KR20140033373A - Optical sheet - Google Patents

Abstract

This invention provides the optical sheet 30 which can make it hard to see the printing dot 38 formed in the back side from the front side, the surface light source device 20 provided with this, and the transmissive image display apparatus 1 provided. In an optical sheet formed of a light-transmissive resin, a side face 33 on which light from the light source 22 is incident, formed in a direction intersecting with the side face, and an exit surface for emitting planar light, and face the exit surface. And a dot printed by inkjet printing, which is printed on the back surface and reflects light incident from the side surface to the exit surface side, and light formed on the exit surface and incident from the side surface can be injected. It has a some convex-shaped part extended in the direction and arrange | positioned in the direction orthogonal to one direction, and a convex-shaped part is set as the structure which satisfy | fills Formula (1). H x T / P ≧ 0.37... (One). However, P is the space | interval (micrometer) of the adjacent convex part, H is the height (micrometer) of convex part, and T is sheet thickness (mm).

Description

Optical sheet {OPTICAL SHEET}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sheet, a surface light source device, and a transmissive image display device that emit light incident from a sheet side surface from an exit surface formed in a direction crossing the side surface.

In the backlight used as a surface light source device of a liquid crystal display (transmission type image display device), a light source such as a cold cathode tube or an LED is arranged on the back side of the light diffusion plate, and the light incident from the back side of the light diffusion plate is placed on the front side. There are the direct type | mold which emits light, and the edge light type which injects light sources, such as a cold cathode tube and LED, on the side surface of the light guide plate which is a transparent plate, and injects the light incident from the side surface of the light guide plate to the front side. Conventionally, the direct type has been the mainstream from the viewpoint that the brightness can be increased, but in recent years, the use of thin and high luminance LED light sources has increased, and the use ratio of the edge light type has been reduced due to the thinning of the liquid crystal display. This is increasing.

In the edge light type, dot printing is applied to the rear surface of the light guide plate to diffuse the light incident from the side surface of the light guide plate on the back side and to emit the light from the front side (see Patent Documents 1 and 2, for example).

(Prior art technical literature)

(Patent Literature)

Patent Document 1: Japanese Patent Laid-Open No. 5-100118

Patent Document 2: Japanese Patent Laid-Open No. 5-313017

In recent years, thinning of a display is progressing. As the thickness of the display advances, the tendency for the defects of the printed dots to be easily recognized becomes stronger.

This invention is made | formed in order to solve such a subject, and an object of this invention is to provide the optical sheet which can make it hard to see the defect of the printing dot formed in the back from the front side, the surface light source device provided with this, and a transmissive image display apparatus. .

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, the defect of the printing dot formed in the back surface of an optical sheet was formed by giving an uneven shape to the front side (panel surface side) of an optical sheet (light guide plate), and making it a diffused surface. It discovered that it was possible to reduce the visibility of, and came to this invention.

The present invention relates to an optical sheet formed of a light-transmissive resin, comprising: a side face incident light emitted from a light source, a direction intersecting the side face, and an exit surface light emitting planar light, and a direction crossing the side face. A printing dot formed on the back surface opposite to the exit surface, printed on the back surface and reflecting light incident from the side surface to the exit surface side, and formed on the exit surface, and capable of injecting light incident from the side surface, Provided is an optical sheet having a plurality of convex portions extending in one direction and arranged in a direction orthogonal to one direction, the outer diameter of the printing dot being 200 μm or less.

According to such an optical sheet, since a plurality of convex portions are formed on the exit surface, light is diffused by the concave-convex shape having the convex portions, and defects of the printed dots formed on the back side are divided and appear small. Thereby, it is difficult to visually recognize the defect of a printing dot from an emission surface side. As a result, the defect of the printing dot formed in the back surface is hard to be seen, and the optical sheet can be thinned. In addition, "the direction orthogonal to one direction" includes the direction substantially orthogonal to one direction.

Moreover, it is preferable that the printing dot is formed by inkjet printing. Thus, when printing dot is formed by inkjet printing, a fine printing dot can be formed. When fine dots are used by inkjet printing, printing dots become difficult to see.

Moreover, it is preferable that a convex-shaped part satisfy | fills following formula (1).

[1]

However, P is the space | interval (micrometer) of the adjacent convex part, H is the height (micrometer) of convex part, and T is sheet thickness (mm).

