KR102002546B1 - Back light unit for picture generate unit - Google Patents

Abstract

The present invention relates to a backlight unit for an image generating apparatus.
A backlight unit for an image producing apparatus according to the present invention includes: a bottom frame; A light emitting portion disposed on an upper surface of the bottom frame; A light diffusion lens disposed on the top surface of the bottom frame so as to cover the light emitting portion; A reflecting wall disposed along an upper surface of the bottom frame and standing up at an obtuse angle with the bottom frame; And a diffusion plate disposed on the reflective wall in parallel with the bottom frame.
Accordingly, it is possible to have a high uniformity while having a thin thickness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit for an image generating apparatus, and more particularly, to a backlight unit for an image generating apparatus having a thin thickness and high uniformity.

The liquid crystal display device includes a liquid crystal display panel for displaying image data and a backlight unit for irradiating light to the liquid crystal display panel. The light source of the backlight unit includes LEDs (LEDs) having high efficiency and high brightness, ; Light Emitting Diode) is widely used. However, since the light emitted from the LED is strong in directivity, a light diffusion lens may be disposed around the LED or an optical gap may be formed between the LED and the liquid crystal display panel in order to allow the LED to exhibit a uniform luminance over the entire area of the liquid crystal display panel. optical gap.

On the other hand, a head up display (HUD) is a device for displaying driving related information such as a running speed, a fuel amount, and the like of a vehicle on a front glass of a vehicle and includes a picture generation unit (PGU) And an optical system for causing the image generated in the front glass portion of the vehicle to appear on the vehicle. The image generating apparatus includes a liquid crystal display device, a backlight unit, and the like.

However, since the image generating apparatus must be disposed within a limited space of the dashboard, there is a limitation in increasing the optical gap.

KR 10-2017-0136807 A

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a backlight unit for an image generating apparatus capable of reducing the optical gap and uniformizing the brightness of an image appearing in the image generating apparatus.

This object is achieved according to the present invention by providing a floor frame, A light emitting portion disposed on an upper surface of the bottom frame; A light diffusing lens disposed on an upper surface of the bottom frame to cover the light emitting portion and having an inner surface through which light is incident from the light emitting portion and an outer surface through which light incident through the inner surface is emitted; A reflecting wall disposed along an upper surface of the bottom frame and standing up at an obtuse angle with the bottom frame; And a diffusion plate disposed in parallel with the bottom frame at an upper portion of the reflecting wall.

Wherein the outer surface of the light diffusing lens

(상기 Z₁는 Z축 상에서 원점으로부터 떨어진 거리, 상기 r₁은 상기 외부면의 바닥부 반지름, 상기 c₁은 상기 외부면의 정중앙부 곡률, 상기 K₁은 코닉상수, 상기 A₁은 4차 비구면 계수, 상기 B₁은 6차 비구면 계수)를 만족하는 곡선을 축회전하여 구현된 형상이고, 0 < r₁ < 10, c₁ = 1/r₁, -2 < K₁ < 0, 0 < A₁ < 0.05, 0 < B₁ < 0.04 인 것을 특징으로 할 수 있다.

(Wherein Z ₁ is a distance, wherein r ₁ is the bottom radius of the outer surface, wherein said c ₁ is a constant center of curvature, wherein K ₁ is the conic constant, wherein A ₁ in the outer side from the reference point on the Z axis is a quaternary aspherical surface coefficient, wherein B ₁ is a sixth-order aspheric coefficient) is implemented by a curved shape that satisfies the rotation _{axis, 0 <r 1 <10,} c 1 = 1 / r 1, -2 <K 1 <0, 0 < A ₁ < 0.05 and 0 < B ₁ < 0.04.

Wherein the inner surface of the light diffusing lens

(상기 Z₂는 Z축 상에서 원점으로부터 떨어진 거리, 상기 r₂는 상기 내부면의 바닥부 반지름, 상기 c₂는 상기 내부면의 정중앙부 곡률, 상기 K₂는 코닉상수, 상기 A₂는 4차 비구면 계수, 상기 B₂는 6차 비구면 계수)를 만족하는 곡선을 축회전하여 구현된 형상이고, 0 < r₂ < 10, r₁ > r₂, c₂ = 1/r₂, -2 < K₂ < 0, 0 < A₂ < 0.05, 0 < B₂ < 0.05 인 것을 특징으로 할 수 있다.

