WO2021166432A1 - Light source unit, display device, and light source unit manufacturing device - Google Patents

Abstract

Provided are a light source unit and a display device that can ensure uniformity of brightness at a light-emitting surface even when reduced in thickness.　A light source unit having: a light source installation surface on which at least one micro light source is installed; a translucent base that is aligned with the light source installation surface; and a reflective pattern formed on a first surface of the base positioned on the light-source-installation-surface side, the reflective pattern being formed on the basis of the light distribution characteristics of the micro light source, wherein the gap between the light source installation surface and a second surface positioned on the side opposite the first surface in the base is 1-2 mm [inclusive].

Description

Light source unit, display device, and light source unit manufacturing device

The present invention relates to a light source unit and a display device, and more particularly to a light source unit and a display device designed in consideration of the light distribution characteristics of a minute light source. The present invention also relates to a light source unit manufacturing apparatus for manufacturing a light source unit.

The light source unit used as the backlight of a display device such as a liquid crystal television is required to have uniform brightness on the light emitting surface in order to display a high-quality image. Examples of the conventional light source unit capable of uniform light irradiation include the light source module described in Patent Document 1.

The light source module described in Patent Document 1 is used as a direct type backlight, and is provided with a transmission reflector (denoted as "lighting curtain" in Patent Document 1) between the light source and the light emitting surface. According to this configuration, even when a light source having strong directivity is used, it is possible to suppress brightness unevenness on the exit surface and uniformly irradiate the light.

Japanese Unexamined Patent Publication No. 2012-174634

It is desired that the light source unit, which is the backlight of the display device, be thinner than the conventional product including the light source module of Patent Document 1. Further, as the quality of the light source unit, further improvement in the uniformity of brightness on the exit surface is required. However, the thinner the light source unit, the more difficult it is to ensure the uniformity of brightness on the exit surface.

The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the following object.
An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a light source unit and a display device capable of ensuring uniformity of brightness on an exit surface even when the thickness is reduced.
Another object of the present invention is to provide a light source unit manufacturing apparatus for manufacturing the above light source unit.

As a result of diligent studies by the present inventors to achieve the above object, the distance between the installation surface of the micro light source and the second surface of the translucent base material having the reflection pattern formed on the first surface has been determined. It was found to affect the uniformity of brightness. Specifically, the wider the interval, the easier it is to form the reflection pattern, and the narrower the interval, the more appropriately the effect of the reflection pattern is exhibited.
Based on the above points, the present inventors have found that when the above interval is within a predetermined numerical range, the light source unit is made thinner while ensuring the uniformity of brightness on the light emitting surface, and the present invention has been made. Was completed. That is, the present inventors have found that the above problem can be solved by the following configuration.

[1] At least on a light source installation surface on which at least one micro light source is installed, a translucent base material arranged side by side with the light source installation surface, and a first surface of the base material located on the light source installation surface side. It has a reflection pattern formed based on the light distribution characteristics of one micro light source, and the distance between the second surface located on the opposite side of the first surface of the base material and the light source installation surface is 1 mm or more and 2 mm. The light source unit below.
[2] A substrate having a flat light source installation surface is provided, and a plurality of micro light emitting elements as at least one micro light source are symmetrically arranged on the light source installation surface with reference to the central position of the light source installation surface. The light source unit according to [1].
[3] The light source unit according to [1] or [2], wherein a plurality of unit patterns as reflection patterns are symmetrically formed on the first surface with respect to the center position of the first surface.
[4] The light source unit according to [3], wherein each of the plurality of unit patterns is composed of titanium oxide.
[5] The light source unit according to [3] or [4], wherein each of the plurality of unit patterns protrudes toward the light source installation surface and has a shape in which the diameter gradually decreases as it approaches the light source installation surface. ..
[6] The description in any one of [3] to [5], wherein each of the plurality of unit patterns is formed on the first surface in order for the index value relating to the brightness distribution on the second surface to satisfy the setting condition. Light source unit.
[7] When the following first condition and second condition are satisfied, the index value satisfies the setting condition, and the thickness, size, and arrangement position of each of the plurality of unit patterns satisfy the first condition and the second condition. The light source unit according to [6], which has the thickness, size, and arrangement position determined in.
First condition: The brightness in each of the specific area located at the position where it overlaps with at least one minute light source and the peripheral area surrounding the specific area on the second surface is equal to or less than the reference value.
Second condition: The degree of dispersion of brightness on the second surface is within the target range.
[8] The light source unit according to any one of [1] to [7], wherein the base material is made of a translucent film material.
[9] The base material and the reflection pattern form a first light scattering body, and a second light scattering body is arranged between the first light scattering body and at least one light source, and the first light scattering body is arranged. The light source unit according to any one of [1] to [8], wherein the reflection pattern is provided only on the first light scattering body among the second light scattering bodies.
[10] Amount of deviation between the regular placement position of the first light scatterer and the actual placement position of the first light scatterer with respect to the light source installation surface in each of the two directions parallel to the light source installation surface and orthogonal to each other. The light source unit according to [9], wherein the light source unit is 0.2 mm or less.
[11] A display device having a liquid crystal display, wherein the light source unit according to any one of [1] to [10] is provided as a backlight unit on the back side of the liquid crystal display.
[12] A light source unit manufacturing apparatus that manufactures the light source unit according to any one of [1] to [10], and a light distribution characteristic acquisition apparatus that acquires the light distribution characteristics of at least one minute light source. A light source unit manufacturing device including a pattern forming device that forms a reflection pattern on the first surface of a base material according to pattern forming data generated based on the light distribution characteristics.

According to the present invention, it is possible to realize a light source unit and a display device that are thin and have uniform brightness on the exit surface.
Further, according to the present invention, it is possible to provide an apparatus for manufacturing the above-mentioned light source unit.

This is an example of a characteristic diagram showing light distribution characteristics. It is a schematic side view of the constituent equipment of a display device. It is a figure which shows the structural example of the light source unit, and shows the II cross section of FIG. It is a graph which shows the index value about the uniformity of the luminance on the exit surface when the base material is not provided with the reflection pattern (the 1). It is a graph which shows the index value about the uniformity of the luminance on the exit surface when the base material is not provided with the reflection pattern (the 2). It is a graph which shows the index value about the uniformity of brightness on an exit surface when a reflection pattern is provided on a base material (No. 1). It is a graph which shows the index value about the uniformity of brightness on an exit surface when a reflection pattern is provided on a base material (the 2). It is a figure which shows the change of the index value about the uniformity of brightness on an exit surface when the arrangement position of a base material is deviated (the 1). It is a figure which shows the change of the index value about the uniformity of brightness on an exit surface when the arrangement position of a base material is deviated (the 2). It is a figure which shows the change of the index value about the uniformity of the luminance on the exit surface when the 2nd light scatterer is further provided (the 1). It is a figure which shows the change of the index value about the uniformity of the luminance on the exit surface when the 2nd light scatterer is further provided (the 2). It is a schematic plan view of the first light scatterer. It is a side view of the unit pattern of a reflection pattern. It is a figure which shows the modification of the unit pattern of a reflection pattern. It is explanatory drawing of the light source unit manufacturing apparatus which concerns on one Embodiment of this invention. It is a figure which shows the arithmetic processing flow for determining the formation condition of a reflection pattern. It is explanatory drawing of the calculation area (the 1). It is explanatory drawing of the calculation area (the 2). It is a figure which shows the state of transition of the region to be calculated (the 1). It is a figure which shows the state of transition of the region to be calculated (the 2). It is explanatory drawing of the simulation model. It is a figure which shows the distribution of the luminance on the exit surface in the comparative example 1. FIG. It is a figure which shows the distribution of the luminance on the exit surface in Example 1. It is a figure which shows the distribution of the luminance on the exit surface in Example 2. It is a figure which shows the distribution of the luminance on the exit surface in Example 3. It is a figure which shows the distribution of the luminance on the exit surface in Example 4. It is a figure which shows the distribution of the luminance on the exit surface in Example 5. It is a figure which shows the distribution of the luminance on the exit surface in Example 6. It is a figure which shows the distribution of the luminance on the exit surface in Example 7. It is a figure which shows the distribution of the luminance on the exit surface in Example 8.

