Dual-color frontlit displays with near uniform color mixing

• US 10,725,230 B1
• Filed: 04/18/2017
• Issued: 07/28/2020
• Est. Priority Date: 04/18/2017
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Jalava, Juho Ilkka
• Primary Examiner(s): Garlen, Alexander K
• Assistant Examiner(s): Eide, Eric T
• Application Number:
  US15/490,808
• Time in Patent Office: 1,197 Days
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

Systems, methods, and computer-readable media are disclosed for dual-color frontlit displays with near uniform color mixing. In one embodiment, an example device may include a light emitting diode (LED) array that includes a first LED that emits light having a first color and a second LED that emits light having a second color, and a light guide that includes a surface having a first portion adjacent to the first LED and a second portion adjacent to the second LED. The first portion may include a first number of binary element surface features formed on the surface, and the second portion may include a second number of binary element surface features formed on the surface. The first number of binary element surface features may be substantially parallel to a first direction of light emitted from the first LED, and the second number of binary element surface features may be substantially parallel to a second direction of light emitted from the second LED, wherein the second direction is substantially perpendicular to the first direction.

Claims

1. A device comprising:

a light emitting diode (LED) array comprising a first LED that emits light having a first color and a second LED that emits light having a second color; and

a light guide comprising a surface having a first portion adjacent to the first LED and a second portion adjacent to the second LED, wherein the first portion comprises a first plurality of binary element surface features formed on the surface, and the second portion comprises a second plurality of binary element surface features formed on the surface;

wherein the first plurality of binary element surface features comprises a first binary element with a first central axis that is substantially parallel to a first direction of light emitted from the first LED, and a second binary element with a second central axis that is substantially perpendicular to a second direction of light emitted from the second LED, wherein the first central axis and the second central axis form an obtuse angle; and

wherein the second plurality of binary element surface features comprises a third binary element, and a fourth binary element; and

wherein the first plurality of binary element surface features and the second plurality of binary element surface features comprise raised linear protrusions.

2. The device of claim 1, wherein the first central axis is substantially parallel to a central axis of the first LED.

3. The device of claim 1, wherein the light guide further comprises a third plurality of binary element surface features formed on a third portion of the surface that is disposed between the first portion and the second portion;

and

wherein the third plurality of binary element surface features comprises a fifth binary element oriented at a first angle and a sixth binary element oriented at a second angle.

4. The device of claim 1, wherein the LED array further comprises a third LED that emits light having the first color and a fourth LED that emits light having the second color, the device further comprising:

a driving circuit configured to provide a first amount of current to the first LED, the first amount of current to the third LED, and a second amount of current to the fourth LED;

wherein the third LED is in a parallel connection with respect to the first LED, and the fourth LED is in a series connection with respect to the first LED.

5. The device of claim 4, wherein the first amount of current is about half of the second amount of current.

6. The device of claim 1, wherein the light guide comprises a fourth portion disposed between the first portion and the second portion, and wherein the fourth portion is devoid of binary element surface features.

7. The device of claim 1, wherein the LED array further comprises a third LED that emits light having the first color and a fourth LED that emits light having the second color;

wherein the second LED is positioned between the first LED and the third LED; and

wherein the first color is an amber white color and the second color is a cool white color.

8. The device of claim 1, wherein the light guide further comprises a third plurality of binary element surface features formed on a third portion of the surface;

and

wherein the first plurality of binary element surface features has a first pattern density, and the third plurality of binary element surface features has a second pattern density.

9. The device of claim 8, wherein the first pattern density is less than the second pattern density.