TWI531843B - Light emitting module and backlight module using the same - Google Patents

Description

Application of light-emitting module and its backlight module

The invention relates to a light-emitting module, and in particular to a light-emitting module with lateral light-emitting and a backlight module application thereof.

The components used in the current light-emitting module are point light sources, such as light-emitting diode strips. However, when the light-emitting diodes emit light in the forward direction, hotspots are generated due to excessive concentration of the light-emitting diodes. The area between the two adjacent light-emitting diode strips may have a halo or dark area due to uneven brightness, which affects the light uniformity and the range of illumination of the light-emitting module. In addition, when the spacing between the light bars is lengthened, there is a problem that the light intensity is insufficient, and a larger number of light-emitting diodes must be added, resulting in an excessive cost. Therefore, the defects of the conventional light-emitting module need to be improved.

The invention relates to an application of a light-emitting module and a backlight module thereof, wherein the light-emitting direction is laterally emitted with respect to the optical axis of the light-emitting element.

According to an aspect of the invention, a lighting module is provided, comprising a circuit board, a light emitting component and a long lens. The light emitting element is disposed on the circuit board, and the light emitting element has a vertical light emitting element and passes through an optical axis at a center point of the light source of the light emitting element. The elongated lens is disposed above the light emitting element. The elongated lens includes an upper surface, a lower surface, and two outer surfaces. The upper surface and the lower surface are located on opposite sides of the elongated lens, wherein the upper surface includes first and second curved surfaces that are symmetrical to each other and intersect with a valley line. The lower surface includes a recess for receiving the light-emitting element, and the recess surface has a light-incident surface facing the light-emitting element. The lower surface includes a third and fourth curved surface that are symmetrical to each other and intersect with a ridge line, and the two inner side surfaces extend from the ends of the third and fourth curved surfaces, respectively, and the vertical projections of the valley lines and the ridge lines coincide with each other. The two outer side surfaces are located on both sides of the elongated lens, respectively connected to the upper and lower surfaces, the thickness of the elongated lens has a maximum at the two outer side surfaces, and the thickness of the long lens has a minimum between the valley line and the ridge line. value. Wherein, the first and second curved surfaces have a point P and a point P' which is at the same curved surface as the point P and approaches the point P, and the distance between the point P and the center point O of the light source is defined as RP, and the point P' is The distance between the center point O of the light source is defined as RP', where the absolute difference |RP'-RP| is defined as ΔR, and the angle between the line between the point P and the center point O of the light source and the optical axis is defined as θP, The angle between a line connecting P' and the center point of the light source and the optical axis is defined as θP', where the absolute difference |θP'-θP| is defined as Δθ, where the light of the light-emitting element is totally reflected at point P. The angle of incidence is defined as θR and satisfies the following equation: , n is the refractive index of the elongated lens.

According to an aspect of the present invention, a backlight module includes: a light box; at least one of the above-mentioned light emitting modules arranged in a strip shape and disposed in the light box; and a diffusing plate covering the light emitting module.

In order to provide a better understanding of the above and other aspects of the present invention, the preferred embodiments of the present invention will be described in detail below.

100‧‧‧Lighting module

101‧‧‧Backlight module

110‧‧‧Circuit board

120‧‧‧Lighting elements

130‧‧‧Large lens

130a‧‧‧ upper surface

130b‧‧‧ lower surface

131‧‧‧First surface

132‧‧‧Second surface

133‧‧‧ Third surface

134‧‧‧fourth surface

135‧‧‧ outside surface

136‧‧‧ inside surface

140‧‧‧Lightbox

150‧‧‧Diffuser

V‧‧‧ Valley

A‧‧‧ ridgeline

C‧‧‧ recess

L‧‧‧ optical axis

O‧‧‧Light source center point

S1, S2‧‧‧ left and right sides

P, P’, P1~P6‧‧ points

θR, θP, θP', θS, ΔR, Δθ, θ1, θ2‧‧‧ angle

T‧‧‧ tangent

RP, RP', △R‧‧‧ distance

’’‧‧‧ 角角

S‧‧‧ total reflection critical point

W1, W2‧‧‧ horizontal width

H1, H2, h1, h2‧‧‧ vertical height

1A and 1B are a perspective view and a side view of a light emitting module according to an embodiment of the invention.