An embodiment of the present invention (hereinafter referred to as the present embodiment) will be described in detail below with reference to the preferred embodiments shown in the accompanying drawings.
The device configuration, use, and usage described below are based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. That is, the present invention may be modified or improved from the embodiments described below without departing from the spirit of the present invention. Also, of course, the present invention includes an equivalent thereof.

In the present specification, the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
Further, in the present specification, "same", "similar" and "same" are generally accepted in the technical field of the present invention, although they are slightly different from each other, except when they are completely the same. It shall include the case where it is within the error range.
Further, in the present specification, the terms "all", "all", "whole surface", etc. include not only the case of 100% but also the error range generally accepted in the technical field to which the present invention belongs, for example. It shall include the case where it is 99% or more, 95% or more, or 90% or more.
Further, in the present specification, "parallel" includes a case where it is parallel to a reference line, a plane or a direction, and a case where it is substantially parallel to a slope of several degrees.

Further, in the following description, the "light distribution characteristic" means the degree of spread of light from the light source, and is the distribution of the intensity (for example, radiant intensity or illuminance) in each direction from the light source. The light distribution characteristics are usually represented by a characteristic diagram as shown in FIG. In the characteristic diagram, the intensity of the emitted light in the direction of maximum intensity is set to 100%, and the intensity of the emitted light in each direction is represented as a relative value (ratio).
The light distribution is divided into a farfield light distribution measured from an infinity distance where the light source can be seen as a point, and a nearfield light distribution measured from a distance at which the distribution of light emitted from various points in the light source can be discriminated. being classified. In the following, unless otherwise specified, light distribution means farfield light distribution.

Also, in the following explanation, "reflection" means diffuse reflection (diffuse reflection) unless otherwise specified, and is synonymous with diffusion.

[Outline of display device according to this embodiment]
As shown in FIG. 2, the display device 10 according to the present embodiment includes a liquid crystal display (hereinafter referred to as LCD) 12 for displaying an image and a light source unit 14 arranged on the back side of the LCD 12. Have.

The LCD 12 functions as an image display panel, and the display screen of the LCD 12 is irradiated with light from the light source unit 14 from the back side thereof.

The light source unit 14 is provided in the display device 10 as a direct type backlight unit, and is a planar illumination device in which the surface facing the LCD 12 side forms an exit surface. As shown in FIG. 3, the light source unit 14 has a light source installation surface 22 on which at least one micro light source 16 is installed, and a translucent base material 24 arranged side by side with the light source installation surface 22. A reflection pattern 30 formed based on the light distribution characteristics of at least one micro light source 16 is provided on the first surface 26 of the base material 24 located on the light source installation surface 22 side. As shown in FIG. 3, the reflection pattern 30 is composed of a plurality of unit patterns 32.
In the cross-sectional view shown in FIG. 3, the number of each of the minute light source 16 and the unit pattern 32 is different from the actual number in order to simplify the illustration.

Further, in the present embodiment, the distance between the second surface 28 located on the opposite side of the first surface 26 and the light source installation surface 22 (indicated by the symbol d in FIG. 3) of the base material is 1 mm or more and 2 mm. It is as follows. Thereby, in the present embodiment, it is possible to secure the uniformity of the brightness on the exit surface while making each of the light source unit 14 and the display device 10 thin.

More specifically, the wider the interval d, the easier it is to provide the reflection pattern 30, and the narrower the interval d, the better the effect of the reflection pattern 30 is exhibited. On the other hand, the display device 10 including the light source unit 14 is required to be thinner, but the thinner the display device 10, the narrower the interval d, which makes it difficult to provide the reflection pattern 30.

Here, if the base material 24 is not provided with the reflection pattern 30, the index values relating to the brightness distribution on the second surface 28, which is the exit surface, show the behaviors shown in FIGS. 4 and 5 with respect to the change in the interval d. It changes with.

The index value (numerical value on the vertical axis) shown in FIG. 4 is a value obtained by dividing the difference between the maximum point and the minimum point on the luminance distribution (histogram) on the second surface 28 by the average luminance value, and is convenient below. It is called "standardized dynamic range". The maximum point of the luminance distribution corresponds to 97% of the cumulative histogram, and the minimum point corresponds to 3% of the cumulative histogram.
The index value (numerical value on the vertical axis) shown in FIG. 5 is a value obtained by dividing the standard deviation (sigma) calculated from the two-dimensional distribution of the brightness on the second surface 28 by the average value of the brightness, and is convenient below. It is called "standardized sigma".
Both the normalized dynamic range and the normalized sigma become smaller as the uniformity of the luminance distribution becomes higher.

When the base material 24 is not provided with the reflection pattern 30, as can be seen from FIGS. 4 and 5, it is necessary to make the interval d relatively large in order to ensure the uniformity of brightness (for example, FIGS. 4 and 5). In the case shown in 5, it shall be over 15 mm).

On the other hand, by forming the reflection pattern 30 on the first surface 26 of the base material 24, as shown in FIGS. 6 and 7, even when the interval d is 1.0 mm to 2.0 mm, the above The uniformity of brightness can be ensured to the same extent. However, as can be seen from FIGS. 6 and 7, when the interval d becomes small, it becomes difficult to secure the uniformity of brightness, and when the interval d is less than 1 mm, it becomes difficult to secure the uniformity only by the reflection pattern 30. Become.

Further, as can be seen from FIGS. 8 and 9, in the configuration in which the reflection pattern 30 is provided on the base material 24, if the arrangement position of the base material 24 deviates from the regular position, the uniformity of brightness decreases.
8 and 9 show changes in the index value when the arrangement position of the base material 24 is displaced (specifically, when the arrangement position is displaced by 0.2 mm in the XY direction, which will be described later). , Changes in normalized dynamic range, FIG. 9 shows changes in normalized sigma. In the cases shown in FIGS. 8 and 9, the index value increases in the direction of the arrow in the figure due to the displacement of the arrangement position of the base material 24.

