TWI671558B - Light emitting device and liquid crystal display device - Google Patents

Abstract

A light emitting device includes a light emitting diode. The light emitting diode includes a blue light emitting layer and a first wavelength conversion layer. The first wavelength conversion layer is disposed on a light emitting surface of the blue light emitting layer. The light emitting device further includes a second wavelength conversion layer and a substrate. The blue light emitting layer is located between the first wavelength conversion layer and the second wavelength conversion layer. The substrate has a reflective surface and an outer surface opposite to the reflective surface, and the first wavelength conversion layer is located between the blue light emitting layer and the reflective surface.

Description

Light emitting device and liquid crystal display

This disclosure relates to a light emitting device and a liquid crystal display.

Liquid crystal display (LCD) has the advantages of power saving, light weight, low radiation, and portability. It can be widely used in televisions, computer screens, notebook computers, car navigation systems, mobile communication devices, etc., and has gradually replaced traditional Display has become the mainstream product on the market. Among them, one of the key components used to provide a light source is a backlight module, which aims to form a point light source or a linear light source emitted by a light emitting element into a uniform surface light source to provide a liquid crystal panel.

The use of light-emitting diodes as light-emitting elements has been widely used in the fields of displays and lighting. However, as far as the structure of the existing light-emitting element using a light-emitting diode as a light source is concerned, it is difficult to uniformize the light emitted from the light-emitting diode. Therefore, how to improve the luminous efficiency of the light-emitting element and the uniformity of the brightness of the light-emitting area has become an urgent problem.

The disclosed embodiments provide a light emitting device and a liquid crystal. monitor. By making the vertical projection area of the first wavelength conversion layer on the first substrate fall within the vertical projection area of the blue light emitting layer on the first substrate, the light conversion efficiency of the first wavelength conversion layer is improved, and by setting the first wavelength The conversion layer and the second wavelength conversion layer are on different sides of the blue light-emitting layer, which can improve the chromaticity uniformity and brightness of the light-emitting device. The light-emitting device further includes a first reflective structure and a second reflective structure. The blue light and the first color light are reflected toward the left and right sides of the first substrate to prevent the blue light and the first color light from being reflected back to the light emitting diode. The second light reflecting structure is used to destroy the total reflection of the light in the light guide layer and improve the light emitting device. Light output efficiency.

In one embodiment, a light emitting device includes a light emitting diode, the light emitting diode includes a blue light emitting layer and a first wavelength conversion layer, and the first wavelength conversion layer is disposed on a light emitting surface of the blue light emitting layer. The light emitting device further includes a second wavelength conversion layer and a substrate. The blue light emitting layer is located between the first wavelength conversion layer and the second wavelength conversion layer. The substrate has a reflective surface and an outer surface opposite to the reflective surface, and the first wavelength conversion layer is located between the blue light emitting layer and the reflective surface.

In one embodiment, a liquid crystal display includes a plurality of light emitting devices as described above and a liquid crystal display panel. The liquid crystal display panel is located on the light emitting device.

