Mua Tivi to nào vừa ngon vừa bổ lại vừa rẻ ???

nick149 · 30/11/10

Nguyenanhson said:

nick149 said:

Cái vụ ngon bổ rẻ này ban đầu mình không để ý lắm, nhưng vừa rồi ông CC mua con Pana Plasma 46X20V, cực rẻ, nhưng mà phân giải chì có 1024x768. Nhưng sau đó xem lại thông số, nó lại cho phép input 1920x1080p mới khiếp, qua đường HDMI. Mà dùng D-sub nó còn cho phép chỉnh lên 1125x1080 nữa chứ. Thế là sao hả các bác ? :? :shock: Ấn tượng ở chỗ là ... giá của nó cho con 46". Tự nhiên lại thấy ngứa tay.
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Nó nhận tín hiệu 1080 sau đó down xuống 1024x768 để thể hiện trên màn hình.
Với 46 inch ngồi xa 4 m khác biệt giữa 720 và 1080 là không đáng kể. Với màn từ 60 inch đặc biệt 100 ich đổ lên thì 1080 mới cực kỳ quan trọng.
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Thks bác, và mình mới thấy bên hdvn có nói về vụ này, hình như nó cho độ phân giải lên cao, nhưng phải set up lại hay sao ấy. Nếu dùng cổng D-sub thì nó có phải là dơn xuống ko vậy bác, vì nó rất rõ mà?

Nguyenanhson · 30/11/10

Không thể cao hơn được độ phân giải của màn hình đâu bác. độ phân giải thực vẫn là 1024x768 thôi nhưng thực tế mình xem các phim 1080 thì sắc màu và độ tương phản đẹp hơn các phim rip 720.
Với máy chiếu thì Nếu xem phim 720 trên may chiếu 1080 thì máy upscale lên 1080 rồi chiếu ra màn hình lúc này hình ảnh sẽ cho đẹp hơn là phim 720 chiếu trên máy chiếu 720.

themask · 30/11/10

Nguyenanhson said:

nhuthungfoto said:

GTC said:

Dưng mà tại sao em thấy thiên hạ toàn đi mua LCD, LED...không mua Plasma, chả nhẽ người ta lại ko hiểu bằng mình :shock:
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Anh yên tâm, phải dùng qua plasma rồi mới biết nó hơn như thế nào !
Em đã dùng qua LCD 40', LED 46"
Bây giờ em xem plasma FULL HD 50" và Plasma 42" Ready thấy mà khó quay trở lại với LCD, còn LED thì có thể xét lại nếu ... dùng dòng cao cấp
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Bổ sung thêm là nếu mục đích chủ yếu là xem phim HD thì máy chiếu là số 1. Ai đã từng xem máy chiếu với màn hình 100' sẽ mất hứng thú và cảm giác phim khi xem lại trên TV dù là dòng 60 inch
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Bác nói wa hợp ý e, các bác nào có kinh nghiệm và hiểu biết về các dòng máy chiếu thì tư vấn giúp ae luôn di ah

PERRY · 30/11/10

Bác cần tư vấn gì về máy chiếu ạ? Em mới lấy máy chiếu nên có tìm hiểu và cũng biết chút ít

Nguyenanhson · 1/12/10

Máy chiếu thì nói hơi miên man. Vấn đề là bác phải giới hạn tầm tiền bác định đầu tư là bao nhiêu?
Mình chỉ cảnh báo thế này:
Dòng DLP thì với một số người, trong đó có mình thấy có hiện tượng cầu vồng như kiểu thỉnh thoảng có ánh như váng dầu trên mặt nước thoáng qua trên màn ảnh. Một số người có cảm giác bị đau đầu khi xem. đa số thì không thất gì. Vì vậy trước khi xuống tiền thì nên đến xem thử loại này ở nhà bạn bè xem mình có bị nằm trong nhóm không tương thích với DLP không. DLP thường có thông số tương phản và sáng hơn loại 3LCD. Nhưng 3LCD lại thường cho màu trung thực và đẹp hơn. Hơn nữa nếu bạn có một phòng xem phim có thể che cửa sổ tối hoàn toàn như trong rạp thì đừng quá quan tâm đến độ sáng lớn hơn 1000lm làm gì. Càng sáng thì sắc đen càng thể hiện kém. Với 1 phòng đủ tối và màn chiếu phủ cát loại ngon thì độ sáng đo tại màn hình chỉ cần trên 400lm là đã chuẩn lắm rồi.
NHớ đừng tham rẻ mà mua loại máy chiếu 720 nhé. Bây giờ cứ phải chơi độ phân giải thực 1080 chứ không phải loại chấp nhận đầu vào 1080. lý do thì mình đã nói ở bài viết trước rồi

themask · 1/12/10

Nguyenanhson said:

Máy chiếu thì nói hơi miên man. Vấn đề là bác phải giới hạn tầm tiền bác định đầu tư là bao nhiêu?
Mình chỉ cảnh báo thế này:
Dòng DLP thì với một số người, trong đó có mình thấy có hiện tượng cầu vồng như kiểu thỉnh thoảng có ánh như váng dầu trên mặt nước thoáng qua trên màn ảnh. Một số người có cảm giác bị đau đầu khi xem. đa số thì không thất gì. Vì vậy trước khi xuống tiền thì nên đến xem thử loại này ở nhà bạn bè xem mình có bị nằm trong nhóm không tương thích với DLP không. DLP thường có thông số tương phản và sáng hơn loại 3LCD. Nhưng 3LCD lại thường cho màu trung thực và đẹp hơn. Hơn nữa nếu bạn có một phòng xem phim có thể che cửa sổ tối hoàn toàn như trong rạp thì đừng quá quan tâm đến độ sáng lớn hơn 1000lm làm gì. Càng sáng thì sắc đen càng thể hiện kém. Với 1 phòng đủ tối và màn chiếu phủ cát loại ngon thì độ sáng đo tại màn hình chỉ cần trên 400lm là đã chuẩn lắm rồi.
NHớ đừng tham rẻ mà mua loại máy chiếu 720 nhé. Bây giờ cứ phải chơi độ phân giải thực 1080 chứ không phải loại chấp nhận đầu vào 1080. lý do thì mình đã nói ở bài viết trước rồi
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E đang xài LCD của Pana thấy cũng được lắm nhưng không thỏa mãn thị nhãn H nhà đang xây, dự tính của e sẽ đầu tư môt máy chiếu cho phòng home threatre, trong khoảng 20t-25t liệu e có sắm được phun het de không ah :mrgreen:

Nguyenanhson · 1/12/10

Khoản đấy cố tý nữa thì chơi được Optoma HD20. đợi đến luc bạn xây xong nhà thì còn rẻ nữa

bv · 1/12/10

Anh Sơn ơi. Khoản đó thì mua được Epson 8100 rồi mà anh Sơn. Đến giờ này thì BV nghĩ là Optoma HD20 ta nên tạm quên nó. Optoma thì chỉ nên quan tâm đến vụ 3D thôi các anh ạ.