Here, when the interval d is 2.0 mm, the influence of the deviation of the arrangement position on the uniformity of the brightness becomes smaller than when the interval d is 1.0 mm. In other words, the arrangement position Robustness (tolerance) to slippage increases.
Based on the above points, in the present embodiment, the interval d is set to 1 mm or more and 2 mm or less, thereby reducing the thickness of the light source unit 14 and improving the uniformity of brightness on the exit surface.

Further, in the present embodiment, the base material 24 and the reflection pattern 30 form the first light scattering body 34, and as shown in FIG. 3, the first light scattering body 34 and at least one micro light source 16 A second light scatterer 36 is arranged between them. Further, the reflection pattern 30 is provided only in the first light scattering body 34 among the first light scattering body 34 and the second light scattering body 36, and is not provided in the second light scattering body 36.

As described above, by arranging the second light scattering body 36 having no reflection pattern 30 between the first light scattering body 34 and the micro light source 16, the base material 24 (that is, the first light scattering body 24) (that is, the first light scattering body) 34) The robustness (resistance) to the deviation of the arrangement position is increased.
More specifically, as can be seen from FIGS. 8 and 9, the effect of the brightness equalization on the exit surface by the reflection pattern 30 of the first light scatterer 34 is that of the first light scatterer 34, like the shading correction of the printer. It is affected by a slight deviation in the placement position.

On the other hand, by combining the second light scattering body 36 with the first light scattering body 34, as shown in FIGS. 10 and 11, the first light scattering body 34 is compared with the case where the second light scattering body 36 is not provided. It is possible to further alleviate the decrease in brightness uniformity when the arrangement position is displaced. The effect of providing such a second light scattering body 36 is particularly effective when the light distribution intensity from the minute light source 16 is high in a limited range (that is, it has a peaky light distribution characteristic). Become.

Note that FIGS. 10 and 11 show changes in the index value when the arrangement position of the base material 24 is displaced under the same conditions as in FIGS. 8 and 9, except that the second light scattering body 36 is provided.

Incidentally, the amount of deviation of the arrangement position of the base material 24 that can be tolerated when the second light scattering body 36 is used is 0.2 mm or less in each of the XY directions. The XY directions correspond to two directions parallel to the light source installation surface 22 and orthogonal to each other. The amount of deviation is the amount of deviation between the regular arrangement position of the first light scattering body 34 with respect to the light source installation surface 22 and the actual arrangement position of the first light scattering body 34.
Further, the interval d is set to 1.0 mm or more and less than 2.0 mm in order to satisfactorily exert the effect of the combined use of the first light scattering body 34 having the reflection pattern 30 and the second light scattering body 36. It is desirable to have it.

[Structure example of the light source unit according to this embodiment]
As shown in FIG. 3, the light source unit 14 according to the present embodiment includes a substrate 20 on which a minute light source 16 is installed, a first light scattering body 34 having a reflection pattern 30, and a second light scattering body 36. Hereinafter, each component device of the light source unit 14 will be described.

(Micro light source)
The micro light source 16 is a point light source having strong directivity. In the present embodiment, the micro light source 16 is composed of the micro light emitting element 18 shown in FIG. 3, and is specifically called a mini LED (Light Emitting Diode) and has a chip size of 100 to 100. It consists of an LED that is 200 μm.
However, the type of the micro light source 16 is not limited to the mini LED, and for example, a micro LED having a chip size of 100 μm or less may be used, or a micro light emitting element other than the LED, specifically, a micro LED. , A minute electroluminescence device, or a minute semiconductor laser may be used.

Explaining the light distribution characteristics of the micro light emitting element 18 (that is, the mini LED) of the present embodiment, the viewing angle when the direction in which the light intensity is highest is 0 degrees among the light emitting directions is ± 65. It is about ± 80 degrees (that is, in the range of about 130 to 160 degrees). The brightness at 0 degrees (that is, the maximum brightness) is not important for the establishment of the present invention and is not particularly limited.

Further, a light diffusing lens (not shown) may be attached to the micro light emitting element 18. The light diffusing lens is a light diffusing lens that diffuses the light emitted from the mini LED, and is, for example, an aspherical lens, and is a known lens member capable of exerting a desired light diffusing effect (for example, Japanese Patent Application Laid-Open No. 2013-12417). The lens member disclosed in Japanese Patent Publication No.) can be used as appropriate. By attaching such a light diffusing lens to the micro light emitting element 18, it is possible to provide a light source unit 14 having higher brightness and excellent brightness uniformity on the emission surface.

(substrate)
The substrate 20 is a flat member, and is a rigid substrate, a flexible substrate, or a rigid flexible substrate which is usually used as a backlight unit of the LCD 12. Further, the substrate 20 has a flat plate-shaped base layer (not shown), and has a light source installation surface 22 on the side where the LCD 12 is located in the base layer. The material of the base layer is not particularly limited, and examples thereof include AGSP (Advanced Grade Solid-Bump Process), alumina, galaepo, PCB (Polychlorinated Biphenyl), and the like, and a material having a particularly high thermal conductivity is preferable.

A metal wiring portion (not shown) is formed on the light source installation surface 22. A plurality of micro light emitting elements 18 (for example, mini LEDs) as at least one micro light source 16 are installed on the light source installation surface 22 via the metal wiring portion. In the present embodiment, the plurality of micro light emitting elements 18 are arranged regularly and symmetrically with respect to the central position of the light source installation surface 22. As an example, a plurality of minute light emitting elements 18 are arranged in a matrix at intervals of 5 to 6 mm in the XY direction from the central position of the light source installation surface 22.
The center position of the light source installation surface 22 corresponds to, for example, the position of the intersection of diagonal lines when the light source installation surface 22 is rectangular or square, and the center position of the circle when the light source installation surface 22 is a circle. do.

Further, the portion of the light source installation surface 22 where the minute light source 16 is not arranged and is exposed (non-light source arrangement region) is covered with a reflective layer and has light reflectivity.
The base layer of the substrate 20 may be formed of a material having light diffusivity, for example, a light diffusing film, and in that case, the reflective layer may not be formed on the base layer.

(First light scatterer)
The first light scattering body 34 is composed of a reflective transmitter, and as shown in FIG. 3, a transparent or translucent base material 24 having light transmission and a reflection pattern 30 formed on the surface of the base material 24. And have.

(Base material)
The base material 24 is made of a film material having a light-transmitting property, and if it transmits light, it is a transparent base material, a translucent base material, and other base materials having a light diffusing property. , Either way.

As shown in FIG. 3, the base materials 24 are arranged side by side so as to be parallel to the light source installation surface 22 of the substrate 20. As for the regular arrangement position of the base material 24 with respect to the light source installation surface 22, the central position of the base material 24 coincides with the center position of the light source installation surface 22 in the XY direction, and the extension direction of the base material 24 is the light source installation surface 22. This is the position when it coincides with the extension direction of.
The center position of the base material 24 corresponds to, for example, the position of the intersection of diagonal lines when the surface of the base material 24 is rectangular or square, and the center position of the circle when the surface of the base material 24 is a circle. Is applicable.