In addition, it is preferable that the length (L1 x L2) of the two sides orthogonal to the exit surface is a large size of 500 mm x 800 mm or more. Since it is necessary to increase the output of a light source with the enlargement of the exit surface, this invention is especially effective at the large size of 500 mm x 800 mm or more.

Moreover, it is preferable that sheet thickness T is 1.0 mm or more and 4.5 mm or less. Thus, when the said convex part is formed in the optical sheet of 1.0 mm-4.5 mm in thickness, since the defect of the printing dot formed in the back surface is preferably divided | segmented and small, it becomes difficult to see a printing dot further from a panel surface.

Moreover, this invention provides the surface light source device provided with the said optical sheet and the light source discretely arrange | positioned along the longitudinal direction of the side surface, facing the side surface of an optical sheet.

According to such a surface light source device, since a plurality of convex portions satisfying the above formula (1) are formed on the exit surface of the optical sheet, defects of the printing dots formed on the rear surface of the optical sheet are divided and appear small, and the emission surface side It can be made difficult to visually recognize a defect of a printing dot.

Moreover, this invention is arrange | positioned facing the said optical sheet, the light source arrange | positioned discretely along the long side direction of the side surface, and the emitting surface of a surface light source device, facing the side surface of an optical sheet, A transmissive image display device having a transmissive image display unit that is irradiated with emitted light to display an image is provided.

According to such a transmissive image display device, since a plurality of convex portions satisfying the above formula (1) are formed on the exit surface of the optical sheet, defects of the printing dots formed on the rear surface of the optical sheet are divided and appear small, and exit. It can make it hard to visually recognize the defect of a printing dot from a surface side.

According to the present invention, since the concave-convex shape having the convex portion is formed on the exit surface, light can be diffused by the concave-convex shape, and it is difficult to see by dividing the defect of the back printing dot to make it appear small. have.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure of one Embodiment of the transmissive image display apparatus which concerns on this invention.
2 is a rear view schematically showing the configuration of an embodiment of the surface light source device according to the present invention.
3 is a rear view schematically showing the configuration of another embodiment of the surface light source device according to the present invention.
It is a front view which shows typically the structure of one Embodiment of the surface light source device which concerns on this invention.
It is a perspective view which shows typically the structure of one Embodiment of the light guide plate which concerns on this invention.
It is a perspective view which shows typically the structure of the other embodiment of the light guide plate which concerns on this invention.
FIG. 7 is an enlarged view showing the convex portion in FIG. 5 from the X-axis direction. FIG.
It is a schematic block diagram which shows the resin sheet manufacturing apparatus concerning embodiment of this invention.
It is a schematic block diagram which shows the resin sheet manufacturing apparatus which concerns on 2nd Embodiment of this invention.
It is a schematic block diagram which shows the resin sheet manufacturing apparatus concerning 3rd Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent element, and the overlapping description is abbreviate | omitted. The dimension ratio of drawing does not necessarily correspond with what was described.

1: is sectional drawing which shows typically the structure of one Embodiment of the transmissive image display apparatus which concerns on this invention. 1 is an exploded view of the transmissive image display apparatus 1.

(Transmission-type image display apparatus)

The transmissive image display apparatus 1 is equipped with the transmissive image display part 10 and the surface light source device 20 arrange | positioned at the back side of the transmissive image display part 10 in FIG. In the following description, as shown in FIG. 1, the arrangement direction of the surface light source device 20 and the transmission type image display part 10 is called a Z direction (plate thickness direction), and is orthogonal to each other as two directions orthogonal to a Z direction. Two directions to be referred to are referred to as the X direction and the Y direction.

As the transmissive image display part 10, the liquid crystal display panel in which the linear polarizing plates 12 and 12 were arrange | positioned on both surfaces of the liquid crystal cell 11 is mentioned, for example. In this case, the transmissive image display apparatus 1 is a liquid crystal display device (for example, liquid crystal TV). The liquid crystal cell 11 and the polarizing plates 12 and 12 can use what is used by the transmissive image display apparatus 1, such as a conventional liquid crystal display device. As the liquid crystal cell 11, well-known liquid crystal cells, such as TFT type and STN type, are illustrated.

