Plane-like lighting units and display equipment provided therewith

• US 20030202363A1
• Filed: 04/01/2003
• Published: 10/30/2003
• Est. Priority Date: 08/31/2000
• Status: Active Grant

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Adachi, Masaya, Endo, Shusuke, Hiyama, Ikuo, Tsumura, Makoto
• Granted Patent: US 6,709,122 B2
• Time in Patent Office: Days
• US Class Current: 362/558
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G02B 6/0076 Stacked arrangements of multiple light guides of the same or different cross-sectional area
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3426 : the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 : Control of matrices with row and column drivers
• CPC Class Codes: Y10S 362/80 : Light emitting diode
• CPC Class Codes: Y10S 385/901 : Illuminating or display apparatus

Abstract

A lighting unit is provided which comprises: a plurality of linear light sources arranged in parallel; light-guiding plates arranged along said light sources; light diffusion means arranged at the top of said light sources and light-guiding plates; and reflection means arranged at the bottom of the light sources; wherein said lighting unit is characterized in that the surface of each light-guiding plate is flat, in that the reverse side of the light-guiding plate includes an inclined face of a curvilinear shape that thins down as the inclined face is more distanced from the light source, and in that when a position relatively near the light source and a position relatively far from the light source, on the reverse side of the light-guiding plate, are inclined by θn1 and θf1, respectively, the relationship of θn1≧θf1 is satisfied and the angle-of-inclination of the thinnest portion on the reverse side of the light-guiding plate is 0 degrees. With this arrangement, supply of a thin lighting unit that is high in luminance and in the in-plane uniformity of luminance can be obtained.

Claims

1. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a plurality of light-guiding plates arranged along both longitudinal sides of said light sources,

a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that the side of the light-guiding plate that faces the light diffuse reflection means is flat, in that the cross section of the light-guiding plate includes an inclined face of a curvilinear shape that thins down as the inclined face is more distanced from the light source, and in that when a position relatively near the light source and a position relatively far from the light source, on the surface of the light-guiding plate, are inclined by θ

n2 and θ

f2, respectively, with respect to the reverse side of the light-guiding plate, the relationship of θ

n2≧

θ

f2 is satisfied and the angle-of-inclination of the thinnest portion on the surface of the light-guiding plate is essentially 0 degrees.

5. A lighting unit according to claim 1 or 3 above, wherein, when the height of the side portion next to said light source is taken as h22 and the height from the end portion near the reflection plate at said side portion next to said light-guiding plate, to the thinnest portion on the surface of the light-guiding plate is taken as h12, the relationship of h12/h22≧

0.75 is satisfied.

14. A lighting unit according to claim 1 above, wherein fine particles different in refractive index are included in dispersed form in the materials constituting each of said light-guiding plates.

16. Display equipment comprising

a display panel that adjusts the transmittance of light, and

a lighting unit for supplying light to said display panel,

wherein said lighting unit is such unit as set forth in claim 1 above and the longitudinal direction of the bar-shaped light sources in the lighting unit is approximately parallel with respect to the lateral direction of the display panel.

17. Display equipment comprising

a display panel that adjusts the transmittance of light, and

a lighting unit for supplying light to said display panel,

wherein said lighting unit is such unit as set forth in claim 1 above and said display equipment has a means for controlling the light sources in the lighting unit according to the particular scanning status of the display panel.

2. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a light-guiding plate having a plurality of grooves to accommodate said light sources,

a light diffuse reflection means provided at either one side of said light-guiding plate,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of the light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that the side of the light-guiding plate that faces the light diffuse reflection means is flat, in that the cross section of the light-guiding plate includes an inclined face of a curvilinear shape that thins down as the inclined face is more distanced from the light source, and in that when a position relatively near the light source and a position relatively far from the light source, on the surface of the light-guiding plate, are inclined by θ

n2 and θ

f2, respectively, with respect to the reverse side of the light-guiding plate, the relationship of θ

n2≧

θ

f2 is satisfied and the angle-of-inclination of the thinnest portion on the surface of the light-guiding plate is essentially 0 degrees.

