Backlight Assembly And Display Device Having The Same

Abstract

A backlight assembly may include a light guide unit, a light source and a reflection module. The light source provides light onto an incident face of the light guide unit. The reflection module may include a first substrate having reflection regions, a lower electrode disposed in each reflection region, a switch element applying an on or off signal to the lower electrode, and an upper electrode. The upper electrode makes contact with or is spaced apart from a reflective face of the light guide unit in accordance with the on or off signal. Thus, light selectively exits the light guide unit through an exiting face of the light guide unit corresponding to each reflection region. A display device has a display module disposed on the exiting face of the light guide unit to display an image. Therefore, the display device has a simplified structure.

1 . A backlight assembly comprising:
 a light guide unit having an incident face and a reflective face;   a light source configured to provide light onto the incident face of the light guide unit; and   a reflection module disposed under the light guide unit and including a plurality of reflection parts movable in response to an electric signal so as to selectively reflect or scatter the light incident on the reflective face.   
   
   
       2 . The backlight assembly of  claim 1 , wherein each of the reflection parts is formed on a first substrate and comprises:
 a lower electrode;   an associated switch element disposed on the first substrate to apply an on signal or an off signal to an associated lower electrode; and   an upper electrode positioned on the lower electrode, the upper electrodes configured to contact the reflective face of the light guide unit in response to one of the on signal and the off signal received at the associated lower electrodes and to be separated from the reflective face of the light guide unit in response to the other of the on signal and the off signal received at the associated lower electrode.   
   
   
       3 . The backlight assembly of  claim 2 , wherein each of the upper electrodes comprise a protrusion configured to scatter incident light. 
   
   
       4 . The backlight assembly of  claim 2 , further comprising an optical member disposed between the light guide unit and the reflection module, the optical member having a refractive index greater than that of the light guide unit. 
   
   
       5 . The backlight assembly of  claim 4 , wherein the optical member makes contact with the reflective face of the light guide unit. 
   
   
       6 . The backlight assembly of  claim 4 , wherein the reflection module comprises:
 a first insulation layer formed on the lower electrode;   a second insulation layer supporting the upper electrode; and   a plurality of spacers formed between the first and second insulation layers to support the second insulation layer, the spacers positioned between adjacent lower electrodes.   
   
   
       7 . The backlight assembly of  claim 6 , wherein the second insulation layer comprises:
 a plurality of fixing portions each fixed to an upper portion of an associated spacer; and   a plurality of free portions, each of the free portions disposed between adjacent fixing portions so that the second insulation layer is bendable such that the upper electrode is capable of moving upwardly or downwardly.   
   
   
       8 . The backlight assembly of  claim 2 , wherein the reflection module further comprises:
 a plurality of first signal lines arranged on the first substrate in a first direction to apply a control signal to the switch elements, the control signal for each switch element configured to control the application of the on signal or the off signal to the associated lower electrode; and   a plurality of second signal lines arranged on the first substrate in a second direction crossing the first direction to apply the on signal or the off signal to the associated lower electrode.   
   
   
       9 . The backlight assembly of  claim 2 , wherein the light guide further includes an exiting face through which the light reflected or scattered by reflection module is capable of passing. 
   
   
       10 . A display device comprising:
 a light guide unit having an incident face and a reflective face;   a light source configured to provide light onto the incident face of the light guide unit;   a reflection module disposed under the light guide unit and including a plurality of reflection parts movable in response to an electric signal so as to selectively reflect or scatter the light incident on the reflective face; and   a display module disposed over the light guide unit to display an image using light from the light guide unit.   
   
   
       11 . The display device of  claim 10 , wherein the display module comprises color pixels formed in a plurality of pixel regions. 
   
   
       12 . The display device of  claim 10 , wherein each of the reflection parts is formed on a first substrate and comprises:
 a lower electrode;   an associated switch element disposed on the first substrate to apply an on signal or an off signal to an associated lower electrode; and   an upper electrode positioned on the lower electrode, the upper electrodes configured to contact the reflective face of the light guide unit in response to one of the on signal and the off signal received at the associated lower electrodes and to be separated from the reflective face of the light guide unit in response to the other of the on signal and the off signal received at the associated lower electrode.   
   
   
       13 . The display device of  claim 12 , wherein the reflection module comprises:
 a first insulation layer formed on the lower electrode;   a second insulation layer supporting the upper electrode; and   a plurality of spacers formed between the first and second insulation layers to support the second insulation layer, the spacers positioned between adjacent lower electrodes.   
   
   
       14 . The display device of  claim 13 , wherein the second insulation layer comprises:
 a plurality of fixing portions each fixed to an upper portion of an associated spacer; and   a plurality of free portions, each of the free portions disposed between adjacent fixing portions so that the second insulation layer is bendable such that the upper electrode is capable of moving upwardly or downwardly.   
   
   
       15 . The display device of  claim 9 , wherein the light guide unit comprises a first layer and a second layer disposed between the first layer and the reflection module, the second layer having a refractive index greater than that of the first layer. 
   
   
       16 . The display device of  claim 9 , wherein the light guide further includes an exiting face through which the light reflected or scattered by reflection module is capable of passing. 
   
   
       17 . A method of displaying an image, the method comprising:
 providing a light to a light guide unit having an incident face, a reflective face and an exiting face;   moving a reflection module so that the reflection part contacts the reflective face; and   reflecting or scattering the light incident onto the reflective face contacting the reflection module so that the light reflected or scattered by the reflection module passes through the exiting face.   
   
   
       18 . The method of  claim 17 , wherein the light incident onto the reflective face is reflected by an interface between the light guide unit and an air when the reflection module is spaced apart from the light guide unit. 
   
   
       19 . The method of  claim 17 , wherein the light reflected at the interface is incident onto the exiting face, and an incident angle of the light reflected by the interface is different from an incident angle of the light reflected or scattered by the reflection module when the lights are incident onto the exiting face.