(Wherein Z ₂ is a distance from a reference point on the Z axis, wherein r ₂ is the c ₂ a bottom radius of the inner surface, is the K ₂ constant center of curvature of the inner surface, the conic constant, wherein A ₂ is a quaternary aspherical surface coefficient, wherein B ₂ is the implementation of a curve that satisfies the sixth-order aspheric coefficient) by axial rotation _{geometry, 0 <r 2 <10,} r 1> r 2, c 2 = 1 / r 2, -2 <K ₂ <0, 0 <A ₂ <0.05, and 0 <B ₂ <0.05.

Preferably, the diffusion plate has a diagonal length of 30.48 mm to 76.2 mm.

The distance between the light emitting portion and the diffusion plate is preferably 20 mm or less.

은 110°± 16°이며, 상기 광확산 렌즈를 지나는 광 중에서, 상기 광확산 렌즈의 중심축과 이루는 각이 42°± 16° 이하인 광은 상기 확산판으로 입사되고, 상기 광확산 렌즈의 중심축과 이루는 각이 42°± 16° 초과인 광은 상기 반사벽으로 입사되도록 하는 것이 바람직하다. 이때, 상기 광확산 렌즈를 지나는 광 중에서 상기 확산판으로 입사되는 광과 상기 반사벽으로 입사되는 광을 구분하는

는 상기 광확산 렌즈의 중심축에 대하여

×0.8 ~

×1.2 의 각도를 갖는 것이 바람직하다.Wherein when one of the light emitting portions is formed on one of the transverse axis and the longitudinal axis of the bottom frame, an angle formed between the reflecting wall positioned at the both ends of the one axis of the bottom frame and the bottom frame

Light having an angle of 42 ° ± 16 ° or less with respect to the central axis of the light diffusing lens among the light passing through the light diffusing lens is incident on the diffusing plate, And the light incident on the reflecting wall is preferably incident on the reflecting wall. At this time, among the light passing through the light diffusion lens, light that is incident on the diffusion plate and light that is incident on the reflection wall are distinguished

Of the light diffusion lens

× 0.8 ~

1.2. &Lt; / RTI &gt;

은 102°± 8° 이며, 인접하는 상기 반사벽 측으로 기울어져 상기 광확산 렌즈를 통과하는 광 중에서, 상기 광확산 렌즈의 중심축과 이루는 각이 38°± 12° 이하인 광은 상기 확산판으로 입사되고, 상기 광확산 렌즈의 중심축과 이루는 각이 38°± 12° 초과인 광은 상기 반사벽으로 입사되도록 하는 것이 바람직하다. 이때, 인접하는 상기 반사벽 측으로 기울어져 상기 광확산 렌즈를 통과하는 광 중에서, 상기 확산판으로 입사되는 광과 상기 반사벽으로 입사되는 광을 구분하는 기준각

는 상기 광확산 렌즈의 중심축에서 인접한 상기 반사벽 방향으로

×0.8 ~

×1.2 의 각도를 갖는 것이 바람직하다.Wherein the distance between the light emitting portions is 12 mm to 20 mm when the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame, The angle that the frame forms

Light having an angle of not more than 38 ° ± 12 ° with respect to the central axis of the light diffusing lens among light passing through the light diffusing lens which is inclined toward the adjacent reflection wall side is incident on the diffusing plate, And light having an angle of 38 ° ± 12 ° with the central axis of the light diffusing lens is made incident on the reflecting wall. At this time, among the light that is tilted toward the adjacent reflection wall side and passes through the light diffusion lens, a reference angle that divides light incident on the diffusion plate and light incident on the reflection wall

Is directed in the direction of the reflective wall adjacent to the center axis of the light diffusion lens

× 0.8 ~

1.2. &Lt; / RTI &gt;

은 102°± 8°이며, 인접하는 상기 반사벽 측으로 기울어져 상기 광확산 렌즈를 통과하는 광 중에서, 상기 광확산 렌즈의 중심축과 이루는 각이 32°± 12° 이하인 광은 상기 확산판으로 입사되고, 상기 광확산 렌즈의 중심축과 이루는 각이 32°± 12° 초과인 광은 상기 반사벽으로 입사되도록 하는 것이 바람직하다. 이때, 인접하는 상기 반사벽 측으로 기울어져 상기 광확산 렌즈를 통과하는 광 중에서, 상기 확산판으로 입사되는 광과 상기 반사벽으로 입사되는 광을 구분하는 기준각