Optoma HD20 có giá từ 21 triệu đến 24 triệu (Thương hiệu Taiwan):

Epson 8100 full HD (Thương hiệu Nhật): shop BV 1.280$ đang giảm 5% còn: 1.216$ (26.250.000)

Cái máy nó to gấp đôi và nặng gấp 3 HD20. Hình ảnh đẹp cũng gấp nhiều lần. Chất lượng phải nói là rất tốt!

Hay quá, tự nhiên tìm được cái này trên mạng. Epson 8100 không to gấp đôi HD20, mà tới gấp 2.5 lận.

PERRY · 1/12/10

Em hoàn toàn đồng ý với chị BV. Đã dùng Epson rùi thì quên Optoma khẩn. Em đang dùng Epson EB-W8 độ phân giải 1280x800 nhưng giờ thấy 8100 full của chị lại thấy thích. 8100 có đẹp hơn W8 nhiều ko chị?

chuvoicon · 2/12/10

Theo em giữa máy chiếu LCD và DLP cũng giống như LCD và Plasma vậy,
Nếu để sử dụng như PC thì nên dùng LCD còn để xem phim như Home Theater thì nên dùng DLP
Nhưng giờ 2 dòng này cũng tiệm cận đến gần nhau về chất lượng rồi,
Cá nhân mình vẫn thích và ủng hộ DLP hơn, nếu có máy chiếu DLP 3 chip thì thôi rồi lượm ơi, nhưng giờ giá còn cao quá...

PERRY said:

Em hoàn toàn đồng ý với chị BV. Đã dùng Epson rùi thì quên Optoma khẩn. Em đang dùng Epson EB-W8 độ phân giải 1280x800 nhưng giờ thấy 8100 full của chị lại thấy thích. 8100 có đẹp hơn W8 nhiều ko chị?
Click to expand...

chuvoicon · 2/12/10

DLP có hệ số tương phản và độ sâu màu tốt hơn LCD --> đó là đặc tính về công nghệ, tuy nhiên giữa 2 món này bây giờ hầu như khó nhận ra vì các hãng đã tối ưu thiết kế của mình.
LCD cho màn hình sáng hơn DLP --> các máy chiếu bussiness thường là LCD vì đòi hỏi sử dụng trong môi trường ánh sáng mạnh như trình chiếu hội nghị, hội thảo... ai lại đi tắt hết đèn khi đang hội họp, ngại chết...
Nếu có điều kiện thì chơi 1080P thì quá OK rồi nhưng 720P cũng No problem, chất lượng về hình ảnh không quá chênh lệch nhiều nếu so cùng hãng với nhau, chơi Home Theater quan trọng nhất là độ tương phản thực phải cao để cho màu đen thật hơn, dải màu sắc thể hiện rộng và đúng màu còn độ phân giải cao không liên quan gì đến các thông số trên.

Nguyenanhson said:

Máy chiếu thì nói hơi miên man. Vấn đề là bác phải giới hạn tầm tiền bác định đầu tư là bao nhiêu?
Mình chỉ cảnh báo thế này:
Dòng DLP thì với một số người, trong đó có mình thấy có hiện tượng cầu vồng như kiểu thỉnh thoảng có ánh như váng dầu trên mặt nước thoáng qua trên màn ảnh. Một số người có cảm giác bị đau đầu khi xem. đa số thì không thất gì. Vì vậy trước khi xuống tiền thì nên đến xem thử loại này ở nhà bạn bè xem mình có bị nằm trong nhóm không tương thích với DLP không. DLP thường có thông số tương phản và sáng hơn loại 3LCD. Nhưng 3LCD lại thường cho màu trung thực và đẹp hơn. Hơn nữa nếu bạn có một phòng xem phim có thể che cửa sổ tối hoàn toàn như trong rạp thì đừng quá quan tâm đến độ sáng lớn hơn 1000lm làm gì. Càng sáng thì sắc đen càng thể hiện kém. Với 1 phòng đủ tối và màn chiếu phủ cát loại ngon thì độ sáng đo tại màn hình chỉ cần trên 400lm là đã chuẩn lắm rồi.
NHớ đừng tham rẻ mà mua loại máy chiếu 720 nhé. Bây giờ cứ phải chơi độ phân giải thực 1080 chứ không phải loại chấp nhận đầu vào 1080. lý do thì mình đã nói ở bài viết trước rồi
Click to expand...

Nguyenanhson · 2/12/10

bv said:

Anh Sơn ơi. Khoản đó thì mua được Epson 8100 rồi mà anh Sơn. Đến giờ này thì BV nghĩ là Optoma HD20 ta nên tạm quên nó. Optoma thì chỉ nên quan tâm đến vụ 3D thôi các anh ạ.

Optoma HD20 có giá từ 21 triệu đến 24 triệu (Thương hiệu Taiwan):

Epson 8100 full HD (Thương hiệu Nhật): shop BV 1.280$ đang giảm 5% còn: 1.216$ (26.250.000)

Cái máy nó to gấp đôi và nặng gấp 3 HD20. Hình ảnh đẹp cũng gấp nhiều lần. Chất lượng phải nói là rất tốt!

Hay quá, tự nhiên tìm được cái này trên mạng. Epson 8100 không to gấp đôi HD20, mà tới gấp 2.5 lận.

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Well Bích Vân! Không ngờ máy Epson 8100 bây giờ lại rẻ thế! Vậy Epson 8100 là lựa chọn số 1 rồi.
@ Chúvoicon: DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ.
Máy 1080 xem phim 720 thì OK bạn ạ. Nhưng máy 720 chiếu phim 1080 lại là một điều khác hẳn, pixel to đùng.

chuvoicon · 2/12/10

Bác cho em dẫn chứng hoặc thử nghiệm nhé:
DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ

Nguyenanhson said:

bv said:

Anh Sơn ơi. Khoản đó thì mua được Epson 8100 rồi mà anh Sơn. Đến giờ này thì BV nghĩ là Optoma HD20 ta nên tạm quên nó. Optoma thì chỉ nên quan tâm đến vụ 3D thôi các anh ạ.

Optoma HD20 có giá từ 21 triệu đến 24 triệu (Thương hiệu Taiwan):

Bác cho em dẫn chứng hoặc thử nghiệm nhé:
DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ

Epson 8100 full HD (Thương hiệu Nhật): shop BV 1.280$ đang giảm 5% còn: 1.216$ (26.250.000)

Cái máy nó to gấp đôi và nặng gấp 3 HD20. Hình ảnh đẹp cũng gấp nhiều lần. Chất lượng phải nói là rất tốt!

Hay quá, tự nhiên tìm được cái này trên mạng. Epson 8100 không to gấp đôi HD20, mà tới gấp 2.5 lận.

Click to expand...

