TW202132721A - Light source unit, display apparatus, 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 tiny light sources. Moreover, the present invention also relates to a light source unit manufacturing device for manufacturing the light source unit.

In order to display high-quality video, a light source unit used as a backlight of a display device such as a liquid crystal television requires uniformity of brightness on the light exit surface. As a conventional light source unit capable of uniform light irradiation, for example, a light source module described in Patent Document 1 can be cited.

The light source module described in Patent Document 1 is used as a direct type backlight, and includes a transflective plate (denoted as “lighting curtain” in Patent Document 1) between the light source and the light exit surface. According to this structure, even when a light source with strong directivity is used, it is possible to suppress uneven brightness on the exit surface and to irradiate light uniformly.

[Patent Document 1] JP 2012-0174634 A

The light source unit as the backlight of the display device is expected to be thinner than the prior product including the light source module of Patent Document 1. In addition, as the quality of the light source unit, it is required to further improve the uniformity of brightness on the exit surface. However, the thinner the light source unit is, the more difficult it is to ensure the uniformity of the brightness on the exit surface.

The present invention was made in view of the above-mentioned circumstances, and its problem is to solve the objects shown below. The purpose of the present invention is to solve the above-mentioned problems of the prior art and provide a light source unit and a display device that can ensure the uniformity of the brightness on the exit surface even in the case of thinning. Furthermore, another object of the present invention is to provide a light source unit manufacturing apparatus for manufacturing the above-mentioned light source unit.

The inventors of the present invention have conducted intensive studies in order to achieve the above object, and found that the distance between the installation surface of the micro light source and the second surface of the translucent substrate with a reflective pattern formed on the first surface is relative to The uniformity of brightness has an impact. Specifically, the wider the interval, the easier it is to form a reflective pattern, and the narrower the interval, the more appropriate the effect of the reflective pattern can be exerted. Based on the above viewpoints, the inventors of the present invention found that when the aforementioned interval is within a predetermined numerical range, the light source unit is made thinner and the brightness uniformity on the light exit surface is ensured, thereby completing the present invention. That is, the inventors of the present invention found that the above-mentioned problem can be solved by the following configuration.

[1] A light source unit having: a light source installation surface, which is provided with at least one micro light source; a substrate, which is arranged in line with the light source installation surface and is transparent; and a reflection pattern, which is based on the at least one micro light source The light distribution characteristics of the base material are formed on the first surface on the side of the light source installation surface, and the distance between the second surface on the opposite side of the first surface and the light source installation surface is 1mm or more and 2mm or less . [2] The light source unit according to [1], which is provided with a substrate having a planar light source installation surface, and on the light source installation surface, a plurality of micro light emitting elements as at least one micro light source are positioned at the center of the light source installation surface It is arranged symmetrically as a reference. [3] The light source unit according to [1] or [2], wherein on the first surface, a plurality of unit patterns as reflection patterns are symmetrically formed with the center position of the first surface as a reference. [4] The light source unit according to [3], wherein the plurality of unit patterns are each composed of titanium oxide. [5] The light source unit according to [3] or [4], wherein the plurality of unit patterns respectively have a shape that protrudes toward the light source installation surface and gradually decreases in diameter as it approaches the light source installation surface. [6] The light source unit according to any one of [3] to [5], wherein a plurality of unit patterns are formed on the first surface in order to satisfy the set conditions for index values related to the brightness distribution on the second surface. noodle. [7] The light source unit according to [6], wherein by satisfying the following first and second conditions, the index value satisfies the setting condition, and the thickness, size and arrangement position of each of the plurality of unit patterns are to satisfy the first The thickness, size and placement position determined by the condition and the second condition. The first condition: the brightness in each of the specific area located at the position overlapping with the at least one tiny light source and the peripheral area surrounding the specific area on the second surface becomes below the reference value. The second condition: the degree of brightness dispersion on the second surface is within the target range. [8] The light source unit according to any one of [1] to [7], wherein the substrate is composed of a thin film material having light transmittance. [9] The light source unit according to any one of [1] to [8], wherein the base material and the reflective pattern constitute a first light scattering body, and a second light scattering body is arranged between the first light scattering body and the at least one light source. The light scattering body is provided with a reflective pattern only on the first light scattering body among the first light scattering body and the second light scattering body. [10] The light source unit according to [9], wherein the normal arrangement position of the first light scatterer relative to the light source installation surface and the first The amount of deviation of the actual arrangement position of the light scattering body is 0.2 mm or less. [11] A display device having a liquid crystal display, and the light source unit described in any one of [1] to [10] as a backlight unit on the back side of the liquid crystal display. [12] A light source unit manufacturing device that manufactures the light source unit described in any one of [1] to [10], the light source unit manufacturing device having: a light distribution characteristic acquisition device that acquires at least one tiny light source Light distribution characteristics; and a pattern forming device, which forms a reflective pattern on the first surface of the substrate in accordance with the pattern formation data generated according to the acquired light distribution characteristics. [Effects of the invention]

According to the present invention, it is possible to realize a light source unit and a display device that are thinner and ensure the uniformity of the brightness on the exit surface. Furthermore, according to the present invention, it is possible to provide an apparatus for manufacturing the above-mentioned light source unit.

Hereinafter, an embodiment of the present invention (hereinafter referred to as this embodiment) will be described in detail with reference to preferred embodiments shown in the accompanying drawings. In addition, the device configuration, usage, and usage described below are based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. That is, the present invention can be changed or improved from the embodiment described below as long as it does not deviate from its spirit. In addition, of course, the equivalents are included in the present invention.

In addition, in this specification, the numerical range represented by "-" means the range which includes the numerical value described before and after "-" as the lower limit and the upper limit. In addition, in this specification, "same", "same" and "equivalent" include not only the case of being completely equivalent, but also includes the difference in the range of error generally allowed in the technical field of the present invention, although the difference is slightly different. Condition. In addition, in this specification, the term "all", "equal", "entire surface", etc., includes not only the case of 100%, but also includes the error range that is generally allowed in the technical field to which the present invention belongs. , Such as 99% or more, 95% or more, or 90% or more. In addition, in this specification, "parallel" includes not only the case of being parallel to the reference line, surface, or direction, but also the case of being substantially parallel although there is an inclination of several degrees.

In addition, in the following description, "light distribution characteristics" refers to the degree of divergence of light from a light source, and is the distribution of intensity (for example, radiation intensity or illuminance, etc.) from the light source in various directions. The light distribution characteristics are usually represented by the characteristic diagram shown in Figure 1. In the characteristic diagram, the intensity of the emitted light in the direction where the intensity becomes the maximum is set to 100%, and the intensity of the emitted light in each direction is expressed as a relative value (ratio). In addition, the light distribution is classified into the far-field light distribution measured from the infinite distance of the point where the light source appears, and the near-field light distribution measured from the distance that can discriminate the distribution of light emitted from various points in the light source ( rear-field) light distribution. Below, unless otherwise specified, the light distribution refers to the far-field light distribution.

