JP2004226710A - Display lighting device using light guide sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display lighting device wherein thickness and weight is not increased so much without increasing the number of light guide bodies even if a display size is enlarged and occurrence of moire fringes is reduced. <P>SOLUTION: In the display lighting device lighting a display consisting of a plurality of image display elements 12 by using a light guide sheet 14, the light guide sheet 14 is constituted of a substrate 16, a light guide body 18 disposed in a bent and folded form on the surface of the substrate 16 byalternately providing long side parts 19 consisting of linear lines and short side parts 20 consisting of linear lines and disposed so as to be nearly vertical to the long side parts 19 and guiding light introduced from an end part 23 along a length direction and a plurality of light emission ports 21 disposed in the surfaces of the long side parts 19 and emitting light guided by the light guide body 18 from the interior to the exterior of the light guide body 18 to light the image display elements 12. Disposition pitch P<SB>2</SB>of the long side parts 19 disposed on the surface of the substrate 16 is made shorter than the pixel pitch P<SB>1X</SB>of the image display elements 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display illuminating device using a light guide sheet, and more particularly, to a display illuminating device using a thin plate light guide sheet that uniformly transmits light from a light source over the entire display screen of a display, and effectively displays the display. The present invention relates to a display lighting device for illuminating a display.
[0002]
[Prior art]
2. Description of the Related Art Among displays having a built-in lighting device, a liquid crystal display (LCD) is remarkably popular, and illumination light from a light source (backlight or edge light) for generating display light is transmitted to a display screen. Of the type provided with a light guide sheet for making the brightness and the irradiation direction uniform at the same time is also remarkably widespread.
[0003]
There are various types of display lighting devices that illuminate such displays. One is a display illumination device of a type that illuminates the display screen directly from the back of the display screen (the side opposite to the observer) (hereinafter, referred to as “backlight illumination device”). In addition, a display lighting device (hereinafter, referred to as a “light-emitting device”) that illuminates a display screen after passing illumination light from a light source disposed outside (eg, a side surface of) the display screen through a light guide sheet disposed on the back of the display screen. Edge light type illumination device ").
[0004]
As an illuminating device for a liquid crystal display, an edge light type illuminating device is often used. A substrate made of a translucent material, a linear light source made of a cold-cathode tube or the like provided at a side end thereof, and a And a light guide sheet formed of a light diffusion film and a lens sheet disposed on the upper surface of a substrate serving as a light output surface.
[0005]
In this type of light guide sheet, a dot-like pattern made of light diffusion ink on the back surface of the substrate increases as the distance from the light source increases, in order to improve unevenness in the amount of light output due to the distance of the light guide from the light source. Countermeasures are taken such as printing.
[0006]
On the other hand, the light diffusion film is arranged mainly for the purpose of uniformly diffusing the light and making the dot pattern printed on the back surface of the substrate invisible, and the lens sheet efficiently converts the light emitted from the substrate to the liquid crystal. One or two light-diffusing films are disposed on the upper surface of the light-diffusing film or between the light-diffusing film and the substrate in order to collect light in the front direction of the panel.
[0007]
As the above-mentioned lens sheet, a lens sheet (prism sheet) in which a large number of triangular prism type unit lens portions are arranged in parallel in order to uniformly and isotropically diffuse radiated light within a desired angle range is used. This lens sheet is called BEF (Brightness Enhancement Film: trade name, manufactured by Sumitomo 3M Limited).
[0008]
In addition, some methods for guiding light from a light source through an optical fiber have been applied to other light guide sheets in an edge light type lighting device or the like. The advantage of using an optical fiber is that the illumination light from the light source can be transmitted to the illumination target with low loss, and that the optical path from the light source to the illumination target can be bent. The flexibility is to be improved.
[0009]
Known documents related to a display lighting device using a light guide sheet using such an optical fiber will be described below.
