover, the present invention is a light guide plate manufacturing apparatus which is composed of an ink jet printer and a computer for printing printed materials of a light reflecting pattern to the printer, and the light reflecting pattern stored in the computer is The printing material is sent to an inkjet printer, and the inkjet printer is used to perform reflective printing on the printing surface of the light guide plate using white ink containing titanium oxide to form a light guide plate, and the reflective printing system is used to emit the light source from the light source. The light to the inside of the light guide plate is diffused; and the printing material used for performing the above-mentioned reflective printing is printed at a concentration from the edge of the four sides of the light guide plate The edge portion of the square becomes higher toward a high concentration set point set in front of the opposite edge portions.

Further, in the present invention, the pattern of the printed material whose density is increased from the edge portion of the four sides toward the high concentration set point is formed by a gradation process.

Further, the present invention is characterized in that the above-described printed material is produced with reference to an ideal luminance distribution pattern required for a light guide plate.

Further, the present invention is characterized in that the ratio of the titanium oxide content of the white ink is set to 10% or less.

Further, the present invention is characterized in that copper phthalocyanine is added to the white ink.

Further, the present invention is characterized in that a white ink supply unit is provided in the ink jet printer, and the white ink supply unit stores a plurality of types of white ink that determine the color temperature of the light-emitting surface of the light guide plate in an ink cartridge one by one; The printer is provided with a plurality of recording heads, one of the ink cartridges is respectively connected to each of the recording heads, and each of the recording heads can eject a different type of white ink; and the inkjet printer forms the reflective printing on the light guide plate. A light guide plate having a color temperature corresponding to the selected one or a plurality of combinations of white inks is produced.

Further, the present invention is characterized in that each of the plurality of white inks which determine the color temperature of the light-emitting surface of the light guide plate has a different particle size distribution of titanium oxide among the various inks.

Further, the present invention is characterized in that each of the plurality of types of white inks which determine the color temperature of the light-emitting surface of the light guide plate has different titanium oxide contents in the various inks.

The present invention can be fabricated near a center when light is emitted from a peripheral portion by a light source such as an LED Since the light guide plate has a high brightness, a good visual effect can be obtained by using it for a liquid crystal screen display device.

Further, it is possible to provide a light guide plate which performs fine printing by changing the printing density by an ink jet method using a white ink using titanium oxide, and which does not detect the dot pattern. Further, since the ink jet method is used, the thickness of the ink can be made thinner, and light emitted by the portion through which the light is transmitted and the portion of the reflection can be provided to generate bright surface light. It is also possible to change the brightness of the fineness by changing the content of the titanium oxide.

2‧‧‧Inkjet printer

4‧‧‧ computer

6‧‧‧Light guide plate

6a‧‧‧Lighting surface

6b‧‧‧Printed surface

8‧‧‧ platform

10‧‧‧ cross rail

12‧‧‧record head

14‧‧‧record head

16‧‧‧record head

18‧‧‧record head

20‧‧‧Printer bracket

22‧‧‧Ink cartridge

24‧‧‧Ink cartridge

26‧‧‧Ink cartridges

28‧‧‧Ink cartridges

30‧‧‧Ink data sheet

32‧‧‧Edge

34‧‧‧Edge

36‧‧‧Edge

38‧‧‧Edge

40‧‧‧Light source

42‧‧‧Ink

44‧‧‧reflector

46‧‧‧ display

48‧‧‧Ink selection button

50‧‧‧mix button

52‧‧‧Print rate button

54‧‧‧ ink points

56‧‧‧Printing information

60‧‧‧Edge

62‧‧‧Edge

64‧‧‧Edge

66‧‧‧Edge

68‧‧‧稜鏡Sheet

70‧‧‧Diffuser

72‧‧‧LED lighting station

74‧‧‧ camera

Figure 1 is a block diagram of the device.

Figure 2 is an explanatory view of the present invention.

Figure 3 is an explanatory view of the present invention.

4 is an explanatory view of a light guide plate.

Fig. 5 is an explanatory view of a light guide plate.

Fig. 6 is an explanatory view of a light guide plate.

Fig. 7 is a partial explanatory view showing a liquid crystal display device.

Fig. 8 is an explanatory view of a light guide plate.

Figure 9 is an explanatory view of the present invention.

Figure 10 is an explanatory view of the present invention.

Figure 11 is an explanatory view of the present invention.

Figure 12 is an explanatory view of the present invention.

