Uniform illumination of interactive display panel

• US 7,515,143 B2
• Filed: 02/28/2006
• Issued: 04/07/2009
• Est. Priority Date: 02/28/2006
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bathiche, Steven N., Keam, Nigel S.
• Primary Examiner(s): Awad; Amr
• Assistant Examiner(s): PELLIGRINO, JEFFREY S
• Application Number:
  US11/364,319
• Publication Number:
  US 20070200970A1
• Time in Patent Office: 1,134 Days
• Field of Search: 345/156, 345/157, 345/158, 345168-172, 345/173, 345/175, 178/18.01, 178/18.09, 178/19.01, 178/19.05
• US Class Current: 345/175
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An interactive display device employing a flat panel display (FPD). The interactive display device includes a housing, a flat panel display, a light diffusing layer, a visible light illumination system, and a non-visible light illumination system that is used for detecting objects adjacent to the FPD. Techniques are also described for providing uniform illumination of the FPD with visible light, when viewed from a plurality of viewing angles by a user, and for diffusing the visible illumination at a surface boundary of the FPD, such that a coherent image of an interior of the housing is at least partially obscured from view by the user. Non-visible light that has passed through the FPD is reflected from objects adjacent to the display, passes back through the FPD, and is detected within the housing.

Claims

1. A method for providing substantially uniform illumination of a liquid crystal display (LCD) panel that is located at a viewing surface of an interactive display, whereby the LCD panel is uniformly illuminated such that graphical output of the LCD panel is homogenously illuminated and visible to a user, regardless of the user'"'"'s viewing angle with respect to the viewing surface and without the effects of parallax that may otherwise cause the user to perceive darkened areas in the LCD panel when viewing the interactive display from certain angles, and for detecting objects that are in contact with or in close proximity to a user interface layer of the viewing surface of the interactive display, comprising the steps of:

(a) illuminating the LCD panel of the interactive display with visible light that has been emitted and diffused by an illumination system, and such that illumination of the LCD panel and of the corresponding viewing surface of the interactive display is substantially uniform when the viewing surface of the interactive display is viewed from a plurality of substantially different viewing angles, wherein the illumination system used to illuminate the LCD panel with visible light in a substantially uniform manner comprises;

a light guide assembly that includes a visible light illuminant and a light guiding layer, wherein the light guiding layer is a physical material directly coupled to the visible light illuminant and that is configured to conduct the light emitted from the visible light illuminant;

a diffusing layer comprising one or more light diffusing layers or collimating lenses configured to condition visible light emitted from the light guide assembly and to transmit diffused light to the LCD panel in order to effectively illuminate the LCD panel; and

a backplane layer;

wherein at least the physical material of the light guiding layer is interposed between the diffusing layer and the backplane layer and wherein the light guide assembly is positioned in direct physical contact with both of the backplane layer and the diffusing layer;

wherein the visible light for illumination of the LCD panel is generated by the following;

the visible light illuminant illuminating the light guiding layer with generated visible light;

the backplane layer substantially reflecting portions of the generated visible light away from the backplane layer and back into the light guiding layer towards the diffusing layer; and

the one or more light diffusing layers or collimating lenses of the diffusing layer conditioning the generated visible light, such that when the generated visible light leaves the illumination system and illuminates the LCD panel, the LCD panel is substantially uniformly illuminated;

(b) diffusing the visible light received at the viewing surface of the interactive display with a layer of diffusing material such that an object below the viewing surface of the interactive display is at least partially obscured from view by the user; and

(c) illuminating the viewing surface of the interactive display with non-visible light for use in detecting objects disposed in contact with or adjacent to the user interface layer of the viewing surface, wherein the viewing surface of the interactive display is composed of materials that are substantially transparent to the non-visible light such that reflected non-visible light, which has passed through the viewing surface of the interactive display and has been reflected back into the interactive display from the objects in contact with or adjacent to the user interface layer of the viewing surface, is detected.

