JP2006210273A - Backlight illumination device and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a backlight illumination device uniformly illuminating a liquid crystal display device turning light from an LED light source into uniform and directional illumination light by using a light guide passage. <P>SOLUTION: The backlight illumination device, illuminating a liquid crystal display panel 20 from backside, has more than one unit of illumination units with identical construction composed of a single LED light source 10 and a light guide passage structure 13 for heightening the directivity of illumination light by guiding the light from the LED light source; and a diffusion plate 15 arranged between the illumination unit and the liquid crystal display panel 20, diffusing the light emitted from the LED light source guided by the light guide structure with a prescribed diffusion angle. The light guide passage structure 13, having hollow light guide space, guides the light by a reflection face having no curvature in light guide direction, of which an opening at light emission side is larger than that at light incident side. A main light beam Ax from the LED light source 10 almost coincides with a light guide passage central line corresponding to the LED light source, and the main light beam Ax crosses the diffusion plate 15 almost at right angle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a backlight illumination device and a liquid crystal display device.

In a liquid crystal display device, it has been conventionally known that backlight illumination is performed by an LED light source from the rear of a liquid crystal display panel (Patent Document 1, etc.).
Since the LED light source emits Lambert light of continuous spectrum light in the ± 90 ° direction, the emitted light has low directivity. When performing “illumination with high directivity and high uniformity of illumination” using an LED light source, illuminate a “light beam in which the directions of light rays are aligned in the same direction” at a position separated from the light emitting part of the LED light source. Although it may be used as light, since a small part of the light emitted from the LED light source cannot contribute to the illumination in this way, there is a problem that the number of LED light sources used must be increased in order to increase the illumination efficiency. .

  As a method for solving such a problem, conventionally, “uniform and directional illumination” is performed on a liquid crystal display panel by combining a lens or a lens array with a plurality of LED light sources. However, when the liquid crystal display panel is increased in area, it is necessary to increase the number of lenses or the size of the lens array. However, this is not always easy to realize.

JP2003-131228A

  In view of the circumstances described above, the present invention can perform uniform and highly directional illumination on a liquid crystal display panel, and can easily cope with an increase in area of the liquid crystal display panel, and the backlight. An object is to realize a liquid crystal display device using an illumination device.

  The backlight illumination device of the present invention is a “backlight illumination device that illuminates the liquid crystal display panel from the back side”, and includes one or more illumination units and a diffusion plate.

One unit of “illumination unit” has a single LED light source and a waveguide structure. That is, one waveguide structure corresponds to one LED light source.
The “waveguide structure” increases the directivity of illumination light by guiding light from the corresponding LED light source.

  A “diffusion plate” is disposed between one or more illumination units and a liquid crystal display panel, and emits light emitted from each LED light source and guided by a corresponding waveguide structure at a “predetermined diffusion angle”. Spread.

  The waveguide structure performs waveguide by a “reflecting surface in which the waveguide space is hollow and has no curvature in the waveguide direction”, and the exit side opening is larger than the entrance side opening. That is, the “waveguide space”, which is a portion where the light of the waveguide structure is guided, is in a hollow state, and the peripheral wall portion of this cavity is a “reflecting surface having no curvature in the waveguide direction”. That is, the reflection surface of the waveguide structure is a straight line in the waveguide direction, and the three-dimensional shape of the reflection surface is a plane or a curved surface having the straight line as a generating line.

  The principal ray from the LED light source substantially coincides with the waveguide center line of the waveguide structure corresponding to the LED light source, and the principal ray is substantially orthogonal to the diffusion plate. The fact that the diffusion plate diffuses light at a “predetermined diffusion angle” means that “the range of the diffusion angle by the diffusion plate is controlled to a predetermined angle range”.

  As described above, the backlight device according to the present invention has a minimum configuration of one unit of lighting, that is, a combination of a “single LED light source and a single waveguide structure” and a diffusion plate. The When two or more units of lighting units are used, the diffuser plate is shared by a plurality of lighting units. In this case, the plurality of lighting units used have the same configuration, that is, the same structure and function.