Figure 2 is a diagram showing the curvature design of the first curved surface when the light emitted from the center point of the light source is totally reflected.

Figure 3 is a schematic view showing the dimensions of the elongated lens.

Figure 4 shows the curvature design of the third curved surface.

FIG. 5 is an exploded view of a backlight module according to an embodiment of the invention.

Figure 6 is a diagram showing the light distribution of the light-emitting module.

The embodiments are described in detail below, and the embodiments are only intended to be illustrative and not intended to limit the scope of the invention.

Please refer to FIGS. 1A and 1B , which are a perspective view and a side view of a light emitting module 100 according to an embodiment of the invention. The light emitting module 100 includes a circuit board 110, a light emitting component 120, and an elongated lens 130. The light emitting element 120 is disposed on the circuit board 110. The elongated lens 130 is disposed above the light emitting element 120 for guiding the light emitted by the light emitting element 120 to the left and right sides S1 and S2 of the elongated lens 130. In one embodiment, the light-emitting element 120 may be formed by arranging a plurality of light-emitting diodes along the long-axis direction of the elongated lens 130 as a linear light-emitting source. However, in another embodiment, the light emitting element 120 can also be a single elongated light emitting element. The invention is not limited thereto.

In FIGS. 1A and 1B, the upper surface 130a of the elongated lens 130 has a valley line V extending in the long axis direction. The valley line V is formed by intersecting two curved surfaces that are symmetrical with each other and recessed inward (that is, the first curved surface 131 and the second curved surface 132 shown in FIG. 1B). Further, the lower surface 130b of the elongated lens 130 has a ridge line A extending along the long axis direction. The ridgeline A is formed by two curved surfaces that are symmetrical with each other and bulged inward (i.e., the third curved surface 133 and the fourth curved surface 134 shown in FIG. 1B). In the present embodiment, the vertical projections of the valley line V and the ridge line A coincide with each other, and the thickness of the elongated lens 130 has a minimum value between the valley line V and the ridge line A, denoted by H2.

As shown in FIG. 1B, the light-emitting element 120 has an optical axis L. This optical axis L is perpendicular to the light-emitting element 120 and passes through the light source center point O of the light-emitting element 120. At the same time, the optical axis L also passes through the valley line V and the ridge line A of the elongated lens 130.

In detail, the elongated lens 130 includes an upper surface 130a, a lower surface 130b, and two outer side surfaces 135. The upper surface 130a and the lower surface 130b are located on opposite sides of the elongated lens 130 (ie, the upper and lower sides), and the two outer side surfaces 135 are located on both sides of the elongated lens 130 (ie, the left and right sides). The two outer side surfaces 135 are respectively connected to the upper and lower surfaces 130b, and the thickness of the elongated lens 130 has a maximum value at the two outer side surfaces 135, denoted by H1.

In an embodiment, the two outer side surfaces 135 extend substantially parallel to the axial direction of the optical axis L.

The upper surface 130a includes a first curved surface 131 and a second curved surface 132 that are symmetrical to each other and intersect the valley line V. The lower surface 130b includes a light-emitting element A recess C of 120, and the surface of the recess C has a light incident surface facing the light emitting element 120. Further, the lower surface 130b includes a third curved surface 133 and a fourth curved surface 134 that are symmetrical to each other and intersect the ridgeline A. That is, the top ends of the third curved surface 133 and the fourth curved surface 134 intersect at the top end of the pocket C.