Examples of the film material constituting the base material 24 include polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polylactic acid (PLA); cellulose resins such as cellulose triacetate; polyethylene (PE). ), Polypropylene (PP), and polyolefin resins such as cycloolefin (COC, COP) resins; acrylic resins such as polymethylmethacrate (PMMA); polycarbonate (PC) resins; polytetrafluoroethylene (PTFE) Fluorescent resin and the like can be mentioned.

Further, the base material 24 may be composed of one layer or two or more layers. For example, the base material 24 composed of a plurality of layers may include a layer composed of a light diffusing film.
Incidentally, the base material 24 of the present embodiment is provided with a reflection layer (not shown) made of the same material as the reflection pattern 30 on the side where the minute light source 16 is located. This reflective layer is a layer having a uniform thickness and being sufficiently small.

When the transparent film is used as the base material 24, the transmittance of the base material 24 (strictly speaking, the average light transmittance in the emission wavelength band of the minute light source 16) is preferably 50% or more, preferably 70%. The above is more preferable, and 85% or more is particularly preferable.

Further, the base material 24 may have light diffusivity. For example, light diffusivity may be imparted to the base material 24 by forming an uneven shape or a prism shape on at least one surface of the base material 24. Further, the base material 24 may be imparted with light diffusivity by interspersing inorganic fine particles or organic fine particles inside the base material 24.

Further, the refractive index of the base material 24 is preferably 1.00 to 2.00 in relation to the refractive index of air so that the incident angle of the light rays passing through the base material 24 is not excessively limited. It is more preferably .30 to 1.80.

Here, the thickness direction of the base material 24, that is, the direction in which the base material 24 and the light source installation surface 22 are aligned is the Z direction, the side where the LCD 12 is located as viewed from the base material 24 is the + Z side, and the light source installation surface 22 is located. The side to be used is the -Z side. The surface of the base material 24 on the −Z side is the first surface 26, and the reflection pattern 30 is formed on the first surface 26 as described above. The surface of the base material 24 on the + Z side is the second surface 28, and the second surface 28 faces, for example, the back surface of the LCD 12, and constitutes the light emitting surface of the light source unit 14 in the present embodiment. ..

(Reflection pattern)
The reflection pattern 30 is formed (patterned) on the first surface 26 of the base material 24, and reflects incident light (strictly speaking, light transmitted through the second light scattering body 36) from the plurality of minute light emitting elements 18. The reflection pattern 30 is laminated with the base material 24 on the −Z side of the base material 24.

In the present embodiment, the reflection pattern 30 is composed of, for example, the same number of unit patterns 32 as the minute light emitting elements 18 as shown in FIG.
In the reflection pattern 30 shown in FIG. 12, the number of unit patterns 32 is different from the actual number for convenience of illustration.

Further, the plurality of unit patterns 32 are regularly and symmetrically arranged with reference to the central position of the first surface 26. Specifically, the unit pattern 32 is formed at equal pitches in each of the XY directions from the center position of the first surface 26. Here, the pitch of the unit pattern 32 on the first surface 26 is the same as or substantially equal to the pitch of the minute light emitting element 18 on the light source installation surface 22. As a result, as shown in FIG. 3, each unit pattern 32 is located directly above each minute light emitting element 18 when the base material 24 is in the regular arrangement position.

Further, each unit pattern 32 is a substantially conical pattern having a relatively wide hem as shown in FIG. That is, in the present embodiment, the unit pattern 32 has a shape that protrudes toward the light source installation surface 22 and whose diameter gradually decreases as it approaches the light source installation surface 22.
As shown in FIG. 13, each unit pattern 32 may have a tapered shape in which the diameter is gradually reduced toward the light source installation surface 22, and as shown in FIG. 14, the diameter is discontinuously reduced at a plurality of reduced diameter points. By doing so, the shape may be a step (step).
Further, the shape of each unit pattern 32 is not limited to a substantially conical shape, and may be a triangular pyramid or a quadrangular pyramid shape, a cylindrical shape, a prismatic shape forming a polygon in a plan view, or an indefinite shape.

The material of the unit pattern 32 is a material having a high light reflectance (hereinafter referred to as a reflective material). Examples of the reflective material include white pigments and the like, and examples of the white pigments include titanium oxide, barium sulfate, potassium carbonate, silica, talc and clay. Examples of the reflective material other than the white pigment include conductive silver ink containing a silver complex as a main component (for example, conductive silver ink containing coated silver ultrafine particles as a main component). Further, as the reflective material, a thermoplastic resin composition containing the above-mentioned white pigment can be used. Specific examples of the thermosetting resin composition used as the reflective material include a combination of a known urethane resin and an isocyanate compound, a combination of an epoxy resin and a polyamine or an acid anhydride, and a combination of a silicone resin and a cross-linking agent. , A two-component thermosetting resin containing a main agent and a curing agent, and a three-component thermosetting resin containing a curing accelerator such as amine, imidazole, and phosphorus can be used. Specifically, a light-reflecting layer using a silicone-based thermosetting resin described in JP-A-2014-129549 can be exemplified.
In this embodiment, titanium oxide is used as a reflective material to form the unit pattern 32.

The formation (patterning) of the reflection pattern 30 on the first surface 26 may be performed by inkjet printing or printing by another method (for example, screen printing). However, the method of pattern formation (patterning) is not limited to printing, and may be metal vapor deposition or application of a reflective material. Further, after applying the reflective material to the entire surface of the first surface 26, the reflective material may be scraped off so that the above-mentioned unit pattern 32 remains to form the reflective pattern 30.

Then, in the present embodiment, the reflection pattern 30 is formed on the first surface 26 based on the light distribution characteristics of the micro light source 16 (specifically, the mini LED which is the micro light emitting element 18) installed on the light source installation surface 22. There is.
Specifically, each of the plurality of unit patterns 32 forming the reflection pattern 30 is set so that the index values (for example, standardized dynamic range and standardized sigma, etc.) relating to the luminance distribution on the second surface 28 satisfy the setting conditions. It is formed on the first surface 26. Here, the setting condition is a numerical range that the index values such as the standardized dynamic range and the standardized sigma should satisfy as the required specifications of the light source unit 14.

More specifically, the thickness, size, and arrangement position of the unit pattern 32 are determined so as to dimming to the target value in the region of the exit surface located directly above the micro light emitting element 18. Further, in the region located immediately above the minute light emitting element 18, the thickness, size and arrangement position of the unit pattern 32 are determined so as to dimming each diffused light and reflected light.
Here, the thickness of the unit pattern 32 is the length from the bottom surface (+ Z side end) to the top (−Z side end) of the unit pattern 32, and the size of the unit pattern 32 is the maximum diameter of the unit pattern 32. Is. The arrangement position of the unit pattern 32 is the center position of the unit pattern 32 in the XY direction (the center position of the bottom surface of the circular unit pattern 32).

Then, the reflection pattern 30 is formed on the first surface 26 so that each unit pattern 32 has a determined thickness, size, and arrangement position. The procedure for forming the reflection pattern 30 will be described in detail in a later section.