  When two or more units of lighting units are used, each lighting unit may be held separately or collectively. For example, a structure in which a portion of the waveguide structure is integrally formed, That is, a configuration in which two or more waveguide spaces are formed in an integral material may be employed.

  The backlight illuminating device according to claim 1, wherein when a plurality of units of illumination units are used, the plurality of units of illumination units are expressed as “one-dimensional or secondary-dimensional depending on the size and shape of the liquid crystal display panel to be illuminated uniformly. It is possible to adopt a configuration in which the arrangement is "manually arranged" (claim 2).

The backlight illuminating device according to claim 1 or 2, wherein the incident side opening and the exit side opening of the waveguide structure have a square shape, the diameter of the entrance side opening: A, the diameter of the exit side opening: B, Waveguide length: L, transmission half angle of liquid crystal display panel to be illuminated: γ, conditions:
(1) 0 <(BA) / (2L) ≦ tan (γ / 2)
(Claim 3).
In this case, the diameter of the incident side opening: A and the diameter of the emission side opening: B are “the length of one side of the square shape” of the opening.

In the backlight illumination device according to claim 1 or 2, the entrance-side opening and the exit-side opening of the waveguide structure have a rectangular shape, and the lengths of two orthogonal sides of the entrance-side opening: Ax, Ay (≠ Ax), the length of two orthogonal sides of the exit side opening: Bx, By (≠ Bx), the waveguide length: L, and the transmission half angle of the liquid crystal display panel to be illuminated: γx, γy.
(2) 0 <(Bx−Ax) / (2L) ≦ tan (γx / 2)
(3) 0 <(By-Ay) / (2L) ≦ tan (γy / 2)
(Claim 4).

3. The backlight illumination device according to claim 1, wherein the incident side opening and the exit side opening of the waveguide structure are similar to each other, and the area ratio of the incident side opening and the exit side opening is A ² : B. ² and A, B, waveguide length: L, transmission half angle of liquid crystal display panel to be illuminated: γ, conditions:
(4) 0 <(BA) / (2L) ≦ tan (γ / 2)
(Claim 5).

  The backlight illumination device according to any one of claims 1 to 5, wherein the diffusion plate is a "directional diffusion plate that scatters in a Gaussian manner in the ± 10 ° direction", and the liquid crystal display plate to be illuminated is “TFT liquid crystal display panel that transmits light in a direction of ± 7 degrees” (Claim 6).

  The liquid crystal display device according to the present invention is a “liquid crystal display device that displays an image by illuminating a liquid crystal display panel from the back side with a backlight illumination device”, and is a backlight illumination device. The liquid crystal display panel of the backlight illuminating device is used so that the diffusion plate and the liquid crystal display panel face each other substantially in parallel (claim 7).

  As described above, in the backlight illumination device of the present invention, the Lambertian light emitted from the LED light source is guided in the waveguide space of the waveguide structure corresponding to the LED light source. At this time, the reflecting surface forming the peripheral wall of the waveguide space does not have a curvature in the waveguide direction, and the waveguide space expands in the waveguide direction from the incident side to the exit side in a “end-spreading manner”.

  Assuming that the angle between the direction of curvature of the reflecting surface and the waveguide center line is α, a light beam inclined by an angle θ with respect to the waveguide center line is reflected once by the reflecting surface. The “inclination angle with respect to the waveguide center line” decreases by 2α per reflection. Therefore, the light beam guided by the reflecting surface while being guided through the waveguide space is emitted from the waveguide structure in a “state in which directivity is increased” with the inclination with respect to the waveguide center line being reduced.

  Thus, the light emitted from the waveguide structure in a state where the directivity is enhanced is diffused by the diffusion plate and irradiates the liquid crystal display plate. Although the diffusion plate slightly deteriorates the directivity of transmitted light, the diffusion angle of the diffusion plate is controlled to be “a predetermined diffusion angle (for example,“ Gaussian scattering in the ± 10 ° direction ”described above). The directivity of transmitted light does not deteriorate significantly. Further, the diffusion of the illumination light by the diffusion plate can eliminate the non-uniformity of illumination caused by “the gap between the LED light source and the waveguide space of the waveguide structure”, and can improve the uniformity.