In addition, in the following description, unless otherwise specified, "reflection" refers to diffuse reflection (diffuse reflection), and its meaning is regarded as the same as diffusion.

[Outline of the display device of this embodiment] As shown in FIG. 2, the display device 10 of this embodiment has a liquid crystal display (Liquid Crystal Display: hereinafter referred to as LCD) 12 for displaying images and a light source unit 14 arranged on the back side of the LCD 12.

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

The light source unit 14 is provided in the display device 10 as a direct type backlight unit, and is a planar lighting device whose surface facing the LCD 12 side constitutes an emission surface. As shown in FIG. 3, the light source unit 14 has a light source installation surface 22 provided with at least one minute light source 16 and a light-transmitting substrate 24 arranged in line with the light source installation surface 22. A reflection pattern 30 formed according to the light distribution characteristics of at least one minute light source 16 is provided on the first surface 26 on the side of the light source installation surface 22 in the substrate 24. As shown in FIG. 3, the reflection pattern 30 is composed of a plurality of unit patterns 32. In addition, in the cross-sectional view shown in FIG. 3, in order to simplify the illustration, the respective numbers of the micro light sources 16 and the unit patterns 32 are set to be different from the actual number.

In addition, in this embodiment, the distance between the second surface 28 on the side opposite to the first surface 26 and the light source installation surface 22 of the substrate (indicated by the symbol d in FIG. 3) is 1 mm or more and Below 2mm. Thereby, in this embodiment, the light source unit 14 and the display device 10 can be made thinner, respectively, and the uniformity of the brightness on the exit surface can be ensured.

Describing in more detail, the wider the interval d, the easier it is to provide the reflective pattern 30, and the narrower the interval d, the better the effect of the reflective pattern 30 can be exerted. On the other hand, the display device 10 including the light source unit 14 is required to be further thinner, but the thinner the thickness, the narrower the interval d, and therefore it is difficult to provide the reflective pattern 30.

Here, assuming that the reflective pattern 30 is not provided on the substrate 24, the index value related to the distribution of the brightness on the second surface 28 as the exit surface with respect to the change in the interval d is shown in FIGS. 4 and 5 The behavior shown changes.

The index value shown in Fig. 4 (the value on the vertical axis) is the value obtained by dividing the difference between the maximum point and the minimum point on the brightness distribution (histogram) on the second surface 28 by the average value of the brightness. Below, for convenience For the sake of this, it is called "normalized dynamic range". In addition, the maximum point of the brightness distribution corresponds to 97% of the cumulative histogram, and the minimum point corresponds to 3% of the cumulative histogram. The index value shown in Figure 5 (the value on the vertical axis) is the value obtained by dividing the standard deviation (sigma) calculated by the two-dimensional distribution of the brightness on the second surface 28 by the average value of the brightness. Below, for convenience Called "normalized sigma". The higher the uniformity of the brightness distribution, the smaller the normalized dynamic range and the normalized sigma.

In the case where the reflective pattern 30 is not provided on the substrate 24, it can be seen from FIGS. 4 and 5 that in order to ensure the uniformity of the brightness, the interval d needs to be set relatively large (for example, as shown in FIGS. 4 and 5) In this case, it is set to exceed 15mm).

On the contrary, by forming the reflective pattern 30 on the first surface 26 of the substrate 24, as shown in FIGS. 6 and 7, even when the interval d is 1.0 mm to 2.0 mm, the same degree as described above can be achieved. To ensure the uniformity of brightness. However, as can be seen from FIGS. 6 and 7, if the interval d becomes smaller, it is difficult to ensure the uniformity of brightness, and if the interval d is less than 1 mm, it is difficult to ensure the uniformity only by the reflective pattern 30.

In addition, as can be seen from FIGS. 8 and 9, in the configuration in which the reflective pattern 30 is provided on the base 24, if the arrangement position of the base 24 deviates from the regular position, the uniformity of brightness will be reduced. 8 and 9 show the change of the index value when the arrangement position of the substrate 24 is deviated (specifically, the arrangement position deviates by 0.2 mm in the XY direction described later), and Fig. 8 shows the change of the normalized dynamic range , Figure 9 shows the change of normalized sigma. In addition, in the cases shown in FIGS. 8 and 9, due to the displacement of the arrangement position of the substrate 24, the index value rises in the direction of the arrow in the figure.

Here, when the interval d is 2.0 mm, compared with the case where the interval d is 1.0 mm, the effect of the deviation of the arrangement position on the uniformity of brightness becomes smaller, in other words, the robustness against the deviation of the arrangement position (Robustness) (resistance) becomes higher. Based on the above point of view, in the present embodiment, the interval d is set to 1 mm or more and 2 mm or less, thereby achieving the thinning of the light source unit 14 and the improvement of the uniformity of the brightness on the exit surface.

Furthermore, in this embodiment, the base material 24 and the reflective pattern 30 constitute the first light scattering body 34. As shown in FIG.体36. In addition, the reflective pattern 30 is only disposed on the first light scattering body 34 among the first light scattering body 34 and the second light scattering body 36, but not on the second light scattering body 36.

As described above, by arranging the second light scattering body 36 without the reflective pattern 30 between the first light scattering body 34 and the micro light source 16, the arrangement of the substrate 24 (that is, the first light scattering body 34) The robustness (resistance) of the deviation of the position becomes higher. In detail, it can be seen from FIGS. 8 and 9 that the effect of uniformizing the brightness on the exit surface of the reflection pattern 30 based on the first light scatterer 34 is like the shading correction of the printer, which receives the first light. The influence of the slight deviation of the arrangement position of the scatterer 34.

On the other hand, by combining the second light scattering body 36 and the first light scattering body 34, as shown in Figs. When the arrangement position of the one light scatterer 34 is shifted, the uniformity of the brightness decreases. Such an effect of providing the second light scatterer 36 is particularly effective when the intensity of the light distribution from the micro light source 16 becomes higher within a limited range (that is, it is a peak-like light distribution characteristic).

In addition, FIGS. 10 and 11 show changes in index values when the arrangement position of the substrate 24 is deviated under the same conditions as in FIGS. 8 and 9 except for the point that the second light scatterer 36 is provided.

