I. Introduction
Uses: With the improvement of quality of life and enhance the living environment, home theater has become many people's pursuit of the goal, I was one of them. One of the focal points of home theater is the screen. If you need large screen size, then the projector is the best choice for this big screen.
Kind: Currently there are many types of projectors, such as short-focus, telephoto, high brightness, commercial and other users are provided for different specific functions. Short shots, for example, are suitable for narrow living rooms or rooms with large screens at short distances, and high-brightness projections that can be taught in bright light.
Portable: home projector usually relatively small, lightweight, and 50-inch LED TV will more than 10 kg, the weight of not only a lot of weight is not convenient to carry than the projector.
Price: 1080P of the Max70 70-inch TV Plus is priced at 10,264 yuan, while the 1080P projector 5000 yuan level has been able to easily reach 100-inch screen, while BenQ TH681 herein may be measured over three meters clear of the vote in a bright room A wide curtain (greater than 120 inches), and a full 300-inch investment is not a problem. This can be seen on more than 70-inch screens, projector prices have overwhelming advantages.
BenQ projectors use Texas Instruments' DLP technology as the leading global DLP brand with excellent technology, long lamp life, clear images, and high cost performance.
TH681 is such a high-end commercial and residential high-definition full-blown Blu-ray 3D projector with BenQ features. It has 1080p HD resolution, can perfectly output full HD video in point-to-point mode, 8000:1 ultra-high contrast, regardless of the size of the conference room and regardless of the indoor light intensity, can ensure the projection of vivid colors, rich layers, vivid and vivid The wonderful picture.
TH681 projector uses RGBYWC six-node gold color wheel, more equipped with BenQ exclusive extreme color technology. With the TH681's 3,000 lumens high brightness, it can not only easily project up to 300 inches of stunning images, but it can also output 1.07 billion real fine colors. Its multiple back interfaces can meet the connection requirements of different signal sources at the same time. Adding up to 6,500 hours of lamp life, enjoyment also eliminates the need for careful lamp life.
Second, product packaging
When I saw it, it was already there waiting for me quietly. The box full of "value" has a slight sour taste typical of the rainy season.
But fortunately, under the protection of the plastic wrap without any moisture.
I was looking forward to the projector for 5 years Can finally touch the palm of your hand. Thanks for what is worth buying
In accordance with BenQ's after-sales service standards, if it is necessary to change the new one, we must return the box together. Therefore, this package must be kept for 2 years until TH681 is overwritten.
The host uses a foam sponge firmly fixed in the box.
Just after unpacking, the lens cap has come off
And bruised the lens during transportation shocks. So distressed, the new machine is hanging. Fortunately, the effect of the trial on imaging is not obvious.
All attachments. The cable is VGA and power cable. The full version of the manual is on the CD-ROM. The paper manual is just about the same, which is equivalent to a quick start guide.
Third, BenQ TH681 projector specifications
Optical:
Resolution: 1920 (Horizontal) x 1080 (Vertical)
Display System: 1-CHIP DMD
Lens Focal Length / Number: F = 2.59–2.87, f = 16.88–21.88 mm
Light Bulb: 210 W Light Bulb
electric:
Power supply: AC100–240V, 3.1 A, 50–60 Hz (automatic)
Power consumption: 315 W (max); <0.5 W (standby)
mechanical:
Weight: 2.8 kg (6.39 lbs)
Output terminal:
RGB output: D-Sub 15 pin (female) x 1
Speaker: (stereo) 10 watts x 1
Audio signal output: PC audio jack x 1
control:
RS-232 serial control, 9-pin x 1, infrared receiver x 2
Input terminal:
Computer input: D-Sub 15 pin (female) x 2,
Video Signal Input: S-Video
Video: RCA jack x 1, analog - component (via RGB input), digital - HDMI x 1
Audio signal input: RCA audio jack (left/right) x 2, PC audio jack x 1
USB port: Mini-B x 1
Operating height:
0–1499 meters at 0°C–35°C
1500–2000 meters at 0°C–30°C
(opens in high altitude mode)
Fourth, BenQ TH681 projector appearance
The TH681 lens is not designed to be overly prominent on the camera body. The lens is also designed to be retracted so that it can be easily carried. The transparent lens cap not only protects the lens from scratches, but also reduces lens damage caused by forgetting to remove the lens cap and turning on the projection. Intimate soft silicone strap prevents accidental loss of the lens cap.