Figure 13 is an explanatory view of the present invention.

Figure 14 is an explanatory view of the present invention.

Figure 15 is an explanatory view of the present invention.

Figure 16 is an explanatory view of the present invention.

Figure 17 is an explanatory view of the present invention.

Figure 18 is an explanatory view of the present invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are schematic views showing a light guide plate printing device including a printer 4 and a computer 4 such as a personal computer connected to a controller of the printer 2 via an input/output interface. As shown in FIG. 4, the light guide plate 6 is such that the printing surface 6b on the back side is raised with respect to the light-emitting surface 6a, and is detachably attached to the stage 8 of the printing apparatus.

The printing (printing) of the light guide plate 6 is performed by the printing unit main body driving unit, and the horizontal rail 10 is set as the printing unit in the single direction (sub-scanning direction), and the horizontal rail is along the other side. 10. The print head carriage 20 having the ink jet recording heads 12, 14, 16, 18 is controlled in the main scanning direction perpendicular to the conveying direction of the cross rail 10 by the control of the head carriage driving portion. Move. When the print head carriage 20 moves in the main scanning direction, the ink is ejected from the nozzles of the recording heads 12 to 18, so that the print data sent from the computer 4 to the controller of the inkjet printer 2 is stored in the control. The software of the device is printed and printed on the printing surface 6b of the light guide plate 6. Furthermore, the printing in the text is synonymous with printing.

In the memory device of the computer 4, a printing program for controlling the printing of the ink jet printer 2 for printing is stored. On the platform 8, the cross rail 10 is configured to be movable in parallel in the sub-scanning direction, and the print head carriage 20 is movably coupled to the cross rail 10 in the main scanning direction. As shown in FIG. 3, a plurality of ink jet recording heads 12, 14 are held in the print head carriage 20. 16, 18.

Each of the recording heads 12, 14, 16, and 18 is provided with a plurality of nozzles for ejecting ink. As shown in FIG. 3, each of the heads 12, 14, 16, and 18 is respectively connected to an ink cartridge corresponding to the white ink supply portions A, B, C, and D of the ink cartridge provided in the body of the printer 2 via an ink supply mechanism such as a catheter. 22, 24, 26, 28 are connected. Along the main scanning direction of the cross rail 10, a plurality of recording heads 12, 14, 16, 18 are arranged side by side in such a manner that the printing areas of each other coincide.

In the memory device of the computer 4, a software (printing program) for printing a material for producing a light reflection pattern is stored, and an ink data table 30 is provided. The data sheet 30 is used to prepare a light guide plate of a plurality of color temperatures by printing a plurality of white inks A, B, C, and D in a single or combined manner, thereby setting a color temperature and ink in advance. A combination of A, B, C, and D, and by using the data sheet 30, a light guide plate of a plurality of color temperatures can be easily produced.

In Table 1, white inks A and B show two kinds of inks having different ink color temperatures according to the particle diameter of titanium oxide, and white ink C indicates white ink in which the content of titanium oxide is different from that of white ink A, and white ink D indicates titanium oxide therein. White ink with a different content than white ink B. In the present embodiment, a plurality of kinds of white inks are prepared for the particle diameter and content of titanium oxide, whereby printing at a plurality of color temperatures or printing of the combinations can be easily performed. It was confirmed in the experiment that the content of the titanium oxide in the white ink is preferably 10% or less, and by reducing the content of the titanium oxide, the slight gradient change of the light-emitting surface of the light guide plate can be easily controlled.

【Table 1】

The printing program for control printing stored in the computer 4 is configured to be capable of producing, correcting, and the like of the ink data sheet 30. The light guide plate 6 is formed by printing a reflection point on a plane portion of the printing surface 6b of a light guide plate such as a transparent acrylic plate, or reflecting a gradient layer (such as a small point of frosted glass), and as shown in FIG. 4 As shown in Fig. 6, by arranging a light source 40 composed of a luminescent material such as a cold cathode tube or an LED at a thickness portion of the edge portion 32 of the upper portion of the rectangular light guide plate 6, the entire surface of the light-emitting surface 6a is visible. By.