Well Bích Vân! Không ngờ máy Epson 8100 bây giờ lại rẻ thế! Vậy Epson 8100 là lựa chọn số 1 rồi.
@ Chúvoicon: DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ.
Máy 1080 xem phim 720 thì OK bạn ạ. Nhưng máy 720 chiếu phim 1080 lại là một điều khác hẳn, pixel to đùng.
Click to expand...

nhuthungfoto · 2/12/10

Đang bàn về TV các bác lại chuyển qua máy chiếu :?:
Nhưng được cái ai cũng nhận xét rất đúng về xu hướng " nghĩ lớn nên nghĩ đến projector " ( em xin mượn câu slogan của Pana khi quảng cáo về plasma )

thanhchi · 2/12/10

nhuthungfoto said:

Đang bàn về TV các bác lại chuyển qua máy chiếu :?:
Nhưng được cái ai cũng nhận xét rất đúng về xu hướng " nghĩ lớn nên nghĩ đến projector " ( em xin mượn câu slogan của Pana khi quảng cáo về plasma )
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Trưa rảnh anh ra tư vấn em với. Đang nghĩ lớn đây. :mrgreen: :lol:

themask · 2/12/10

nhuthungfoto said:

Đang bàn về TV các bác lại chuyển qua máy chiếu :?:
Nhưng được cái ai cũng nhận xét rất đúng về xu hướng " nghĩ lớn nên nghĩ đến projector " ( em xin mượn câu slogan của Pana khi quảng cáo về plasma )
Click to expand...

Hehehe điều cơ bản là với dân nghiện AV thì LCD không tạo được cảm giác như đang ở trong rạp, mà e thì rất thích cảm giác được xem fim sống động như ở rạp :mrgreen:

Nguyenanhson · 2/12/10

chuvoicon said:

Bác cho em dẫn chứng hoặc thử nghiệm nhé:
DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ

Gửi bạn đọc tham khảo. Nếu bạn ở HP bạn có thể mang một cái máy chiếu DLP có cùng tầm tiền với máy chiếu Mitsubishi HC6000 của mình đến nhà mình để cùng thử nghiệm cho biết.

Weaknesses and limitations of DLP

Color wheels can produce rainbow artifacts. The problem people point to most frequently as a weakness in DLP is its tendency to produce "rainbow artifacts." Rainbow artifacts (sometimes referred to as color separation artifacts) are momentary flashes of banded color that look like rainbows. They occur at random, and they only last for an instant. But for people who are sensitive to them, they can be quite distracting. If you are engrossed in a film or video, they can take you entirely out of the video experience.

Rainbow artifacts are a problem only on single-chip DLP products, and for the most part, only those using slower speed color wheels. They can also occur on LED-based models due to the sequential strobing of red, green, and blue LEDs. Typically the problem manifests itself when the viewer is watching movies or video. When viewing static images such as presentation charts or photographs, people generally do not experience the problem.

The rainbows occur because of the sequential color updating from the wheel or LED. As the color wheel spins or the LEDs change, the image on the screen is either red, green, or blue at any given instant in time. The technology relies upon your eyes not being able to detect the changes from one to the other. However, when your eye moves rapidly in response to some movement in the picture, you can get a red, green, and blue update on three different points on your retina, thus producing the impression of a rainbow. Not everyone perceives rainbows the same way. Many people have less sensitive eyes and cannot detect rainbow artifacts at all. Others see them quite readily. There is no way to know whether you are among those who can or cannot see them except by watching a DLP projector yourself.

Since LCD projectors and 3-chip DLP projectors always deliver a constant red, green, and blue image simultaneously, they do not create rainbow artifacts.

On DLP projectors with color wheels, rainbow artifacts are reduced by increasing the speed of the wheel. The first generation DLP projectors incorporated a color wheel that rotated sixty times per second, or 3600 RPM. With one red, green, and blue filter in the color wheel, updates on each color happened 60 times per second. This rotation speed in the first generation products was known as a "1x" rotation speed. In second-generation DLP products, the color wheel rotation speed was doubled to 2x, or 7200 RPM. The doubling of the color refresh rate reduced the time between color updates, and so reduced the visibility of rainbow artifacts for most people. But a 2x rotation speed was still not fast enough for products to be used in home theater and video applications.

Today, some DLP projectors being built for the home theater market use a color wheel containing two sets of red, green, and blue filters. This wheel still spins at 7200 RPM, but because red, green, and blue are refreshed twice in every rotation rather than once, the industry refers to this as a 4x rotation speed. And by increasing the physical rotation speed beyond 7200 RPM, some projectors now have 5x or 6x speed wheels. For the large majority of users, the 5x and 6x speed wheels in most current home theater models have reduced rainbow artifacts in video display to the point where they are of little or no concern.

However, most DLP projectors built for commercial/presentation use still use 2x speed wheels because they are less expensive. This is perfectly fine if the presentation matter is static charts, graphics, photography, or anything that does not stimulate rapid eye movement. We do not recommend DLP projectors with 2x speed wheels to buyers for whom video display or part time home theater are important intended uses.

Color saturation/color brightness. Some DLP projectors have excellent color saturation, and some are exceptionally poor. This is related more to the vendor's implementation than anything inherent in the technology itself. Advocates of 3LCD technology have been quite vocal about the lack of color brightness on single-chip DLP products, particularly those that have white segments in the color wheel. This phenomenon is worth commenting on.

When a color wheel has a white (clear) segment, the lumen output of the projector is increased dramatically, and the ANSI lumen rating skyrockets. Most business class DLP products have white segments in the wheel to boost the all-important lumen rating. Conversely, most DLP projectors built for home theater have no white segments because they can compromise color saturation and the overall balance of the video image. Moreover, the lumen rating is not a big driving factor in the sale of home theater projectors.

When you use a light meter to measure the brightness of red, green, and blue on an LCD projector, the sum of the values usually adds up to the brightness reading you get for white. This makes sense because on an LCD projector, white is created by turning the red, green, and blue channels all fully on. But on a DLP projector, this is often not the case. Due to the presence of a white segment in the wheel, the white reading can be as much as double the sum of the brightness readings for red, green, and blue. In other words, if an LCD projector measures 2000 lumens of white light, you will also get 2000 lumens of color light out of it. If a DLP projector measures 2000 lumens of white, you might get only 1000 lumens of actual color light from it, the rest being white light.

Because of this, proponents of 3LCD technology have been lobbying for color brightness specs to be included along with ANSI lumen specs on the industry's specification sheets, and support for this has been building in the industry. In the spec wars, quite clearly this would be one metric on which LCD has a commanding advantage over DLP. Not surprisingly, Epson and Sony have already begun to publish color brightness specs on their LCD projectors to drive home the point. The color spec is always the same as the ANSI lumen rating, and the specs will read, as an example, "2600 lumens color light output, 2600 lumens white light output."

As a rule, DLP projectors with a white segment in the wheel do not look very appealing when measured for color brightness. The color reading always fall short of the white reading, and sometimes it falls short by 50% or more. This is especially true when the color wheel contains the basic red, green, blue, and white filters only. Many DLP projectors have complementary color filters such as cyan, magenta, and yellow. In this situation the color brightness measurements become more problematic. Thus we can understand why Texas Instruments and the DLP projector vendors have little interest in publishing color brightness specifications.