Hot air vent design can be said to be a more intimate design in the front of the fuselage, when you put the projector on the conference table will never want to put the hot vent on your customers. But in front of the fuselage can avoid this flaw, this design is not used by all projectors.
There are 3 feet below the fuselage.
The front foot adjusts the projection height of the projector.
The built-in 10W speaker responds to ordinary business presentations and friends who are not demanding on the sound quality and enough to carry additional sound.
The back of the projector has a rich interface. Everything from the earliest AV interface to the latest HDMI can be easily connected, and anyone who is a business user does not want to waste valuable time trying to find a connection.
Using the HDMI interface allows the TH681 display to achieve the best picture quality. It is also very user-friendly to provide audio output interface, when connected to the HDMI interface can be connected to the external speaker through the audio output interface, without the need to purchase additional transfer wiring.
It is worth noting that the mass production version lacks a USB type A interface compared to the TH681 photo that was circulated on the Internet. This simple configuration makes the USB read function a lot of tasteless. This may be due to differences in performance and shape that are very similar to the MH680.
The lifting holes of the TH681 are relatively common, and there are no 1/4 or 3/8 screw holes commonly used on tripods. If it is a front-mounted projector, it may require additional projector brackets if it requires a higher scene.
First use the zoom lens to adjust the projected image to the desired size, then use the focus ring to focus the image on the screen. Although focusing is fully manual operation, the focusing ring is properly damped and feels good, and novices can also adjust the image very clearly.
The side inlet of the TH681 is specially designed as a honeycomb, which not only allows the air volume to increase, but also makes the body more robust and beautiful.
TH681 uses a full plastic body. Even so, the combination of mirror and matte still makes it look "luxury."
The design of the body's nine function buttons + power button allows the user to set the adjustments quickly and efficiently. More quick function settings need to use the remote control to achieve.
The middle of the up and down buttons can be directly trapezoidal adjustment, positive and negative 40-speed adjustment. Left and right buttons can adjust the volume level. Other buttons include menus, automatic adjustment, signal source selection, and energy-saving screens. The AUTO key automatically adjusts the picture quality when using analog signals.
Energy-saving screens are a feature of BenQ's projectors. Pressing the ECO BLANK button instantly hides the image, and the lamp power is reduced while the image is hidden.
There are three LED lights above the button that can be used to determine the projector's working status or existing faults, allowing users to do simple troubleshooting: POWER indicates the working status of the projector; TEMP warning light will be on when the projector temperature is too high; The LAMP indicator will indicate the failure of the lamp.
The remote controller is an indispensable tool, and it is the only medium to communicate with the TH681 when it is inconvenient to reach the hoisting projector.
The remote controller uses two No. 7 batteries to facilitate purchase and replacement. Both the front and the top of the projector are equipped with infrared sensors that can be operated with the remote control facing the TH681 or directly at the screen. Due to the room size, the projector can still be controlled normally with a distance of 6 meters from the projector.
The buttons on the bottom of the remote control are equipped with a series of shortcut keys like Freeze (Quick Frame), Quick Instal (Quick Setup), 3D Settings (3D Settings), CC (Closed Caption), and Demo Timer Settings. You can avoid long search in the settings menu.
TH681 is also equipped with a common menu. The display and operation modes are exactly the same as BenQ's displays. Friends who have used BenQ display can easily get started.
In the menu, you can not only find common settings such as projector installation, but also features such as digital zoom and wall color selection.
Digital Zoom: Select Digital Zoom and press Digital Zoom+ to zoom in on the center of the screen and press the arrow keys to move the zoom position.
Wall color: When the color of the wall is not pure white, you can turn this option on and select the color similar to the wall, the projector will correct the color difference of the projected image. This function is particularly useful when used in some harsh environments.
Five: can be improved
When the projector needs to be projected on the ceiling, the access cable at the back of the TH681 becomes an obstacle. If these interfaces are moved to the side of the projector, they can be easily erected.
However, this problem can also be solved by using existing materials.
Use the foam pad in the packaging of the TH681 to cut off the upper part of the air outlet.
The HDMI interface and power interface behind the device are not completely blocked and can be accessed normally.
Then place it on the reverse bench and you're done.
Looking at the projection in bed is also a pleasure.
Of course, if it is often necessary to project to the ceiling or to buy a dedicated projector is better.
Six: Replace the bulb
There is a screw on the side of the fuselage. After unscrewing, the lampshade can be opened to change the bulb. Simple and convenient. 