[0010]
Patent Literature 1 discloses an illuminating device for illuminating a liquid crystal display from behind, which comprises a micro-converging lens array and a micro-secondary light source arranged at the focal point of each micro-converging lens, and irradiates substantially parallel light. Discloses a technique to which an optical fiber is applied.
[0011]
Patent Document 2 discloses a display panel for a liquid crystal display provided with pixels corresponding to the three primary colors of red, green, and blue, a light source unit for a backlight-type lighting device that illuminates the display panel with light transmitted from the back, and a display panel. There is disclosed a lighting device for a full-color liquid crystal display, which is provided with wavelength selecting means for transmitting only the primary colors corresponding to the respective pixels. Here, the light source unit of the backlight type illumination device is characterized in that the light emitting surface is divided into red, green and blue light emitting blocks corresponding to the pixels of the display panel.
[0012]
Patent Literature 3 discloses an optical fiber backlight module for a color display lighting device. This consists of a light source, a plurality of side-emitting optical fibers connected to the light source, arranged in parallel, transmitting light emitted from the light source, and emitting light from the side to form an optical fiber of the first layer, and a side-emitting optical fiber. A plurality of column isolation parts provided between adjacent columns are provided.
[0013]
In Patent Document 4, at least one LED, a plurality of optical fibers having an emitting end arranged substantially linearly and an incident end facing the LED, and a light for optically connecting the LED and the incident end of the optical fiber are disclosed. A lighting device having a connecting means is disclosed.
[0014]
As exemplified above, any of the lighting devices using the light guide sheet to which the optical fiber is applied is configured so that a light beam is incident from one end and the light is emitted as illumination light toward an illumination target. I have.
[0015]
[Patent Document 1]
JP-A-6-222362
[Patent Document 2]
Japanese Patent Application Laid-Open No. 9-252825
[Patent Document 3]
JP-A-10-288782
[Patent Document 4]
JP 2000-231816 A
[Problems to be solved by the invention]
However, such a conventional display lighting device has the following problems.
[0020]
That is, in the case of a display lighting device using the light guide sheet as described above, in order to uniformly illuminate the entire display screen, as the size of the display screen increases, the light guide sheet requires a large number of optical fibers. In addition, an increase in the length and the number of optical fibers leads to an increase in the size of the light guide sheet. Further, as the length and the number of optical fibers increase, the arrangement of the optical fibers on the surface of the light guide sheet becomes complicated.
[0021]
Further, it is known that when the thickness of the light guide sheet is increased, moiré easily occurs between the light guide sheet and an image display element constituting a display.
[0022]
Therefore, a display illuminating device using such a light guide sheet, as the size of the display screen increases, the thickness and weight thereof also increase correspondingly, so that not only moiré is easily generated but also the manufacturing becomes difficult. There is a problem of complexity.
[0023]
The present invention has been made in view of such circumstances, and allows an optical fiber to be freely and compactly arranged over the entire surface of a light guide sheet. It is an object of the present invention to provide a display lighting device capable of reducing the occurrence of moiré without increasing the number and the thickness and weight thereof.
[0024]
[Means for Solving the Problems]
In order to achieve the above object, the present invention takes the following measures.
[0025]
That is, a display lighting device according to the first aspect of the present invention is a display lighting device that illuminates a display including a plurality of image display elements by using a light guide sheet, wherein the light guide sheet has a length formed of a substrate and a straight line. By alternately providing sides and short sides composed of straight lines arranged so as to be substantially perpendicular to the long sides, they are arranged in a folded shape on the surface of the substrate, and light is introduced from the ends. Then, a tubular light guide that guides the introduced light along the length direction, and a light that is arranged on the surface of the long side of the light guide and guided by the light guide, The image display device includes a plurality of light emission ports that emit light from inside to outside to illuminate the image display element. The arrangement pitch of the long sides arranged on the surface of the substrate is set to be smaller than the pixel pitch of the pixel display element.
[0026]
Therefore, in the display lighting device of the first aspect of the present invention, by taking the above measures, the optical fibers can be freely and compactly arranged over the entire surface of the light guide sheet. As a result, it is possible to realize a display illuminating device using a light guide sheet that does not increase the thickness and weight without increasing the number of optical fibers even if the size of the display increases. This also makes it possible to reduce the occurrence of moire.