The light emitted from the light source 40 to the light guide plate 6 enters the inside from the edge portion 32 of the light guide plate 6, and is internally reflected and diffused to the entire light guide plate 6 as indicated by the arrow. The light is scattered upward, or passes through the ink 42, returns from the reflection plate 44, is reflected by the edge portions 34, 36, 38 of the light guide plate 6, and the like, and diffuses to the entire light guide plate 6. When an ink containing titanium oxide is used, white ink having a different color temperature is prepared according to the distribution of the particle diameter of the titanium oxide in the ink. When the variation in the particle size distribution is changed, the reflected light is different and the color temperature is different. Since the particle diameter of titanium oxide in the ink is different, the intensity of light scattered after printing differs depending on the wavelength of light, and as a result, the color temperature of the scattered light of the printed light guide plate is different.

[About white ink and color temperature]

White ink uses titanium oxide as a pigment for inks. Titanium oxide particles have the strongest energy The property of the wavelength light of 2 times the particle diameter is strongly reflected, and the distribution of the particle diameter of the titanium oxide which is preferable as the white ink is uniformly present in the range of 200 nm to 400 nm as shown in FIG. 14 . In this case, it is a white light having a wavelength of twice from 200 nm to 400 nm, that is, 400 nm to 800 nm (visible light).

However, in the actual white ink, it is rare that the distribution of the particle diameter uniformly exists at 200 nm to 400 nm.

(1) When the particle diameter is present in a large amount at 200 nm (refer to Fig. 15), it is a white ink which strongly reflects light of 400 nm (short wavelength), a white ink having a high color temperature and a blue color.

(2) When the particle diameter is present in a large amount at 400 nm (refer to Fig. 16), it is a white ink that strongly reflects light of 800 nm (long wavelength), a white ink having a low color temperature and having red, or yellow, and green.

In the adjustment of the color temperature, a combination of the white inks having different color temperatures (different distributions of titanium oxide) is used to produce a light guide plate having a desired color temperature = a desired titanium oxide distribution = a desired light wavelength region. However, when it is difficult to adjust the color temperature only by the particle diameter of titanium oxide, a desired light wavelength region can be obtained by adding other particles, copper indigo or the like.

14 to 16 are image diagrams showing the particle size distribution of titanium oxide in the ink, in which the horizontal axis represents the particle diameter and the vertical axis represents the degree of distribution. Fig. 14 shows the distribution of titanium oxide particles in an ideal white ink, and Figs. 15 to 16 show the distribution of titanium oxide particles in an actual white ink.

A trace amount of copper indigo was added to the ink used in the present embodiment. The amount of this addition was obtained as a result of facilitating the control of the color temperature of the ink by selecting an appropriate amount in the experiment. When the light guide plate 6 is printed, the operator selects the ink selection button 48 displayed on the display 46 of the computer 4 by a mouse or the like, thereby selecting the white inks A, B, C, and D, and by operating. By mixing the buttons 50, the white inks can be configured to be mixed into a desired combination. In addition, a plurality of inks of A, B, A, and C may be specified, and may also correspond to the printed materials produced by the printing. System, which ink is specified for which print portion.

Fig. 9 is a view showing a printing material 56 for a reflecting surface which is produced on a computer by using a printing material for producing a reflective pattern of a light guiding plate. The printed material 56 is formed in a rectangular area corresponding to the rectangular shape of the light guide plate, and is formed in such a manner that the printing density (density) is increased toward a high concentration set point set in the rectangular area. Since the reflection pattern of the light guide plate is printed, the printout is performed on the whole, and the gradient direction of the print density therein is displayed. In addition, FIG. 9 is only an example, and a shape etc. are not specifically limited to this. In Fig. 18, a specific image of the print density (printing density) of the print material 66 is stereoscopically formed, and in the figure, the symbol P indicates a high density set point. The high-concentration set point indicates the highest concentration portion. In the present embodiment, the high-concentration set point is only one point, but is not particularly limited to one point, and may have a certain degree of expansion (space) toward the square as shown in FIG. Further, in Fig. 18, numeral 1 indicates the direction of the light source, and numerals 1 to 7 indicate that the light source side edge portion 60 of the printed material 56 and the edge portion 62 opposite thereto are equally divided into seven. Further, S1, S3, and S5 indicate scales between the left and right edge portions 64 and 66. A high-density set point P is set in the vicinity of the center of the lower portion in the rectangular region, and the portion where the printing density is concentrated is concentrated at the point because the farther away from the portion of the light source, the higher the reflectance, etc., but other surrounding portions are required. There is also a portion that is affected by the reflection from the return of the end portion (see Fig. 6). Therefore, the material of the printed pattern can also be produced in consideration of the portion.