Incidentally, when the second light scatterer 36 is used, the allowable deviation of the arrangement position of the base material 24 is 0.2 mm or less in the XY directions. The XY direction corresponds 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 normal arrangement position of the first light scattering body 34 and the actual arrangement position of the first light scattering body 34 with respect to the light source installation surface 22. In addition, in order to effectively exert the effect of the combined use of the first light scattering body 34 and the second light scattering body 36 having the reflective pattern 30, the interval d is preferably set to be 1.0 mm or more and less than 2.0 mm.

[Configuration example of light source unit of this embodiment] As shown in FIG. 3, the light source unit 14 of this embodiment includes a substrate 20 provided with a micro light source 16 and a first light scattering body 34 and a second light scattering body 36 having a reflective pattern 30. Hereinafter, each component device of the light source unit 14 will be described.

(Tiny light source) The micro light source 16 is a point light source with strong directivity. In this embodiment, it is composed of the micro light emitting element 18 shown in FIG. , The chip size is 100-200μm LED structure. However, the type of micro light source 16 is not limited to mini LEDs. For example, micro LEDs with a chip size of 100 μm or less or micro light emitting elements other than LEDs can also be used. Specifically, micro electroluminescent elements or micro light emitting elements can be used. Semiconductor laser.

The light distribution characteristics of the micro light-emitting element 18 (ie, mini LED) of this embodiment will be described. The viewing angle when the direction in which the light intensity becomes the highest in the light emission direction is set to 0 degrees, the viewing angle is about ±65 to ±80 degrees. (That is, the range of about 130 to 160 degrees). In addition, 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.

In addition, a light diffusion lens (not shown) may be attached to the micro light emitting element 18. The light diffusion type lens is a light diffusion type lens that diffuses the light emitted from the mini LED, such as an aspheric lens, and it is possible to appropriately use a known lens member capable of exhibiting the desired light diffusion effect (for example, Japanese Patent Application Publication 2013- Lens components disclosed in Bulletin No. 012417). By mounting such a light-diffusing lens on the micro light-emitting element 18, it is possible to provide a light source unit 14 with higher brightness and excellent brightness uniformity on the exit surface.

(Substrate) The substrate 20 is a planar member, which is generally used as a rigid substrate, a flexible substrate, or a rigid-flexible substrate of the backlight unit of the LCD 12. In addition, the substrate 20 has a flat base layer (not shown), and a light source installation surface 22 is provided on one side of the base layer where the LCD 12 is located. The material of the base layer is not particularly limited. Examples include AGSP (Advanced Grade Solid-Bump Process), alumina, glass epoxy resin, and PCB (Polychlorinated Biphenyl), etc. It is particularly preferably thermally conductive. High-rate material.

A metal wiring part (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 provided on the light source installation surface 22 via the metal wiring portion. In this embodiment, the plurality of micro light emitting elements 18 are arranged regularly and symmetrically with the center position of the light source installation surface 22 as a reference. As an example, a plurality of micro light emitting elements 18 are arranged in a matrix form at an interval of 5 to 6 mm in the XY direction from the center position of the light source installation surface 22. In addition, with regard to the central position of the light source installation surface 22, for example, if the light source installation surface 22 is rectangular or square, the position of the intersection of the diagonal lines corresponds to the central position of the light source installation surface 22. If the light source installation surface 22 is a circle , The center position of the circle corresponds to the center position of the light source installation surface 22.

In addition, the exposed portion (non-light source arrangement area) of the light source installation surface 22 where the micro light source 16 is not arranged is covered by the reflective layer and has light reflectivity. In addition, the base layer of the substrate 20 may be formed of a material having light diffusivity, such as a light-diffusing film. In this 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 transmissive body, and as shown in FIG.

(Substrate) The substrate 24 is made of a light-transmitting thin film material, but as long as it transmits light, it may be any of a transparent substrate, a translucent substrate, and other substrates with light diffusibility.

As shown in FIG. 3, the base material 24 is arranged in parallel with the light source installation surface 22 of the substrate 20. The regular arrangement position of the substrate 24 relative to the light source installation surface 22 is that the center position of the substrate 24 in the XY direction coincides with the center position of the light source installation surface 22 and the extension direction of the substrate 24 is the same as the extension direction of the light source installation surface 22 Position at the time of agreement. In addition, with regard to the center position of the substrate 24, for example, if the surface of the substrate 24 is rectangular or square, the position of the intersection of the diagonal lines corresponds to the center position of the substrate 24. If the surface of the substrate 24 is round , The center position of the circle corresponds to the center position of the base material 24.

Examples of the film material constituting the substrate 24 include polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polylactic acid (PLA); cellulose triacetate Cellulose resins such as polyethylene (PE), polypropylene (PP) and cycloolefin (COC, COP) resins and other polyolefin resins; polymethyl methacrylate (PMMA) and other acrylic resins; polycarbonate (PC) resin; fluorine-based resins such as polytetrafluoroethylene (PTFE).

In addition, the base material 24 may be composed of one layer, or may be composed of two or more layers. For example, the substrate 24 composed of a plurality of layers may include a layer composed of a light diffusion film. Incidentally, on the substrate 24 of this embodiment, a reflective layer (not shown) made of the same material as the reflective pattern 30 is provided on one side where the micro light source 16 is located. The reflective layer is a layer having a uniform thickness and a sufficiently small thickness.

Furthermore, when a transparent film is used as the substrate 24, the transmittance of the substrate 24 (strictly speaking, the average light transmittance of the micro light source 16 in the emission wavelength band) is preferably 50% or more, more preferably 70% Above, 85% or more is particularly preferred.

In addition, the base material 24 may be one having light diffusivity. For example, it is possible to impart light diffusibility to the base 24 by forming a concave-convex shape or a scallop shape on at least one surface of the base 24. In addition, by dispersing inorganic fine particles or organic fine particles in the interior of the base 24, the base 24 may be imparted with light diffusibility.

In addition, with regard to the refractive index of the substrate 24, in order to prevent the incident angle of the light passing through the substrate 24 from being excessively restricted, it is preferably 1.00 to 2.00, more preferably 1.30 to 1.80 in terms of the relationship with the refractive index of air. .

Here, the thickness direction of the substrate 24, that is, the arrangement direction of the substrate 24 and the light source installation surface 22 is set to the Z direction, and the side of the LCD 12 when viewed from the substrate 24 is set to the +Z side, and the light source installation surface The side where 22 is located is set to the -Z side. The surface on the -Z side of the substrate 24 is the first surface 26, and as described above, the reflection pattern 30 is formed on the first surface 26. In addition, the +Z side surface of the substrate 24 is the second surface 28. The second surface 28 faces the back surface of the LCD 12, for example, and constitutes the light emitting surface of the light source unit 14 in this embodiment.

(Reflective pattern) The reflective pattern 30 is formed (patterned) on the first surface 26 of the substrate 24 and reflects incident light from a plurality of micro light emitting elements 18 (strictly speaking, the light transmitted through the second light scatterer 36). The reflection pattern 30 is laminated on the base 24 on the −Z side of the base 24.