  In the above conditional expressions (1) to (4), when the lower limit is 0 or less, the angle between the direction of inflexion of the reflecting surface of the waveguide space and the waveguide center line becomes 0, and the incurvence is This means that the direction of is parallel to the waveguide center line, or the angle is negative, and the waveguide space becomes smaller from the entrance side to the exit side. Even if the waveguide space is guided, the directivity of the reflected light beam by the reflecting surface cannot be improved.

  If the upper limit is exceeded, the “corresponding portion of the light beam emitted from the waveguide structure” will be outside the angular range that transmits the liquid crystal display panel, and light that cannot be transmitted through the liquid crystal display panel even if diffused using the diffusion plate. Since it becomes large, the light use efficiency of illumination cannot be raised sufficiently.

As described above, according to the backlight illumination device of the present invention, it is possible to realize uniform illumination with excellent directivity for the liquid crystal display panel. Further, by increasing the number of lighting units, it is possible to easily and reliably cope with an increase in the area of the liquid crystal display panel.
Therefore, a liquid crystal display device using the backlight illumination device of the present invention can display a good image with illumination with uniform directivity and uniform light, and can easily increase the area.

FIG. 1 is a diagram for explaining a configuration of a liquid crystal display device.
In FIG. 1A, reference numeral 10 denotes an LED light source, reference numeral 11 denotes a substrate, reference numeral 13 denotes a waveguide structure, reference numeral 15 denotes a diffusion plate, and reference numeral 20 denotes a liquid crystal display panel.

  The LED light source 10 is held on the substrate 11. The waveguide structure 13 has a hollow waveguide space, and its peripheral wall portion is a reflecting surface 13A. The LED light source 10 is provided close to the incident side opening of the waveguide structure 13 (in terms of structure, the LED light source 10 is fixedly provided at the incident side opening of the waveguide structure 13). The waveguide space is “larger toward the end” from the incident side opening toward the emission side opening at the top of the figure.

  The light emitted from the LED light source 10 is continuous spectrum light that emits Lambert light in the ± 90 ° direction, is emitted in the ± 90 ° direction, and guides the waveguide space of the waveguide structure 13 from below to above. Waved.

  The “principal ray” of the guided light is light that travels in the direction perpendicular to the light emitting surface from the center of the light emitting surface of the LED light source 10, and is denoted by reference numeral Ax in FIG. The chief ray Ax substantially coincides with the “waveguide center line” of the waveguide structure 13. Of the light emitted from the LED light source 10, a light beam having a small inclination with respect to the principal light beam AX travels straight through the waveguide space of the waveguide structure 13 and exits from the exit-side opening at the upper end.

  Of the light emitted from the LED light source 10, one having a large inclination with respect to the principal ray Ax is guided through the waveguide space while being reflected by the reflecting surface 13 </ b> A, and exits from the exit side opening of the waveguide structure 13. In FIG. 1A, the symbol L represents “one of such rays” as a representative. Of the light rays L, the larger the inclination with respect to the principal ray Ax, the greater the number of repetitions of reflection by the reflecting surface 13A. The illustrated light beam L is reflected three times by the reflecting surface 13A and then exits from the exit-side opening.

  Since the reflecting surface 13A has no curvature in the waveguide direction (vertical direction in FIG. 1A), as described above, if the angle of inclination of the reflecting surface 13A with respect to the principal ray Ax is α, the reflecting surface 13A is reflected by the reflecting surface 13A. Each time a reflected ray is reflected, the “absolute value of the inclination with respect to the principal ray Ax (and hence the waveguide center line)” decreases by 2α, and approaches the direction of the principal ray Ax. In this way, the light emitted from the exit side opening of the waveguide structure 13 is in the “state with enhanced directivity” from the Lambertian emission state.

  When the light having the enhanced directivity is transmitted through the diffusion plate 15, the directivity is slightly weakened by the diffusion action of the diffusion plate 15, but the diffusion angle of the diffusion plate 15 is "a predetermined diffusion angle (for example, ± Therefore, the light L10 transmitted through the diffuser plate 15 has sufficient directivity while increasing the uniformity of the light.