However, replacing the bulb must destroy this label. The projector is warranted for two years and the lamp life in the power saving mode is 6,500 hours. Simple calculations, if you use an average of 8.9 hours a day, you just need to replace the bulb on the out day. According to the eight-hour work schedule, TH681 will not need to change the bulb before it is released.
If it is used in the normal mode, it is only 3000-4000 hours, and the average daily use is 5.48 hours in 2 years. The equivalent of watching two movies is almost enough.
It looks perfect, but the page that pops up after typing http://lamp.benq.com/ is: "HTTP Error 404. The requested resource is not found." BenQ ... ... the dirt.
But it does not matter, there is a saying to call yourself hands-on food and clothing, which is to try to change the light bulb. First of all to prepare a word and cross two screwdrivers.
Use a flat-blade screwdriver to remove the screw, then lift it up from the front of the projector to open the lamp cover. (It is the black plastic cover above.)
This screw cannot be lost.
The label will become two layers up and down with the twist of the lampshade. This is the legendary tear label.
Labels are tough and won't break.
The lamp shelf is sealed by a plastic film.
After unscrewing the plastic film, unscrew this last set screw. 
Then pull up the handle and lift it up to pull the lamp holder out of the body. The plastic power connector on the rear of the main unit needs to be lifted slightly.
The TH681 projector uses a 210 watt Osram ultra-high pressure mercury lamp
Light bulb power supply adopts socket design, easy to install. 
The lamp life is 3000 to 4000 hours in normal mode, and the lamp life is up to 6500 hours in Intelligent Power Saving mode. 
Located on the fuselage of the bulb fiber entrance. 
The front of the fuselage cooling fan. 
According to the reverse order of disassembly, there is a positioning device next to the screw. When replacing the screw holder, pay attention to the tightening. 
The warranty label cannot be returned to the original. 
Posted with special tape ~ suddenly felt a lot of good ~
From the above steps, you can feel that the TH681 bulb is very convenient and requires low operating requirements. However, do not touch the internal parts of the body during the replacement to prevent the stains from affecting the image quality. At the time of replacement, at least the body must be fully cooled (at least 45 minutes) before it can be burned.
Seven, projector power and heat
The TH681 has an excellent energy-saving design and consumes only 0.1W in standby mode.
After power-on, power consumption increased from 98W to 251W, and power consumption dropped to 208W. In the ECO smart mode, the power consumption is about 200W, and the minimum is 160W. 
Under the 250W power consumption, the whole host heat is not small. At an indoor temperature of 33 degrees, the average outlet temperature is about 50 degrees, and the outlet reaches 86 degrees. If you don’t have a barbecue, you’re really good for yourself. In winter, you can save heating money. )
The TH861 offers two shutdown modes:
1: Normal mode The projector will continue to operate the fan for 90 seconds after it is turned off. If you have previously selected the “Restart Now†option in the menu, the projector will still start up and enter the normal projection state immediately after you press it for 90 seconds.
2: "quick cooling" The shutdown time in the off mode will be much shorter, the lens will be turned off and the fan will be turned off immediately after pressing the shutdown button in less than 10 seconds. If you select Quick Off, you cannot select the "Restart Now" function at the same time. Under normal circumstances, it is not recommended to select this function. It looks like the heat is hoarded inside the host when it is turned off.
Eight, TH681 projection effect
3000 lumens of brightness can clearly see the picture in a bright room. There is no need to deliberately arrange an office or room into a small dark room.
Photos and videos are projected on the ceiling near the window at noon on sunny days. Limited to shooting equipment, the actual projection effect is better than the one I took and the color is more accurate.
What if there are no curtains or even flat walls?
Projected on the more complex curtain lines, although the picture quality is not satisfactory, but overall it is also able to watch.
At noon on cloudy days, projections can be clearly displayed on the screen.
However, the effects of night and night are better, the contrast and the details of the shadows are improved to the extreme, the colors are more vivid, and the images are more detailed and clear.
The 150-inch 4:3 curtain has a width of about 3 meters. The projector is almost completely full of 4 meters from the curtain. Hahahahaha, big picture is great!
The display delay of the display device is required to play the game. When the game is delayed too much, it will not only make the user feel difficult to control, but also causes a long time to cause physical discomfort.
The TH681 is well controlled in terms of delay. The basic game feels the same as LCD TVs. The number of game frames is sufficient, the picture is clear and bright, there is no smear and dropped frames. It is a good choice for playing games. At high contrast, the TH681's overall color is soft and the transition is natural.