In addition, the lower surface 130b further includes two inner side surfaces 136 extending from the ends of the third curved surface 133 and the fourth curved surface 134, respectively. In an embodiment, the two inner side surfaces 136 extend substantially parallel to the axial direction of the optical axis L.

The structural design of the appearance of the elongated lens 130 is further described below in order to achieve the purpose of the lateral light output of the light-emitting module 100. Please refer to FIGS. 2~4, wherein FIG. 2 is a view showing the curvature design of the first curved surface 131 when the light emitted from the center point O of the light source is totally reflected, and FIG. 3 is a schematic view showing the size of the elongated lens 130, FIG. The curvature design of the third curved surface 133 is illustrated. In the following figures, since the elongated lens 130 is a bilaterally symmetrical structure, only the right half of the elongated lens 130 is illustrated, and the structures of the left half and the right half are symmetrical, and therefore will not be described again.

Referring to FIG. 2, the first curved surface 131 has a point P and a point P' which is on the same curved surface as the point P and approaches the point P. The distance between the point P and the center point O of the light source is defined as RP, point P. 'The distance from the center point O of the light source is defined as RP', where the absolute difference |RP'-RP| is defined as ΔR, and the angle between the line between the point P and the center point O of the light source and the optical axis L is defined as θP, the angle between a line between the point P' and the center point O of the light source and the optical axis L is defined as θP', where the absolute difference |θP'-θP| is defined as Δθ. In the present embodiment, the incident angle when the light of the light-emitting element 120 is totally reflected at the point P is defined as θR, and satisfies the following equation (1): , n is the refractive index of the elongated lens 130.

The refractive index of the elongated lens 130 is, for example, between 1.45 and 1.6.

In the above equation (1), as can be seen from Fig. 2, (i) the sum of the incident angle θR and the complementary angle θ' is 90 degrees, and (ii) the line passing through the tangent T of the point P and the point P to the point P" The angle between them is θS, and the sum of the angle θS and the residual angle θ' is also 90 degrees. It can be inferred from the relationship between (i) and (ii) above and the tangent function of the triangle PP'P". Incident angle

Further, in the above equation (1), the critical angle θc at which total reflection occurs is derived using the law of reflection as follows: n *sin θ c = n 2*sin θt , where the incident angle θR is equal to the angle of refraction θt equal to 90 degrees The critical angle θc at which total reflection occurs. Therefore, as long as the incident angle θR is larger than the critical angle θc, the light is totally reflected. Substituting n2=1 and θt=90 degrees into the above equation, the critical angle can be known.

Therefore, by integrating the above formulas (2) and (3), the above equation (1) can be obtained.

Next, referring to FIG. 3, the size of the elongated lens 130 is designed as follows: H1 represents the maximum height of the exit curve (first curved surface 131) of the elongated lens 130. H2 represents the minimum height of the exit curve (first curved surface 131) of the elongated lens 130; W1 represents the maximum width of the exit curve (first curved surface 131) of the elongated lens 130; W2 represents the incident curve of the elongated lens 130 ( The maximum width of the third curved surface 133); h2 represents the maximum height of the incident curve (third curved surface 133) of the elongated lens 130; h1 represents the minimum height of the incident curve (third curved surface 133) of the elongated lens 130.

In FIG. 3, the vertical height of the elongated lens 130 at the two outer side surfaces 135 (the vertical distance from the point P5 to the point P6) is defined as H1, the vertical height between the valley line V and the center point O of the light source (point P4 to The vertical distance of the center point O is defined as H2, and the ratio of H1/H2 is preferably between 2.2 and 2.9.

The horizontal width of the elongated lens 130 between the two outer side surfaces 135 (twice the horizontal distance W1 of the point P4 to the point P5) is defined as 2W1, and the horizontal width of the elongated lens 130 between the two inner side surfaces 136 ( The horizontal distance W2 from point P3 to point P2 is defined as 2W2, and the ratio of W1/W2 is preferably between 3.6 and 4.4.