  In this way, when the uniform light L10 that is transmitted through the diffusion plate 15 and has directivity and irradiates the liquid crystal display plate 20 from the back side, “of the incident light has an incident angle that can be transmitted through the liquid crystal display plate 20”. The “component” is transmitted through the liquid crystal display panel 20 and “image display” is performed on the pixel-displayed image. In the figure, symbol L20 indicates light transmitted through the liquid crystal display panel 20.

  If the “effect of increasing the directivity of the illumination light beam” by the waveguide structure 13 and the “predetermined diffusion angle” by the diffusion plate 15 are optimized according to the “incident angle through which the liquid crystal display plate 20 can be transmitted”, then it is uniform. A bright image can be displayed. In the configuration shown in FIG. 1A, the combination of the LED light source 10 and the waveguide structure 15 constitutes “one unit of illumination unit”.

  That is, in the liquid crystal display device shown in FIG. 1A, the LED light source 10, the waveguide structure 13, and the diffusion plate 15 constitute a “backlight illumination device”. This “backlight illuminating device” is a backlight illuminating device that illuminates the liquid crystal display panel 20 from the back side, and directs illumination light by guiding light from the single LED light source 10 and the LED light source 10. 1 unit of an illumination unit having the same configuration with the waveguide structure 13 for enhancing the performance as one unit, and is disposed between the unit of illumination unit and the liquid crystal display panel 20, and is emitted from the LED light source 10. And a diffusion plate 15 for diffusing the light guided by the corresponding waveguide structure 13 at a “predetermined diffusion angle”. The waveguide structure 13 has a “waveguide space is hollow” and has a curvature in the waveguide direction. A waveguide of the waveguide structure 13 corresponding to the LED light source 10 in which the exit-side opening is larger than the incident-side opening, and the principal ray Ax from the LED 10 light source corresponds to the LED light source 10. Approximately coincides with the center line, and In which the principal ray Ax is substantially perpendicular to the diffusion plate 15 (claim 1).

  The basic condition of the structure of the waveguide structure 13 is that “the waveguide space is hollow and the waveguide is guided by a reflecting surface having no curvature in the waveguide direction, and the exit side opening is more than the entrance side opening. As long as this condition is satisfied, there are no particular restrictions on the shapes of the entrance-side opening and the exit-side opening, and various shapes are allowed for these openings.

  FIGS. 1B to 1I show examples of “combination of incident side opening and emission side opening”. Hereinafter, in this figure, the incident side opening is denoted by reference character AP1, and the emission side opening is denoted by reference character AP2.

  FIG. 1B shows a case where the incident-side opening AP1 and the exit-side opening AP2 are both “square”, and FIG. 1C shows that the incident-side opening AP1 and the exit-side opening AP2 are “similar to each other”. In the case of “horizontal rectangle”, (d) is the incident side opening AP1, and the exit side opening AP2 is “both are horizontally long but not similar to each other”. When both side openings AP2 are “regular triangles”, (f) is a case where both the incident side openings AP1 and the exit side openings AP2 are “circular”.

  (G) of FIG. 1 shows that the incident side opening AP1 and the exit side opening AP2 are both “elliptical and similar to each other”, and (h) shows that the incident side opening AP1 is “circular” and the exit side. When the opening AP2 is “elliptical”, (i) is when the incident-side opening AP1 is “elliptical” and the emission-side opening AP2 is “circular”. Of course, other various combinations of shapes of the incident side opening and the emission side opening are possible.

  The liquid crystal display device / backlight illumination device described in the embodiment with reference to FIG. 1 uses one unit of illumination unit. Since the light emission amount of the LED light source 10 is limited, if the size of the liquid crystal display panel 20 is increased, sufficient brightness cannot be obtained by illumination with a single illumination unit.

