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Method and apparatus to project plain white image on screen with programmable transparency

IP.com Disclosure Number: IPCOM000235877D
Publication Date: 2014-Mar-28
Document File: 3 page(s) / 33K

Publishing Venue

The IP.com Prior Art Database

Abstract

During a presentation of any kind, many times there is a need to use the whiteboard either for Q/A session or to elucidate the material in an interactive way. This paper describes a method to project plain white image or adjust the transperancy of the image being projected.

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Method and apparatus to project plain white image on screen with programmable transparency

Method and apparatus to project plain white image on screen with programmable transparency.

During a presentation of any kind, many times there is a need to use the whiteboard either for Q/A session or to elucidate the material in an interactive way.

Case A

This generally cannot be done on the same whiteboard on which a slide is being projected using an LED/LCD projector, as it becomes too cluttered if the presented text/diagrams/charts interfere with the material drawn on whiteboard.

In such a scenario presenters commonly use two approaches

1) switch on the lights and turn off projector or

2) present a blank notepad on to screen.

   Case B
There is another case where the presented slide is required as reference while explaining the concept during an interactive session. As explained earlier, having slide material projected with something drawn on whiteboard makes it too cluttered to enable both (projected image and handwritten overlay) on the same whiteboard at the same time.

Below we propose a solution for both of these problems.

1) To have a function CleanSlate which can be invoked with a single button of the projector remote controller. This will directly project clean white light (blank image) on the screen for whiteboard interactive session, overriding the current content from the source connected to the projector.

2) To have another function TranSlate which will have a control over the transparency of image being projected on the whiteboard. This is achieved using two additional buttons on the remote, TranSlate+ (to increase) and TranSlate- (to decrease) the transparency. TranSlate+ at it's maximum level will be same as presenting the slide with zero percent transparency. TranSlate- at it's maximum level will be presenting only white light on screen which is similar to CleanSlate function mentioned above.

The above two functions can be achieved without additional consumption of power.

Technical Description

Fig. 1 shows a typical LCD projector.

Background

1


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Figure 1.

As shown in Fig.1 white light from the source is split into 3 basic colour sources that is Red,Blue and Green. These beams are then incident on 3 independent LCD panels. The transparency of each of the panels is adjusted based on the colour composition of each pixel. The light passing through three LCD panels in mixed in a dichroic prism and then it i...