[0027]
According to a second aspect of the present invention, in the display lighting device of the first aspect, the pixel pitch (P ₁ ) and the arrangement pitch (P ₂ ) are 1 / | m / P ₁ for all m and n. −n / P ₂ | <10 × P ₂ , where m and n satisfy an integer of 1 or more and 10 or less.
[0028]
That is, the display lighting device according to the second aspect of the present invention further restricts the range of the pixel pitch (P ₁ ) and the arrangement pitch (P ₂ ) from the range of the first embodiment. It becomes possible to further reduce the occurrence of moiré. The pixel pitch (P ₁ ) and arrangement pitch (P ₂ ) are 1 / | m / P ₁ −n / P ₂ | <10 × P ₂ for all m and n, where m and n are 1 When the relationship of an integer of 10 or more and 10 or less is satisfied, the moiré intensity is at a level that can hardly be recognized by the naked eye. Note that the light guide disposed on the light guide sheet has a plurality of arrangement pitches (P _2x and P _2Y ) that differ depending on the direction (for example, the X direction and the Y direction) depending on the pattern. Then, the gist is to apply to any arrangement pitch.
[0029]
The invention according to claim 3 is a display illumination device for illuminating a display including a plurality of image display elements using a light guide sheet, wherein the light guide sheet includes a substrate, a long side portion formed of a straight line, and a long side. And alternately with short sides consisting of straight lines arranged to be substantially perpendicular to each other, so that they are arranged in a folded shape on the surface of the substrate, and when light is introduced from the end, they are introduced. Tubular light guide that guides the light along the length direction, and light that is arranged on the surface of the long side of the light guide and emitted by the light guide from the inside of the light guide to the outside In this way, the image display device is configured to have a plurality of light emission ports for illuminating the image display device. The arrangement pitch of the light exit ports is set to be smaller than the pixel pitch of the pixel display element.
[0030]
Therefore, in the display lighting device according to the third aspect of the present invention, by taking the above measures, the optical fibers can be freely and compactly arranged over the entire surface of the light guide sheet. As a result, it is possible to realize a display illuminating device using a light guide sheet that does not increase the thickness and weight without increasing the number of optical fibers even if the size of the display increases. This also makes it possible to reduce the occurrence of moire.
[0031]
According to a fourth aspect of the present invention, in the display lighting device of the third aspect, the pixel pitch (P ₁ ) and the arrangement pitch (P ₃ ) are 1 / | m / P ₁ for all m and n. −n / P ₃ | <10 × P ₃ , where m and n satisfy an integer of 1 or more and 10 or less.
[0032]
That is, in the display lighting device according to the invention of claim 4, the range of the pixel pitch (P ₁ ) and the arrangement pitch (P ₃ ) is further limited as compared with that of claim 3. It becomes possible to further reduce the occurrence of moiré. The pixel pitch (P ₁ ) and arrangement pitch (P ₃ ) are 1 / | m / P ₁ −n / P ₃ | <10 × P ₃ for all m and n, where m and n are 1 When the relationship of an integer of 10 or more and 10 or less is satisfied, the moiré intensity is at a level that can hardly be recognized by the naked eye. Note that the arrangement pitch of the light exit ports has a plurality of arrangement pitches (P _{3 x} and P _3Y ) that differ depending on the direction (for example, the X direction and the Y direction) depending on the pattern. This is also intended to be applied to the arrangement pitch of.
[0033]
According to a fifth aspect of the present invention, in the display lighting device according to the first or third aspect, the arrangement pitch is determined by a random number.