는 상기 광확산 렌즈의 중심축에서 인접한 상기 반사벽 방향으로

×0.8 ~

×1.2 의 각도를 갖는 것이 바람직하다.Wherein the distance between the light emitting portions is 7 mm to 13 mm when the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame, The angle that the frame forms

Of the light passing through the light diffusing lens and having an angle of 32 DEG +/- 12 DEG or less with respect to the central axis of the light diffusing lens is incident on the diffusing plate at an angle of 102 DEG +/- 8 DEG, And light having an angle of 32 ° ± 12 ° with respect to the central axis of the light diffusion lens is made incident on the reflection wall. At this time, among the light that is tilted toward the adjacent reflection wall side and passes through the light diffusion lens, a reference angle that divides light incident on the diffusion plate and light incident on the reflection wall

Is directed in the direction of the reflective wall adjacent to the center axis of the light diffusion lens

× 0.8 ~

1.2. &Lt; / RTI &gt;

The light diffusion lens may be formed of any one material selected from the group consisting of PMMA (Poly (methylmethacrylate), PC (Polycarbonate), Cyclin Olefin Copolymer (COC), and Cyclo-olefin Polymer .

The backlight unit for an image producing apparatus according to the present invention can uniformly introduce light into the diffuser plate even though it has a short optical gap.

Therefore, it is possible to provide a homogeneous surface light source for the liquid crystal display of the image generating apparatus.

By optimizing the angle of the reflecting wall and the shape of the light diffusion lens in the backlight unit for the image generating apparatus, light can be more uniformly incident on the reflecting plate.

1 is a sectional view of a backlight unit for an image producing apparatus according to the present invention,
Fig. 2 is an explanatory view of the operation of the backlight unit for image production according to the present invention,
3 is an explanatory diagram of a backlight unit for image production according to the present invention,
FIG. 4 is an explanatory diagram of a case where two light emitting units are provided on one axis of the backlight unit for image production according to the present invention;
5 is an explanatory diagram of a case where three light-emitting units are provided on one axis of the backlight unit for image generation according to the present invention;
6 is a table showing results of simulation of a backlight unit for an image generating apparatus according to the present invention,
Fig. 7 is an explanatory diagram of a result of simulating a backlight unit for an image generating apparatus according to the present invention and a conventional backlight unit for an image generating apparatus. Fig.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

The present invention relates to a backlight unit for an image generating apparatus, and in the description of the present invention, the backlight unit is used in an image generating apparatus constituting a head-up display. However, It is a matter of course that the backlight unit for the display device can be applied to other display devices.

1 is a cross-sectional view of a backlight unit 1 for an image producing apparatus according to the present invention.

The backlight unit 1 for an image producing apparatus according to the present invention comprises a bottom frame 10, a light emitting portion 20, a light diffusion lens 30, a reflecting wall 40 and a diffuser plate 50.

The bottom frame 10 has a horizontal plate shape and includes a printed circuit board for driving the light emitting portion 20.

The light emitting unit 20 may be a light emitting diode (LED) or the like for converting current into light. The light emitting portion 20 is formed on the printed circuit board of the bottom frame 10 and emits light in a direction toward the upper side of the bottom frame 10. [

The light diffusion lens 30 is formed so as to cover the light emitting portion 20 on the top surface of the bottom frame 10 and has a space close to the hemisphere and a space close to the hemisphere at the center. The light emitting portion 20 is located in the space and light is incident on the inner surface 32 facing the space from the light emitting portion 20 and the outer surface 31, the light incident through the inner surface 32 is diverted to the outside of the light diffusing lens 30. Accordingly, the light emitted from the light emitting portion 20 is refracted and diffused twice on the inner surface 32 and the outer surface 31 while passing through the light diffusing lens 30.

The light diffusing lens 30 is made of a light transmissive material such as PMMA (Polymethyl Methacrylate), PC (Polycarbonate), Cyclin Olefin Copolymer (COC) and Cyclo-olefin Polymer And the like.

The diffusion plate 50 is in the form of a horizontal plate disposed at a position spaced upward in the light diffusing lens 30 and is parallel to the bottom frame 10. The light emitted from the light emitting portion 20 and passed through the light diffusion lens 30 is incident on the diffuser plate 50 so that the diffuser plate 50 emits light from the surface light source of the liquid crystal display device do.