The vertical height of the ridge line A from the center point O of the light source (the distance from the point P3 to the center point O of the light source) is defined as h2, and the vertical height of the inner side surface 136 (point The distance from P2 to point P1 is defined as h1, and the ratio of h2/h1 is preferably between 1.4 and 2.1.

In FIG. 3, the light ray L1 is incident into the elongated lens 130 from the incident curve (point P3 to point P2), is totally reflected to the outer side surface 135 via the first curved surface 131, and is emitted outside the elongated lens 130. Further, the light ray L2 may be incident into the elongated lens 130 from the inner side surface 136 (point P2 to point P1) and out of the elongated lens 130 via the outer side surface 135.

Next, referring to Fig. 4, the curvature of the third curved surface 133 is designed to satisfy the following equation (4): y = -0.531 x ⁵ +1.958 x ⁴ -2.072 x ³ +0.329 x ² -0.057 x +h2

Where y is the vertical distance between a punctuation point on the third curved surface 133 and the center point O of the light source, and x is the horizontal distance between the coordinate point of the third curved surface 133 and the center point O of the light source, and h2 is long. The incident curve of the strip lens 130 (the third curved surface 133) has a vertical height at x=0.

In one embodiment, the third curved surface 133 has a total reflection critical point S whose vertical height is between h1 and h2. This critical point has a maximum value of the negative slope change, that is, the curvature of the third curved surface 133 changes to: the slope from the point P3 is 0, and the negative slope increases until the critical point S is the maximum value of the negative slope change.

In one embodiment, the angle θ1 between the line connecting the total reflection critical point S and the center point O of the light source (the line segment O-S) and the optical axis L is preferably between 30 and 60 degrees. In addition, the intersection of the third curved surface 133 and the inner surface 136 has a cross The point P2 is set, and the angle θ2 between the line (the line segment O-P2) between the intersection point P2 and the center point O of the light source and the optical axis L is preferably between 30 and 90 degrees.

Please refer to FIG. 5, which is an exploded view of the backlight module 101 according to an embodiment of the invention. The backlight module 101 includes the light emitting module 100 (the circuit board 110, the light emitting element 120, and the elongated lens 130) of the above embodiment, a light box 140, and a diffusion plate 150. The above-described light emitting modules 100 are disposed in the light box 140 and arranged in a strip shape. In addition, the diffusion plate 150 covers the light emitting module 100. In this embodiment, since the light emitting module 100 is laterally illuminated, the light emitting surface thereof is not directed toward the diffusing plate 150, so the light can be uniformly distributed in the light box 140, and then the uniformly distributed light is transmitted through the diffusing plate 150 to the light box 140. outer. Therefore, it is possible to avoid a phenomenon in which hot spots and uneven brightness distribution are likely to occur when the light-emitting surface of the conventional light-emitting module faces the diffusion plate.

In addition, please refer to FIG. 6 , which is a light distribution diagram of the light-emitting module 100, which is measured according to the light intensity measured on the optical axis (indicated by 0 degree) and in the direction of the vertical optical axis (indicated by plus or minus 90 degrees). The light intensity of the light-emitting module 100 is applied to the backlight module 101 because the light intensity of the lateral light is relatively greater than the light intensity of the forward light. Therefore, when the distance between the two adjacent light-emitting modules 100 is When the size is increased, the brightness of the dark area is not insufficient due to the increased spacing. Therefore, the backlight module 101 of the embodiment can apply a small number of light-emitting modules with increased spacing to reduce the backlight module 101. cost.