In this embodiment, for example, as shown in FIG. 12, the reflective pattern 30 is composed of the same number of unit patterns 32 as the micro light emitting elements 18. In addition, in the reflection pattern 30 shown in FIG. 12, for the convenience of illustration, the number of unit patterns 32 is set to a different number from the actual number.

In addition, the plurality of unit patterns 32 are regularly and symmetrically arranged with the center position of the first surface 26 as a reference. Specifically, the unit patterns 32 are formed at equal intervals in the XY direction from the center position of the first surface 26. Here, the pitch of the unit patterns 32 on the first surface 26 and the pitch of the minute light emitting elements 18 on the light source installation surface 22 are the same or approximately the same. As a result, as shown in FIG. 3, in a state where the substrate 24 is located at a regular arrangement position, each unit pattern 32 is located directly above each micro light emitting element 18.

In addition, as shown in FIG. 13, each unit pattern 32 is a substantially conical pattern with a relatively wide lower end. That is, in this embodiment, the unit pattern 32 has a shape that protrudes toward the light source installation surface 22 and gradually decreases in diameter as it approaches the light source installation surface 22. In addition, each unit pattern 32 may have a tapered shape gradually reduced in diameter toward the light source installation surface 22 as shown in FIG. It is in the shape of a step (difference). In addition, 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 polygonal prismatic shape in a plan view, or the like, or an irregular shape.

The material of the unit pattern 32 is a material with high light reflectivity (hereinafter referred to as a reflective material). Examples of the reflective material include white pigments, and examples of white pigments include titanium oxide, barium sulfate, potassium carbonate, silica, talc, and clay. Examples of reflective materials other than white pigments include conductive silver inks mainly composed of silver complexes (for example, conductive silver inks mainly composed of coated silver ultrafine particles). In addition, as the reflective material, a thermoplastic resin composition containing the above-mentioned white pigment can be used. As a specific example of a thermosetting resin composition used as a reflective material, a combination of a known urethane resin and an isocyanate compound, a combination of an epoxy resin and a polyamine or an acid anhydride, a combination of a silicone resin and a crosslinking agent, etc. can be used A two-component type thermosetting resin containing a main agent and a hardener, and a three-component type thermosetting resin containing hardening accelerators such as amine, imidazole, and phosphorus. Specifically, a light reflection layer using a silicone-based thermosetting resin described in JP 2014-129549 can be exemplified. In addition, in this embodiment, titanium oxide is used as a reflective material to form the unit pattern 32.

The formation (patterning) of the reflective pattern 30 on the first surface 26 can be performed by inkjet printing or printing by other methods (for example, screen printing, etc.). However, the method of pattern formation (patterning) is not limited to printing, and metal vapor deposition or coating of reflective materials may be used. In addition, after coating the reflective material on the entire surface of the first surface 26, the reflective material may be shaved off in such a way that the unit pattern 32 is retained to form the reflective pattern 30.

Then, in the present embodiment, the reflection pattern 30 is formed on the first surface 26 according to the light distribution characteristics of the micro light source 16 (specifically, the mini LED as the micro light emitting element 18) installed on the light source installation surface 22. Specifically, the plurality of unit patterns 32 constituting the reflective pattern 30 are respectively formed in such a manner that the index values related to the distribution of the brightness on the second surface 28 (for example, normalized dynamic range and normalized sigma, etc.) satisfy the set conditions. First side 26. Here, the setting condition is a numerical range that should be satisfied by index values such as normalized dynamic range and normalized sigma as the required specifications of the light source unit 14.

Described in more detail, the thickness, size, and arrangement position of the unit pattern 32 are determined in a region directly above the micro light emitting element 18 on the exit surface to reduce the light to a target value. In addition, in a region located directly above the micro light emitting element 18, the thickness, size, and arrangement position of the unit pattern 32 are determined so as to reduce the respective diffused light and reflected light. Here, the thickness of the unit pattern 32 is the length from the bottom surface (the end on the +Z side) to the top (the end on the −Z side) of the unit pattern 32, and the size of the unit pattern 32 is the maximum diameter of the unit pattern 32. In addition, 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 unit pattern 32 in a circular shape).

Furthermore, the reflection pattern 30 is formed on the first surface 26 so that each unit pattern 32 has a predetermined thickness, size, and arrangement position. In addition, the procedure for forming the reflective pattern 30 will be described in detail in the following item.

(Second light scatterer) The second light scattering body 36 scatters and diffuses the light from the micro light source 16 inside. In this embodiment, the second light scattering body 36 is in the shape of a flat plate or a film, as shown in FIG. The elements 18) are arranged in parallel with the first light scatterer 34.

The light emitted from each small light emitting element 18 enters the second light scatterer 36 and is scattered in the second light scatterer 36 and finally transmits the second light scatterer 36. Thereby, the uniformity of the brightness on the second surface 28 as the exit surface can be improved, and the robustness against the positional deviation 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 light-transmitting plate material or film material, for example, a translucent resin film containing polycarbonate or acrylic resin, etc., with a light diffusion structure (for example, a small and irregular lens array, etc.) formed on the optical The film can be used as the base layer. The scattering layer is not scattered like the reflection pattern 30, but is formed on the entire surface of the base layer (for example, the surface on the side of the first light scattering body 34) with a substantially uniform thickness. The material constituting the scattering layer is the same reflective material as the reflective pattern 30, for example, titanium oxide, barium sulfate, potassium carbonate, silicon dioxide, talc, clay, etc. can be used. In addition, the second light scattering body 36 is not limited to the above-mentioned laminated body, and a light guide member formed 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 may be used. Used as the second light scatterer 36.

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

The configuration example of the light source unit 14 of the present embodiment has been described above, but the above configuration is only an example, and other configurations can also be considered. In this embodiment, the second surface 28 which is the surface on the +Z side of the base 24 is the exit surface, but it is not limited to this. For example, it is also possible to superimpose a scallop on the second surface 28, and use the +Z side surface of the scallop as the exit surface. In addition, in this embodiment, the second light scattering body 36 is provided, but it may be a configuration in which the second light scattering body 36 is not provided. In addition, the light source unit 14 of this embodiment is used as a backlight unit of the display device 10, but it is not limited to this, and it can also be used as a surface-emitting lighting device.

[Light source unit manufacturing device] Next, the light source unit manufacturing apparatus 40 which manufactures the light source unit 14 of this embodiment is demonstrated. As shown in FIG. 15, the light source unit manufacturing device 40 has a light distribution characteristic acquiring device 42, a pattern forming data generating device 44, and a pattern forming device 46.