(Second light scatterer)
The second light scatterer 36 scatters and diffuses the light from the minute light source 16 inside the second light scatterer 36. In the present embodiment, the second light scattering body 36 is in the form of a flat plate or a thin film, and as shown in FIG. 3, the first light scattering body 34 and at least one micro light source 16 (that is, a plurality of micro light emitting elements) in the Z direction. It is arranged so as to be parallel to the first light scattering body 34 with 18).

The light emitted from each micro light emitting element 18 is incident on the second light scattering body 36, scattered in the second light scattering body 36, and eventually passes through the second light scattering body 36. As a result, the uniformity of the brightness on the second surface 28, which is the exit surface, can be improved, and the robustness against the misalignment of the first light scatterer 34 can be improved.

As described above, the reflection pattern 30 is not formed on the second light scattering body 36. Specifically, the second light scattering body 36 is composed of a laminated body including a base layer and a scattering layer. The base layer is composed of a translucent plate material or film material, and a light diffusion structure (for example, a minute and random lens array or the like) is formed on a translucent resin film made of, for example, polycarbonate or acrylic resin. An optical film can be used as the base layer. The scattering layers are not scattered like the reflection pattern 30, but are formed with a substantially uniform thickness on the entire surface of the base layer (for example, the surface located on the first light scattering body 34 side). The material constituting the scattering layer is the same reflective material as the reflective pattern 30, and for example, titanium oxide, barium sulfate, potassium carbonate, silica, talc, clay and the like can be used.
The second light scattering body 36 is not limited to the above-mentioned laminated body, and is configured by dispersing light scattering particles having a refractive index different from that of the base material in a base material formed of a transparent resin. The optical member may be used as the second light scattering body 36.

The closer the second light scattering body 36 is to the light source installation surface 22, the greater the spread of light from the minute light source 16 toward the second light scattering body 36. Further, the larger the distance between the first light scattering body 34 and the second light scattering body 36, the larger the spread (diffusion degree) of the light from the second light scattering body 36. In consideration of such a tendency, it is desirable that the second light scattering body 36 is arranged at a position where the effect of light spreading can be maximized.

Although the configuration example of the light source unit 14 of the present embodiment has been described above, the above configuration is merely an example, and other configurations are also conceivable.
In the present embodiment, the second surface 28, which is the surface on the + Z side of the base material 24, is the exit surface, but the present invention is not limited to this. For example, a prism sheet may be superposed on the second surface 28, and the surface on the + Z side of the prism sheet may be used as the exit surface.
Further, in the present embodiment, the second light scattering body 36 is provided, but the configuration may be such that the second light scattering body 36 is not provided.
Further, the light source unit 14 according to the present embodiment is used as a backlight unit of the display device 10, but is not limited to this, and may be used as a surface emitting lighting device.

[Light source unit manufacturing equipment]
Next, the light source unit manufacturing apparatus 40 for manufacturing the light source unit 14 of the present embodiment will be described. As shown in FIG. 15, the light source unit manufacturing apparatus 40 includes a light distribution characteristic acquisition apparatus 42, a pattern forming data generating apparatus 44, and a pattern forming apparatus 46.

(Light distribution characteristic acquisition device)
The light distribution characteristic acquisition device 42 is a device that acquires the light distribution characteristics (strictly speaking, information on the light distribution characteristics) of the minute light source 16 used in the light source unit 14, and is composed of, for example, a known light distribution characteristic measuring device. NS. As the light distribution characteristic measuring device, a device in which a light source is rotated by a goniometer, a rotating stage or a rotating mirror, and the illuminance (luminous intensity) at that angle is measured by an illuminance meter or a luminance meter can be used. Examples thereof include the LED illumination orientation measurement system NeoLight manufactured by System Engineering Co., Ltd. and the luminance light distribution characteristic measuring device C9920-11 manufactured by Hamamatsu Photonics Co., Ltd.
Further, as a light distribution characteristic measuring device other than the above, an LED light distribution measuring device (for example, a measuring device manufactured by OptiCom) that measures the light distribution spectral distribution characteristics of the LED element or the LED module under preset conditions can also be used. be. In this device, the vertical light distribution stage and the horizontal light distribution stage are controlled to adjust the LED emission angle, and the LED emission angle is positioned so as to face the photodetector, and then the lighting power supply of the device is controlled according to the measurement conditions. And turn it on, and measure the spectral distribution with a measurement control device.

(Pattern formation data generator)
The pattern formation data generation device 44 is a device that generates data for forming the reflection pattern 30 (hereinafter, referred to as pattern formation data), and is configured by, for example, a computer provided with a processor (not shown). The processor is composed of, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), and executes a program for optical simulation stored in a storage device (not shown) in the device. Through the execution of this simulation program, the pattern formation data generation device 44 determines the formation conditions of the reflection pattern 30 based on the light distribution characteristics of the minute light source 16, and generates pattern formation data indicating the conditions.

Specifically, the pattern formation data generation device 44 acquires information (for example, a measured value of the light distribution characteristic) regarding the light distribution characteristic of the minute light source 16 from the light distribution characteristic acquisition device 42. The pattern formation data generation device 44 determines the thickness, size, and arrangement position (hereinafter, thickness, etc.) of each unit pattern 32 through optical simulation based on the acquired light distribution characteristics. At this time, the thickness and the like are determined so as to satisfy the following first and second conditions.
First condition: The brightness in each of the specific region located at the position overlapping with at least one micro light source 16 and the peripheral region surrounding the specific region on the second surface 28 is equal to or less than the reference value.
Second condition: The degree of dispersion of the brightness on the second surface 28 is within the target range.

Then, when the first condition and the second condition are satisfied, the index values such as the standardized sigma and the standardized dynamic range satisfy the above-mentioned setting conditions.
The "specific region" in the first condition is a region of the second surface 28 that overlaps with each of the minute light emitting elements 18 in the Z direction, and is easily understood as a region directly above each of the minute light emitting elements 18. Is. Assuming that a plurality of unit patterns 32 are not formed on the first surface 26, the brightness in a specific region is the highest.
The "peripheral region" in the first condition is a region arranged so as to surround the specific region on the second surface 28, and exists in a layered manner from the side adjacent to the specific region to the outside.
The "reference value" in the first condition is a target value set for the brightness in a specific region, and for example, each of the second surfaces 28 when a plurality of unit patterns 32 are not formed on the first surface 26. It is a value obtained by averaging the brightness in the region (average brightness).

The "luminance dispersion degree" in the second condition is an evaluation index regarding the distribution of luminance in each region of the second surface 28 (that is, each of the specific region and the peripheral region), in other words, the smoothness of luminance. Shown.
The "target range" in the second condition is a numerical range set with respect to the degree of dispersion of the luminance, and is, for example, a range (error range) that can be regarded as the same as or the same as the target value of the degree of dispersion. In the present embodiment, the target range is set based on the reference value of the first condition.

The pattern formation data generation device 44 performs a predetermined arithmetic process in determining the thickness and the like of each unit pattern 32 so that the above first condition and the second condition are satisfied. This arithmetic processing flow proceeds according to the procedure shown in FIG. Hereinafter, the above arithmetic processing flow will be described with reference to FIG.