10, 10a, 10b ‧‧‧ light-emitting devices

12‧‧‧ LCD

14‧‧‧light source module

16‧‧‧LCD panel

18‧‧‧ lead

100‧‧‧light-emitting diode

102‧‧‧Blue light emitting layer

102a‧‧‧light surface

104‧‧‧first wavelength conversion layer

106‧‧‧Second wavelength conversion layer

108‧‧‧First substrate

108a‧‧‧Reflective surface

108b‧‧‧outer surface

109‧‧‧Reflecting wall

110‧‧‧first reflective structure

111‧‧‧base

112‧‧‧Second reflective structure

114a‧‧‧First insulating bump

114b‧‧‧Second insulation bump

116a‧‧‧First reflective layer

116b‧‧‧Second reflective layer

118‧‧‧ light guide layer

120‧‧‧ transparent medium layer

122‧‧‧Second substrate

124‧‧‧First semiconductor layer

126‧‧‧Second semiconductor layer

128‧‧‧first electrode

130‧‧‧Second electrode

132‧‧‧Third electrode

134‧‧‧Fourth electrode

136‧‧‧light diffusion layer

136a‧‧‧Top

136b‧‧‧ Underside

B1, B2 ‧‧‧ underside

BL‧‧‧ Blu-ray

D1, D2‧‧‧ distance

H1, H2‧‧‧ height

L1‧‧‧First color

L2‧‧‧Second color light

S1, S2‧‧‧ side

T‧‧‧thickness

WL‧‧‧White

θ 1‧‧‧ first angle

θ 2‧‧‧ second angle

Read the following detailed description and the corresponding drawings to understand the multiple aspects of this disclosure. It should be noted that many features in the drawings are not drawn according to the standard practice in the industry. In fact, the dimensions of the features can be arbitrarily increased or decreased to facilitate the clarity of the discussion.

FIG. 1A is a cross-sectional view of a light-emitting device according to an embodiment of the present disclosure; FIG. 1B is a schematic view of a light-emitting path of FIG. 1A; FIG. FIG. 3 is a cross-sectional view of a liquid crystal display according to an embodiment of the present disclosure; and FIG. 4 is a plan view of a light source module according to an embodiment of the present disclosure.

The following will clearly illustrate the spirit of this disclosure with drawings and detailed descriptions. Any person with ordinary knowledge in the technical field who understands the embodiments of this disclosure can be changed and modified by the techniques taught in this disclosure. Depart from the spirit and scope of this disclosure. For example, describing "the first feature is formed on or above the second feature", in the embodiment will include the first feature and the second feature having direct contact; and will also include the first feature and the second feature as indirect The contact has additional features formed between the first feature and the second feature. In addition, the disclosure will reuse component numbers and / or text in multiple examples. The purpose of repetition is to simplify and clarify, and does not itself determine the relationship between the various embodiments and / or the configuration in question.

In addition, relative vocabulary such as "below", "below", "below", "above" or "up" or similar words are used in the text to facilitate description of the Relationship of one element or feature to another element or feature. In addition to describing the orientation of the device in the drawings, the term relative orientation includes different orientations of the device under use or operation. When the device is set separately (Rotated 90 degrees or other oriented orientation), the relative vocabulary of orientation used in this article can also be interpreted accordingly.

FIG. 1A illustrates a cross-sectional view of a light emitting device 10 according to an embodiment of the present disclosure. FIG. 1B is a schematic diagram of a light emitting path in FIG. 1A. Please refer to FIG. 1A and FIG. 1B together. The light emitting device 10 includes a light emitting diode 100. The light emitting diode 100 includes a blue light emitting layer 102 and a first wavelength conversion layer 104. The first wavelength conversion layer 104 is disposed on the light emitting surface 102a of the blue light emitting layer 102. The blue light emitting layer 102 emits blue light BL. The first wavelength conversion layer 104 is used to convert the blue light BL into the first color light L1. The light emitting device 10 further includes a second wavelength conversion layer 106, a first substrate 108, and a reflection wall 109. The first substrate 108 and the reflection wall 109 constitute a base 111. The light emitting diode 100 is located on the second wavelength conversion layer 106 and the first substrate 108. In between, the blue light emitting layer 102 is located between the first wavelength conversion layer 104 and the second wavelength conversion layer 106. The first substrate 108 has a reflective surface 108a and an outer surface 108b opposite to the reflective surface 108a. The material of the first substrate 108 may be a light-transmitting material. For example, the first substrate 108 may be a glass substrate, a quartz substrate, a sapphire substrate, or other suitable rigid or flexible substrates, but the disclosure is not limited to this. . The reflecting wall 109 is capable of reflecting light, so its material is a reflecting material. The material of the reflection wall 109 may include a metal material or a non-metal material. The metal material may include a composite metal such as titanium, gold, aluminum, silver, platinum, palladium or more. The non-metallic material may be selected from polyphthalamide, ceramics, and polycarbonate. The non-metallic material may also be a polymer material doped with a reflective material, wherein the doped material includes a non-metallic material or a metallic material with a reflective effect.