(Optical distribution characteristic acquisition device) The light distribution characteristic acquisition device 42 is a device that acquires the light distribution characteristic (strictly speaking, information related to the light distribution characteristic) of the micro light source 16 used in the light source unit 14, and is constituted by, for example, a known light distribution characteristic measuring device. As a light distribution characteristic measuring device, a device that rotates the light source with a goniometer, a rotating table, or a rotating mirror, and measures the illuminance (luminous intensity) at the angle with an illuminance meter or a luminance meter. As an example, the LED lighting alignment measurement system NeoLight manufactured by Systems Engineering, and the brightness distribution characteristic measurement device C9920-11 manufactured by Hamamatsu Photonics K.K. can be cited. In addition, as a light distribution characteristic measuring device other than the above, it is also possible to use an LED light distribution measuring device that measures the light distribution spectral distribution characteristics of LED elements or LED modules under preset conditions (for example, OptCom Co., Ltd.'s Measuring device, etc.). In this device, the vertical light distribution table and the horizontal light distribution table are controlled to adjust the LED radiation angle, and after positioning to face the photodetector, the lighting power supply of the device is controlled according to the measurement conditions to make it light. , And measure the spectral distribution by measuring and controlling equipment.

(Pattern forming data generating device) The pattern forming data generating device 44 is a device for generating data for forming the reflective pattern 30 (hereinafter referred to as pattern forming data), and is constituted by, for example, a computer equipped with a processor (not shown). The processor is composed of a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit), for example, and executes an optical simulation program stored in a storage device (not shown) in the device. By executing the simulation program, the pattern formation data generating device 44 determines the formation conditions of the reflective pattern 30 according to the light distribution characteristics of the micro light source 16, and generates pattern formation data representing the conditions.

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

Then, by satisfying the first condition and the second condition, the index values such as the normalized sigma and the normalized dynamic range meet the aforementioned setting conditions. In addition, the "specified area" under the first condition is the area on the second surface 28 that overlaps each of the micro light emitting elements 18 in the Z direction. To put it simply, it is located directly above each of the micro light emitting elements 18的区。 The area. If it is assumed that a plurality of unit patterns 32 are not formed on the first surface 26, the brightness in the specific area becomes the highest. The "peripheral area" under the first condition is an area arranged in a manner surrounding the specific area in the second surface 28, which exists in a layered arrangement from the side adjacent to the specific area toward the outside. The "reference value" under the first condition is the target value set for the brightness in a specific area, for example, it is to set the target value for the brightness in the specific area. The value obtained by averaging the brightness (average brightness).

The "degree of dispersion of brightness" under the second condition is an evaluation index related to the distribution of brightness in each area of the second surface 28 (that is, each of the specific area and the surrounding area), in other words, it represents the smoothness of the brightness. The "target range" under the second condition is a numerical range set for the degree of dispersion of brightness, for example, a range (error range) that is equal to or can be regarded as the target value of the degree of dispersion. In addition, in this embodiment, the target range is set based on the reference value of the first condition.

When the thickness of each unit pattern 32 is determined so as to satisfy the above-mentioned first condition and the second condition, the pattern formation data generating device 44 performs a predetermined calculation process. This calculation processing flow is performed in accordance with the program shown in FIG. 16. Hereinafter, referring to FIG. 16, the above-mentioned arithmetic processing flow will be described.

(Operation processing flow) When implementing the arithmetic processing flow, the second surface 28 is partitioned into a plurality of calculation units. Specifically, the second surface 28 is divided in the XY direction into a plurality of regions with the arrangement position of each micro light emitting element 18 as the center, and each is used as a calculation unit. Here, the calculation unit has the same number of micro light emitting elements 18 on the second surface 28, and in this embodiment, as shown in FIGS. 17A and 17B, it becomes a square-shaped area.

As shown in FIG. 17A and FIG. 17B, each calculation unit is further divided into small calculation areas. Here, the calculation areas may be arranged in a grid in the XY direction as shown in FIG. 17A, or may be arranged in concentric circles as shown in FIG. 17B. In each calculation unit, the calculation area P1 located at the same position as the arrangement position of the micro light emitting elements 18 in the XY direction corresponds to the above-mentioned specific area. The calculation areas P2 to P6 arranged in a square frame or ring surrounding the specific area on the outside of the specific area correspond to the above-mentioned peripheral area.

In addition, the size (mesh size) of the calculation area and the division method are not particularly limited. The following is an example where each calculation unit is divided into a multi-layer calculation area with the arrangement position of the micro light emitting element 18 as the center. illustrate. For example, when the calculation unit illustrated in FIG. 17A is used, it becomes a form of processing 9×9 calculation areas arranged in a matrix in the XY direction. On the other hand, when the calculation unit illustrated in FIG. 17B is used, it becomes a form of processing six calculation regions arranged in concentric circles.

Each step in the arithmetic processing flow is implemented for one calculation unit. In the arithmetic processing flow, as shown in Figure 16, first, all the calculation areas in the calculation unit are set to initial values (S001). In order to obtain the initial value, suppose that a case where a plurality of unit patterns 32 are not formed on the first surface 26 is assumed, and the brightness distribution in each area of the second surface 28 in this case is obtained. Then, the smoothness, which is the degree of brightness dispersion, is evaluated, and the thickness at which the evaluation value becomes the minimum is taken as the initial value.

Next, in a state where each calculation area is set to an initial value, the brightness distribution in the calculation unit when the micro light emitting element 18 is lit is calculated, and the smoothness is evaluated (S002). Then, the average value of the brightness distribution calculated in step S002 is set as the target value (that is, the reference value of the aforementioned first condition) (S003).

The subsequent steps are repeated for each calculation area, so the calculation area as the calculation object is set to Pi, and set to i=1 (S004). Here, i is determined based on the arrangement position of the micro light emitting element 18 in the XY direction, and the smaller i means the closer to the micro light emitting element 18. In addition, the calculation area in the case of i=1, that is, P1 is a specific area located directly above the micro light emitting element 18.

In the next step S005, it is determined whether the brightness of the distribution calculated in step S002 is within a preset error range relative to the target value (average brightness) set in step S003. Furthermore, in step S005, it is determined whether the smoothness evaluated in step S002 is within a set range determined with the target value as a reference. Specifically, it is determined whether it is within the error range of the target value and whether the target value is satisfied.

When the determination result in step S005 is "Yes", the distributed brightness meets the target value and the smoothness is within the set range, so the calculation processing flow ends. On the other hand, when the determination result in step S005 is "No", it is determined whether the brightness in the calculation area Pi reaches the target value (S006). In addition, in the first step S006, i=1, so it is determined whether the brightness in the specific area reaches the target value.