(Surface light source device)

2 is a rear view schematically showing the configuration of one embodiment of the surface light source device according to the present invention, and FIG. 3 is a rear view schematically showing the configuration of another embodiment of the surface light source device according to the present invention. 4 is a front view schematically showing the configuration of an embodiment of the surface light source device according to the present invention. As shown in FIGS. 1 to 4, the surface light source device 20 includes a light guide plate (optical sheet) 30 and an LED light source (point light source) disposed to face the side surface 33 of the light guide plate 30 ( 22). In addition, on the front side of the light guide plate 30, the structure in which the various films 41 are arrange | positioned between the light guide plate 30 and the transmissive image display part 10 may be sufficient. As various films 41, a diffusion film, a prism film, a brightness improving film, etc. are mentioned.

(Light source)

The LED light source 22 functions as a point light source of the surface light source device 20, and is disposed to face the side surfaces 33 and 33 extending in the Y-axis direction of the light guide plate 30 as shown in FIG. 2. It is. The plurality of LED light sources 22 are disposed discretely along the long side direction (Y-axis direction) of the side surface 33. The spacing of the LED light sources 22 is usually 5 mm to 20 mm. The point light source may be disposed to face the four sides of the light guide plate 30, may be disposed on two sides opposing in the X-axis direction (see FIG. 2), or on two sides opposing in the Y-axis direction, and one side. May be arranged only (see FIGS. 3 and 4). The point light source is not limited to the LED light source but may be other point light sources. The light source is not limited to a point light source, but may be a configuration in which a linear light source (cold cathode tube) is disposed.

The white LED may be sufficient as the LED light source 22, and you may arrange | position a some LED at one location, and may comprise one light source unit. For example, as one light source unit, LEDs of three different colors of red, green, and blue may be arranged adjacent to each other. And the light source unit which has several LED is discretely arrange | positioned along the arrangement direction mentioned above. In such a case, it is preferable that different LEDs are arranged as close as possible.

As an LED light source, what has various emission distributions can be used, but it is preferable that the luminous intensity in the normal line direction (Z-axis direction) of an LED light source is the largest, and it has an emission distribution whose half value width of a luminous intensity distribution is 40 degree | times or more and 80 or less. Specific examples of the type of the LED light source include a lambsion type, a shell type, a side emission type and the like.

(Light guide plate)

As shown in Figs. 2 to 4, the light guide plate 30 has a rectangular shape, and the size of the planar shape is selected to be suitable for the screen size of the transmissive image display apparatus 10 as desired, The length L1 × L2 is preferably 250 mm × 440 mm or more, preferably a large size of 500 mm × 800 mm or more. The shape seen from the plane of the light guide plate 30 is not limited to the rectangle, but may be square, but will be described below as a rectangle unless specifically excluded.

Here, a rectangle of 250 mm x 440 mm or more means a rectangle of which one side is 250 mm or more and the other side is 440 mm or more. In addition, the rectangle of 500 mm x 800 mm or more means the rectangle whose one side is 500 mm or more and the other side is 800 mm or more.

The light guide plate 30 is formed of a light transmitting resin that transmits light and forms a plate shape. In addition, the light guide plate 30 may be a sheet form, or may be a film form. It is preferable that the thickness T of the light guide plate 30 is 1.0 mm or more and 4.5 mm or less.

The light guide plate 30 has a pair of main surfaces 31 and 32 opposing each other in the Z-axis direction (thickness direction), a pair of side surfaces 33 and 33 opposing the X-axis direction, and as long as they oppose in the Y-axis direction. A pair of side surfaces 34 and 34 are provided. The main surfaces 31 and 32 are formed in the direction crossing the side surfaces 33 and 34.

One of the main surfaces 31 of the pair of main surfaces facing in the Z-axis direction functions as an exit surface 31 capable of emitting planar light. The exit surface 31 is disposed on the transmissive image display unit 10 side, and the other main surface (back surface 32) is disposed on the side opposite to the transmissive image display unit 10. In addition, the reflective sheet 42 which reflects the light in the light guide plate 30 to the emission surface 31 side is constructed in the position which faces the back surface 32. As shown in FIG.

(Reflective processing)

2 and 3, the back surface 32 of the light guide plate 30 is subjected to reflection processing (for example, silk printing) that diffusely reflects light. As a printing method performed as reflection processing, inkjet printing may be performed in addition to silk printing. Or as a method of reflection processing, you may provide dot-shaped unevenness | corrugation not by printing but by laser irradiation.