(Calculation processing flow)
In carrying out the calculation processing flow, the second surface 28 is divided into a plurality of calculation units. Specifically, the second surface 28 is divided into a plurality of regions centered on the arrangement position of each minute light emitting element 18 in the XY direction, and each of them is used as a calculation unit. Here, there are as many calculation units as the micro light emitting elements 18 on the second surface 28, and in the present embodiment, they are rectangular regions as shown in FIGS. 17A and 17B.

Each calculation unit is further divided into smaller calculation areas as shown in FIGS. 17A and 17B. Here, the calculation regions may be arranged in a grid pattern in the XY direction as shown in FIG. 17A, or may be arranged concentrically as shown in FIG. 17B.
Of each calculation unit, the calculation area P1 at the same position as the arrangement position of each minute light emitting element 18 in the XY direction corresponds to the above-mentioned specific area. The calculation areas P2 to P6 arranged so as to form a square frame or a ring surrounding the specific area outside the specific area correspond to the above-mentioned peripheral area.

The size (mesh size) and partitioning method of the calculation area are not particularly limited, but in the following, each calculation unit is divided into a multi-layered calculation area centered on the arrangement position of the minute light emitting element 18 as an example. I will explain it by listing it. For example, when the calculation unit shown in FIG. 17A is used, a 9 × 9 calculation area arranged in a matrix in the XY directions is handled. On the other hand, when the calculation unit shown in FIG. 17B is used, six calculation areas arranged concentrically are handled.

Each step in the calculation processing flow is carried out for one calculation unit. In the calculation processing flow, as shown in FIG. 16, first, all the calculation areas in the calculation unit are set to the initial values (S001). In order to obtain the initial value, it is assumed that a plurality of unit patterns 32 are not formed on the first surface 26, and the brightness distribution in each region of the second surface 28 in that case is obtained. Then, the smoothness as the degree of dispersion of the brightness is evaluated, and the thickness at which the evaluation value is the smallest is set as the initial value.

Next, with each calculation area set to the initial value, the brightness distribution in the calculation unit when the minute light emitting element 18 is turned on is calculated, and the smoothness is evaluated (S002). Then, the average value in the luminance distribution calculated in step S002 is set as the target value (that is, the reference value of the first condition described above) (S003).

Since the subsequent steps are repeated for each calculation area, the calculation area to be calculated is set to Pi and i = 1 is set (S004). Here, i is determined based on the arrangement position of the minute light emitting element 18 in the XY direction, and the smaller i is, the closer to the minute light emitting element 18. The calculation area when i = 1, that is, P1 is a specific area located directly above the minute light emitting element 18.

In the next step S005, it is determined whether the brightness of the distribution calculated in step S002 is within the preset error range with respect to the target value (average brightness) set in step S003. Further, in step S005, it is determined whether the smoothness evaluated in step S002 is within the set range determined with reference to the target value, and more specifically, is within the error range of the target value and satisfies the target value.

When the determination result in step S005 is "Yes", the luminance of the distribution satisfies the target value and the smoothness is within the set range, so that the calculation processing flow is terminated.
On the other hand, when the determination result in step S005 is "No", it is determined whether or not the brightness in the calculation area Pi has achieved the target value (S006). In the first step S006, since i = 1, it is determined whether or not the brightness in the specific region has achieved the target value.

If the determination result in step S006 is "Yes", that is, if the brightness in the calculation area Pi satisfies the target value, i is incremented and the calculation area Pi to be calculated is changed to the next area ( S007). Then, the process returns to step S005.

On the other hand, if the determination result in step S006 is "No", that is, if the brightness in the calculation area Pi does not satisfy the target value, another determination is made in step S008 described later. Then, when the determination result in step S008 is "No", the thickness in the calculation area Pi (that is, the thickness of the unit pattern 32 on the calculation area Pi) is changed (S009).

In step S009, when the brightness in the calculation area Pi greatly exceeds the target value, the thickness is changed so as to reduce the brightness. On the contrary, when the brightness in the calculation area Pi is much lower than the target value, the thickness is changed so as to increase the brightness.
When changing the thickness, it is preferable to specify in advance the relationship (correlation) between the amount of change in thickness and the amount of change in brightness, and store the specified correlation as table data. Then, in step S009, it is preferable to obtain a change amount of the thickness so as to obtain an appropriate brightness by referring to the table data, and change the thickness according to the obtained change amount.

Further, in step S009, the thickness is changed so that the changed thickness does not exceed the predetermined thickness adjustment range. When the changed thickness reaches the upper limit value or the lower limit value of the above adjustment range, the number of calculations for the calculation area Pi is changed to a predetermined value (specifically, the upper limit number of times). In that case, the determination result in step S008 described later becomes “Yes” and returns to step S002, the brightness distribution is calculated, and the smoothness is evaluated. After that, the next step S003 is performed to set the target value.

Specifically, in the calculation area Pi where the thickness reaches the upper limit, the brightness cannot be reduced any more, so it is necessary to lower the target value. Here, since the brightness of the calculation area Pi is calculated in the order of decrease, the above situation occurs only in i = 1, that is, a specific area. Based on this point, the thickness is increased from the initial value, and the average value is recalculated in a state where the brightness of the specific region is reduced. As a result, the average brightness, that is, the target value, is lower than the previous values. As a result, the possibility of satisfying the target value while reducing the thickness of the pattern is increased.

On the contrary, in the calculation area Pi where the thickness reaches the lower limit, the brightness is lower than the target value. In that case, it is necessary to reduce (scatter) the brightness in a region closer to the specific region to guide the light to the above-mentioned calculation region Pi. In the calculation area P [i-1] or the like in front of the above calculation area Pi, the brightness satisfies the target value. Therefore, when the average value is calculated, the average value is lower than the previous target value (average brightness). Based on this point, in the calculation area P [i-1] and the like in the foreground, the target value is set so that the thickness is scattered thicker. As a result, in the calculation area Pi, the possibility that the target value is satisfied with a value having a large pattern thickness increases.

Returning to the flow of FIG. 16, after changing the thickness in the calculation area Pi in step S009, the changed thickness is applied to distribute the brightness in the calculation unit when the minute light emitting element 18 is lit. Is calculated (S010). At this point, the number of calculations for the calculation area Pi is increased (counted up) by +1.

After that, the process returns to step S006, and it is determined whether or not the brightness in the calculation area Pi has achieved the target value. If the determination result is "Yes", step S007 is performed, and then the process returns to step S005. On the contrary, when the determination result in step S006 is "No", step S008 is executed to determine whether the number of calculations for the calculation area Pi exceeds a predetermined value (upper limit number of times). If the determination result in step S008 is "No", step S009 is executed to change the thickness in the calculation area Pi.

On the other hand, when the determination result in step S008 is "Yes", the process returns to step S002 to correct the target value. That is, step S002 is performed, and the distribution of the brightness in the calculation unit when the minute light emitting element 18 is turned on is calculated based on the thickness in each calculation area set at this time. After that, step S003 is performed, and the average value of the brightness in the distribution calculated in step S002 is set as a new target value.