[0034]
Therefore, in the display lighting device according to the fifth aspect of the present invention, as described above, the arrangement of the light guide is not given regularity, so that the display lighting device according to the first or third aspect of the present invention is further improved. Moire can be reduced. The setting range of the random number can be freely set in a range smaller than the pixel pitch and larger than the width of the light guide, but is set in consideration of the luminance balance of the entire display screen. A plurality of arrangement pitches (P _3x and P _{3Y in} the case of the subordinate claim 1, P _3x and P _{3Y in} the case of the subordinate claim 3) differ depending on the direction (for example, the X direction and the Y direction). However, here, the gist is to apply to any of the arrangement pitches.
[0035]
According to a sixth aspect of the present invention, in the display lighting device according to the first or third aspect, the arrangement pitch is reduced as the distance of the light guide from the end into which light is introduced is longer.
[0036]
Therefore, in the display lighting device according to the sixth aspect of the present invention, by taking the above measures, moire can be reduced. In selecting the method of arranging the light emitting ports, the setting is made in consideration of the luminance balance of the entire surface. Note that the arrangement pitch is different depending on the direction (for example, the X direction and the Y direction). A plurality of arrangement pitches (P _3x and P _3Y if dependent on claim 1, P _3x and P _3Y if dependent on claim 3) ), But here, the gist is to apply to any arrangement pitch.
[0037]
According to a seventh aspect of the present invention, in the display lighting device according to the third aspect of the present invention, the opening area of the light exit is increased as the distance of the light guide from the end into which light is introduced is increased.
[0038]
Therefore, in the display lighting device according to the seventh aspect of the present invention, by taking the above-described means, it is possible to reduce the moire by applying a displacement without making the opening area of the light exit opening constant. Also in this case, when selecting the method of arranging the light exit ports, the setting is made in consideration of the luminance balance of the entire surface.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0040]
(First Embodiment)
A first embodiment of the present invention will be described with reference to FIGS.
[0041]
FIG. 1 is a plan view showing a configuration example of the display lighting device according to the first embodiment.
[0042]
That is, the display lighting device according to the present embodiment illuminates the display including the plurality of pixel display elements 12 using the light guide sheet 14. The light guide sheet 14 includes a substrate 16, a tubular light guide 18, and a plurality of light exit ports 21 formed by perforating the surface of the light guide 18.
[0043]
The light guide 18 uses, for example, an optical fiber and has a uniform shape and size along the length direction. That is, the shape and dimensions of the cross section orthogonal to the length direction are constant over the length direction. In the present embodiment, such a light guide 18 is provided with a long side portion 19 formed of a straight line and a short side portion 20 formed of a straight line arranged substantially perpendicular to the long side portion 19 alternately. Thereby, it is arranged so as to be folded on the surface of the substrate 16. Then, the incident light emitted from the light source 22 is introduced into the inside from the end portion 23, and the introduced incident light is guided along the length direction.
[0044]
The light exit port 21 is provided by drilling in the surface of the long side portion 19 of the light guide 18, and emits the incident light guided into the light guide 18 from the inside of the light guide 18 to the outside. Thus, the pixel display element 12 is illuminated. The emission characteristics at the light exit 21 are determined by the size (width, thickness, etc.) and the refractive index. For this reason, by mechanically processing the light exit port 21, fine irregularities and the like can be formed, and light scattering and diffraction can be generated according to the irregularities.
[0045]
Further, as shown in the following formulas (1) and (2), the arrangement pitch (P ₂ ) of the long sides 19 is less than the pixel pitch (P _1X ) of the pixel display element 12 in the same direction, and the light exit port The arrangement pitch (P ₃ ) of the pixels 21 is set to be smaller than the pixel pitch (P _1Y ) of the pixel display element 12 in the same direction.
[0046]
P _1X > P ₂ (1)
P _1Y > P ₃ (2)
As an example of a method of forming the arrangement pattern of the light guides 18 as shown in FIG. 1, for example, a photosensitive resin layer such as a photoresist is formed on the entire surface of the substrate 16 and the photosensitive pattern is formed into a desired pattern. There are a method using a photolithography method for patterning the resin layer, and a method in which an originally fiber-shaped light guide 18 is stretched around the surface of the substrate 16 in a pattern. As another method of forming a pattern with the photosensitive resin layer, there is a method of forming a groove corresponding to the pattern in advance on the surface of the substrate 16 and embedding the light guide 18 in the groove.