Nine, entertainment work correct teaching template function
The TH681's own template function can project lines on the blackboard or whiteboard, making the writing of the blackboard clear and clear. It looks at a glance. It's a piece of cake to report to the blackboard.
Ten, projectors can still be used
When the screen is used as a background, the background light appears more realistic, and as long as the foreground light is processed, it can be well integrated with the background. (Please forgive my hand-sliding broke my camera with my one-handed shot. The photo is from the phone)
A little shooting experience:
When using the projector, the background can be lighted on the foreground, even with the colors and patterns needed, so that the objects you want to capture will integrate into the background more naturally. This is not possible with other background props.
However, the brightness should be mastered. If the background is dark, the photo corresponding to the area where the projector is projected onto the object needs to be covered with a layer of gray to reduce the brightness.
The camera's automatic metering may not be able to cope with such complex light, so it is recommended to manually adjust the exposure in the M-range will be better.
Of course, this can not only create a background for the shooting model, but also give people a "tattoo."
No flash
Slow sync flash
how? Are you worthwhile?
Eleven, advantages and disadvantages
advantage:
1:1080p Full HD resolution provides true 1:1 image rendering for HD video.
2: SmartEco technology dynamically adjusts the brightness level of the projector lamp to save lamp power consumption and extend life.
3: Convenient power-saving screens can instantly hide the image, while lowering the lamp power while the image is hidden.
4: Ultra-low standby power consumption.
5: The quick cooling function accelerates the cooling process after the projector is turned off.
6: Restart immediately The projector can be restarted immediately within 90 seconds after the projector is turned off.
7: Supports 3D functions and common 3D video formats.
8: Built-in 10W speaker.
9:3000 lumens brightness and 8000:1 contrast ratio.
10: The top lampshade can be opened separately. It is easy and convenient to change the bulb either in the right way or in the ceiling.
Disadvantages:
1: The user will replace the lamp by himself and he will lose his warranty.
2: Horizontal keystone correction is not supported.
3: Stand-up playback must rely on additional support equipment, but now the projector is mostly like this.
4: The projector is packaged without attaching the lens cap so that it falls off during transportation and damages the lens.
Twelve, summary
The brightness of 3000 lumens and the contrast ratio of 8000:1 coupled with advanced DLP technology allow it to be used in almost any indoor environment. Rich remote control function can quickly set the projector, 1080P Full HD makes the details of the picture more perfect, both text and video can be complete. ECO energy-saving technology combined with the long lamp life effectively reduces the cost of use. The TH681 high specification hardware configuration and effect make me unable to be picky about this projector.
Thirteen, some projector installation experience
First of all: Projector arrival does not mean the end of a pickpocket, but just the beginning . To buy curtains, hangers, long wires for projectors, projector stands, etc... There should be ample budget in addition to the projector.
2: The same brand, the same material, the same width of the 4:3 screen is cheaper than 16:9, so pick the right time to pick the right one. 
3: There are many issues to consider when installing your own curtain. 
If it is projected longitudinally in a room like me, the nominal width of the curtain is narrower than the room width by at least 60 cm. Because the curtain edge and the shell edge there is still a small distance. It is best to confirm the length to the seller before buying the curtain, so as to avoid the curtain that the curtain is too long to install.
4: If you do not know how much to choose the curtain. You can refer to the following table. Simple example The first line of parameters indicates that a 0.886-meter wide image is required to be at least 1.013 meters. If you only have a distance of 1 meter, then buying a 50-inch screen is a bit wasteful.
It does not matter if you do not understand the above table. Buy the projector first, and after installation, see how wide the image can be cast, and select the curtain according to this width.
5: Conditional player is best to hang the projector. In this way, sitting in front of the screen does not easily cover the light of the projector.
6: Audio wiring is the most annoying thing after installing the projector. The screen does not make sound like TV. It's best to think ahead of time about where to put the sound and where to go. If the projection distance is 4 meters, the line may be quite long. If only one person at home watches, using a wireless headset like the SONY DS7500 will solve the problem.
7: The TH681 must be installed on the centerline of the screen. Because the TH681 only has vertical trapezoidal correction, horizontal trapezoidal tilt correction is not provided. If it is not in the middle line, it will cause the picture to be slightly deformed.
8: The best choice for the TH681 is to use the bracket. If you have a tripod that can support 2.7 kilograms, you can also buy a "projector tray" to place the projector, but keep in mind that this tray must have a fixed strap. The advantage of using a tripod is that the upper and lower angles and height adjustment of the projector are more convenient and flexible. 
Thanks for what is worth buying for me
Thank you for your patience~