The smaller the dot diameter, the more difficult it is to visually recognize the printing dot from the emission surface side, so inkjet printing is preferable. The dot diameter of inkjet printing is 200 micrometers or less normally, Preferably it is 150 micrometers or less, Especially preferably, it is 100 micrometers or less.

(Uneven shape)

5 is a perspective view schematically showing the configuration of one embodiment of the light guide plate according to the present invention, and FIG. 6 is a perspective view schematically showing the configuration of another embodiment of the light guide plate according to the present invention. The convex part 35 which is convex is formed in the exit surface 31 in the outer side of a Z-axis direction. The convex portions 35 extend in the X-axis direction (one direction) and are arranged in a plurality in the Y-axis direction. The plurality of convex portions 35 are parallel to each other.

Examples of the shape of the convex portion 35 include a prism shape, a semicircle shape, a semi-elliptic shape, and the like. A shape continuously changing in one convex portion 35 (shape unit) is preferable. For example, a semi-circle shape or a semi-ellipse shape is more preferable than a prism shape. Moreover, it is preferable that the extending direction of the convex part 35 is parallel to the direction of ejection of the light from a light source. In addition, in the direction (Y-axis direction) which the convex part 35 adjoins, the planar part may be formed between the convex part 35 and 35 which adjoin.

FIG. 7 is an enlarged view showing the convex portion in FIG. 5 from the X-axis direction. FIG. Here, the convex part 35 satisfies following formula (1).

[Number 2]

However, P is the space | interval (micrometer) of the adjacent convex-shaped parts 35 and 35, H is height (micrometer) of the convex-shaped part 35, and T is sheet thickness (mm). As shown in FIG. 7, the interval P is a distance between the vertices 35a and 35a of the adjacent convex portions 35. The height H of the convex portion 35 is the distance between the lower end 35b of the convex portion 35 and the vertex 35a. The sheet thickness T is a distance between the vertex 35a of the convex portion 35 and the back surface 32.

(Constituent material of light guide plate)

The light guide plate 30 is formed of a light transmitting resin. Translucent resin is resin which permeate | transmits light. The refractive index of translucent resin is 1.49-1.59 normally. As translucent resin used for the light guide plate 30, methacryl resin is mainly used. As translucent resin used for the light guide plate 30, other resin may be used and styrene resin may be used. As the translucent resin, acrylic resins, styrene resins, carbonate resins, cyclic olefin resins, MS resins (copolymers of acrylic and styrene) and the like can be used.

In applying the light guide plate to the liquid crystal display device (transmissive image display device 1), additives such as a light diffusing agent, an ultraviolet absorber, a heat stabilizer, and a photopolymerization stabilizer may be added to the light guide plate 30.

(Molding method of light guide plate)

As the molding method of the light guide plate, extrusion molding can be applied. 8 is a schematic configuration diagram showing a resin sheet manufacturing apparatus according to an embodiment of the present invention. The resin sheet manufacturing apparatus 50 shown in FIG. 8 is an apparatus which can manufacture the light guide plate 30 which concerns on embodiment of this invention. The resin sheet manufacturing apparatus 50 uses the die | dye 51 which continuously extrudes the resin of a hot melt state, and obtains the continuous resin sheet 60, and the continuous resin sheet 60 extruded from the die 51 of thickness direction. The 1st press roll 52a and the 2nd press roll 52b which pressurize from both sides are provided.

When manufacturing the light guide plate 30, resin used as a raw material is thrown in from the resin inlet 50. As shown in FIG. The injected resin is heated in the extruder 58, transferred to the die 51 in a molten state, and extruded. Resin extruded from the die 51 turns into a sheet form continuously. Thereby, the continuous resin sheet 60 can be obtained.

The continuous resin sheet 60 extruded from the die 51 is pressed from both sides in the thickness direction of the sheet by the first press roll 52a and the second press roll 52b, and the second press roll 52b. The transfer mold formed on the peripheral surface of the (roll) is transferred to the surface of the continuous resin sheet 60. The light guide plate 30 can be obtained by cut | disconnecting the resin sheet 60 in which the shape was given to the surface to the predetermined magnitude | size.