6. A lighting unit according to claim 2 or 4 above, wherein, when the depth of the side portion of the light source accommodation groove in said light-guiding plate is taken as h22 and the height from the end portion of said light source accommodation groove in the light-guiding plate to the thinnest portion on the surface of the light-guiding plate is taken as h12, the relationship of h12/h22≧

0.75 is satisfied.

3. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a plurality of light-guiding plates arranged along both longitudinal sides of said light sources,

a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that the side of the light-guiding plate that faces the light diffuse reflection means is flat, in that the cross section of the light-guiding plate includes an inclined face of a curvilinear shape that thins down as the inclined face is more distanced from the light source, and in that when a position relatively near the light source and a position relatively far from the light source, on the surface of the light-guiding plate, are inclined by θ

n2 and θ

f2, respectively, with respect to the reverse side of the light-guiding plate, the relationship of θ

n2≧

θ

f2 is satisfied and the angle-of-inclination of the thinnest portion on the surface of the light-guiding plate is essentially 0 degrees.

4. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a light-guiding plate having a plurality of grooves to accommodate said light sources,

a light diffuse reflection means provided at either one side of said light-guiding plate,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of the light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that the side of the light-guiding plate that faces the light diffuse reflection means is flat, in that the cross section of the light-guiding plate includes an inclined face of a curvilinear shape that thins down as the inclined face is more distanced from the light source, and in that when a position relatively near the light source and a position relatively far from the light source, on the surface of the light-guiding plate, are inclined by θ

n2 and θ

f2, respectively, with respect to the reverse side of the light-guiding plate, the relationship of θ

n2≧

θ

f2 is satisfied and the angle-of-inclination of the thinnest portion on the surface of the light-guiding plate is essentially 0 degrees.

7. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a light-guiding plate having a plurality of grooves to accommodate said light sources,

a light diffuse reflection means provided at either one side of said light-guiding plate,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of the light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that it is further provided with an optical path changing means at the side opposite to that which faces the light-guiding plate of the light diffuse reflection means.

9. A lighting unit according to claim 7 above, wherein said optical path changing means is a prismatic sheet having a curvilinear cross section of a corrugated shape at one side and a flat and smooth surface at the other side and the longitudinal direction with respect to said cross section is parallel to the axial direction of said light source.

8. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a plurality of light-guiding plates arranged along both longitudinal sides of said light sources,

a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a first light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that it is further provided with an optical path changing means at the side opposite to that which faces the light-guiding plate of the light diffuse reflection means.

10. A lighting unit comprising

a plurality of light source sets arranged in parallel, each consisting of two or more linear or bar-shaped light sources,

a light-guiding plate having a plurality of grooves to accommodate said light source sets,

a light diffuse reflection means provided at either one side of said light-guiding plate,

a light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of the light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means.

11. A lighting unit comprising

a plurality of light source sets arranged in parallel, each consisting of two or more linear or bar-shaped light sources,

light-guiding plates arranged along both longitudinal sides of said light source sets,

a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a first light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means.

12. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

a light-guiding plate having a plurality of grooves to accommodate said light sources,

a light diffuse reflection means provided at either one side of said light-guiding plate,

a first light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of the light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that a second light diffusion means is further located with a clearance at the side opposite to that which faces the light-guiding plate of the first light diffusion means.

13. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

light-guiding plates arranged along both longitudinal sides of said light sources, a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a first light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that a second light diffusion means is further located with a clearance at the side opposite to that which faces the light-guiding plate of the first light diffusion means.

15. A lighting unit comprising

a plurality of linear or bar-shaped light sources arranged in parallel,

light-guiding plates arranged along both longitudinal sides of said light sources, a light diffuse reflection means provided at either one side of each of said light-guiding plates,

a first light diffusion means provided at the side opposite to that which faces the light diffuse reflection means of each light-guiding plate, and

a light semi-transmitting reflection means provided between each light source and said light diffusion means,

wherein said lighting unit is characterized in that each of said light-guiding plates has a cross section made of laminated wedge-type plate-shaped members.