Talk:LCD projector

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How to setup a ceiling mounted LCD projector

Drill holes in ceiling, screw in projector bracket and mount projector, use long cables to plug projector into source material and power, grab some trunking pipe

I don't think this article does a good job of describing what part the LCD plays. Is it multiple LCDs? What do they do exactly? 213.100.90.101 (talk) 22:21, 9 November 2010 (UTC)[reply]

And here I thought LCD projector just a misnomer of video projector. 14:53, 20 July 2011 (UTC)

Hi,

The LCD concept has 3 lcd panels for each color (Red, Green, Blue). Each LCD manage the image in it's own color. Since there is only one light source, it's decomposed via color filters, pass trough the 3 lcd and then recombined trough a prism to reform the image. Misaligned lcd's is easy and can be seen like an old tv set on the corners that colors had shift.

I have pictures that I will (some day) put on the site for showing this. MaDCocktail — Preceding unsigned comment added by MaDCocktail (talk • contribs) 02:24, 1 March 2011 (UTC)[reply]

Proposed changes to History[edit]

It is doubtful whether Gene Dolgoff was the inventor of the LCD projector. He was certainly not alone in thinking about using LCDs as light valves^[1].

A patent application was filed in Switzerland on Dec. 3, 1971 by Brown, Boveri & Cie with Alfred de Quervain and Peter Wild as inventors entitled Information-bearing Devices and Projection Display Systems therefor and published as US Patent 3,895,866 on July 22, 1975. The invention was based on an LCD cell in the transmissive mode, addressed as a passive, direct-driven matrix display, its intersections acting as individual light valves, mounted in a slide frame of a traditional slide projector. At the time it was not yet possible to implement such matrix arrays with sufficient resolution (number of pixels) to project images of typical complexity. Therefore, a combination of a static image with only a few variable elements implemented as an LCD matrix was proposed for particular applications. The US patent examiner did not mention any prior art related to Gene Dolgoff.

Such an LCD projection system was explained and shown in operation at the SID conference in San Francisco, CA by Peter J. Wild of Brown, Boveri & Cie AG in 1972 ^[2].

Passive (without TFT), matrix-addressed LCDs with sufficient resolution for displaying typical images are not possible using either DSM or TN LCDs (excluding e-beam-addressing^[3]). The invention of the super-twisted nematic (STN) LCD by a team at Brown, Boveri & Cie, Switzerland, in 1983 provided the long awaited breakthrough. More than 60 companies became licensees of the corresponding patents (US 4,634,229). This is why Dolgoff finally could realize his ideas in 1984.

A TI report on the evolution of projection technologies mentions the Sharp Corp. of Japan as first in launching a commercial LCD color projector in 1989^[4].

I ask for comments before changing the article.

References[edit]

^ P. J. Wild, J. Nehring: Turn-on Time Reduction and Contrast Enhancement in Matrix-addressed Liquid-crystal Light Valves, Appl. Phys. Lett., vol. 19, no. 9, pp. 335-336, Nov. 1971
^ P.J. Wild, Matrix-addressed liquid crystal projection display, Digest of Technical Papers, International Symposium, Society for Information Display, June 1972, pp. 62-63
^ J.A. van Raalte, Reflective liquid crystal television display, Proc. IEEE, Vol. 56, No. 12, pp. 2146-2149, 1968
^ http://focus.ti.com/download/dlpdmd/166_History_Electronic_Proj_Tech_Hornbeck.pdf

Sorry, forgot to sign SwissLCD (talk) 16:26, 17 November 2012 (UTC)[reply]

External links modified[edit]

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History, invention claim by Dolgoff[edit]

A video on Youtube, created in 2018, was added as a reference to this lemma under the title: “Inventor Gene Dolgoff discusses his invention of the LCD projection”.[1]

Dogloff claims to be the inventor of LCD projectors. Although he might have had such ideas as a student, there is no evidence provided. To substantiate such a claim on WP, at least one reliable independent source or a patent granted would be needed as citation. He tells in that video, that he prepared a patent application in 1968 but did not file it. According to him, he included an LCD as light modulator in his design in 1971. However, the US Patent shown in the background of his video has been identified as US5012274A with a priority date of 1987-12-31 granted and published on 1991-04-30. Two patent searches on Espacenet and patents.google.com revealed no earlier patents by Eugene Dolgoff!!

If no additional info is provided to prove earlier work by Dolgoff, I will change the corresponding section to his later work when he was able to build a prototype.--BBCLCD (talk) 08:23, 25 September 2020 (UTC)--BBCLCD (talk) 14:01, 26 September 2020 (UTC)[reply]

[1] P. J. Wild, J. Nehring: Turn-on Time Reduction and Contrast Enhancement in Matrix-addressed Liquid-crystal Light Valves, Appl. Phys. Lett., vol. 19, no. 9, pp. 335-336, Nov. 1971

[2] P.J. Wild, Matrix-addressed liquid crystal projection display, Digest of Technical Papers, International Symposium, Society for Information Display, June 1972, pp. 62-63

[3] J.A. van Raalte, Reflective liquid crystal television display, Proc. IEEE, Vol. 56, No. 12, pp. 2146-2149, 1968

[4] ttp://focus.ti.com/download/dlpdmd/166_History_Electronic_Proj_Tech_Hornbeck.pdf

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