From a practical perspective, we have mixed feelings about all of this. Clearly, the 3LCD camp is correct that the traditional ANSI lumen spec does not tell the whole story. But neither does the color brightness spec. To be sure, the color on some DLP projectors looks dull and anemic next to some LCD models of the same lumen rating. Ironically, this can be particularly true when the "BrilliantColor" feature is enabled. Though BrilliantColor boosts the brightness of the image, it can substantially reduce color saturation in the process. It is peculiar that in order to get the richest and most saturated color from many DLP projectors, one needs to turn BrilliantColor off. (This is not universally true of all DLP projectors with BrilliantColor, since the BrilliantColor system can behave quite differently based on how it is implemented by the vendor.)

Oddly enough, on some DLP models with white segments in the wheel, even those on which color brightness falls far short of white, we see a rich, vibrant color that can easily match an LCD projector in the same price and lumen class. One reason is that the color filter configuration of the wheel has a lot to do with the end results. Another reason is that, though the DLP's color brightness may fall short of white, the effect of the DLP's inherent contrast advantage helps to compensate for it. That compensating effect cannot be quantified in a spec. Even when color brightness falls very far short, the picture sometimes does not end up looking much dimmer at all when put side by side with an LCD projector of the same white light output.

When a DLP projector's color vibrancy looks poor next to a comparably priced and spec'd LCD projector, it is due to a variety of design and product cost decisions made by the vendor, and not anything inherent to DLP technology per se. DLP can look truly spectacular or downright dismal depending on what is done with it. With so many variables in play, the specs can't tell the whole story, even if a color brightness spec were added to the mix. The publication of color brightness specs would be interesting, and would certainly draw attention to a noteworthy technical difference between LCD and DLP. But it is not conclusive information that would help an astute buyer sort out which model to buy.

Dithering artifacts. At any moment in time, each mirror position on a DLP chip is either fully on to render maximum brightness, or fully off to render black. There is no way a DLP mirror can be "partially on" to represent gray, like an LCD liquid crystal can. Therefore, the way the DLP chip renders gray is to flip the mirrors on and off very rapidly, such that they are on just enough of the time for the eye to average the "on's and off's" to a desired level of perceived brightness. This approach to rendering grays is called dithering. It works well enough for rendering gray values, but it can produce some visible instability in solid fields, mostly dark areas, referred to as dithering artifacts. It looks like digital noise, but it is a separate type of artifact caused by DLP technology itself, and not by the signal.

Dithering artifacts do not occur on LCD products because there is no dithering used to achieve varying levels of gray. The liquid crystals can be either fully open, or closed, or partially opened at intermediate positions to achieve the desired level of light transmission--again, similar in concept to shutters on a window.

Restricted compatibility with zoom lenses and lens shift. Due to the nature of DLP light engine mechanics, it is difficult for vendors to incorporate long zoom lenses or extended range lens shift features into a DLP projector. These limitations are not relevant in mobile presentation projectors since the primary design objective is small physical size, so none of them have big zooms or lens shift anyway. But in the home theater market in particular, LCD vendors have captured significant market share in part due to their ability to incorporate long 2.0x zoom lenses and extensive lens shift capability into LCD projectors. This makes it much easier for the consumer to install the projector anywhere they want, which is quite frequently on a rear shelf in the room. Due to lens restrictions on DLP projectors it is rare to be able to install a DLP model on a rear shelf.

The Advantages of 3LCD

Many of the advantages and limitations of 3LCD have already been touched on above within the context of the DLP discussion. However, there are several advantages of LCD not yet discussed, and some of the issues already noted warrant a recap and/or further expansion. The following are the key benefits of LCD technology:

Better price/performance in HT products. The primary key to the success of LCD products in the home theater market is their tremendous price advantage. In the 1080p niche in particular, LCD products deliver outstanding image quality performance for the money. Moreover, they are generally loaded with extra features that don't appear on DLP models in the same price range, if they are offered on any DLP model at all.

The price advantage of LCD over DLP is most obvious in consumer/home theater products. There is no similar disparity in pricing on commercial products built for mobile presentation and conference room use. One reason is that DLP makers can use the cheaper 2x speed wheels on most business products, whereas it is mandatory to have high speed color wheels and the faster electronics associated with them on products designed for home theater.

Higher contrast in HT products. Many LCD projectors built for home theater have achieved better overall contrast performance and deeper black levels than DLP models. This is specifically the case on LCD models using inorganic LCD panels and auto iris technology. Inorganic panels are more expensive to produce, so they are not used in cheaper, commercial grade business projectors. They achieve higher contrast due in part to the fact that the resting position of the liquid crystal is closed (i.e., black), and voltage is required to open it. This is the opposite of traditional organic LCDs wherein the resting position is open (maximum light transmission), and voltage is required to close it. The inherent contrast advantage of inorganic panels has made LCD substantially more competitive in the home theater marketplace. ANSI contrast in particular has seen significant improvement. In our measurements, LCD projectors with organic panels typically run in the range of 250:1 ANSI contrast, whereas the models with inorganic panels have been reaching performance levels of 400:1 to 450:1.

3LCD vendors have been aggressive in developing effective auto iris systems which contribute an incremental perceived contrast advantage on screen. There is no technical restriction that we know of that would prohibit DLP vendors from doing the same thing. But it would add further cost to DLP projectors that are already at an apparent cost disadvantage relative to LCD in the home theater market. There is also a perception among vendors that DLP contrast, while not leading edge, is sufficient, so enhancement via auto iris is not vital. Thus, most DLP vendors have been slow to incorporate auto iris systems on DLP projectors being marketed for home theater.

Fewer artifacts/greater image stability. As noted previously, dithering artifacts and rainbow artifacts are unique to single-chip DLP projectors. Since these artifacts do not exist on LCD products, it is not unusual to perceive a more stable video image on an LCD projector when viewed side by side with a DLP counterpart in a similar price and performance class. The LCD's video image can look cleaner and more free of noise.

Sharper image with data display. Since LCD pixel structure is more sharply defined that DLP pixel structure, it tends to render a sharper image. This is most noticeable in lower resolution business products (SVGA and XGA), and specifically with data display. It is in these resolutions that LCD's screendoor effect is somewhat more visible in a video image, but the advantage is that the sharper pixel definition can produce a sharper display of data. By comparison, a DLP projector in SVGA and XGA resolution can look a bit soft when displaying data images.

On higher resolution products the difference in apparent sharpness is minimal, and it is a non-issue with video display on 1080p products. Both technologies can produce very sharp images in 1080p, and any perceived differences in sharpness typically have to do with factors unrelated to the display technology, such as lens quality and video processing.

Greater installation flexibility in HT products. LCD projectors built for home theater often feature 2.0x zoom lenses and extensive vertical and horizontal lens shift. This makes them easy to install just about anywhere. By comparison, DLP projectors usually have short zooms with little or no lens shift. Fixed throw angles limit the projection geometry, and often dictate where a DLP projector must be placed in order to accommodate a given screen size and location.