The vertical projection area of the first wavelength conversion layer 104 on the first substrate 108 is located within the vertical projection area of the blue light emitting layer 102 on the first substrate 108. Here, since the blue light BL beam emitted from the blue light emitting layer 102 is approximately circular, and its light intensity is similar to the Lambertian distribution, so that the blue light BL emitted from the blue light emitting layer 102 easily enters the first place. The wavelength conversion layer 104 improves the light conversion efficiency of the first wavelength conversion layer 104 and allows the blue light BL and the first color light L1 to be mixed uniformly.

The second wavelength conversion layer 106 can convert the blue light BL emitted from the blue light emitting layer 102 into a second color light L2. The wavelength of the first color light L1 is different from the wavelength of the second color light L2. In an embodiment, the first color light L1, the second color light L2, and the blue light BL are mixed into white light WL. By disposing the first wavelength conversion layer 104 and the second wavelength conversion layer 106 in different layers, the first color light L1, the second color light L2, and the blue light BL can be sufficiently mixed into the white light WL, so that the chromaticity of the light emitting device 10 and the Uniform brightness. In one embodiment, the first wavelength conversion layer 104 includes a red light wavelength conversion material, the second wavelength conversion layer 106 includes a green light wavelength conversion material, the first color light L1 is red light, and the second color light L2 is green light. Since the green light is easily absorbed by the red light wavelength conversion material, the second wavelength conversion layer 106 and the first wavelength conversion layer 104 are disposed on different sides of the blue light emitting layer 102, and the second wavelength conversion layer 106 is more than the first wavelength. The conversion layer 104 is further away from the reflective surface 108a of the first substrate 108, and the vertical projection area of the first wavelength conversion layer 104 on the first substrate 108 is smaller than the vertical projection area of the second wavelength conversion layer 106 on the first substrate 108, which can reduce the green The probability that light is absorbed by the first wavelength conversion layer 104 increases the light output brightness of the light emitting device 10.

In addition, the second wavelength conversion layer 106 is spaced a distance D1 from the light emitting diode 100. In this way, sufficient space can be provided to sufficiently mix the first color light L1, the second color light L2, and the blue light BL. First wavelength conversion layer 104 and second wave The material of the long conversion layer 106 is, for example, a phosphor, a quantum dot, or a light conversion substance.

The light emitting surface 102a of the blue light emitting layer 102 faces the light reflecting surface 108a of the first substrate 108, and the first wavelength conversion layer 104 is located between the blue light emitting layer 102 and the light reflecting surface 108a. The reflective surface 108a has at least a first reflective structure 110 and a plurality of second reflective structures 112. In one embodiment, the first reflective structure 110 has a first insulating bump 114a and a first reflective layer 116a, and the second reflective structure 112 has a first The two insulating bumps 114b and the second reflective layer 116b, and the first reflective layer 116a and the second reflective layer 116b are respectively located on the first insulating bump 114a and the second insulating bump 114b. The first and second insulating bumps 114a and 114b may include an inorganic dielectric material and a resin material. The inorganic dielectric material may be selected from boron nitride, aluminum oxide, aluminum nitride, beryllium oxide, barium sulfate, magnesium oxide, or zirconia. . The first and second reflective layers 116a and 116b may be metal reflective layers. For example, the materials of the first and second reflective layers 116a and 116b include aluminum, silver, other materials with high reflectivity, or a combination thereof. In one embodiment, the base 111 is cup-shaped, and the first color light L1, the second color light L2, and the blue light BL reflected by the first reflective structure 110 and the second reflective structure 112 can be reflected to the outside by the reflective wall 109, thereby Increasing the light emitting efficiency of the light emitting device 10.