The calculation processing flow is executed by the above procedure, and steps S002 to S010 are repeated (looped) while changing the calculation area Pi to be calculated until the determination result in step S005 becomes "Yes". Thereby, as shown in FIGS. 18A and 18B, the thickness of the unit pattern 32 in each calculation area Pi is determined.
In addition, in each figure of FIGS. 18A and 18B, the thickness in each calculation area is sequentially determined from the top to the bottom, and the calculation area in which the thickness is newly calculated (newly in each figure). The colored part) moves from the inside to the outside.

As a processing algorithm, it is necessary to stop the flow properly even in a situation where there is no solution originally, so the total number of loops is counted separately, and when the number of loops exceeds the upper limit, "Solution" Stop the flow as "None".

Then, when the determination result in step S005 becomes "Yes", the thickness in each calculation area Pi (that is, the thickness of the unit pattern 32) is determined. As a result, for each unit pattern 32, the thickness and the like that satisfy the above-mentioned first condition and second condition are determined.

(Pattern forming device)
The pattern forming apparatus 46 forms the reflection pattern 30 on the first surface 26 of the base material 24 according to the pattern forming data generated by the pattern forming data generating apparatus 44. The pattern forming apparatus 46 of the present embodiment is composed of an inkjet printer, and ejects ink containing a reflective material toward each part of the first surface 26 to form a plurality of unit patterns 32. At this time, the pattern forming apparatus 46 adjusts the ink ejection timing, the ejection amount, and the like so that the thickness and the like of each unit pattern 32 become the thickness and the like specified in the pattern forming data.

That is, the pattern formation data of this embodiment is data for printer control (print data). The pattern forming apparatus 46, which is a printer, ejects ink according to the pattern forming data, so that a predetermined amount of ink lands at a predetermined position on the first surface 26. As a result, a plurality of unit patterns 32 are formed on the first surface 26 so as to have a thickness that satisfies the first condition and the second condition.

As described above, the pattern forming apparatus 10 manufactures the base material 24 (that is, the first light scattering body 34) on which the reflection pattern 30 is formed. Then, the light source unit 14 is manufactured by combining the first light scattering body 34, the substrate 20 on which the minute light emitting element 18 is installed, and the second light scattering body 36.

The pattern forming apparatus 46 is not limited to the inkjet printer, and may be configured by other apparatus, for example, a printing type printer other than the inkjet printer, or an ink coating apparatus. Alternatively, it may be an apparatus that uses screen printing technology to create a plate for forming a predetermined reflection pattern 30, and prints using the plate.

Hereinafter, the present invention will be described in more detail based on the following examples.
The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the invention should not be construed as limiting by the examples below.

[Optical simulation of brightness distribution]
In Examples 1 to 8 and Comparative Example 1, the brightness distribution on the exit surface of the light source unit was calculated by optical simulation. Here, the brightness of each part of the exit surface is assumed to fluctuate, and is evaluated by a relative value divided by the average value.

In the model used for the optical simulation (hereinafter, simulation model), a square substrate 20 was used in a plan view. Further, on the light source installation surface 22, mini LEDs, which are minute light emitting elements 18, are arranged at each of the plurality of arrangement positions shown in FIG. Specifically, a total of nine mini LEDs were arranged at a substantially constant pitch in each direction in the XY directions from the central position of the light source installation surface 22. The pitch of the mini LEDs in the X direction was 5.386 mm, and the pitch of the mini LEDs in the Y direction was 6.066 mm.

The chip size of each mini LED was 230 μm × 120 μm × 130 μm. The light distribution characteristics of each mini LED were the light distribution characteristics shown in FIG. 1, the viewing angle was 130 degrees, and the intensity in the vicinity directly above the brightest mini LED was 0.32 W / sr mm ² .

Further, in the simulation model, the light scattering in the exposed portion of the light source installation surface 22 is the scattering according to the incident angle of the light, and it is determined that the COSN power law (N = 2) is obeyed.
The reflectance, transmittance and absorption of the substrate 20 were set to 90%, 5% and 5%, respectively.

Further, in the simulation model, the first light scattering body 34 is placed above the light source installation surface 22, parallel to the light source installation surface 22, and at the center position of the light source installation surface 22 and the center position of the surface of the base material 24 in the XY directions. Arranged so that they match. As the base material 24 of the first light scatterer 34, a polyethylene terephthalate (PET) film having a thickness of 0.1 mm was used. The PET film had a square shape in a plan view, and its refractive index n was set to 1.576.
Further, in the simulation model, the surface on the + Z side of the PET film (that is, the second surface located on the side opposite to the light source installation surface 22) is set as the light emitting surface, and the spreading angle at each part of the emitting surface is 10 degrees. bottom.

(Comparative Example 1)
A first light scatterer 34 made of PET film on which the reflection pattern 30 was not formed was used, and the distance between the light source installation surface 22 and the emission surface (that is, the surface on the + Z side of the PET film) was set to 14 mm. The distribution of brightness on the exit surface in this case is simulated, and the simulation result is shown in FIG.
When the reflection pattern 30 is not formed, as can be seen from FIG. 20, the brightness increases remarkably in the position directly above the mini LED and in the vicinity thereof on the exit surface, and between these places and other places. The difference in brightness is relatively large.
In each figure after FIG. 20, the magnitude of brightness is visualized by shading in black and white (graph on the left side in each figure), and the smoothness of brightness is shown by a histogram (in each figure). The graph on the right side of).

(Example 1)
In Example 1, a reflection pattern 30 composed of a plurality of unit patterns 32 is provided on the −Z side surface (that is, the first surface) of the PET film used in the simulation model. The unit pattern 32 is made of titanium oxide, is arranged around the position directly above the mini LED in the XY direction, and is provided with a reflection pattern 30 consisting of a total of nine unit patterns 32, three in each of the vertical and horizontal directions.

As shown in FIG. 14, each unit pattern 32 is a concentric stack of five columnar pattern fragments having different diameters from each other. The radii of each pattern fragment were 0.5 mm, 1.0 mm, 1.6 mm, 2.2 mm, and 2.65 mm in order from the tip side. The thickness of each pattern fragment was set to the value shown in Table 1. The thickness shown in Table 1 is a value expressed as a ratio with respect to the reference thickness t (t = 0.00759 mm).

Further, in the present embodiment, a layer (flat portion) made of titanium oxide is provided on the entire surface of the PET film on the −Z side as a base of the reflection pattern 30. The thickness of the flat portion was uniform and was 0.1 times the above-mentioned reference thickness t.

Further, regarding the optical parameters (diffusion coefficient, absorption coefficient, etc.) of the PET film provided with the reflection pattern 30, it was determined that the transmittance and the reflectance match between the calculated value by the simulation and the measured value. Ray tracing simulation software (product name: Light Tools) was used to measure the transmittance and reflectance.
The refractive index n of the PET film provided with the reflection pattern 30 was 1.4, and the absorption coefficient was 0.

Further, in Example 1, the distance between the light source installation surface 22 and the exit surface (that is, the surface on the + Z side of the PET film) is set to 1 mm.