[0047]
The arrangement pattern of the light guides 18 is not limited to the arrangement pattern in which one light guide 18 is folded back and forth so as to be arranged over almost the entire surface of the substrate 16 as shown in FIG. 2 to 6 may be used.
[0048]
The arrangement pattern shown in FIG. 2 is an arrangement pattern in which one light guide 18 is swirled so as to be arranged over substantially the entire surface of the substrate 16. The arrangement pattern shown in FIG. 3 is an arrangement pattern in which the light guide 18 of a type that branches at a plurality of locations is arranged over almost the entire surface of the substrate 16. Also, as shown in FIGS. 4 to 6, a folded type arrangement pattern as shown in FIG. 1, a spiral type arrangement pattern as shown in FIG. 2, and a branch type arrangement pattern as shown in FIG. An arrangement pattern formed by appropriately combining any arbitrary arrangement patterns may be used.
[0049]
Next, the operation of the display lighting device according to the present embodiment configured as described above will be described.
[0050]
That is, in the display lighting device according to the present embodiment, the incident light emitted from light source 22 is introduced into light guide 18 from end 23. The introduced incident light is guided inside the light guide 18 to the other end side along the length direction.
[0051]
As the light guide 18, for example, an optical fiber having a uniform shape and size along the length direction is used. As shown in the plan view of FIG. 1, for example, such a light guide 18 has a long side 19 formed of a straight line and a short side formed of a straight line arranged substantially perpendicular to the long side 19. The portions 20 are alternately arranged on the surface of the substrate 16 so as to be alternated.
[0052]
Alternatively, a spiral arrangement pattern as shown in FIG. 2, a branch arrangement pattern as shown in FIG. 3, or a folded arrangement pattern as shown in FIG. 1 as shown in FIGS. An arrangement pattern obtained by appropriately combining any one of a spiral arrangement pattern as shown in FIG. 2 and a branch arrangement pattern as shown in FIG. 3 may be used.
[0053]
The arrangement pattern of the light guide 18 may be, for example, a photolithography method in which a photosensitive resin layer such as a photoresist is formed on the entire surface of the substrate 16 and the photosensitive resin layer is patterned into a desired pattern, It can be easily realized by a method in which the light guide 18 having a shape is stretched around the surface of the substrate 16 in a pattern. Alternatively, it can be easily realized by forming a groove corresponding to the pattern in advance on the surface of the substrate 16 and embedding the light guide 18 in this groove.
[0054]
The incident light guided to the inside of the light guide 18 arranged as described above is applied to the inside of the light guide 18 at a light exit 21 provided by perforating the surface of the long side portion 19 of the light guide 18. It is ejected from outside. The emission characteristics of the light emission port 21 are adjusted by applying fine irregularities or the like to the light emission port 21 by machining.
[0055]
Then, even in any arrangement pattern, arrangement pitch P ₂ of the long side portion 19 is smaller than the pixel pitch P _1X in the same direction, the arrangement pitch P ₃ of the light exit opening 21 is also in the same direction pixel pitch P _Since it is smaller than _1Y , one pixel display element 12 always has a plurality of long sides 19 and a plurality of light exits 21 provided in each long side 19. That is, one pixel display element 12 is illuminated by the emission light emitted from at least four light emission ports 21.
[0056]
As described above, in the display lighting device according to the present embodiment, the light guide 18 can be freely and compactly arranged over the entire surface of the light guide sheet 14 by the above-described operation. As a result, even if the size of the display increases, it is possible to realize a display lighting device using the light guide sheet 14 without increasing the thickness and weight without increasing the number of the light guides 18.
[0057]
In addition, by further restricting the configuration of the light guide sheet 14, it is possible to reduce moire.
[0058]
For example, the arrangement pitch (P ₂ ) in the light guide sheet 14 and the pixel pitch (P _1X ) in the same direction are set for all m and n.