  Therefore, in the backlight illumination device, it is preferable to arrange a plurality of illumination units one-dimensionally or two-dimensionally according to the size and shape of the liquid crystal display panel to be illuminated uniformly. It is easily understood that a large-area liquid crystal display panel can be well illuminated by arranging the illumination units as shown in FIG. 1A in the left-right direction of FIG. 1A or in the direction orthogonal to the drawing. Like.

FIG. 2 is a view for explaining an embodiment of a backlight illumination device according to claim 2 and a liquid crystal display device using the backlight illumination device.
In this embodiment, a liquid crystal display panel 200 having a “rectangular image display region” having a relatively large area size is backlit, and six LED light sources 10a arranged in two rows and three columns. To 10 f (LED light sources 10e and 10f are not shown).

  The waveguide structure 130 corresponding to these six LED light sources is configured as “the whole as an integral structure”, and as shown in FIG. 1C, the waveguide space (incident side openings AP1a to AP1f, emission side) In the hollow portion between the openings AP2a to AP2f, the peripheral wall portion is formed as a “reflecting surface having no curvature in the waveguide direction”, and the waveguide center line of each waveguide space is shown in FIG. Is arranged in 2 rows and 3 columns. These six waveguide spaces are identical in shape.

  2A is a cross-sectional view showing the “array in the row direction” of the illumination units, and FIG. 2B is a cross-sectional view showing the “array in the column direction”. The waveguide structure 130 is formed with a waveguide space that expands toward the exit side opening from the incident side opening, and a reflection surface (collectively denoted by reference numeral 131) by the peripheral wall is in the waveguide direction. No curvature. In addition, the chief ray of light emitted from each LED light source (collectively indicated by the symbol Ax) substantially matches the “waveguide center line” of the corresponding waveguide structure.

  As shown in FIGS. 2A and 2B, the light from the nuclear LED light source 10a and the like is enhanced in directivity by the corresponding waveguide and is transmitted through the diffusion plate 150 to become illumination light L100. The display panel 200 is irradiated from the back side, and image display is performed by the light L200 transmitted through the liquid crystal display panel 200. The “interval between the integrated waveguide structure 130 and the diffusion plate 150” means that the light emitted from each waveguide structure is appropriately overlapped on the incident side surface of the diffusion plate 150, and the light intensity distribution on the incident surface. Is set to a size that can be uniformly uniform.

  Further, the “interval between the diffusion plate 150 and the liquid crystal display panel 200” is set to a size such that the illumination light L100 transmitted through the diffusion plate 150 uniformly irradiates the liquid crystal display panel 200.

  As shown in FIG. 2C, in the embodiment of FIG. 2, the waveguide spaces of the waveguide structure have the same form, and the incident side openings AP1a (the incident side openings AP1a to AP1f all have the same shape). Therefore, both the exit side aperture AP2a (incident side apertures AP2a to AP2f have the same shape and will be described by using AP2a) are rectangular. .

  As shown in FIG. 2C, the length of the incident side opening AP1a in the row direction is Ax, the length of the incident side opening AP2a in the row direction is Bx, and the length of the incident side opening AP1a in the column direction. The length is Ay, the length of the side in the column direction of the incident side opening AP2a is Bx, and the waveguide length of the waveguide structure is L as shown in FIG.

  At this time, if Ax = Ay and Bx = By, the incident-side opening AP1a and the emission-side opening AP2a are both square and have similar shapes. In this case, Ax = Ay = A, Bx = By = B, it is preferable that A, B, and L satisfy the above-described condition (1) with respect to the transmission half angle γ of the liquid crystal display panel 200 to be illuminated (Claim 3).

  If Ax ≠ Ay and the length of two orthogonal sides of the exit side opening: Bx ≠ By, Ax, Ay, Bx, By, and waveguide length: L are in the x direction of the liquid crystal display to be illuminated, It is preferable that the above-described conditions (2) and (3) are satisfied with respect to the transmission half angle in the y direction: γx and γy (Claim 4).