In addition, you may shape | mold the light guide plate 30 using the resin sheet manufacturing apparatus 50b, 50c shown in FIG. 9 and FIG. 10 as an apparatus which manufactures a light guide plate.

The resin sheet manufacturing apparatus 50b shown in FIG. 9 is equipped with the 3rd press roll 52c in the rear end of the 2nd press roll 52b. The continuous resin sheet 60 pressed by the 1st press roll 52a and the 2nd press roll 52b is conveyed in close contact with the circumferential surface of the 2nd press roll 52b. The conveyed continuous resin sheet 60 is pressurized again through the 2nd press roll 52b and the 3rd press roll 52c. Thus, you may perform pressurization by a press roll multiple times.

The resin sheet manufacturing apparatus 50c shown in FIG. 10 is equipped with the precompression roll 52d in the front end of the 1st press roll 52d. The resin extruded from the die 51 is pressurized between the preload roll 52d and the first press roll 52a. Thus, before pressurization (transfer) by the 1st and 2nd press rolls 52a and 52b, you may perform pressurization previously.

(Action)

According to such a light guide plate 30 of the present embodiment, the surface light source device 20 and the transmissive image display device 1 having the same, the light guide plate 30 is disposed from the light source 22 disposed to face the side surface 33 of the light guide plate 30. Light is incident from the side surface 33, and surface-shaped light can be emitted from the exit surface 31 orthogonal to the side surface 33. At this time, a part of the light incident on the light guide plate 30 from the side surface 33 of the light guide plate 30 is diffusely reflected by the printing dots 38 on the back surface 32 as shown in FIG. do.

In the light guide plate 30 of the present embodiment, the dots printed by inkjet printing are formed as the printing dots 38. According to the light guide plate 30 in which the printing dots 38 are formed, since fine printing dots are formed by inkjet printing, it becomes difficult to see the printing dots when viewed from the front. As a result, the printed dot 38 formed on the back surface 32 is hard to be seen, and the light guide plate 30 can be enlarged and thinned.

In the light guide plate 30 of this embodiment, the some convex part 35 is formed in the exit surface 31, and this convex part 35 satisfy | fills following formula (1).

[Number 3]

However, P is the space | interval (micrometer) of the adjacent convex part, H is the height (micrometer) of convex part, and T is sheet thickness (mm).

According to the light guide plate 30 in which the convex part 35 is formed, since light is diffused by the uneven shape which has the convex part 35, the printing dot of the back 32 of the light guide plate 30 is seen from the front. (38) appears to be finely divided. That is, the printing dot 38 can be made hard to see. As a result, the printed dot 38 formed on the back surface 32 is hard to be seen, and the light guide plate 30 can be enlarged and thinned. In addition, even when there are defects in the printing dots 38, since the defects appear to be finely divided, the defects can be hardly seen from the front. Since the defect of the printing dot 38 is hard to be seen, the yield rate of a printing light guide plate can be improved.

In the light guide plate 30, the surface light source device 20, and the transmissive image display device 1 of the present invention, the printing dots 38 are hard to be seen, and the output of the light source can be increased. In addition, in the light guide plate 30, the surface light source device 20, and the transmissive image display device 1 of the present invention, the gray scale change of the dot diameter can be largely corresponded to correspond to the enlargement of the display. In addition, in the light guide plate 30, the surface light source device 20, and the transmissive image display device 1 of the present invention, the printing dots 38 are hard to be seen, and the thickness can be reduced.

As defects of the printing dots, there are light and shade phenomena (fog spots) caused by the roughness of the arrangement of the print dots, phenomenon in which the print dots are densely present in a straight line shape (smear spots) and the like. In the light guide plate 30 of the present embodiment, since a predetermined shape (convex portion) is provided on the light guide plate surface, it is possible to make the defects of the printing dots substantially invisible.

(Example)

Hereinafter, one Example of the optical sheet of this invention is described.

The optical sheet which concerns on the Example of this invention, and the optical sheet which concerns on a comparative example were created, and the evaluation test was done about these. In the comparative example 1, the optical sheet was created using acrylic resin (Sumipex EXN by Sumitomo Chemical Co., Ltd.). The optical sheet which concerns on the comparative example 1 is a flat form in which the convex part is not formed in the exit surface.