The printed material 56 is produced by a gradient pattern. Here, the gradient layer refers to a print density change pattern formed by a gradient pattern generation mode of a software for printing a material. In the pattern of the gradation pattern, the printing density can vary from 0% to 100%. Fig. 10 is an explanatory diagram of the concentration in the gradient pattern diagram, in which Fig. 10 shows (A) indicating a concentration of 0%, (B) indicating a concentration of 25%, and (C) indicating a concentration of 50%, (D). Indicates 75% concentration, (E) means 100% Concentration. Furthermore, FIG. 10 is only briefly described. In the actual printing, since the printing is performed at a plurality of points, the position of the printing is specified by the resolution of the printer, and the range is specified. It can print in any range from 0 to 100%.

In the print data 56, the first density change portion is set from the light source arrangement side edge portion 60 of the print material 56 to the high density set point set in the print region, so that the print density is from a lighter state. The manner in which the gradation pattern is formed is changed to the most concentrated state. The arrow a indicates a case where the concentration is increased from a lighter state toward a direction of an arrow, that is, a high concentration set point, in the first concentration change portion.

The second concentration change portion is a high-concentration set point from the opposite side edge portion 62 of the light source arrangement side edge portion 60 toward the print region in a shorter range, so that the print density is from a lighter state to form a gradation. It is formed by changing to the most concentrated state.

The arrow b indicates a case where the concentration is increased from a lighter state toward a direction of an arrow, that is, a high concentration set point, in the second concentration change portion. Also, from the edge portions 64 and 66 of the left and right sides, the high concentration set point toward the printing area in a shorter range is used, so that the printing density changes from the lighter state to the gradual pattern to the thickest. In the state, the third concentration changing unit and the fourth concentration changing unit are formed. The arrow c indicates that the concentration is thicker in the direction of the arrow from the lighter state in the third concentration changing portion, and the arrow d indicates that the concentration is thicker in the direction of the arrow from the lighter state in the fourth concentration changing portion. Happening.

The printed material 56 is designed with reference to the ideal brightness distribution pattern of the previously prepared light guide plate. Fig. 17 is a graph showing the relationship between dot density and luminance, in which X represents the direction of the light source, and each horizontal axis represents the distance from the light source. If the high concentration set point is at substantially the center between the left and right edge portions and the distance between the light source arrangement side edge portion 60 and the edge portion 62 on the opposite side thereof is set to 1. The high-concentration set point is set at any position that is more than 1/2 from the edge portion 60 and is less than 1 (that is, in front of the edge portion 62), and is divided into seven equal parts in the present embodiment. The peak of the high concentration portion appears at a position of about 6/7 from the edge portion 60, but the position depends on the material, the thickness of the light guide plate, the type of the ink, the brightness of the light source, and the like. For example, when the thickness of the light guide plate is thin, 1/4, 1/3, etc. from the edge portion 62 may occur, and the closer to the vicinity of the center, the better. Further, the magnitude of the change in the printing density can also be changed depending on the conditions. This time, the printing density is changed toward the high-concentration set point P at the front end portion of the high-concentration portion, but the portion is not necessarily the front end state as shown in FIG. 18, and may be changed toward a flat region above a certain fixed level. .

Further, when the printing of the light source is performed on the upper and lower edge portions 60 and 62, the high concentration set point is substantially at the center between the left and right edge portions, and the distance between the edge portion 60 and the edge portion 62 on the opposite side is set to 1, it is preferable to set the distance to the edge portion 62 by about 1/2. The brightness of an ideal brightness distribution pattern is displayed by color (color). Fig. 12 is a view showing a luminance distribution pattern of the light guide plate in the embodiment, which is substantially identical to the ideal luminance distribution pattern as a reference.

The area a of the light-emitting surface 6a of the light guide plate 6 is 1000 to 1500 (the following units are: candela/square meter), the area b is 1500 to 2500, the area c is 2500 to 3500, and the area d is 3500. ~4000, the area e is 4500~.

【Table 2】

The light guide plate 6 having the ideal brightness distribution pattern shown in FIG. 12 is used for a liquid crystal television or a liquid crystal screen including a prism sheet 68, a diffusion plate 70, and a reflection plate 44 as shown in FIG. In the liquid crystal display device, an optimum surface light-emitting device suitable for human vision with high luminance at the center and a slightly low luminance at the end portion can be obtained. When the reflective print material 56 made of the soft body is printed on the light guide plate 6, the operator selects the type of ink to be used or the ink mixing condition, inputs it to the computer 4, and clicks the print button.

