Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – Plural light emitting devices
Reexamination Certificate
2002-06-18
2004-03-30
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
Plural light emitting devices
C257S088000, C257S089000, C257S098000, C257S099000, C257S040000, C257S773000
Reexamination Certificate
active
06713787
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to surface light-emitting devices, more specifically to a surface light-emitting device capable of using for an optical-input/output device and an image display device including a surface light-emitting device.
2. Description of the Related Art
Various devices for inputting/outputting light are known as light-input/output devices. In the light-input/output devices, both of beam generators such as flashlights, turn-signals used for an vehicle, optical pointers using laser beams and beam output part and the like in a laser printer, and image display devices and so on displaying visual information including images and characters in fixed manner and/or in dynamic manner, are used as devices for outputting light.
On the contrary, both of an optical pickup device and a bar-code reader and so on are used as a device for outputting light therefrom and inputting reflected light therethrough among the light-input/output devices. The optical pickup device and the bar-code reader may also be used as the beam generator because these include a beam output part.
Details of such light-input/output devices will be described hereunder by using an optical pickup device as an example. The optical pickup device is a device for reading out information recorded on a compact disc (hereinafter referred to as CD) and the like.
FIG. 41
is a conceptual view for describing a prior art optical pickup device PU. The optical pickup device PU comprises a laser diode LD, a half-mirror HM, a lens L, coils FC for carrying out auto-focus, a photo-detector S, and a control circuit CT.
A laser beams emitted from the laser diode LD and pass through the half-mirror HM reaches to the recording layer (not shown) of the CD after focusing with the lens L. Both the laser diode LD and the lens L form the beam output part. The light reflected by the recording layer is focused again with the lens L, and a part of the light reaches to the photo-detector S as a result of reflecting with the half-mirror IM. The data recorded on the recording layer are read out with the photo-detector S by detecting the amount of light detected thereby. The focal point of the laser beam can automatically be located on the recording layer of the CD by moving the lens L in a direction of X shown in the drawing with the coils FC.
The control circuit CT controls operations of all the laser diode LD, the coils FC and the photo-detector S according to a command from the outside while outputting the data read out thereby.
The conventional optical pickup device, however, has the following problems to be solved. The beam output part in the optical pickup device PU requires the lens L for focusing the laser beams in addition to the laser diode LD acting as the light source in consideration of such part. In order to carry out a proper focusing, positioning between the laser diode LD and the lens L need to be performed. Accordingly, it is difficult to make the beam output part smaller in size, and the manufacturing cost thereof may also be increased rapidly in accordance with its size.
FIG. 42
is a conceptual view for describing another prior art optical pickup device PU. The pickup device PU depicted in
FIG. 42
includes a laser diode LD, a half-mirror HM, a lens L, a photo-detector S, and a control circuit CT.
A laser beams emitted from the laser diode LD and pass through the half-mirror HM reaches on the recording layer (not shown) of the CD after focusing by the lens L. Both the laser diode LD and the lens L form the beam output part. Light reflected by the recording layer is focused again with the lens L, and a part of the light reaches to the photo-detector S as a result of reflecting with the half-mirror HM. The data recorded on the recording layer are read out with the photo-detector S by detecting the amount of light detected thereby.
The control circuit CT controls operations of all the laser diode LD, the coils FC and the photo-detector S according to a command from the outside while outputting the data read out thereby.
The conventional optical pickup device, however, also has the following problems to be solved. The optical pickup device PU requires the lens L for focusing the laser beams and the half-mirror acting as a beam-splitter in addition to the laser diode LD acting as the light source and the photo-detector S for detecting light because the pickup device PU outputs light to the outside thereof and receives reflected light thereby. In other words, the pickup device PU requires a lot of components. In order to carry out proper focusing, positioning among these components need to be performed. Accordingly, it is difficult to make the pickup device PU smaller in size, and the manufacturing cost thereof may also be increased rapidly in accordance with its size.
FIG. 43
is a conceptual view for describing a prior art laser printer LP. Laser printers are used for printing images and/or characters on a printing paper and the like.
The laser printer LP comprises a laser diode LD, a collimator lens CL, a polygon mirror (which has flat reflective surfaces around the perimeter) PM, a condensing lens L, and a photosensitive drum SD formed in a cylindrical shape. The surface of the drum SD is charged with electrostatic, and a part of the electrostatic on the drum is eliminated when light is directed on that part.
A laser beam emitted from the diode LD is collimated with the lens CL, and is reflected with the polygon mirror PM. Thereafter, the reflected beam reaches on the drum SD by focusing with the lens L. The diode LD, the lens CL, the mirror PM, and the lens L form the beam output part described earlier.
A laser beam is repeatedly scanned on the drum SD along with scanning lines SL in a direction such as top to bottom in the drawing because the polygon mirror PM is in rotation of a R
2
direction. The drum SD, on the contrary, is rotated in a R
3
direction synchronistical with the rotation of the polygon mirror PM as shown in the drawing. In this way, the laser beam is scanned all over the surface of the drum SD. As a result, the laser beam can be directed on predetermined areas of the drum SD by blinking the laser beam at a proper timing. In other words, electrostatic on the predetermined areas of the drum SD can be eliminated.
This allows printing of images and/or characters on a paper and the like by fixing images and/or characters after attracting toner on the area corresponding to existence of electrostatic on the surface of the drum SD.
The prior art laser printer, however, has the following drawbacks. Various optical components are needed such as the lens CL for collimating the beam, the polygon mirror PM for scanning the beam, and the lens L for focusing the beam, in addition to the diode LD acting as the light source in consideration of the beam output part in the printer LP. In order to carry out proper focusing, positioning among these components need to be conducted. Accordingly, it is hard to make the printer LP smaller in size, and the manufacturing cost thereof may also be increased rapidly in accordance with its size.
Mechanical rotation of the polygon mirror PM suppresses its rotation speed and decreases durability of the printer LP.
In addition to laser printers, image display devices for displaying visual information including images and characters in fixed manner and/or in dynamic manner such as light-emitting diode display (LED) devices, liquid crystal display (LCD) devices, plasma display devices, fluorescent display devices, are known.
FIG. 44
is a view illustrating an image displayed on a screen D in one of such conventional display devices. The transfer of information and/or propagation thereof such as advertisement can be carried out through the screen D.
However, the prior art image display devices described above have the following disadvantages. In these display devices, images and/or characters are just displayed on the screen D itself. In other words, these visual informations can not be reproduced on the screen D in three-d
Sai Hironobu
Tanaka Haruo
Flynn Nathan J.
Forde Remmon R.
Merchant & Gould P.C.
Rohm & Co., Ltd.
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