Since the light emitting surface 102a of the blue light emitting layer 102 faces the light reflecting surface 108a of the first substrate 108, the blue light BL emitted from the blue light emitting layer 102 and the first color light L1 converted by the first wavelength conversion layer 104 are directed toward the first substrate. The light-reflecting surface 108 a of 108 is directed toward the first light-reflecting structure 110 and the second light-reflecting structure 112. In an embodiment, the first reflective structure 110 is an axisymmetric structure. For example, the first reflective structure 110 may be an isosceles triangle, and the insulating projection 114 of the first reflective structure 110 is vertically projected on the first substrate 108. Partly overlaps the vertical projection of the light emitting diode 100 on the first substrate 108, so the first reflective structure 110 can Most of the blue light BL and most of the first color light L1 are reflected toward the left and right sides of the first substrate 108. In this way, the blue light BL and the first color light L1 can be prevented from being reflected back to the light emitting diode 100, so that the light emitting diode The body 100 reduces light loss during operation, improves its light output efficiency, and improves the brightness of the light emitting device 10. The vertical distance D2 between the light-emitting diode 100 and the top of the first reflective structure 110 is between about 10 microns and about 100 microns. In this way, the first reflective structure 110 can make the blue light BL and the first color light L1 effectively face The left and right sides of the first substrate 108 are reflected.

The light-emitting device 10 further includes a light guide layer 118 and a light-transmitting medium layer 120. The light guide layer 118 is located between the blue light-emitting layer 102 and the first reflective structure 110 and the second reflective structure 112. The thickness T of the light guide layer 118 is greater than the first The height of the reflective structure 110 (for example, the sum of the height H of the first insulating bump 114a and the thickness of the first reflective layer 116a) is greater than the height of the second reflective structure 112 (for example, the height H of the second insulating bump 114b and the second The total thickness of the reflective layer 116b), and the light-transmitting medium layer 120 is located between the light guide layer 118 and the second wavelength conversion layer 106. The refractive index of the light-transmitting medium layer 120 is smaller than the refractive index of the light-guiding layer 118. In one embodiment, the refractive index of the light guide layer 118 is between about 1.46 and about 5, and the refractive index of the transparent medium layer 120 is between about 1 and about 1.3. The travel path of the blue light BL and the first color light L1 first enters the light-transmitting medium layer 120 and the light guide layer 118 in sequence, and is then reflected by the first light reflecting structure 110 and the second light reflecting structure 112. The light guide layer 118 is used for The blue light BL and the first color light L1 reflected by the light reflecting structure 110 and the second light reflecting structure 112 are emitted toward the light-transmitting medium layer 120, thereby improving the light emitting efficiency of the front surface of the light emitting device 10. The travel path of the second color light L2 sequentially enters the light-transmitting medium layer 120 and the light guide layer 118, and is then reflected by the first light reflecting structure 110 and the second light reflecting structure 112. The light guide layer 118 is used to connect the first light reflecting structure 110 and First reflected by the second reflective structure 112 The two-color light L2 is emitted toward the light-transmitting medium layer 120, and the light emission efficiency of the front surface of the light-emitting device 10 is improved. The thickness T of the light guide layer 118 is between about 10 micrometers and about 100 micrometers, so as to effectively reflect the blue light BL, the first color light L1, and the second color light L2 to the light-transmitting medium layer 120. The material of the light guide layer 118 may be a resin material or a silicon material. In one embodiment, the light-transmitting medium layer 120 may be air, and its refractive index approaches 1.

The size of the first reflective structure 110 is different from the size of each second reflective structure 112. In one embodiment, the vertical projection area of the first reflective structure 110 on the first substrate 108 is larger than the vertical projection area of each second reflective structure 112 on the first substrate 108. In an embodiment, the side surface S1 and the bottom surface B1 of the first insulating bump 114a are at a first angle θ1, and the side surface S2 and the bottom surface B2 of the second insulating bump 114b are at a second angle θ2, the first angle θ1 and The second angle θ 2 is greater than about 30 ° and less than about 60 °, and the first angle θ 1 is smaller than the second angle θ 2. In this way, the second reflective structure 112 may destroy the first color light L1, the second color light L2, and Total reflection of the blue light BL in the light guide layer 118, thereby increasing the light emitting efficiency of the first color light L1, the second color light L2, and the blue light BL.