For the DIY home theater enthusiast on a budget, the lens flexibility of LCD models has great appeal. For the fact is, most DLP projectors need to be ceiling mounted, and most LCD projectors don't. Thus they save the extra cost of a ceiling mount and long run video cables. They also eliminate the prospect of having to run cables through walls and ceiling, or living with an unsightly track of cables across the ceiling.

Better light efficiency, less power usage. LCD technology is inherently more light efficient. For the most part LCD projectors use lower wattage lamps to produce the same image brightness that you'd get from DLP. This is most noticeable when comparing LCD projectors to DLP projectors that have no white segment in the color wheel. As an example, compare two currently popular 1080p home theater projectors--the Panasonic AE3000 LCD projector uses a 165-watt lamp to produce 1600 ANSI lumens. Meanwhile, the Sharp Z15000 DLP projector needs a 250-watt lamp to get the same 1600 lumens. That can make a noticeable difference in power consumption. It can also make a difference in the amount of heat being generated by the projector's exhaust in the viewing room.

Weaknesses and Limitations of LCD

Unknown lifespan of LCD panels. Given enough prolonged exposure to high intensity UV light and extreme heat, the organic compounds used in most LCD panels are expected to degrade over long periods of time. This degradation can lead to a discoloration of the image and a reduction in contrast. The only way to fix it is to replace the damaged LCD panel, which is typically a cost-prohibitive proposition. You are normally better off buying a new projector.

The big question of course is how long the panels will last. There is no good data on this subject that has been compiled by an independent lab and published for general consumption. LCD vendors do not typically acknowledge LCD degradation can occur, so they don't make any representations about expected life. In general, most LCD vendors maintain that to the degree LCD panels might be subject to eventual degradation, it will be beyond the practical life of the product.

One trusted and very experienced industry source who develops products using both LCD and DLP technology believes that LCD panels have a lifespan in the range of 4,000 to 10,000 hours, with the lifespan depending on how bright the projector is--the brightest LCD light cannons will produce the most stress on the panels resulting in quicker degradation. Low brightness models such as those made for home theater will produce the least stress, and are expected to last longer.

Texas Instruments has performed several tests on LCD lifespan over the past seven years. Based on these tests, they believe that LCD panels will degrade faster than the LCD vendors are willing to admit, and certainly more quickly than the 4000 hours just quoted. The 3LCD camp's response is that TI's tests have been performed by running LCD projectors continuously 24 hours a day, 7 days a week, for several months straight. According to 3LCD and Epson, since the projectors used in TI's lab tests were never designed for a continuous operation high-stress duty cycle, the results are not indicative of what the typical user would experience.

The introduction of inorganic LCD panels is an important new development that is germane to this issue. Inorganic LCD panels, in theory, should not be subject to the same degradation patterns as organic LCDs, simply because the organic compounds that fail under intense heat and UV light are not present in inorganic LCDs. However, the LCD camp will not confirm or deny any anticipated differences in panel life because as a matter of policy they do not discuss the issue at all. Texas Instruments has not commented on the expected lifespan of inorganic LCDs either.

Lower contrast ratings in business products. Most commercial and education LCD projectors are made with the relatively inexpensive organic LCDs and no auto-iris. Contrast ratings on these models typically run in the 400:1 to 700:1 range. Meanwhile, DLP projectors in the same resolution, lumen, and price class can often be rated at 2000:1 or higher.

In reality, this constitutes more of a marketing disadvantage than a technical one. In most business/commercial and classroom settings, projection display is done with room lights on. With moderate ambient light--enough for children in a classroom to take notes for example--a projector's contrast rating is largely irrelevant. Actual contrast on screen with moderate ambient light is typically in the range of 50:1 regardless of the theoretical contrast potential of the projector. But for buyers who are not aware of the huge impact of ambient light on contrast ratios, the apparent advantage of DLP over LCD in contrast ratings can appear to be more significant than it really is.

Susceptible to dust spots. Since LCD light engines are not sealed, it is possible for dust particles to alight on the LCD panels, thereby creating a dull, indistinct spot on the projected image. This usually causes little distraction when displaying static images such as data or photographs. But in full motion video, seeing a stationary element in a moving picture can be extremely distracting.

When dust lands on an LCD in the red or blue channel it is rarely visible enough to create a distraction. But when it occurs in the green channel it can become quite visible. Some vendors have provided methods by which the user can remove the dust without having to send the unit in for cleaning. Sanyo's home theater models come with a hand pump that will blow a jet of air across the panels, but since we've never seen a dust spot on a Sanyo projector, we've never been able to test the device. Other than this sort of solution, packing the projector up and sending it to a maintenance depot for cleaning is the method of last resort for getting the projector back into serviceable shape.

LCD makers claim that today's air filter systems are superior than those of the past, and that dust contamination is highly unusual if the filters are cleaned and replaced as per normal maintenance instructions. Most LCD vendors cover dust removal under warranty, which is a good reason to buy LCD projectors with extended warranties.

When we review projectors, we have no way to assess the actual risk to the user of dust contamination on any particular model. We can say that it is rare for us to notice dust spots on LCD projectors that we get in for review, or on units that we keep in operation for ongoing reference purposes. However, it is easy for users to forget to clean filters since under normal usage vendors recommend this be done every two months or so. When filters are left unattended, the user increases the risk that dust will eventually find its way into the projector.

Conclusion

The fight for market share between 3LCD and DLP continues at a fevered pitch. It is a fascinating thing to watch as vendors of both technologies continue to innovate to stay a step ahead of the competition. Picture quality in digital projectors has improved dramatically over the past decade with significant increases in contrast, resolution, and color performance. Prices have dropped like a rock, and high quality projection systems that once were within financial reach of wealthy consumers or businesses who really needed them, are now within the budgets of mass consumers. Thus the consumer is the ultimate beneficiary of the intense competitive struggle between the DLP and 3LCD technologies.

As we've tried to make clear in this article, both DLP and 3LCD have key advantages over the other. They also both have limitations that the buyer should be aware of. But in the end, we see better image quality performance today from both LCD and DLP than we've ever seen in the past. And it just keeps getting better.
nguồn: http://www.projectorcentral.com/lcd_dlp_comparison.htm
và còn nhiều nguồn đọc tham khảo nữa
Click to expand...

Sonnguyen-corp · 2/12/10

Ngất, đọc kg nổi.....

nick149 · 2/12/10

Bùm, không tv máy chiếu gì hết, cho khỏi đọc tài liệu :lol:

Copy rồi paste dễ quá, bác cho cái link để anh em còn ... hứng thú theo dõi. Thấy cả post dài sợ quá :shock:

chuvoicon · 2/12/10

OK bác, đúng là ưu thế về độ bão hoà màu (Saturation Color) của LCD chiếm ưu thế với DLP do LCD sử dụng 3 tấm LCD riêng cho 3 màu còn DLP dùng bánh xe màu để điều khiển, tuy nhiên nếu máy chiếu DLP sử dụng 3 chip DLP để điều khiển riêng rẽ 3 màu thì trình chiếu chắc là không kém LCD. Tuy nhiên giá thành rất đắt, nhất trí với bác điểm này, với các máy chiếu bình dân thì LCD tốt hơn DLP về độ bão hoà màu.
Tuy nhiên em vẫn thích DLP hơn vì đặc tính độ tương phản cao cho màu đen thật hơn. Nếu có điều kiện thì em chơi máy chiếu LCos tổng hoà các ưu thế của cả 2 loại LCD và DLP nhưng giá thì khá đắt.