  FIG. 3 shows three examples of a structure in which a plurality of waveguide structures are integrated, that is, a configuration in which two or more waveguide spaces are formed in an integrated material. In FIG. 3, each of the waveguide structures is collectively indicated by reference numeral 131. The configuration 130A in which “a plurality of waveguide spaces are formed in a single material” shown in FIG. 3 (a) is the same as the structure 130A shown in FIG. 1 (d) in which both the entrance-side opening and the exit-side opening are circular. This is an example in which a plurality of “waveguide structures” are arranged in a staggered arrangement.

  The configuration 130B in which “a plurality of waveguide spaces are formed in a single material” shown in FIG. 3B is the same as the structure 130B shown in FIG. 1E, in which both the entrance-side opening and the exit-side opening are triangular. This is an example in which a plurality of “waveguide structures” are densely arranged. A configuration 130C in which “a plurality of waveguide spaces are formed in a single material” shown in FIG. 3C is a honeycomb structure having a plurality of “waveguide structures in which both the entrance-side opening and the exit-side opening are hexagonal”. It is an example arranged in a shape.

In the waveguide structure as illustrated in FIG. 3, the shape of the incident side opening and the shape of the emission side opening are similar to each other. ^2: when the B ^2, a, B, waveguide length: L, transparent half angle of the liquid crystal display to be illuminated: gamma is, it is preferable to satisfy the above conditions (4) (claim 5).

  Two examples of the backlight illumination device are given below. Since the form of these embodiments is a specific example of the form as shown in FIG. 2, the LED light source 10a and the like will be described as “continuous spectrum light” in both Embodiments 1 and 2. LED that emits Lambert light in the ± 90 ° direction ”, the diffusion plate 150 is“ a directional diffusion plate that scatters in a Gaussian manner in the ± 10 ° direction ”, and the liquid crystal display panel 200 is“ ± 7 ° direction ”. A TFT liquid crystal display panel that transmits light to the light source.

Opening side of waveguide structure: square shape and one side length A = 4 mm
Output side opening of waveguide structure: square shape with one side length B = 8.5 mm
Distance between LED light source and incident side opening of waveguide structure: 0.5 mm
Waveguide length: L = 40mm
Distance between the exit side opening of the waveguide structure and the diffusion plate: 2.4 mm
Diffuser thickness: 0.5mm
Distance between diffusion plate and liquid crystal display panel: 6.4 mm
Light transmission angle of LCD panel: γ = 7 °
Number of LED light sources and waveguide structures: 1 row by 3 columns Pitch of LED light sources and waveguide structures: 9 mm
Parameter value of condition (1) (BA) / (2L) = 0.0562
tan (γ / 2) = 0.0612
Therefore, the condition (1) is satisfied.

  According to Example 1, a 30 mm × 12 mm size liquid crystal display panel could be favorably backlit, and a bright, clear and uniform brightness image could be displayed.

Incident side opening of waveguide structure: square shape Ax × Ay = 4 mm × 4 mm
Output side opening portion of waveguide structure: rectangular shape Bx × By = 8.5 mm × 9.5 mm
Distance between LED light source and incident side opening of waveguide structure: 0.5 mm
Waveguide length: L = 45mm
Distance between the exit side opening of the waveguide structure and the diffusion plate: 2.4 mm
Diffuser thickness: 0.5mm
Spacing between diffusion plate and liquid crystal display panel: 2.6 mm
Light transmission angle of liquid crystal display panel γx = γy = 7 °
Number of LED light sources and waveguide structures: 2 columns and 3 rows Pitch of LED light sources and waveguide structures (Χ / Y): 9 mm / 10 mm
Parameter value of conditions (2) and (3) (Bx−Ax) / (2L) = 0.05
tan (γx / 2) = 0.0612
(By-Ay) / (2L) = 0.0611
tan (γy / 2) = 0.0612
Therefore, the conditions (2) and (3) are satisfied.

  According to Example 2, a liquid crystal display panel having a size of 30 mm × 25 mm could be favorably illuminated, and a bright, clear and uniform brightness image could be displayed.