The light emitting diode 100 further includes a second substrate 122, a first semiconductor layer 124, a second semiconductor layer 126, a first electrode 128, and a second electrode 130. The first electrode 128 is electrically opposite to the second electrode 130. The blue light emitting layer 102 is disposed on the first semiconductor layer 124, and the first wavelength conversion layer 104 is provided between the blue light emitting layer 102 and the second semiconductor layer 126. The first electrode 128 is disposed on the first semiconductor layer 124, and the second electrode 130 is disposed on the second semiconductor layer 126. The top surface of the light guide layer 118 is provided with a third electrode 132 and a fourth electrode 134. The third electrode 132 and the fourth electrode 134 are electrically opposite to each other. The first electrode 128 and the light guide layer of the light emitting diode 100 The third electrode 132 of 118 is electrically connected, and the second electrode 130 of the light emitting diode 100 is electrically connected to the fourth electrode 134 of the light guide layer 118. In an embodiment, the first electrode 128, The two electrodes 130 are electrically connected to the third electrode 132 and the fourth electrode 134, respectively.

In some embodiments, the second substrate 122 is made of a transparent material to facilitate light exit. For example, the second substrate 122 may be a glass substrate, a quartz substrate, a sapphire substrate, or other suitable rigid or flexible substrates, but the disclosure is not limited thereto. In one embodiment, the first semiconductor layer 124 is an N-type semiconductor layer, the second semiconductor layer 126 is a P-type semiconductor layer, the first electrode 128 is a positive electrode, the second electrode 130 is a negative electrode, the N-type semiconductor layer and the P-type semiconductor. The material of the layer is gallium nitride (GaN). The N-type semiconductor layer mainly provides electrons, and the P-type semiconductor layer mainly provides holes. The material of the blue light emitting layer 102 includes a multiple quantum well (MQW) structure, which may include a gallium nitride-based material, which mainly gathers electrons and holes to generate light.

FIG. 2 is a cross-sectional view of a light-emitting device 10a according to another embodiment of the present disclosure. The light-emitting path of the light-emitting device 10a is similar to the light-emitting device 10, and thus is omitted in the figure. As shown in FIG. 2, the difference between this embodiment and the embodiments shown in FIGS. 1A and 1B is mainly that this embodiment further includes a light diffusion layer 136, and the light diffusion layer 136 is disposed at the second wavelength conversion. Between the layer 106 and the blue light emitting layer 102, that is, the light diffusion layer 136 is disposed between the second wavelength conversion layer 106 and the light emitting diode 100. The light diffusion layer 136 has opposite top surfaces 136a and bottom surfaces 136b. The bottom surface 136b may have a matte surface treatment, a scattering point design, or a similar design. The bottom surface 136b contacts the light-transmitting medium layer 120, so that the first color light L1 and the blue light BL are uniformly mixed. The top surface 136a of the light diffusion layer 136 contacts the second wavelength conversion layer 106. In this way, when the uniformly mixed first color light L1 and blue light BL reach the second wavelength conversion layer 106, the blue light BL can be uniformly converted into the second color light L2 by the second wavelength conversion layer 106. Improve the uniformity of the mixed light of the first color light L1, the second color light L2, and the blue light BL of the light emitting device 10a. In addition, when the second color light L2 emitted toward the light-transmitting medium layer 120 is reflected back to the light diffusion layer 136, the light diffusion layer 136 can also uniformly mix the second color light L2 with the first color light L1 and the blue light BL, thereby improving The first color light L1, the second color light L2, and the blue light BL have mixed light uniformity, so that the light emitting device 10a emits light with uniform brightness and high color rendering.