The distance between the light emitting portion 20 and the diffusion plate 50, that is, the optical gap is 20 mm or less, and the distance between the light emitting portion 20 and the diffusion plate 50 is 20 mm or less. So that the image generating apparatus does not occupy a large space in the dashboard of the vehicle. The diffusion plate 50 has a diagonal length as described above and has a ratio of width to width of about 4: 3.

The reflecting wall 40 is disposed along the upper surface of the bottom frame 10 between the bottom frame 10 and the diffuser plate 50 and is formed so as to have a white or metallic luster on the surface thereof, And reflects a part of light emitted from the light source. The reflecting wall 40 is erected at an obtuse angle with the bottom frame 10 so that the light reflected by the reflecting wall 40 is uniformly incident on the diffuser plate 50.

2, part of the light emitted through the light diffusion lens 30 is directly incident on the diffuser plate 50, and the remaining light is incident on the diffuser plate 50. In the backlight unit 1 according to the present invention, The light reflected by the reflecting wall 40 and incident on the diffuser plate 50 due to the inclination of the reflecting wall 40 is incident on the diffuser plate 50 The light is directly incident on the diffusing plate 50 and uniformly incident on the diffusing plate 50. Thus, the backlight unit 1 according to the present invention can provide a planar light source homogeneous to the liquid crystal display of the image generating apparatus.

The outer surface 31 of the light diffusing lens 30 may be formed by axially rotating a curve defined by the following equation.

( ₁₎ where Z ₁ is the distance from the origin on the Z axis, r ₁ is the bottom radius of the outer surface 31, c ₁ is the central curvature of the outer surface 31, K ₁ is the conic constant, A ₁ R ₁ is greater than 0 and less than 10, and c ₁ is defined as 1 / r ₁ , where B ₁ is the sixth order aspherical surface coefficient. And K ₁ is greater than -2 and less than 0, A ₁ is greater than 0 and less than 0.05, and B ₁ is greater than 0 and less than 0.04. To make the aspheric surface of the outer surface 31 more elaborate, higher order terms with aspheric coefficients other than A _1, B ₁ may be added.

The inner surface 32 of the light diffusing lens 30 may be formed by axially rotating a curve defined by the following equation.

Where Z ₂ is a distance from a reference point on the Z axis, r ₂ is a bottom radius of the inner surface (32), c ₂ is a front center of curvature of the inner surface (32), K ₂ is the quaternary conic constant, A ₂ B ₂ is a sixth-order aspheric coefficient, r ₂ is greater than 0 and less than 10, and c ₂ is 1 / r ₂ . And K ₂ is greater than -2 and less than 0, A ₂ is greater than 0 and less than 0.05, and B ₂ is greater than 0 and less than 0.05. It should also be r ₂ , <r ₁ . To make the aspheric surface of the inner surface 32 more elaborate, a higher order term with an aspherical surface coefficient other than A _2, B ₂ may be added.

The light diffusion lens 30 having the outer surface 31 and the inner surface 32 can diffuse the light emitted from the light emitting portion 20 evenly.

The backlight unit 1 according to the present invention may include one or more light emitting units 20 on either one of a transverse axis and a longitudinal axis of the floor frame 10, The angle formed by the reflecting wall 40 and the bottom frame 10 may vary.

은 110°± 16°로 형성된다. 3, when one light emitting portion 20 is formed on one of the transverse axis and the longitudinal axis of the bottom frame 10, The angle formed by the wall 40 and the bottom frame 10

Is formed at 110 ° ± 16 °.

At this time, among the light passing through the light diffusion lens 30, light having an angle of 42 ° ± 16 ° or less with respect to the central axis of the light diffusion lens 30 is incident on the diffusion plate 50, The distance between the light diffusing lens 30 and the reflecting wall 40 and the distance between the light diffusing lens 30 and the diffusing plate 40 such that light having an angle of 42 ° ± 16 ° or more with respect to the central axis of the diffusing lens 30 is incident on the reflecting wall 40, (50) is determined.

The arrangement relationship of the light diffusing lens 30, the reflecting wall 40 and the diffusing plate 50 is such that the light incident on the diffusing plate 50 directly from one light diffusing lens 30, The light reflected by the reflecting wall 40 located on both sides of the diffuser plate 50 and incident on the diffuser plate 50 can be uniformly incident on the diffuser plate 50.