The application of the light-emitting module and the backlight module thereof disclosed in the above embodiments of the present invention, because the light-emitting direction is laterally emitted relative to the optical axis of the light-emitting element, When the light-emitting surface of the conventional light-emitting module is faced to the diffusing plate, the phenomenon of hot spot and uneven brightness distribution is likely to occur, so as to achieve uniform light output.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧Lighting module

110‧‧‧Circuit board

120‧‧‧Lighting elements

130‧‧‧Large lens

S1, S2‧‧‧ left and right sides

V‧‧‧ Valley

Claims (10)

A lighting module comprising: a circuit board; a light emitting element disposed on the circuit board, the light emitting element having an optical axis perpendicular to the light emitting element and passing through a center point of the light source of the light source element; a long lens disposed above the light emitting element, comprising: an upper surface and a lower surface positioned on opposite sides of the elongated lens, wherein the upper surface includes a first and a first symmetry and intersecting a valley line a second curved surface, the lower surface includes a recess for accommodating the light-emitting element, and the surface of the recess has a light-incident surface facing the light-emitting element, and includes a third and fourth curved surface which are symmetrical to each other and intersect with a ridge line. And the inner side surfaces respectively extend from the ends of the third and fourth curved surfaces, and the vertical projections of the valley lines and the ridge lines coincide with each other; and the two outer side surfaces are located on opposite sides of the elongated lens, respectively connecting the upper and lower sides a surface, the thickness of the elongated lens has a maximum at the two outer side surfaces, and the thickness of the lens has a minimum between the valley line and the ridge line; wherein the first and second curved surfaces have a point P and a point at the same surface as the point P and approaching the point P' of the point P, the distance of the point P from the center point O of the light source is defined as RP, the point P' and the center point of the light source O The distance is defined as RP', where the absolute difference |RP'-RP| is defined as ΔR, and the angle between the line between the point P and the center point O of the light source and the optical axis is defined as θP, which is The angle between a line connecting P' and the center point of the light source and the optical axis is defined as θP', wherein the absolute difference |θP'-θP| is defined as Δθ, where the light of the light-emitting element is at the point P The angle of incidence when total reflection is produced is defined as θR and satisfies the following equation: , n is the refractive index of the elongated lens. The illuminating module of claim 1, wherein the vertical height of the ridge line from the center point of the light source is defined as h2, the vertical height of each of the two inner side surfaces is defined as h1, and the ratio of h2/h1 is between 1.4~ Between 2.1. The illuminating module of claim 2, wherein the illuminating surface has to satisfy the following equation: y = -0.531 x ⁵ +1.958 x ⁴ -2.072 x ³ +0.329 x ² -0.057 x +h2 wherein y The vertical distance between a punctuation point on the third and fourth curved surfaces and the center point of the light source, where x is the horizontal distance between the coordinate point on the third and fourth curved surfaces and the center point of the light source. The illuminating module of claim 2, wherein the third and fourth curved surfaces have a total reflection critical point, and the vertical height of the total reflection critical point is between h1 and h2. The illuminating module of claim 4, wherein a line between the total reflection critical point and the center point of the light source and the optical axis is between 30 and 60 degrees. The illuminating module of claim 1, wherein the third and fourth curved surfaces respectively have an intersection with the two inner side surfaces, and a connection between the intersection point and the center point of the light source is The angle between the optical axes is between 30 and 90 degrees. The illuminating module of claim 1, wherein a vertical height of the elongated lens at the two outer side surfaces is defined as H1, and a vertical height between the valley line and a center point of the light source is defined as H2, wherein The ratio of H1/H2 is between 2.2 and 2.9. The illuminating module of claim 1, wherein a horizontal width of the elongated lens between the two outer side surfaces is defined as W1, and a horizontal width of the elongated lens between the two inner side surfaces is defined as W2 , where the ratio of W1/W2 is between 3.6 and 4.4. The light-emitting module of claim 1, wherein the elongated lens has a refractive index between 1.45 and 1.6. A backlight module comprising: a light box: at least one of the light-emitting modes according to any one of claims 1-9 The groups are arranged in a strip shape and disposed in the light box; and a diffusion plate covers the light emitting module.