1 / | m / P _1X −n / P ₂ | <10 × P ₂ (3)
However, m and n are set to satisfy the relationship of 1 to 10 integers.
[0059]
In the case of a configuration that satisfies the above expression (3), the moiré intensity is at a level that cannot be recognized by the naked eye, so that the occurrence of moiré can be reduced.
[0060]
Alternatively, the arrangement pitch (P ₃ ) in the light guide sheet 14 and the pixel pitch (P _1Y ) in the same direction are set for all m and n.
1 / | m / P _1Y -n / P ₃ | <10 × P ₃ (4)
However, m and n are set to satisfy the relationship of 1 to 10 integers.
[0061]
Also in the case of a configuration that satisfies the above expression (4), the intensity of moiré is almost at a level that cannot be recognized by the naked eye, so that the occurrence of moiré can be reduced.
[0062]
Further, when the configuration is such that the above-mentioned expressions (3) and (4) are simultaneously satisfied, it is possible to further reduce the occurrence of moire.
[0063]
(Second embodiment)
A second embodiment of the present invention will be described with reference to FIGS.
[0064]
That is, the display lighting device according to the second embodiment is a modification of the display lighting device according to the first embodiment.
[0065]
7 to 12 are plan views showing a configuration example of such a display lighting device according to the present embodiment, and the same portions as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. Only different parts will be described.
[0066]
FIG. 7 differs from the configuration shown in FIG. 1 only in that the arrangement pitch (P ₂ ) is randomly determined by random numbers.
[0067]
FIG. 8 differs from the configuration shown in FIG. 1 only in that the arrangement pitch (P ₂ ) is reduced as the distance of the light guide from the end 23 increases.
[0068]
FIG. 9 differs from the configuration shown in FIG. 1 only in that two light emission ports 21 are arranged at positions where the light guide distance from the end 23 is equal.
[0069]
FIG. 10 is different from the configuration shown in FIG. 1 only in that a random number of light exit ports 21 are arranged at positions where the light guide distance from the end 23 is equal.
[0070]
FIG. 11 differs from the configuration shown in FIG. 1 only in that the number of light exit ports 21 is increased as the light guide body distance from the end 23 is increased.
[0071]
FIG. 12 differs from the configuration shown in FIG. 1 only in that the opening area of the light exit port 21 is increased as the light guide body distance from the end 23 increases.
[0072]
Further, FIG. 13 differs from the configuration shown in FIG. 1 only in that the arrangement pitch (P ₃ ) of the light emission ports 21 is determined at random by random numbers.
[0073]
Further, FIG. 14 is different from the configuration shown in FIG. 1 only in that the arrangement pitch (P ₃ ) of the light exit ports 21 is reduced as the light guide body distance from the end 23 becomes longer.
[0074]
The display lighting device having the above-described configuration can reduce the occurrence of moiré by not keeping the number and the positions of the light emitting ports 21 for emitting the illumination light to the pixel display element 12 constant.
[0075]
In the present invention, a plurality of light guide sheets may be used as needed. When a plurality of light guide sheets are used, moire between each light guide sheet and the pixel display element 12 and moire between each light guide sheet are considered.
[0076]
Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to such configurations. Within the scope of the technical idea described in the claims, those skilled in the art can come up with various modified examples and modified examples, and these modified examples and modified examples are also within the technical scope of the present invention. It is understood that it belongs to.
[0077]
【The invention's effect】
As described above, according to the present invention, the optical fibers can be freely and compactly arranged over the entire surface of the light guide sheet, so that the number of optical fibers can be increased even when the size of the display increases. Thus, it is possible to realize a display lighting device in which the thickness and the weight do not increase so much and the occurrence of moire can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view (a folded type) showing a configuration example of a display lighting device according to a first embodiment.