  As a modification of the present invention, as shown in FIG. 4, a combination of a plurality of LED light sources that are closely combined can be made to correspond to one waveguide structure. FIG. 4A is an example in which two LED light sources 10a and 10b are closely combined, and FIG. 4B is an example in which three LED light sources 10a, 10b and 10c are closely combined, FIG. (C), (d) is an example in which four LED light sources 10a, 10b, 10c, 10d are intimately combined. Thus, when a plurality of LED light sources are closely combined, the direction of the chief rays from the light sources is the direction of “virtual line that passes through the position of the center of gravity of each LED light source light emitting unit and is orthogonal to the light emitting surface” ( It is assumed that it is indicated by a symbol Ax in the figure).

It is a figure for demonstrating the structure of a liquid crystal display device. It is a figure for demonstrating the embodiment of a liquid crystal display device. It is a figure which shows three examples of the arrangement | sequence of a waveguide structure in the case of arranging and forming several waveguide structure in the integral material. It is a figure which shows four examples in the case of combining a some LED light source closely.

Explanation of symbols

10 LED light source 13 Waveguide structure 15 Diffusion plate 20 Liquid crystal display plate

Claims (7)

A backlight illumination device for illuminating a liquid crystal display panel from the back side,
Having at least one unit of an illumination unit having the same configuration with a single LED light source and a waveguide structure for guiding the light from the LED light source to enhance the directivity of illumination light as one unit;
A diffusion plate is disposed between the one or more illumination units and the liquid crystal display plate, and diffuses light emitted from each LED light source and guided by a corresponding waveguide structure at a predetermined diffusion angle. And
The waveguide structure performs waveguide by a reflecting surface having a hollow waveguide space and no curvature in the waveguide direction, and the exit side opening is larger than the entrance side opening.
A backlight illuminating device, wherein a principal ray from the LED light source substantially coincides with a waveguide center line of a waveguide structure corresponding to the LED light source, and the principal ray is substantially orthogonal to the diffusion plate. The backlight illumination device according to claim 1,
A backlight illumination apparatus, wherein a plurality of illumination units are arranged one-dimensionally or two-dimensionally according to the size and shape of a liquid crystal display panel to be illuminated uniformly. The backlight illumination device according to claim 1 or 2,
The entrance side opening and the exit side opening of the waveguide structure are square-shaped,
The diameter of the incident side opening: A, the diameter of the exit side opening: B, the waveguide length: L, the transmission half angle of the liquid crystal display panel to be illuminated: γ, the conditions:
(1) 0 <(BA) / (2L) ≦ tan (γ / 2)
A backlight illumination device characterized by satisfying The backlight illumination device according to claim 1 or 2,
The entrance-side opening and the exit-side opening of the waveguide structure are rectangular,
Length of two orthogonal sides of incident side opening: Ax, Ay (≠ Ax), Length of two orthogonal sides of exit side opening: Bx, By (≠ Bx), waveguide length: L, liquid crystal to be illuminated The transmission half angle of the display panel: γx, γy is the condition:
(2) 0 <(Bx−Ax) / (2L) ≦ tan (γx / 2)
(3) 0 <(By-Ay) / (2L) ≦ tan (γy / 2)
A backlight illumination device characterized by satisfying The backlight illumination device according to claim 1 or 2,
The entrance-side opening and the exit-side opening of the waveguide structure are similar to each other, and the area ratio of the upper entrance-side opening and the exit-side opening is A ² : B ^2. L, the transmission half angle of the liquid crystal display panel to be illuminated: γ is the condition:
(4) 0 <(BA) / (2L) ≦ tan (γ / 2)
A backlight illumination device characterized by satisfying In the backlight illuminating device according to any one of claims 1 to 5,
The diffusion plate is a directional diffusion plate that scatters in a Gaussian manner in the ± 10 ° direction, and the liquid crystal display plate to be illuminated is a TFT liquid crystal display plate that transmits light in the ± 7 ° direction. Backlight lighting device. A liquid crystal display device that displays an image by illuminating a liquid crystal display panel from the back side with a backlight illumination device,
A backlight illuminating device according to any one of claims 1 to 6, wherein a diffuser plate of the backlight illuminating device and a liquid crystal display plate are disposed so as to face each other substantially in parallel. Display device.

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