2. An interactive display system that provides for detection of objects that are disposed adjacent to a user interface surface while simultaneously providing for homogeneous illumination with visible light of a liquid crystal display (LCD) panel such that graphical output of the LCD panel is uniformly illuminated and visible by a user from a plurality of viewing angles without perceived dark areas that may otherwise occur as a result of parallax, the interactive display system comprising:

an interactive display housing;

a user interface surface, which is part of a viewing surface of the interactive display system;

a first light diffusing layer, which is part of the viewing surface of the interactive display system, and which obscures, from view of the user, components of the interactive display system that are below the viewing surface and not intended to be seen;

a liquid crystal display (LCD) panel, which is part of the viewing surface of the interactive display system;

an illumination system, which generates the homogeneous illumination with visible light of the LCD panel, wherein each component of the illumination system is directly coupled to at least one other component of the illumination system, the illumination system comprising

a light guide assembly that includes a visible light illuminant and a light guiding layer, wherein the light guiding layer includes a physical material that is directly coupled to the visible light illuminant and that is configured to conduct the light emitted from the visible light illuminant;

a second diffusing layer comprising one or more light diffusing layers or collimating lenses configured to condition visible light emitted from the light guide assembly and to transmit diffused light to the LCD panel in order to effectively illuminate the LCD panel; and

a backplane layer;

wherein at least the physical material of the light guiding layer is interposed between the second diffusing layer and the backplane layer and wherein the light guide assembly is positioned in direct physical contact with both of the backplane layer and the second diffusing layer;

a non-visible light illumination system for illuminating the objects that are adjacent to the user interface surface with non-visible light that has passed from the non-visible light illumination system through the viewing surface of the interactive display system; and

a sensor for detecting non-visible light that is reflected back through the viewing surface of the interactive display system from the objects that are adjacent to the user interface surface.

3. The interactive display system of claim 2, wherein the second diffusing layer of the illumination system is a Fresnel lens configured to condition visible light emitted from the light guide in order to provide uniform illumination to the LCD panel.

4. The interactive display system of claim 2, wherein the light guiding layer comprises an acrylic sheet, and wherein the visible light illuminant comprises at least one of a fluorescent tube or an LED positioned along an edge of the acrylic sheet light guiding layer such that light emitted from the light illuminant is caused to be guided by the acrylic sheet.

5. The interactive display of claim 2, wherein the illumination system is disposed immediately adjacent to the LCD panel.

6. The interactive display system of claim 2, wherein the illumination system is substantially spaced apart from the LCD panel.

7. The interactive display system of claim 6, wherein a main portion surface area of the illumination system comprises the surface area of a topmost layer of the illumination system, and wherein the main portion surface area of the illumination system is substantially greater than a surface area of the LCD panel such that illumination of the LCD panel is substantially uniform when viewed from a plurality of viewing angles by a user.

8. The interactive display system of claim 6, wherein the illumination system further comprises side portions being reflective of visible light and being disposed perpendicular to a main portion of the illumination system and extending from the main portion to the user interface surface thereby forming a closed illumination system with the LCD panel and the user interface surface such that illumination of the LCD panel is substantially uniform when viewed from a plurality of viewing angles by a user.

9. The interactive display system of claim 6, wherein a main portion of the illumination system is substantially curvilinear such that a continuous surface is formed extending to the user interface surface from a center point of the main portion thereby forming a closed illumination system with the LCD panel and user interface surface such that illumination of the LCD panel is substantially uniform when viewed from a plurality of viewing angles by a user.

10. The interactive display system of claim 6, wherein the illumination system further comprises illuminated side portions disposed substantially perpendicular to a main portion of the illumination system and extending to the viewing surface of the interactive display system from the main portion of the illumination system to form a closed illumination system with the LCD panel such that illumination of the LCD panel is substantially uniform when viewed from a plurality of viewing angles by a user, wherein the illuminated side portions are similar in composition to the main portion of the illumination system such that each comprise the light guide assembly, including the second diffusing layer, and the reflective backplane.

11. The interactive display system of claim 2, wherein the non-visible light illumination system comprises a plurality of infrared illuminants disposed within the interactive display housing for illuminating the interactive display surface with infrared illumination and wherein the sensor for detecting non-visible light comprises a digital camera sensitive to infrared illumination.

12. The interactive display of claim 5, wherein the illumination system is immediately adjacent and coupled to the LCD panel and comprises:

the light guide assembly having the visible light illuminant configured to illuminate at least one edge of the light guiding layer with visible light;

the second diffusing layer comprising at least one Fresnel lens and at least one light diffuser; and

the backplane comprising a cold mirror that is specifically configured to allow passage of the reflected non-visible light through the cold mirror, which is reflected from the objects to the sensor, and while causing visible light generated by the light guide assembly to be reflected away from the sensor.

13. The interactive display of claim 2, wherein the first diffusing layer is interposed between the user interface surface and the liquid crystal display (LCD) panel.