Nguyenanhson said:

chuvoicon said:

Bác cho em dẫn chứng hoặc thử nghiệm nhé:
DLP Chỉ cho độ tương phản cao hơn thôi chứ độ trung thực màu sắc thì lại không thể bằng 3LCD được bạn ạ

Gửi bạn đọc tham khảo. Nếu bạn ở HP bạn có thể mang một cái máy chiếu DLP có cùng tầm tiền với máy chiếu Mitsubishi HC6000 của mình đến nhà mình để cùng thử nghiệm cho biết.

Weaknesses and limitations of DLP

Color wheels can produce rainbow artifacts. The problem people point to most frequently as a weakness in DLP is its tendency to produce "rainbow artifacts." Rainbow artifacts (sometimes referred to as color separation artifacts) are momentary flashes of banded color that look like rainbows. They occur at random, and they only last for an instant. But for people who are sensitive to them, they can be quite distracting. If you are engrossed in a film or video, they can take you entirely out of the video experience.

Rainbow artifacts are a problem only on single-chip DLP products, and for the most part, only those using slower speed color wheels. They can also occur on LED-based models due to the sequential strobing of red, green, and blue LEDs. Typically the problem manifests itself when the viewer is watching movies or video. When viewing static images such as presentation charts or photographs, people generally do not experience the problem.

The rainbows occur because of the sequential color updating from the wheel or LED. As the color wheel spins or the LEDs change, the image on the screen is either red, green, or blue at any given instant in time. The technology relies upon your eyes not being able to detect the changes from one to the other. However, when your eye moves rapidly in response to some movement in the picture, you can get a red, green, and blue update on three different points on your retina, thus producing the impression of a rainbow. Not everyone perceives rainbows the same way. Many people have less sensitive eyes and cannot detect rainbow artifacts at all. Others see them quite readily. There is no way to know whether you are among those who can or cannot see them except by watching a DLP projector yourself.

Since LCD projectors and 3-chip DLP projectors always deliver a constant red, green, and blue image simultaneously, they do not create rainbow artifacts.

On DLP projectors with color wheels, rainbow artifacts are reduced by increasing the speed of the wheel. The first generation DLP projectors incorporated a color wheel that rotated sixty times per second, or 3600 RPM. With one red, green, and blue filter in the color wheel, updates on each color happened 60 times per second. This rotation speed in the first generation products was known as a "1x" rotation speed. In second-generation DLP products, the color wheel rotation speed was doubled to 2x, or 7200 RPM. The doubling of the color refresh rate reduced the time between color updates, and so reduced the visibility of rainbow artifacts for most people. But a 2x rotation speed was still not fast enough for products to be used in home theater and video applications.

Today, some DLP projectors being built for the home theater market use a color wheel containing two sets of red, green, and blue filters. This wheel still spins at 7200 RPM, but because red, green, and blue are refreshed twice in every rotation rather than once, the industry refers to this as a 4x rotation speed. And by increasing the physical rotation speed beyond 7200 RPM, some projectors now have 5x or 6x speed wheels. For the large majority of users, the 5x and 6x speed wheels in most current home theater models have reduced rainbow artifacts in video display to the point where they are of little or no concern.

However, most DLP projectors built for commercial/presentation use still use 2x speed wheels because they are less expensive. This is perfectly fine if the presentation matter is static charts, graphics, photography, or anything that does not stimulate rapid eye movement. We do not recommend DLP projectors with 2x speed wheels to buyers for whom video display or part time home theater are important intended uses.

Color saturation/color brightness. Some DLP projectors have excellent color saturation, and some are exceptionally poor. This is related more to the vendor's implementation than anything inherent in the technology itself. Advocates of 3LCD technology have been quite vocal about the lack of color brightness on single-chip DLP products, particularly those that have white segments in the color wheel. This phenomenon is worth commenting on.

When a color wheel has a white (clear) segment, the lumen output of the projector is increased dramatically, and the ANSI lumen rating skyrockets. Most business class DLP products have white segments in the wheel to boost the all-important lumen rating. Conversely, most DLP projectors built for home theater have no white segments because they can compromise color saturation and the overall balance of the video image. Moreover, the lumen rating is not a big driving factor in the sale of home theater projectors.

When you use a light meter to measure the brightness of red, green, and blue on an LCD projector, the sum of the values usually adds up to the brightness reading you get for white. This makes sense because on an LCD projector, white is created by turning the red, green, and blue channels all fully on. But on a DLP projector, this is often not the case. Due to the presence of a white segment in the wheel, the white reading can be as much as double the sum of the brightness readings for red, green, and blue. In other words, if an LCD projector measures 2000 lumens of white light, you will also get 2000 lumens of color light out of it. If a DLP projector measures 2000 lumens of white, you might get only 1000 lumens of actual color light from it, the rest being white light.

Because of this, proponents of 3LCD technology have been lobbying for color brightness specs to be included along with ANSI lumen specs on the industry's specification sheets, and support for this has been building in the industry. In the spec wars, quite clearly this would be one metric on which LCD has a commanding advantage over DLP. Not surprisingly, Epson and Sony have already begun to publish color brightness specs on their LCD projectors to drive home the point. The color spec is always the same as the ANSI lumen rating, and the specs will read, as an example, "2600 lumens color light output, 2600 lumens white light output."

As a rule, DLP projectors with a white segment in the wheel do not look very appealing when measured for color brightness. The color reading always fall short of the white reading, and sometimes it falls short by 50% or more. This is especially true when the color wheel contains the basic red, green, blue, and white filters only. Many DLP projectors have complementary color filters such as cyan, magenta, and yellow. In this situation the color brightness measurements become more problematic. Thus we can understand why Texas Instruments and the DLP projector vendors have little interest in publishing color brightness specifications.

From a practical perspective, we have mixed feelings about all of this. Clearly, the 3LCD camp is correct that the traditional ANSI lumen spec does not tell the whole story. But neither does the color brightness spec. To be sure, the color on some DLP projectors looks dull and anemic next to some LCD models of the same lumen rating. Ironically, this can be particularly true when the "BrilliantColor" feature is enabled. Though BrilliantColor boosts the brightness of the image, it can substantially reduce color saturation in the process. It is peculiar that in order to get the richest and most saturated color from many DLP projectors, one needs to turn BrilliantColor off. (This is not universally true of all DLP projectors with BrilliantColor, since the BrilliantColor system can behave quite differently based on how it is implemented by the vendor.)