FIG. 3 is a cross-sectional view of a liquid crystal display (LCD) 12 according to an embodiment of the present disclosure. The liquid crystal display 12 includes a light source module 14 and a liquid crystal display panel 16 composed of a plurality of light emitting devices 10b. The structure of the device 10b can adopt the structure of the light-emitting device 10 or the light-emitting device 10a as required. The light-emitting devices 10b can be arranged in a matrix. The liquid crystal display panel 16 is located on the light source module 14 to receive light from the light source module 14. The liquid crystal display panel 16 is provided with light of uniform brightness and high color rendering, thereby improving the display quality of the liquid crystal display panel 16. FIG. 4 is a top view of a light source module 14 according to an embodiment of the disclosure. Please refer to FIG. 3 and FIG. 4 together. The light source module 14 further includes a plurality of wires 18. The conductive end is electrically connected to the light-emitting device 10 b, and the other end is electrically connected to the control circuit and the ground (not shown). The lead 18 may be electrically connected to the third electrode 132 and the fourth electrode 134 by means such as welding or hot pressing. The connection method of the light-emitting devices 10b is not limited here. The light-emitting devices 10b may be connected in parallel, in series, or partially in parallel or in series. Those with ordinary knowledge in this field can use the number of light-emitting devices 10b and the actual use requirements. The connection method of the light emitting device 10b is adjusted. Understandably, in order to fill In order to meet the demand for light with greater power, the number of light-emitting devices 10b can be selected according to needs.

The light source module 14 may further include an optical sheet (not shown) such as a diffusion sheet, a fascia sheet, and a brightness enhancement sheet, and the optical sheet may be disposed between the liquid crystal display panel 16 and the light emitting device 10b. In other embodiments, if the light source module 14 is implemented by using a side-light-type backlight module, the light source module 14 may include a light guide plate having an adjacent light-incident surface and a light-exit surface. At this time, the light emitting direction of the light emitting device 10 b may be toward the light incident surface of the light guide plate, and the light emitting surface of the light guide plate may face the liquid crystal display panel 16.

The light emitting device improves the light conversion efficiency of the first wavelength conversion layer by making the vertical projection area of the first wavelength conversion layer on the first substrate fall within the vertical projection area of the blue light emitting layer on the first substrate. A wavelength conversion layer and a second wavelength conversion layer are on different sides of the blue light emitting layer, which can improve the chromaticity uniformity and brightness of the light emitting device. The light emitting device further includes a first reflective structure and a second reflective structure. The blue light and the first color light are reflected toward the left and right sides of the first substrate to prevent the blue light and the first color light from reflecting back to the light emitting diode. The second light reflecting structure is used to destroy the total reflection of the light in the light guide layer and improve the light emission. Light efficiency of the device.

The features of several implementations or examples are summarized above, so that those with ordinary knowledge in the art can better understand this disclosure from various aspects. Those with ordinary knowledge in the technical field should understand and can easily design or modify other processes and structures based on this disclosure, and thereby achieve the same purpose and / or achieve the implementation methods or embodiments described herein. The same advantages. Those of ordinary skill in the art should also understand that these equivalent structures do not depart from this disclosure. The spirit and scope of the disclosure. Without departing from the spirit and scope of this disclosure, various changes, substitutions or modifications can be made to this disclosure.

Claims (12)