Thereby, the printed data is sent from the computer 4 to the printer 2, and thereafter, the data is processed by the printer 2, and then the print width bracket is set by the cross rail 10 as the sub-scanning direction, and the print head carriage is transported. 20 is driven in the main scanning direction to perform printing on the light guide plate 6 by the white ink of the selected printing condition. In the present embodiment, the thickness H of the ink dot 54 as shown in Fig. 13 is set to 0.5 μm, which is very thin compared to screen printing (about 100 μm).

Thereby, the light guide plate 6 which is brighter than the previous one can be obtained by the multiplication effect of the light reflected from the point of the white ink and the light reflected from the reflection plate 44 through the ink. The white ink used for printing adjusts the content of titanium oxide in order to facilitate the use of fine gradient printing to control the brightness. By changing the content of titanium oxide, the amount of reflection is changed accordingly, so that it can be changed in response to small changes. The amount of reflection or amount of light can be easily controlled.

In order to perform such fine control, it is preferable that the content of the titanium oxide of the white ink is 10% or less. Further, in the present case, a white ink of about 1% is prepared for finer control, by a single white ink or a combination of a plurality of white inks. It is used to control the brightness of the printing with a slight gradient.

Further, in an ink jet printer that controls the ink ejection amount by using a plurality of ink ejection wavelengths or driving voltages and can change the dot diameter, since a plurality of resolutions can be matched, for example, a resolution of 1440 dpi is filled in. (dots per inch) The required dot diameter of about 25 μm is used for printing, and it is easy to control the brightness by a slight gradation, and it is also possible to use a dot diameter of about 100 μm required for filling 360 dpi. Improve printing speed. Further, it is also possible to perform printing by filling in a dot diameter of about 50 μm required for 720 dpi. Furthermore, in the actual printing, the print head is moved while printing, so that the dot diameter is elliptical, so that in the resolution to be used, the diameter of the dot can be filled even in the narrow width direction. Yes, you can also combine multiple dot diameters for printing if you cannot fill them in.

When the printing of the light guide plate 6 is completed, the printed light guide plate 6 is attached to the LED lighting table 72 shown in FIG. 2, the LED is lit, and the light emitting surface of the light guide plate 6 is photographed by the camera 74, and the light emitting surface is measured. Brightness distribution.

The brightness data measured by the camera 74 (the brightness is displayed in color) is displayed as a brightness distribution pattern on the screen of the computer 4 or printed, and compared with the ideal brightness distribution pattern as a reference, if the light guide 6 The brightness distribution is consistent or similar to the ideal brightness distribution pattern, and the printing data production operation on the computer ends. If the result that should be satisfactory is not obtained at this time, the printed data is corrected, and the operation is repeated until the desired brightness distribution pattern is obtained. For example, when the portion having the higher luminance in FIG. 12 is slightly shifted downward, the printing density of the printing portion of the corresponding portion in the printing material shown in FIG. 9 is changed, or the printing density is increased. The position correction is to move slightly upwards. Further, it is also possible to cope with changing the type of ink used at the position or the diameter of the ink dot used.

In the above embodiment in which the printing density is changed by the ink jet method using the white ink of titanium oxide to perform fine printing, it is possible to provide a light guiding plate which does not cause a so-called dot pattern to be seen. Further, since the thickness of the ink can be made thinner in the ink jet method, bright surface light can be provided by the light transmitted through the portion and the reflecting portion. By preparing a plurality of white inks having different color temperatures in advance, it is possible to easily print at a plurality of color temperatures, and it is also possible to perform combination printing, so that fine color temperature control can be performed.

When reducing the content of titanium oxide, it is possible to easily control the slight change of the amount of light reflection, and it is also possible to provide a plurality of white inks which change the content of titanium oxide, and when printing with a smaller spot diameter More detailed control is possible.

When the light guide plate manufactured by the present apparatus is used in a liquid crystal display device or the like, the diffusion plate or the like can be eliminated if the conditions of the user are satisfied, and the thickness of the structure can be reduced. In addition, the number of parts can be reduced in terms of cost.