는 상기 광확산 렌즈(30)의 중심축에 대하여

×0.8 ~

×1.2 의 각도를 갖는 것이 확산판(50)으로 입사되는 광의 균제도를 향상시키는 면에서 보다 바람직하다.A reference angle &lt; RTI ID = 0.0 &gt; (angle) &lt; / RTI &gt; that separates light incident on the diffuser plate 50 and light incident on the reflective wall 40,

(30) with respect to the central axis of the light diffusing lens

× 0.8 ~

× 1.2 is more preferable in terms of improving uniformity of light incident on the diffuser plate 50.

은 102°± 8°로 형성된다.4, when two light emitting portions 20 are formed on one of the transverse axis and the longitudinal axis of the bottom frame 10, the distance between the light emitting portions 20 is 12 mm to 20 mm And the angle formed between the bottom wall 10 and the reflecting wall 40 located at both ends of the one axis of the bottom frame 10

Is formed at 102 DEG +/- 8 DEG.

At this time, among the light that tilts toward the adjacent reflecting wall 40 and passes through the light diffusing lens 30, the light with the center axis of the light diffusing lens 30 is 38 占 占 12 or less passes through the diffusing plate 50 And the distance between the light diffusing lens 30 and the reflecting wall 40 is set such that light having an angle of 38 ° ± 12 ° or more with the central axis of the light diffusing lens 30 is incident on the reflecting wall 40 And the interval between the light diffusion lens 30 and the diffusion plate 50 are determined.

The arrangement relationship of the light diffusing lens 30, the reflecting wall 40 and the diffusing plate 50 is determined by the relationship between the light incident on the diffusing plate 50 directly from the two light diffusing lenses 30, So that the light reflected by the reflecting wall 40 positioned adjacent to the diffuser plate 30 and incident on the diffuser plate 50 can be uniformly incident on the diffuser plate 50. Since the light emitted from the light diffusing lens 30 on one side can be incident on the portion of the diffusing plate 50 located on the upper side of the other light diffusing lens 30 in the case where there are two light diffusing lenses 30, The light can be uniformly incident on the diffuser plate 50 even when the angle of the reflecting wall 40 with respect to the bottom frame 10 is made smaller than when the diffuser lens 30 has only one diffuser lens.

는 상기 광확산 렌즈(30)의 중심축에서 인접한 상기 반사벽(40) 방향으로

×0.8 ~

×1.2의 각도를 갖는 것이 확산판(50)으로 입사되는 광의 균제도를 향상시키는 면에서 보다 바람직하다.A reference angle that divides the light incident on the diffuser plate 50 and the light incident on the reflection wall 40 among the light that is inclined toward the adjacent reflection wall 40 and passes through the light diffusion lens 30. [

(30) in the direction of the reflective wall (40) adjacent to the center axis of the light diffusion lens

× 0.8 ~

× 1.2 is more preferable in terms of improving uniformity of light incident on the diffuser plate 50.

은 102°± 8°로 형성된다.5, when three light emitting portions 20 are formed on one of the transverse axis and the longitudinal axis of the bottom frame 10, the distance between the light emitting portions 20 is 7 mm to 13 mm And the angle formed between the bottom wall 10 and the reflecting wall 40 located at both ends of the one axis of the bottom frame 10

Is formed at 102 DEG +/- 8 DEG.

At this time, among the light that is inclined toward the adjacent reflecting wall 40 and passes through the light diffusing lens 30, light having an angle of 32 占 賊 12 占 or less with the central axis of the light diffusing lens 30 passes through the diffusing plate 50 And the interval between the light diffusion lens 30 and the reflection wall 40 is set so that light having an angle of 32 ° ± 12 ° or more with the central axis of the light diffusion lens 30 is incident on the reflection wall 40 And the interval between the light diffusion lens 30 and the diffusion plate 50 are determined.