When the determination result in step S006 is "Yes", that is, if the brightness in the calculation area Pi meets the target value, i is increased, and the calculation area Pi as the calculation target is changed to the next area (S007). Then, it returns to step S005.

On the other hand, when the determination result in step S006 is "No", that is, if the brightness in the calculation area Pi does not meet 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 by reducing the brightness. Conversely, when the brightness in the calculation area Pi is much lower than the target value, the thickness is changed in such a way that the brightness is increased. In addition, when changing the thickness, the relationship (correlation) between the thickness change and the brightness change is determined in advance, and the determined correlation relationship can be stored as table data. Then, in step S009, it is preferable to refer to the table data to obtain the amount of change in the thickness that becomes an appropriate brightness, and to change the thickness with the obtained amount of change.

In addition, 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 or lower limit 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). In this case, the result of the determination in step S008 described later becomes "Yes", and the process returns to step S002 to calculate the brightness distribution and evaluate the smoothness. Then, the next step S003 is implemented to set the target value.

Specifically, in the calculation area Pi where the thickness reaches the upper limit, the brightness cannot be further reduced, so the target value needs to be lowered. Here, the brightness of the calculation area Pi is calculated in descending order, so the above situation only occurs in i=1, that is, in a specific area. Based on this, the thickness is increased compared to the initial value, and the average value is calculated again while the brightness of the specific area is reduced. As a result, the average brightness, that is, the target value, is reduced compared to the previous value. As a result, the possibility of setting the thickness of the pattern to a small value and meeting the target value increases.

Conversely, in the calculation area Pi where the thickness reaches the lower limit, the brightness is lower than the target value. In this case, it is necessary to reduce (scatter) the brightness in the area closer to the specific area and guide the light to the aforementioned calculation area Pi. In the previous calculation area P[i-1] and the like of the calculation area Pi, the brightness has already met the target value, and therefore, if the average value is calculated, it will be lower than the previous target value (average brightness). Based on this, in the previous calculation area P[i-1], etc., the target value is set in such a way that the thickness is scattered more thickly. As a result, in the calculation area Pi, the possibility that the thickness of the pattern has a large value and satisfies the target value increases.

Returning to the flow of FIG. 16 for description, after the thickness in the calculation area Pi is changed in step S009, the changed thickness is applied to calculate the brightness distribution in the calculation unit when the micro light emitting element 18 is lit (S010). In addition, at this point in time, the number of calculations for the calculation area Pi will only be counted up by +1.

Then, return to step S006 to determine whether the brightness in the calculation area Pi reaches the target value. If the result of this determination is "Yes", step S007 is implemented, and then returns to step S005. Conversely, when the determination result in step S006 is "No", step S008 is implemented to determine whether the number of calculations for the calculation area Pi exceeds a predetermined value (upper limit). When the determination result in step S008 is "No", step S009 is implemented to change the thickness in the calculation area Pi.

On the other hand, when the result of the determination in step S008 is "YES", the process returns to step S002 in order to correct the target value. That is, step S002 is implemented to calculate the brightness distribution in the calculation unit when the micro light emitting element 18 is lit based on the thickness in each calculation area set at that time. Then, step S003 is implemented, and the average value of the brightness in the distribution calculated in step S002 is set as a new target value.

In the arithmetic processing flow implemented by the above program, steps S002 to S010 are repeated (looped) while changing the calculation area Pi as the calculation target 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 of the diagrams in Figures 18A and 18B, the thickness in each calculation area is determined sequentially from top to bottom, and the calculation area for recalculating the thickness (the recolored part in each figure) is from the inside to the outside move.

In addition, as a processing algorithm, it is necessary to appropriately stop the flow even when there is no solution. Therefore, the total number of loops is separately counted. When the number of loops exceeds the upper limit, the flow is stopped as "no solution".

Then, when the result of the determination in step S005 becomes "Yes", the thickness in each calculation area Pi (that is, the thickness of the unit pattern 32) is determined. In this way, for each unit pattern 32, the thickness and the like are determined so as to satisfy the aforementioned first condition and second condition.

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

That is, the pattern formation data of this embodiment is data for printer control (print data). The pattern forming device 46 as a printer ejects ink according to the pattern forming data, whereby a predetermined amount of ink is landed on 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.

In the above manner, the substrate 24 (that is, the first light scatterer 34) on which the reflection pattern 30 is formed is manufactured by the pattern forming apparatus 10. Then, the light source unit 14 is manufactured by combining the first light scattering body 34, the substrate 20 provided with the micro light emitting element 18, and the second light scattering body 36.

In addition, the pattern forming device 46 is not limited to an inkjet printer, and may be constituted by a device other than the inkjet printer, for example, a printer or an ink application device of a printing method other than the inkjet printer. Alternatively, it may also be a device that uses screen printing technology to produce a plate for forming the predetermined reflection pattern 30 and use the plate for printing. [Example]

Hereinafter, the present invention will be described in more detail based on the following examples. In addition, the materials, usage amounts, ratios, processing contents, processing procedures, etc. shown in the following examples can be appropriately changed as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the following examples.

[Optical simulation related to 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 set as a variable, and the evaluation is performed by dividing the relative value by the average value.

In the mode used in the optical simulation (hereinafter referred to as the simulation mode), the substrate 20 having a square shape in a plan view is used. In addition, mini LEDs as micro light-emitting elements 18 are respectively arranged at the plural arrangement positions shown in FIG. 19 on the light source installation surface 22. Specifically, a total of 9 mini LEDs are arranged at a substantially constant pitch in each direction in the XY direction from the center position of the light source installation surface 22. The spacing of the mini LEDs in the X direction is set to 5.386mm, and the spacing of the mini LEDs in the Y direction is set to 6.066mm.

The chip size of each mini LED is set to 230 μm×120 μm×130 μm. The light distribution characteristic of each mini LED is set to the light distribution characteristic shown in Figure 1, the viewing angle is set to 130 degrees, and the intensity at the vicinity of the brightest mini LED is set to 0.32W/sr mm ² .

In addition, in the simulation mode, the light scattering system of the exposed part of the light source installation surface 22 scatters corresponding to the incident angle of the light, which is set to follow the COSN screen law (N=2). In addition, the reflectance, transmittance, and absorptivity of the substrate 20 are set to 90%, 5%, and 5%, respectively.

In addition, in the simulation mode, the first light scatterer 34 is placed in the light source installation so that the center position of the light source installation surface 22 is parallel to the light source installation surface 22 and the center position of the light source installation surface 22 coincides with the center position of the surface of the substrate 24 in the XY direction. Above the surface 22. As the base material 24 of the first light scatterer 34, a film made of polyethylene terephthalate (PET) with a thickness of 0.1 mm was used. The PET film has a square shape in a plan view, and its refractive index n is set to 1.576. Also, in the simulation mode, the +Z side surface of the PET film (that is, the second surface on the side opposite to the light source installation surface 22) is used as the light exit surface. Regarding the divergence angle at each part of the exit surface, Set to 10 degrees.