In the above embodiment, the light source 40 is disposed on the edge portion 32 of one side of the light guide plate 6. However, the light source 40 is not particularly limited thereto, and as shown in FIG. 8, the light source may be disposed at the edge portions 32 and 34 on both sides. 40, 40 and. When a light source is provided at the end of both sides, the luminance distribution also changes, so that a print pattern to be matched with it is required, and in the data aspect, the portion having a high print density moves toward the center. Furthermore, even if there is unevenness in the brightness of the light source, the desired brightness distribution can be obtained by correcting the portion using the printing pattern, and Corresponding to the difference in light source at both ends.

Further, although the present invention has been described with respect to an apparatus in which an inkjet head is moved by a fixed medium, the present invention is not limited thereto, and may be a device for printing a medium to be printed or a line head. The printer or the like can be printed by an inkjet method.

Further, in the ink jet printer, a plurality of resolutions can be used depending on the specifications of the product. Therefore, the resolution can be selected as needed (for example, selecting a necessary printing mode such as 180 to 1440 dpi).

56‧‧‧Printing information

60, 62, 64, 66‧‧‧ edge

a, b, c, d‧‧‧ arrows

Claims (10)

A method for manufacturing a light guide plate, wherein the printed material stored in a light reflection pattern of a computer is sent to an inkjet printer, and the inkjet printer is used to surround the upper and lower edges of the light guide plate. a method of producing a light guide plate by performing reflective printing on a printed surface of a rectangle, the reflective printing for diffusing light emitted from the light source to the inside of the light guide plate; and printing the printed material for performing the reflective printing to have a concentration The edge portions corresponding to the edge portions of the four sides of the light guide plate become higher toward the high concentration set point set before the opposite edge portions, and the above-mentioned reflective printing is performed using white ink containing titanium oxide; the titanium oxide content of the above white ink The ratio is set to 10% or less. The light guide plate manufacturing apparatus according to claim 1, wherein one of the edge portions of the four sides of the printed material is disposed as a light source, and the light source is disposed at an edge portion and opposite to the edge portion. When the distance between the side edge portions is set to 1, the high-concentration set point is set at any position that is more than 1/2 from the edge portion of the light source arrangement and is less than one, and is set to be between the remaining two edge portions. Basically central. A light guide plate making device is composed of an ink jet printer and a computer for printing printed materials of a light reflection pattern to the printer, and transports the printed data of the light reflection pattern stored in the computer to the spray An ink jet printer for producing a light guide plate by using a white ink containing titanium oxide on a printing surface of a light guide plate to produce a light guide plate for emitting light from a light source to the inside of the light guide plate Light diffusion; the printing material used for performing the above-mentioned reflective printing is printed at a concentration concentration from a peripheral edge portion corresponding to the edge portion of the four sides of the light guide plate toward a high concentration set point located before the opposite edge portion The height is increased; the ratio of the titanium oxide content of the above white ink is set to 10% or less. The light guide plate manufacturing apparatus according to claim 3, wherein one of the edge portions of the four sides of the printed material is disposed as a light source, and the light source is disposed at an edge portion and opposite to the edge portion. When the distance between the side edge portions is set to 1, the high-concentration set point is set to a position that is more than 1/2 from the edge portion of the light source arrangement and is less than one, and is set to be between the remaining two edge portions. It is roughly central. The light guide plate manufacturing apparatus according to claim 3, wherein the pattern of the printed material whose density is increased from the edge portion of the four sides toward the high concentration set point is formed by a gradation process. The light guide plate manufacturing apparatus of claim 3, wherein the print data is produced by referring to an ideal brightness distribution pattern required for the light guide plate. The light guide plate manufacturing apparatus of claim 3, wherein the white ink is added with copper phthalocyanine. The light guide plate manufacturing apparatus according to claim 3, wherein the ink jet printer is provided with a white ink supply unit that stores a plurality of types of white ink that determine the color temperature of the light-emitting surface of the light guide plate in the ink cartridge one by one. a plurality of recording heads are disposed on the inkjet printer, and one of the ink cartridges is respectively connected to each of the recording heads, and each of the recording heads can eject a different type of white ink; and the inkjet printer is in the above-mentioned guide The light plate is formed into the above-described reflective printing to produce a light guide plate having a color temperature corresponding to a combination of one or a plurality of types of white inks selected. The light guide plate manufacturing apparatus of claim 3, wherein each of the plurality of white inks that determine the color temperature of the light-emitting surface of the light guide plate has a different particle size distribution of titanium oxide among the various inks. The light guide plate manufacturing apparatus according to claim 3, wherein each of the plurality of white inks that determine the color temperature of the light-emitting surface of the light guide plate has a different titanium oxide content in each of the inks.