A light emitting device includes: a first substrate having a reflective surface and an outer surface opposite to the reflective surface; a light emitting diode including a second substrate, a blue light emitting layer, and a first wavelength conversion layer, The first wavelength conversion layer is disposed on a light emitting surface of the blue light emitting layer, and the first wavelength conversion layer is located between the blue light emitting layer and the reflective surface, and the blue light emitting layer is located on the second substrate and the first wavelength. Between the conversion layers, the reflecting surface has at least a first reflecting structure and a plurality of second reflecting structures, and the light emitting diode is located above the first reflecting structure and not above the second reflecting structures; and a first A two-wavelength conversion layer, wherein the blue light emitting layer is located between the first wavelength conversion layer and the second wavelength conversion layer. The light-emitting device according to claim 1, further comprising: a reflective wall, which forms a base with the first substrate, the base is cup-shaped, and the size of the first reflective structure is different from each of the second reflective structures. , The first reflective structure is located between the second reflective structures. The light-emitting device according to claim 2, wherein the first reflective structure has a first insulating bump and a first reflective layer, the first reflective layer is located on the first insulating bump, and the first insulating bump The vertical projection part on the first substrate overlaps the vertical projection of the light emitting diode on the first substrate. The light-emitting device according to claim 2, wherein a vertical projection area of the first reflective structure on the first substrate is larger than a vertical projection area of each of the second reflective structures on the first substrate, wherein the second reflective structure has a A second insulating bump and a second reflective layer, the second reflective layer is located on the second insulating bump, and a side of the first insulating bump is at a first angle with a bottom surface, A second angle is formed between the side surface and the bottom surface, the first angle and the second angle are greater than about 30 ° and less than about 60 °, and the first angle is smaller than the second angle. The light emitting device according to claim 2, wherein the light emitting diode includes: a first semiconductor layer, the blue light emitting layer is disposed on the first semiconductor layer; a second semiconductor layer, the first wavelength conversion layer is disposed Between the blue light emitting layer and the second semiconductor layer; a first electrode disposed on the first semiconductor layer; and a second electrode disposed on the second semiconductor layer, wherein the light emitting diode and the A vertical distance between the tops of the first reflective structures is between about 10 microns and about 100 microns. The light-emitting device according to claim 2, further comprising: a light-guiding layer between the blue-light-emitting layer and the first light-reflecting structure and the second light-reflecting structures. The thickness of the light-guiding layer is about 10 microns. Between about 100 microns; and a light-transmitting medium layer between the light-guiding layer and the second wavelength conversion layer, wherein the refractive index of the light-transmitting medium layer is lower than the refractive index of the light-guiding layer, the light-transmitting layer The refractive index of the optical medium layer is between about 1 and about 1.3. The light emitting device according to claim 6, further comprising: a light diffusion layer disposed between the second wavelength conversion layer and the blue light emitting layer, and the light diffusion layer is in contact with the second wavelength conversion layer and the transparent medium Floor. The light emitting device according to claim 1, wherein a vertical projection area of the first wavelength conversion layer on the first substrate is within a vertical projection area of the blue light emitting layer on the first substrate. The light emitting device according to claim 1, wherein the first wavelength conversion layer includes a red light wavelength conversion material, and the second wavelength conversion layer includes a green light wavelength conversion material. A liquid crystal display includes: a plurality of light emitting devices as described in any one of claims 1 to 9; and a liquid crystal display panel located on the light emitting devices. A light-emitting device includes: a first substrate having a reflective surface and an outer surface opposite to the reflective surface, wherein the reflective surface has at least one first reflective structure; a light-emitting diode includes: a second substrate A blue light emitting layer; a first wavelength conversion layer, the first wavelength conversion layer is disposed on a light emitting surface of the blue light emitting layer, the blue light emitting layer is located between the second substrate and the first wavelength conversion layer; A first semiconductor layer, the blue light emitting layer is disposed on the first semiconductor layer; a second semiconductor layer, the first wavelength conversion layer is disposed between the blue light emitting layer and the second semiconductor layer; a first electrode, Disposed on the first semiconductor layer; and a second electrode disposed on the second semiconductor layer, wherein a vertical distance between the light emitting diode and a top end of the first reflective structure is between about 10 μm and about 100 μm Between; and a second wavelength conversion layer, wherein the blue light emitting layer is located between the first wavelength conversion layer and the second wavelength conversion layer, and the second substrate is at a distance from the second wavelength conversion layer A light-emitting device includes: a first substrate having a reflective surface and an outer surface opposite to the reflective surface, wherein the reflective surface has at least one first reflective structure; a light-emitting diode includes: a second substrate A blue light emitting layer; and a first wavelength conversion layer, the first wavelength conversion layer is disposed on a light emitting surface of the blue light emitting layer, the blue light emitting layer is located between the second substrate and the first wavelength conversion layer; A second wavelength conversion layer, wherein the blue light emitting layer is located between the first wavelength conversion layer and the second wavelength conversion layer; a light guide layer is located between the blue light emitting layer and the first light reflecting structure, and the light guide layer The thickness of the optical layer is between about 10 microns and about 100 microns; and a light-transmitting medium layer is located between the light-guiding layer and the second wavelength conversion layer, wherein the refractive index of the light-transmitting medium layer is lower than the The refractive index of the light guide layer is between about 1 and about 1.3.