(Comparative example 1) The first light scatterer 34 made of PET film without the reflection pattern 30 is used, and the interval 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 14 mm. The brightness distribution on the exit surface in this case was simulated, and the simulation result is shown in FIG. 20. When the reflective pattern 30 is not formed, it can be seen from FIG. 20 that the brightness of the light-emitting surface directly above and near the mini LED rises significantly, and the brightness difference between these parts and other parts is relatively large. In addition, in each of the graphs after FIG. 20, the magnitude of brightness is visually represented by black and white (the graph on the left in each graph), and the smoothness of brightness is represented by a histogram (the graph on the right in each graph).

(Example 1) In Embodiment 1, the reflection pattern 30 composed of a plurality of unit patterns 32 is provided on the surface (that is, the first surface) on the -Z side of the PET film used in the simulation mode. The unit pattern 32 is made of titanium oxide and is arranged with the position directly above the mini LED as the center in the XY direction, and a reflection pattern 30 composed of 3 vertical and horizontal 9 unit patterns 32 in total is provided.

As shown in FIG. 14, each unit pattern 32 is formed by overlapping five cylindrical pattern segments with different diameters into concentric circles. The radius of each pattern segment is set to 0.5 mm, 1.0 mm, 1.6 mm, 2.2 mm, and 2.65 mm in order from the front end side. The thickness of each pattern segment was set to the value shown in Table 1. In addition, the thickness shown in Table 1 is a value expressed as a ratio to the reference thickness t (t=0.00759mm).

【Table 1】 Pattern thickness interval Deviation of position The presence or absence of the second scatterer 0.5mm 1.0mm 1.6mm 2.2mm 2.65mm Flat part Example 1 19.76285 5.928854 2.108037 1 0.922266 0.1 1.0mm - without Example 2 35.57312 28.98551 1.317523 0.6 0.5 0.1 2.0mm - without Example 3 19.76285 5.928854 2.108037 1 0.922266 0.1 1.0mm 0.2mm without Example 4 35.57312 28.98551 1.317523 0.6 0.5 0.1 2.0mm 0.2mm without Example 5 26.35046 13.17523 5.270092 2.635046 1.317523 0.1 1.0mm - Have Example 6 35.57312 28.98551 1.317523 0.6 0.5 0.1 2.0mm - Have Example 7 26.35046 13.17523 5.270092 2.635046 1.317523 0.1 1.0mm Have Example 8 35.57312 28.98551 1.317523 0.6 0.5 0.1 2.0mm Have Comparative example 1 - - - - - - 14mm - -

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

In addition, the optical parameters (diffusion coefficient, absorption coefficient, etc.) of the PET film provided with the reflection pattern 30 are determined in such a way that the transmittance and reflectance are consistent between the calculated value obtained by the simulation and the actual measured value. Ray tracing simulation software (product name: Light Tools) was used for the measurement of transmittance and reflectance. In addition, the refractive index n of the PET film provided with the reflection pattern 30 was set to 1.4, and the absorption coefficient was set to 0.

In addition, in Example 1, the interval 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 1 mm.

Under the above conditions, the brightness distribution on the exit surface was simulated, and the simulation results are shown in Fig. 21. It can be seen from this figure that if the PET film provided with the reflective pattern 30 is used and the distance between the light source installation surface 22 and the exit surface is set to 1 mm, compared with the case where the reflective pattern 30 is not provided, the exit surface can be The brightness distribution is smoothed. In addition, if the interval is reduced, the thickness of the entire light source unit can be reduced accordingly.

(Example 2) In Example 2, the thickness of each of the five pattern segments constituting each unit pattern 32 was set to the value shown in Table 1. In addition, in Example 2, the interval between the light source installation surface 22 and the emission surface (that is, the surface on the +Z side of the PET film) is set to 1 mm. Regarding the other conditions, the same conditions as in Example 1 were used.

Regarding Example 2, the brightness distribution on the exit surface was simulated, and the simulation results are shown in FIG. 22. It can be seen from FIG. 22 that by setting the interval between the light source installation surface 22 and the exit surface to 2 mm, the brightness distribution on the exit surface can be made smoother.

(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 only 0.2 mm in the horizontal direction. Moreover, in Example 3, the interval between the light source installation surface 22 and the exit surface was set to 1 mm, and in Example 4, the interval was set to 2 mm. In addition, in Examples 3 and 4, the thickness of each of the five pattern segments constituting each unit pattern 32 was set to the value shown in Table 1. Regarding the other points, the same conditions as in Example 1 were used.

Regarding each of Examples 3 and 4, the luminance distribution on the exit surface was simulated, and the simulation results of each are shown in FIGS. 23 and 24. It can be seen from these figures that if the arrangement position of the PET film provided with the reflection pattern 30 deviates, the smoothness of the brightness on the exit surface decreases. In particular, when the interval between the light source installation surface 22 and the exit surface is 1 mm, the reduction in smoothness becomes remarkable compared with the case where the interval is 2 mm.

(Examples 5-8) In Examples 5 to 8, a diffusion plate as the 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 formed by coating titanium oxide on both sides of the PET film (thickness 0.3 mm) of the same type as that of the base material 24 of the first light scatterer 34 so as to have a uniform thickness. The thickness of the titanium oxide layer is 2.63 times the thickness of the aforementioned reference thickness t. In addition, the diffuser plate is arranged so that the surface of the diffuser plate facing the light source installation surface 22 in the Z direction is at a position separated from the light source installation surface 22 by 0.2 mm. In addition, in Examples 5 and 6, the PET film was arranged at a regular position. In Examples 7 and 8, the position of the PET film was horizontally shifted from the regular position by only 0.2 mm. In addition, in Examples 5 and 7, the interval between the light source installation surface 22 and the emission surface was set to 1 mm, and in Examples 6 and 8, the interval was set to 2 mm. In addition, in Examples 5 to 8, the thickness of each of the five pattern segments constituting each unit pattern 32 was set to the value shown in Table 1. Regarding the other points, the same conditions as in Example 1 were used.

Regarding each of Examples 5 to 8, the luminance distribution on the exit surface was simulated, and the simulation results of each are shown in FIGS. 25-28. It can be seen from these figures that by arranging the additional diffuser between the PET film and the light source installation surface 22, the brightness distribution on the exit surface can be further smoothed. In addition, by installing an additional diffuser, it is possible to reduce the reduction in smoothing caused by the positional deviation of the PET film.