The arrangement relationship of the light diffusing lens 30, the reflecting wall 40 and the diffusing plate 50 is such that the light incident on the diffusing plate 50 directly from the three light diffusing lenses 30, So that the light reflected by the reflecting wall 40 positioned adjacent to the diffuser plate 30 and incident on the diffuser plate 50 can be uniformly incident on the diffuser plate 50. Since the light emitted from the light diffusing lens 30 on one side can be incident on the portion of the diffusing plate 50 located on the upper portion of the remaining light diffusing lens 30 in the case where there are three light diffusing lenses 30, The light can be uniformly incident on the diffuser plate 50 even when the angle of the reflecting wall 40 with respect to the bottom frame 10 is made smaller than when the diffuser lens 30 has only one diffuser lens.

는 상기 광확산 렌즈(30)의 중심축에서 인접한 상기 반사벽(40) 방향으로

×0.8 ~

×1.2 의 각도를 갖는 것이 확산판(50)으로 입사되는 광의 균제도를 향상시키는 면에서 보다 바람직하다.A reference angle that divides the light incident on the diffuser plate 50 and the light incident on the reflection wall 40 among the light that is inclined toward the adjacent reflection wall 40 and passes through the light diffusion lens 30. [

(30) in the direction of the reflective wall (40) adjacent to the center axis of the light diffusion lens

× 0.8 ~

× 1.2 is more preferable in terms of improving uniformity of light incident on the diffuser plate 50.

과 기준각

는,

=

×0.8 ~

×1.2 의 관계를 가지고, 가로방향 축 상에서 바닥 프레임(10)에 대한 반사벽(40)의 각도

과 기준각

는,

=

×0.8 ~

×1.2 의 관계를 갖는다.Fig. 6 is a table showing results of simulation of a backlight unit for an image generating apparatus according to the present invention. In the simulation, the diagonal length of the diffuser plate 50 is 30.48 mm to 76.2 mm, the optical gap is 20 mm or less, two light emitting portions 20 are formed on the transverse axis of the bottom frame 10, And one light emitting portion 20 is formed on the directional axis. The angle of the reflective wall 40 with respect to the bottom frame 10 on the longitudinal axis

And reference angle

Quot;

=

× 0.8 ~

× 1.2, and the angle of the reflecting wall 40 with respect to the bottom frame 10 on the horizontal axis

And reference angle

Quot;

=

× 0.8 ~

1.2. &Lt; / RTI &gt;

6 (a) shows the result of the longitudinal axis, that the angle of the reflecting wall 40 with respect to the bottom frame 10 has a uniformity of 82% or more at 94 ° to 122 °, When the angle of the reflecting wall 40 is 110 degrees, it has a high uniformity of 85% or more. 6 (b) shows the result that the angle of the reflecting wall 40 with respect to the bottom frame 10 as a result of the lateral axis has a uniformity of 80% or more at 94 ° to 110 °, When the angle of the reflecting wall 40 is 112 degrees with respect to the center of the reflecting wall 40, a high uniformity of 85% or more can be seen.

Fig. 7 is an explanatory diagram of a result of simulating a backlight unit for an image generating apparatus according to the present invention and a conventional backlight unit for an image generating apparatus. Fig. For reference, FIG. 7 shows the luminance distribution of the diffusion plate. As the luminance is closer to the blue color and closer to the red color, the luminance is higher.

7A is a simulation result of a conventional backlight unit for an image forming apparatus having an optical gap of 13.7 mm and not having a reflecting wall. As a result, the uniformity is as low as 72%, and the brightness of the center portion and the brightness of the outer portion are greatly different Can be seen. 7B is a simulation result of a conventional backlight unit for an image forming apparatus having an optical gap of 25 mm and no reflection wall, which is higher than the case where the uniformity is 79% and the optical gap is 13.7 mm, but it is sufficiently high There is a difference between the luminance of the center portion and the luminance of the outer portion.

On the other hand, as a result of simulating the backlight unit for an image producing apparatus according to the present invention, even though the optical gap is as short as 13.7 mm as shown in Fig. 7C, it exhibits a very high uniformity of 85%. In addition to this, it can be seen that there is almost no difference between the luminance of the center portion and the luminance of the outer portion.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

1: Backlight unit for image generating apparatus
10: bottom frame 20:
30: light diffusing lens 31: outer surface
32: inner surface 40: reflective wall
50: diffusion plate

Claims (12)