Under the above circumstances, the distribution of brightness on the exit surface was simulated, and the simulation results are shown in FIG. As can be seen from the figure, when a PET film provided with the reflection pattern 30 is used and the distance between the light source installation surface 22 and the emission surface is 1 mm, the emission surface is compared with the case where the reflection pattern 30 is not provided. The distribution of brightness in is smoothed. Further, the thickness of the light source unit as a whole can be reduced by the amount that the interval is reduced.

(Example 2)
In Example 2, the thickness of each of the five pattern fragments constituting each unit pattern 32 was set to the value shown in Table 1. Further, in Example 2, the distance between the light source installation surface 22 and the exit surface (that is, the surface on the + Z side of the PET film) was set to 1 mm. Other than that, the conditions were the same as in Example 1.

For Example 2, the distribution of brightness on the exit surface was simulated, and the simulation result is shown in FIG. As can be seen from FIG. 22, by setting the distance between the light source installation surface 22 and the emission surface to 2 mm, the brightness distribution on the emission surface can be further smoothed.

(Examples 3 and 4)
In Examples 3 and 4, the arrangement position of the PET film provided with the reflection pattern 30 was shifted from the regular position by 0.2 mm in the horizontal direction. Further, in Example 3, the distance between the light source installation surface 22 and the exit surface was set to 1 mm, and in Example 4, the distance was set to 2 mm. Further, in Examples 3 and 4, the thickness of each of the five pattern fragments constituting each unit pattern 32 was set to the value shown in Table 1. Other than that, the conditions were the same as in Example 1.

The brightness distribution on the exit surface was simulated for each of Examples 3 and 4, and the simulation results are shown in FIGS. 23 and 24. As can be seen from these figures, if the arrangement position of the PET film provided with the reflection pattern 30 is displaced, the smoothness of the brightness on the exit surface is lowered. In particular, when the distance between the light source installation surface 22 and the exit surface is 1 mm, the smoothness is significantly reduced as compared with the case where the distance is 2 mm.

(Examples 5 to 8)
In Examples 5 to 8, a diffuser plate as a second light scatterer 36 was additionally arranged between the PET film provided with the reflection pattern 30 and the light source installation surface 22.
The diffuser plate used is configured by applying titanium oxide to both sides of a PET film (thickness 0.3 mm) of the same type as the base material 24 of the first light scattering body 34 so as to have a uniform thickness. The titanium oxide layer is 2.63 times thicker than the above-mentioned reference thickness t. Further, the diffuser plate is arranged so that the surface of the diffuser plate facing the light source installation surface 22 is 0.2 mm away from the light source installation surface 22 in the Z direction.
Further, in Examples 5 and 6, the PET film was arranged at a regular position, and in Examples 7 and 8, the position of the PET film was shifted horizontally by 0.2 mm from the regular position. Further, in Examples 5 and 7, the distance between the light source installation surface 22 and the exit surface was set to 1 mm, and in Examples 6 and 8, the distance was set to 2 mm. Further, in Examples 5 to 8, the thickness of each of the five pattern fragments constituting each unit pattern 32 was set to the value shown in Table 1. Other than that, the conditions were the same as in Example 1.

The brightness distribution on the exit surface was simulated for each of Examples 5 to 8, and the simulation results are shown in FIGS. 25 to 28. As can be seen from these figures, by arranging the additional diffuser plate between the PET film and the light source installation surface 22, the brightness distribution on the exit surface can be further smoothed. Further, by providing an additional diffusion plate, it is possible to alleviate the deterioration of smoothing due to the misalignment of the PET film.

Since each of the conditions of Examples 1 to 8 of the present invention described above is within the scope of the present invention, the effect of the present invention is clear.

10 Display device 12 LCD (Liquid Crystal Display)
14 Light source unit 16 Micro light source 18 Micro light emitting element 20 Substrate 22 Light source installation surface 24 Base material 26 First surface 28 Second surface 30 Reflection pattern 32 Unit pattern 34 First light scatterer 36 Second light scatterer 40 Light source unit manufacturing equipment 42 Light distribution characteristic acquisition device 44 Pattern formation data generation device 46 Pattern formation device

Claims (12)

1. A light source installation surface on which at least one micro light source is installed,
   A translucent base material arranged side by side with the light source installation surface,
   The base material has a reflection pattern formed based on the light distribution characteristics of at least one micro light source on the first surface located on the light source installation surface side.
   A light source unit in which the distance between the second surface of the base material, which is located on the side opposite to the first surface, and the light source installation surface is 1 mm or more and 2 mm or less.
2. It has a substrate having a flat surface for installing the light source, and has a flat substrate.
   The light source unit according to claim 1, wherein a plurality of micro light emitting elements as the at least one micro light source are symmetrically arranged on the light source installation surface with respect to a central position of the light source installation surface.
3. The light source unit according to claim 1 or 2, wherein a plurality of unit patterns as the reflection patterns are symmetrically formed on the first surface with respect to the central position of the first surface.
4. The light source unit according to claim 3, wherein each of the plurality of unit patterns is composed of titanium oxide.
5. The light source unit according to claim 3 or 4, wherein each of the plurality of unit patterns protrudes toward the light source installation surface and has a shape in which the diameter gradually decreases as the light source installation surface approaches the light source installation surface.
6. The invention according to any one of claims 3 to 5, wherein each of the plurality of unit patterns is formed on the first surface in order for the index value relating to the brightness distribution on the second surface to satisfy the setting condition. Light source unit.
7. When the following first condition and second condition are satisfied, the index value satisfies the setting condition.
   The light source unit according to claim 6, wherein the thickness, size, and arrangement position of each of the plurality of unit patterns are the thickness, size, and arrangement position determined so as to satisfy the first condition and the second condition.
   First condition: The brightness in each of the specific region located at the position overlapping the at least one micro light source and the peripheral region surrounding the specific region on the second surface is equal to or less than the reference value.
   Second condition: The degree of dispersion of the brightness on the second surface is within the target range.
8. The light source unit according to any one of claims 1 to 7, wherein the base material is made of a film material having translucency.
9. The base material and the reflection pattern form a first light scatterer.
   A second light scatterer is arranged between the first light scatterer and the at least one light source.
   The light source unit according to any one of claims 1 to 8, wherein the reflection pattern is provided only on the first light scattering body among the first light scattering body and the second light scattering body.
10. The deviation between the regular arrangement position of the first light scatterer and the actual arrangement position of the first light scatterer with respect to the light source installation surface in each of the two directions parallel to the light source installation surface and orthogonal to each other. The light source unit according to claim 9, wherein the amount is 0.2 mm or less.
11. A display device having a liquid crystal display, wherein the light source unit according to any one of claims 1 to 10 is provided as a backlight unit on the back side of the liquid crystal display.
12. A light source unit manufacturing apparatus for manufacturing the light source unit according to any one of claims 1 to 10.
    A light distribution characteristic acquisition device that acquires the light distribution characteristics of at least one of the minute light sources, and
    A light source unit manufacturing apparatus comprising a pattern forming apparatus for forming the reflection pattern on the first surface of the base material according to the pattern forming data generated based on the acquired light distribution characteristics.

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