Oddly enough, on some DLP models with white segments in the wheel, even those on which color brightness falls far short of white, we see a rich, vibrant color that can easily match an LCD projector in the same price and lumen class. One reason is that the color filter configuration of the wheel has a lot to do with the end results. Another reason is that, though the DLP's color brightness may fall short of white, the effect of the DLP's inherent contrast advantage helps to compensate for it. That compensating effect cannot be quantified in a spec. Even when color brightness falls very far short, the picture sometimes does not end up looking much dimmer at all when put side by side with an LCD projector of the same white light output.

When a DLP projector's color vibrancy looks poor next to a comparably priced and spec'd LCD projector, it is due to a variety of design and product cost decisions made by the vendor, and not anything inherent to DLP technology per se. DLP can look truly spectacular or downright dismal depending on what is done with it. With so many variables in play, the specs can't tell the whole story, even if a color brightness spec were added to the mix. The publication of color brightness specs would be interesting, and would certainly draw attention to a noteworthy technical difference between LCD and DLP. But it is not conclusive information that would help an astute buyer sort out which model to buy.

Dithering artifacts. At any moment in time, each mirror position on a DLP chip is either fully on to render maximum brightness, or fully off to render black. There is no way a DLP mirror can be "partially on" to represent gray, like an LCD liquid crystal can. Therefore, the way the DLP chip renders gray is to flip the mirrors on and off very rapidly, such that they are on just enough of the time for the eye to average the "on's and off's" to a desired level of perceived brightness. This approach to rendering grays is called dithering. It works well enough for rendering gray values, but it can produce some visible instability in solid fields, mostly dark areas, referred to as dithering artifacts. It looks like digital noise, but it is a separate type of artifact caused by DLP technology itself, and not by the signal.

Dithering artifacts do not occur on LCD products because there is no dithering used to achieve varying levels of gray. The liquid crystals can be either fully open, or closed, or partially opened at intermediate positions to achieve the desired level of light transmission--again, similar in concept to shutters on a window.

Restricted compatibility with zoom lenses and lens shift. Due to the nature of DLP light engine mechanics, it is difficult for vendors to incorporate long zoom lenses or extended range lens shift features into a DLP projector. These limitations are not relevant in mobile presentation projectors since the primary design objective is small physical size, so none of them have big zooms or lens shift anyway. But in the home theater market in particular, LCD vendors have captured significant market share in part due to their ability to incorporate long 2.0x zoom lenses and extensive lens shift capability into LCD projectors. This makes it much easier for the consumer to install the projector anywhere they want, which is quite frequently on a rear shelf in the room. Due to lens restrictions on DLP projectors it is rare to be able to install a DLP model on a rear shelf.

The Advantages of 3LCD

Many of the advantages and limitations of 3LCD have already been touched on above within the context of the DLP discussion. However, there are several advantages of LCD not yet discussed, and some of the issues already noted warrant a recap and/or further expansion. The following are the key benefits of LCD technology:

Better price/performance in HT products. The primary key to the success of LCD products in the home theater market is their tremendous price advantage. In the 1080p niche in particular, LCD products deliver outstanding image quality performance for the money. Moreover, they are generally loaded with extra features that don't appear on DLP models in the same price range, if they are offered on any DLP model at all.

The price advantage of LCD over DLP is most obvious in consumer/home theater products. There is no similar disparity in pricing on commercial products built for mobile presentation and conference room use. One reason is that DLP makers can use the cheaper 2x speed wheels on most business products, whereas it is mandatory to have high speed color wheels and the faster electronics associated with them on products designed for home theater.

Higher contrast in HT products. Many LCD projectors built for home theater have achieved better overall contrast performance and deeper black levels than DLP models. This is specifically the case on LCD models using inorganic LCD panels and auto iris technology. Inorganic panels are more expensive to produce, so they are not used in cheaper, commercial grade business projectors. They achieve higher contrast due in part to the fact that the resting position of the liquid crystal is closed (i.e., black), and voltage is required to open it. This is the opposite of traditional organic LCDs wherein the resting position is open (maximum light transmission), and voltage is required to close it. The inherent contrast advantage of inorganic panels has made LCD substantially more competitive in the home theater marketplace. ANSI contrast in particular has seen significant improvement. In our measurements, LCD projectors with organic panels typically run in the range of 250:1 ANSI contrast, whereas the models with inorganic panels have been reaching performance levels of 400:1 to 450:1.

3LCD vendors have been aggressive in developing effective auto iris systems which contribute an incremental perceived contrast advantage on screen. There is no technical restriction that we know of that would prohibit DLP vendors from doing the same thing. But it would add further cost to DLP projectors that are already at an apparent cost disadvantage relative to LCD in the home theater market. There is also a perception among vendors that DLP contrast, while not leading edge, is sufficient, so enhancement via auto iris is not vital. Thus, most DLP vendors have been slow to incorporate auto iris systems on DLP projectors being marketed for home theater.

Fewer artifacts/greater image stability. As noted previously, dithering artifacts and rainbow artifacts are unique to single-chip DLP projectors. Since these artifacts do not exist on LCD products, it is not unusual to perceive a more stable video image on an LCD projector when viewed side by side with a DLP counterpart in a similar price and performance class. The LCD's video image can look cleaner and more free of noise.

Sharper image with data display. Since LCD pixel structure is more sharply defined that DLP pixel structure, it tends to render a sharper image. This is most noticeable in lower resolution business products (SVGA and XGA), and specifically with data display. It is in these resolutions that LCD's screendoor effect is somewhat more visible in a video image, but the advantage is that the sharper pixel definition can produce a sharper display of data. By comparison, a DLP projector in SVGA and XGA resolution can look a bit soft when displaying data images.

On higher resolution products the difference in apparent sharpness is minimal, and it is a non-issue with video display on 1080p products. Both technologies can produce very sharp images in 1080p, and any perceived differences in sharpness typically have to do with factors unrelated to the display technology, such as lens quality and video processing.

Greater installation flexibility in HT products. LCD projectors built for home theater often feature 2.0x zoom lenses and extensive vertical and horizontal lens shift. This makes them easy to install just about anywhere. By comparison, DLP projectors usually have short zooms with little or no lens shift. Fixed throw angles limit the projection geometry, and often dictate where a DLP projector must be placed in order to accommodate a given screen size and location.

For the DIY home theater enthusiast on a budget, the lens flexibility of LCD models has great appeal. For the fact is, most DLP projectors need to be ceiling mounted, and most LCD projectors don't. Thus they save the extra cost of a ceiling mount and long run video cables. They also eliminate the prospect of having to run cables through walls and ceiling, or living with an unsightly track of cables across the ceiling.

Better light efficiency, less power usage. LCD technology is inherently more light efficient. For the most part LCD projectors use lower wattage lamps to produce the same image brightness that you'd get from DLP. This is most noticeable when comparing LCD projectors to DLP projectors that have no white segment in the color wheel. As an example, compare two currently popular 1080p home theater projectors--the Panasonic AE3000 LCD projector uses a 165-watt lamp to produce 1600 ANSI lumens. Meanwhile, the Sharp Z15000 DLP projector needs a 250-watt lamp to get the same 1600 lumens. That can make a noticeable difference in power consumption. It can also make a difference in the amount of heat being generated by the projector's exhaust in the viewing room.