FIG. 2 is a plan view (spiral type) showing another configuration example of the display lighting device according to the first embodiment;
FIG. 3 is a plan view (branch type) showing another configuration example of the display lighting device according to the first embodiment;
FIG. 4 is a plan view showing another configuration example of the display lighting device according to the first embodiment (return type + branch type);
FIG. 5 is a plan view showing another configuration example of the display lighting device according to the first embodiment (a two-way branching type).
FIG. 6 is a plan view (double spiral type) showing another configuration example of the display illumination device according to the first embodiment.
FIG. 7 is a plan view showing a configuration example of a display illumination device according to a _second embodiment (arrangement pitch P2 random);
FIG. 8 is a plan view showing another configuration example of the display lighting device according to the _second embodiment (the arrangement pitch P2 is gradually reduced).
FIG. 9 is a plan view (two light emission ports) showing another configuration example of the display illumination device according to the second embodiment.
FIG. 10 is a plan view showing another configuration example of the display lighting device according to the second embodiment (the number of light emission ports is random).
FIG. 11 is a plan view showing another example of the configuration of the display lighting device according to the second embodiment (increase of light exit ports).
FIG. 12 is a plan view showing another example of the configuration of the display illumination device according to the second embodiment (the opening area of the light emission port is increased).
Figure 13 is a plan view showing another configuration example of a display illumination device according to the second embodiment (arrangement pitch P ₃ Random)
Figure 14 is a plan view showing another configuration example of a display illumination device according to the second embodiment (small gradual arrangement pitch P ₂₃₎
[Explanation of symbols]
12 pixel display element, 14 light guide sheet, 16 substrate, 18 light guide, 19 long side, 20 short side, 21 light exit port, 22 light source, 23 end

Claims (7)

A display illumination device that illuminates a display including a plurality of image display elements using a light guide sheet,
The light guide sheet,
Board and
By alternately including a long side portion formed of a straight line and a short side portion formed of a straight line arranged substantially perpendicular to the long side portion, the long side portion is arranged to be folded on the surface of the substrate, When light is introduced from the end, a tubular light guide that guides the introduced light along the length direction,
The light guide is disposed on a surface of a long side portion of the light guide, and light guided by the light guide is emitted from the inside of the light guide to the outside to illuminate the image display element. It consists of multiple light exits,
A display lighting device, wherein an arrangement pitch of long sides arranged on a surface of the substrate is smaller than a pixel pitch of the pixel display element. The display lighting device according to claim 1,
The pixel pitch (P ₁ ) and the arrangement pitch (P ₂ ) are 1 / | m / P ₁ −n / P ₂ | <10 × P ₂ for all m and n, where m and n Is a display lighting device that satisfies the relationship of 1 to 10 inclusive. A display illumination device that illuminates a display including a plurality of image display elements using a light guide sheet,
The light guide sheet,
Board and
By alternately including a long side portion formed of a straight line and a short side portion formed of a straight line arranged substantially perpendicular to the long side portion, the long side portion is disposed so as to be folded on the surface of the substrate, When light is introduced from the end, a tubular light guide that guides the introduced light along the length direction,
The light guide is disposed on a surface of a long side portion of the light guide, and light guided by the light guide is emitted from the inside of the light guide to the outside to illuminate the image display element. It consists of multiple light exits,
A display lighting device, wherein an arrangement pitch of the light exit ports is smaller than a pixel pitch of the pixel display element. The display lighting device according to claim 3,
The pixel pitch (P ₁ ) and the arrangement pitch (P ₃ ) are 1 / | m / P ₁ −n / P ₃ | <10 × P ₃ for all m and n, where m and n Is a display lighting device that satisfies the relationship of 1 to 10 or less. The display lighting device according to claim 1 or 3,
A display lighting device wherein the arrangement pitch is determined by a random number. The display lighting device according to claim 1 or 3,
A display lighting device in which the arrangement pitch is reduced as the distance of the light guide from an end into which the light is introduced increases. The display lighting device according to claim 3,
A display lighting device, wherein the opening area of the light exit is increased as the distance of the light guide from the end into which the light is introduced increases.

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