In Example 1-2, the optical sheet was created using styrene resin (Toyo sterol HRM40 by Oriental styrene company) as translucent resin. The optical sheet according to Example 1-2 is a shape plate in which a plurality of convex portions are formed on the exit surface.

In Example 3-9, the optical sheet was created using acrylic resin (Sumipex EXN by Sumitomo Chemical Co., Ltd.) as translucent resin. The optical sheet according to Example 3-9 is a shape plate in which a plurality of convex portions are formed on the exit surface.

In Example 10-15, the optical sheet was created using carbonate resin (Calibur 200-30 made by Sumitomo Dow) as translucent resin. The optical sheet according to Examples 10-15 is a shape plate in which a plurality of convex portions are formed on the exit surface.

Table 1 below shows the specifications of the optical sheet of Comparative Example 1 and Examples 1-15.

(Evaluation test)

The evaluation test regarding the visibility of the printing dot by inkjet printing was performed. Explain the evaluation method. The PMMA board in which the translucent dot of 80 micrometers in diameter was printed by inkjet printing was arrange | positioned so that the printing surface might face the back surface of an optical sheet. The optical sheet which concerns on Example 1-13 and the comparative example 1 was arrange | positioned so that an emission surface (shape surface) may face upward. From the upper surface of the shape, it was confirmed how printing dots and printing defects looked. As a printing defect, evaluation was performed about two types of the mild unevenness seen by mist shape, and the strong blemish-shaped unevenness by nozzle clogging. The printing dot was not visually recognized in either of Examples 1-13 and Comparative Example 1.

Table 2 below shows evaluation results regarding the visibility of defects of the printing dots. In the table, "A" shows that the defect of a printing dot was not visually recognized, and "B" shows that the defect of a printing dot can be visually recognized.

In addition, the evaluation result of the blemish-shaped unevenness is a case where it is arrange | positioned so that the direction of a bleed and the extension direction of the convex part 35 may become parallel. In the case where the extending direction and the spreading direction of the convex portion 35 are in the same direction, the spreading stain is no longer seen.

(Industrial availability)

Since the uneven | corrugated shape is formed in the exit surface of an optical sheet, the optical sheet, the surface light source device, and the transmission type image display apparatus of this invention can diffuse light by uneven | corrugated shape, and visually recognize the defect of a printing dot from the exit surface side. It can be difficult to do. In addition, the thickness of the optical sheet can be reduced.

1: transmissive image display device
10: transmissive image display unit
11: liquid crystal cell
12: polarizer
20: surface light source device
22: LED light source (point shape light source)
30: Light guide plate (optical sheet)
31: injection surface
32: back side
33: side
34: side
35 convex shape
38: dot

Claims (7)

As an optical sheet formed of a light transmitting resin,
A side to which light emitted from the light source is incident;
An emission surface formed in a direction crossing the side surface and emitting light having a planar shape,
A back surface formed in a direction crossing the side surface and facing the exit surface,
A printing dot printed on the rear surface and reflecting light incident from the side surface to the exit surface;
A plurality of convex portions formed on the exit surface, capable of emitting light incident from the side surface, and extending in one direction and arranged in a direction orthogonal to the one direction,
The outer diameter of the printing dot is 200 μm or less
Optical sheet.
The method of claim 1,
The optical sheet in which the said printing dot is formed by inkjet printing.
3. The method according to claim 1 or 2,
The convex portion satisfies the following formula (1),
[Number 1]

However, P is an optical sheet which is space | interval (micrometer) of adjacent convex parts, H is height (micrometer) of convex part, and T is sheet thickness (mm).
4. The method according to any one of claims 1 to 3,
The said exit surface is the optical sheet whose length (L1 * L2) of two sides orthogonally crosses is a large size of 500 mm x 800 mm or more.
5. The method according to any one of claims 1 to 4,
The optical sheet whose said sheet thickness T is 1.0 mm or more and 4.5 mm or less.
The optical sheet according to any one of claims 1 to 5,
Opposed to the side surface of the optical sheet, having a light source disposed discretely along the long side direction of the side surface
Cotton light source device.
The optical sheet according to any one of claims 1 to 5,
A light source disposed discretely along the long side direction of the side surface, opposite the side surface of the optical sheet,
A transmissive image display unit disposed to face the exit surface of the optical sheet, and configured to display an image by irradiating with light emitted from the optical sheet.
Type display device.

Images