The conditions of each of Examples 1 to 8 of the present invention described above are all within the scope of the present invention, so the effect of the present invention is clear.

10: Display device 12: LCD (liquid crystal display) 14: light source unit 16: Tiny light source 18: Tiny light-emitting element 20: substrate 22: Light source setting surface 24: Substrate 26: First side 28: second side 30: reflection pattern 32: unit pattern 34: The first light scatterer 36: second light scatterer 40: Light source unit manufacturing device 42: Light distribution characteristic acquisition device 44: Pattern formation data generating device 46: Pattern forming device

Fig. 1 shows an example of a characteristic diagram of light distribution characteristics. Fig. 2 is a schematic side view of the constituent equipment of the display device. Fig. 3 is a diagram showing a configuration example of the light source unit, and shows the I-I section of Fig. 2. Fig. 4 is a graph showing the index values related to the uniformity of brightness on the exit surface when no reflective pattern is provided on the substrate (Part 1). Fig. 5 is a graph showing the index values related to the uniformity of brightness on the exit surface when no reflective pattern is provided on the substrate (Part 2). Fig. 6 is a graph showing index values related to the uniformity of brightness on the exit surface in the case where a reflective pattern is provided on the substrate (Part 1). Fig. 7 is a graph showing the index values related to the uniformity of brightness on the exit surface when the reflective pattern is provided on the substrate (Part 2). Fig. 8 is a graph showing the change of the index value related to the uniformity of brightness on the exit surface when the arrangement position of the substrate is deviated (Part 1). Fig. 9 is a graph showing the change of the index value related to the uniformity of the brightness on the exit surface when the arrangement position of the substrate is deviated (Part 2). Fig. 10 is a diagram showing the change in the index value related to the uniformity of the brightness on the exit surface when the second light scatterer is further provided (Part 1). FIG. 11 is a diagram showing the change in the index value related to the uniformity of the brightness on the exit surface when the second light scatterer is further provided (Part 2). Fig. 12 is a schematic plan view of the first light scatterer. Fig. 13 is a side view of the unit pattern of the reflection pattern. FIG. 14 is a diagram showing a modification example of the unit pattern of the reflection pattern. Fig. 15 is an explanatory diagram of a light source unit manufacturing apparatus according to an embodiment of the present invention. FIG. 16 is a diagram showing the flow of arithmetic processing for determining the formation conditions of the reflection pattern. Fig. 17A is an explanatory diagram of the calculation area (Part 1). Fig. 17B is an explanatory diagram of the calculation area (Part 2). FIG. 18A is a diagram (Part 1) showing how the area to be calculated is shifted. FIG. 18B is a diagram (Part 2) showing how the area to be calculated is shifted. Fig. 19 is an explanatory diagram of the simulation mode. FIG. 20 is a diagram showing the distribution of brightness on the exit surface in Comparative Example 1. FIG. FIG. 21 is a diagram showing the distribution of brightness on the exit surface in Example 1. FIG. FIG. 22 is a diagram showing the brightness distribution on the exit surface in Example 2. FIG. FIG. 23 is a diagram showing the brightness distribution on the exit surface in Example 3. FIG. FIG. 24 is a diagram showing the brightness distribution on the exit surface in Example 4. FIG. FIG. 25 is a diagram showing the brightness distribution on the exit surface in Example 5. FIG. FIG. 26 is a diagram showing the brightness distribution on the exit surface in Example 6. FIG. FIG. 27 is a diagram showing the brightness distribution on the exit surface in Example 7. FIG. FIG. 28 is a diagram showing the brightness distribution on the exit surface in Example 8. FIG.

14: light source unit

16: Tiny light source

18: Tiny light-emitting element

20: substrate

22: Light source setting surface

24: Substrate

26: First side

28: second side

30: reflection pattern

32: unit pattern

34: The first light scatterer

36: second light scatterer

Z: direction

Claims (12)

A light source unit, which has: The light source setting surface is provided with at least one tiny light source; The base material is arranged in line with the aforementioned light source installation surface and has light transmittance; and The reflective pattern is formed on the first surface of the substrate on the side of the light source installation surface according to the light distribution characteristics of the at least one tiny light source, The distance between the second surface on the side opposite to the first surface of the base material and the light source installation surface is 1 mm or more and 2 mm or less. The light source unit according to claim 1, which is provided with a substrate having a planar light source installation surface, On the light source installation surface, a plurality of micro light emitting elements as the at least one micro light source are symmetrically arranged with the center position of the light source installation surface as a reference. The light source unit according to claim 1, wherein On the first surface, a plurality of unit patterns as the reflection patterns are formed symmetrically with the center position of the first surface as a reference. The light source unit according to claim 3, wherein The plurality of unit patterns are each made of titanium oxide. The light source unit according to claim 3, wherein Each of the plurality of unit patterns has a shape that protrudes toward the light source installation surface and gradually decreases in diameter as it approaches the light source installation surface. The light source unit according to any one of claim 3 to claim 5, wherein The plurality of unit patterns are respectively formed on the first surface so that the index value related to the brightness distribution on the second surface satisfies a set condition. The light source unit according to claim 6, wherein By satisfying the following first and second conditions, the aforementioned index value satisfies the aforementioned setting condition, The thickness, size and arrangement position of each of the plurality of unit patterns are the thickness, size and arrangement position determined in a manner that satisfies the aforementioned first condition and the aforementioned second condition, The first condition: the brightness in each of the specific area on the second surface that overlaps the at least one tiny light source and the peripheral area surrounding the specific area is below the reference value, The second condition: the degree of dispersion of the brightness on the aforementioned second surface is within the target range. The light source unit according to claim 1, wherein The aforementioned substrate is composed of a thin film material having light transmittance. The light source unit according to claim 1, wherein The aforementioned substrate and the aforementioned reflection pattern constitute a first light scatterer, A second light scatterer is arranged between the first light scatterer and the at least one light source, The reflection pattern is provided only on the first light scattering body among the first light scattering body and the second light scattering body. The light source unit according to claim 9, wherein The amount of deviation between the normal arrangement position of the first light scatterer and the actual arrangement position of the first light scatterer relative to the light source installation surface in two directions that are parallel to and orthogonal to the light source installation surface, respectively It is 0.2mm or less. A display device having a liquid crystal display and the light source unit described in claim 1 as a backlight unit on the back side of the liquid crystal display. A light source unit manufacturing device, which is the light source unit described in claim 1, and the aforementioned light source unit manufacturing device has: The light distribution characteristic obtaining device is to obtain the light distribution characteristic of the aforementioned at least one tiny light source; and The pattern forming device forms the reflection pattern on the first surface of the substrate according to the pattern formation data generated according to the acquired light distribution characteristics.

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