Weaknesses and Limitations of LCD

Unknown lifespan of LCD panels. Given enough prolonged exposure to high intensity UV light and extreme heat, the organic compounds used in most LCD panels are expected to degrade over long periods of time. This degradation can lead to a discoloration of the image and a reduction in contrast. The only way to fix it is to replace the damaged LCD panel, which is typically a cost-prohibitive proposition. You are normally better off buying a new projector.

The big question of course is how long the panels will last. There is no good data on this subject that has been compiled by an independent lab and published for general consumption. LCD vendors do not typically acknowledge LCD degradation can occur, so they don't make any representations about expected life. In general, most LCD vendors maintain that to the degree LCD panels might be subject to eventual degradation, it will be beyond the practical life of the product.

One trusted and very experienced industry source who develops products using both LCD and DLP technology believes that LCD panels have a lifespan in the range of 4,000 to 10,000 hours, with the lifespan depending on how bright the projector is--the brightest LCD light cannons will produce the most stress on the panels resulting in quicker degradation. Low brightness models such as those made for home theater will produce the least stress, and are expected to last longer.

Texas Instruments has performed several tests on LCD lifespan over the past seven years. Based on these tests, they believe that LCD panels will degrade faster than the LCD vendors are willing to admit, and certainly more quickly than the 4000 hours just quoted. The 3LCD camp's response is that TI's tests have been performed by running LCD projectors continuously 24 hours a day, 7 days a week, for several months straight. According to 3LCD and Epson, since the projectors used in TI's lab tests were never designed for a continuous operation high-stress duty cycle, the results are not indicative of what the typical user would experience.

The introduction of inorganic LCD panels is an important new development that is germane to this issue. Inorganic LCD panels, in theory, should not be subject to the same degradation patterns as organic LCDs, simply because the organic compounds that fail under intense heat and UV light are not present in inorganic LCDs. However, the LCD camp will not confirm or deny any anticipated differences in panel life because as a matter of policy they do not discuss the issue at all. Texas Instruments has not commented on the expected lifespan of inorganic LCDs either.

Lower contrast ratings in business products. Most commercial and education LCD projectors are made with the relatively inexpensive organic LCDs and no auto-iris. Contrast ratings on these models typically run in the 400:1 to 700:1 range. Meanwhile, DLP projectors in the same resolution, lumen, and price class can often be rated at 2000:1 or higher.

In reality, this constitutes more of a marketing disadvantage than a technical one. In most business/commercial and classroom settings, projection display is done with room lights on. With moderate ambient light--enough for children in a classroom to take notes for example--a projector's contrast rating is largely irrelevant. Actual contrast on screen with moderate ambient light is typically in the range of 50:1 regardless of the theoretical contrast potential of the projector. But for buyers who are not aware of the huge impact of ambient light on contrast ratios, the apparent advantage of DLP over LCD in contrast ratings can appear to be more significant than it really is.

Susceptible to dust spots. Since LCD light engines are not sealed, it is possible for dust particles to alight on the LCD panels, thereby creating a dull, indistinct spot on the projected image. This usually causes little distraction when displaying static images such as data or photographs. But in full motion video, seeing a stationary element in a moving picture can be extremely distracting.

When dust lands on an LCD in the red or blue channel it is rarely visible enough to create a distraction. But when it occurs in the green channel it can become quite visible. Some vendors have provided methods by which the user can remove the dust without having to send the unit in for cleaning. Sanyo's home theater models come with a hand pump that will blow a jet of air across the panels, but since we've never seen a dust spot on a Sanyo projector, we've never been able to test the device. Other than this sort of solution, packing the projector up and sending it to a maintenance depot for cleaning is the method of last resort for getting the projector back into serviceable shape.

LCD makers claim that today's air filter systems are superior than those of the past, and that dust contamination is highly unusual if the filters are cleaned and replaced as per normal maintenance instructions. Most LCD vendors cover dust removal under warranty, which is a good reason to buy LCD projectors with extended warranties.

When we review projectors, we have no way to assess the actual risk to the user of dust contamination on any particular model. We can say that it is rare for us to notice dust spots on LCD projectors that we get in for review, or on units that we keep in operation for ongoing reference purposes. However, it is easy for users to forget to clean filters since under normal usage vendors recommend this be done every two months or so. When filters are left unattended, the user increases the risk that dust will eventually find its way into the projector.

Conclusion

The fight for market share between 3LCD and DLP continues at a fevered pitch. It is a fascinating thing to watch as vendors of both technologies continue to innovate to stay a step ahead of the competition. Picture quality in digital projectors has improved dramatically over the past decade with significant increases in contrast, resolution, and color performance. Prices have dropped like a rock, and high quality projection systems that once were within financial reach of wealthy consumers or businesses who really needed them, are now within the budgets of mass consumers. Thus the consumer is the ultimate beneficiary of the intense competitive struggle between the DLP and 3LCD technologies.

As we've tried to make clear in this article, both DLP and 3LCD have key advantages over the other. They also both have limitations that the buyer should be aware of. But in the end, we see better image quality performance today from both LCD and DLP than we've ever seen in the past. And it just keeps getting better.
nguồn: http://www.projectorcentral.com/lcd_dlp_comparison.htm
và còn nhiều nguồn đọc tham khảo nữa
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Only Time · 3/12/10

Nếu không cầu kỳ lắm em vẫn vote cho Pana C10... giờ chắc < 10M... em đang đi xem mấy cái Samsung led đắt lè mà chuyển động thể hiện cũng không tốt lắm.

mac309 · 8/1/11

vote cho Pana 42A10 về việc xem THC
Thằng bạn ngoài quê nhờ mua Plas 42, thế là chay đi làm 2 em plas để kiểm tra thực tế.
1. Pana 42A10 (giá 9tr6): xem THC (trên tuyệt vời), Phim HD tốt --> giữ lại, chuyển giao LCD pana 37LZ nổi tiếng 1 thời cho bx
2. Samsung 42C430 (giá 8tr): xem THD (tuyệt vời), Phim HD tốt --> chuyển cho thằng bạn

denbandan · 10/1/11

em cũng vote cho Plasma Pa na, có cái dòng 42S10S đẹp phết

MinhPT · 16/1/11

Nhà em quen với cái TV có 2 tuner, tức là xem 2 kênh truyền hình song song và bên cạnh nhau, giờ muốn nâng cấp mà ra HC, Pico tìm cái nào có chức năng này mà chưa thấy.

Các bác tư vấn cho em LCD 4x" full HD có 2 tuner

Thank các bác,
Minh

thanglong · 16/1/11

MinhPT said:

Nhà em quen với cái TV có 2 tuner, tức là xem 2 kênh truyền hình song song và bên cạnh nhau, giờ muốn nâng cấp mà ra HC, Pico tìm cái nào có chức năng này mà chưa thấy.

Các bác tư vấn cho em LCD 4x" full HD có 2 tuner

Thank các bác,
Minh
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bác mua thêm cái tv box garmei về sài là ok đó

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