A bottom frame; A light emitting portion disposed on an upper surface of the bottom frame; A light diffusing lens disposed on an upper surface of the bottom frame to cover the light emitting portion and having an inner surface through which light is incident from the light emitting portion and an outer surface through which light incident through the inner surface is emitted; A diffusion plate disposed in parallel with the bottom frame so as to have a distance of 20 mm or less from the light emitting unit and having a diagonal length of 30.48 mm to 76.2 mm; And a reflecting wall disposed along the circumference of the space between the bottom frame and the diffuser plate and erected at an obtuse angle with the bottom frame to uniformly reflect the light incident from the light diffusing lens to the diffuser plate,
Wherein when one of the light emitting portions is formed on one of the transverse axis and the longitudinal axis of the bottom frame, an angle formed between the reflecting wall positioned at the both ends of the one axis of the bottom frame and the bottom frame

Light having an angle formed by the light passing through the light diffusion lens with the central axis of the light diffusion lens is 42 ° ± 16 ° or less is incident on the diffusion plate, Light having an angle of more than 42 DEG +/- 16 DEG is incident on the reflecting wall,
Wherein the distance between the light emitting portions is 12 mm to 20 mm when the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame, The angle that the frame forms

Is 102 ° ± 8 ° and light having an angle of 38 ° ± 12 ° or less with respect to the central axis of the light diffusing lens that is inclined toward the adjacent reflection wall and passes through the light diffusing lens is incident on the diffusing plate Light having an angle of 38 DEG +/- 12 DEG with the central axis of the light diffusion lens is incident on the reflection wall,
Wherein the distance between the light emitting portions is 7 mm to 13 mm when the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame, The angle that the frame forms

Light having an angle of not more than 32 ° ± 12 ° with respect to the central axis of the light diffusing lens among light passing through the light diffusing lens which is inclined toward the adjacent reflecting wall is incident on the diffusing plate Wherein light having an angle of 32 DEG +/- 12 DEG with an axis of the light diffusion lens is incident on the reflection wall.
The method according to claim 1,
Wherein the outer surface of the light diffusing lens

(Wherein Z ₁ is a distance from a reference point on the Z axis, wherein r ₁ is the A ₁ wherein K ₁ is the conic constant, wherein c ₁ is a constant center of curvature of the outer side bottom radius of the outer surface, the quaternary The aspherical surface coefficient, and the B ₁ is a sixth order aspherical surface coefficient)
Wherein 0 <r ₁ <10, c ₁ = 1 / r ₁ , -2 <K ₁ <0, 0 <A ₁ <0.05, 0 <B ₁ <0.04.
3. The method of claim 2,
Wherein the inner surface of the light diffusing lens

(Wherein Z ₂ is a distance from a reference point on the Z axis, wherein r ₂ is the c ₂ a bottom radius of the inner surface, is the K ₂ constant center of curvature of the inner surface, the conic constant, wherein A ₂ is a quaternary The aspherical surface coefficient, and the B ₂ is a sixth-order aspherical surface coefficient)
Wherein 0 <r ₂ <10, r ₁ > r ₂ , c ₂ = 1 / r ₂ , -2 <K ₂ <0, 0 <A ₂ <0.05, 0 <B ₂ < Backlight unit.
delete delete delete The method according to claim 1,
When one light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame,
A reference angle separating light incident on the diffusing plate and light incident on the reflecting wall among lights passing through the light diffusion lens;

Of the light diffusion lens

× 0.8 ~

X 1.2. &Lt; / RTI &gt;
delete The method according to claim 1,
When the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame,
A reference angle which divides the light incident on the diffusing plate and the light incident on the reflecting wall among the light that is inclined toward the adjacent reflecting wall and passes through the light diffusing lens,

Is directed in the direction of the reflective wall adjacent to the center axis of the light diffusion lens

× 0.8 ~

X 1.2. &Lt; / RTI &gt;
delete The method according to claim 1,
When the light emitting portion is formed on one of the transverse axis and the longitudinal axis of the bottom frame,
A reference angle which divides the light incident on the diffusing plate and the light incident on the reflecting wall among the light that is inclined toward the adjacent reflecting wall and passes through the light diffusing lens,

Is directed in the direction of the reflective wall adjacent to the center axis of the light diffusion lens

× 0.8 ~

X 1.2. &Lt; / RTI &gt;
The method according to claim 1,
The light diffusion lens includes:
Wherein the substrate is formed of one of PMMA (Poly (methylmethacrylate), PC (Polycarbonate), Cyclin Olefin Copolymer (COC), and Cyclo-olefin Polymer Backlight unit for generating device.

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