With an LED projector you will experience first-class cinema feeling in your living room. Our team checked many different comparisons and tests on the Internet to generate a leaderboard with ratings for weight, resolution, image formats and much more.
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The history of the LED projector
The history of the LED projector is based on two fundamental inventions: that of the projector and that of LED technology.
The combination of the two forms the basis of modern LED projectors.
The history of the projector
The first classic projector was described in 1589 by the Italian universal scholar Giovan Battista dellaPorta in the form of a shadow- casting magic lantern .
The combination with a lens finally led to the well-known Laternamagica by the scholar Christian Huygens from 1659.
Continuous further development took place above all through the optimization of the used light source.
These projectors to play real image templates were used to start only the viewing of photographs in the form of photographic plates and contact copies.
Parallel to the dependent development of miniature photography emerged first projectors with the possibility for increased representation of photographs.
The first slide was of the German company Leitz in 1926, 1 year before the first miniature camera of , Leica introduced. This created the basis for slide projectors that were known, popular and popular for many years .
The 1920s saw the emergence of the first film projectors in increasingly open movie theaters.
The next fundamental step in developing today’s projectors was to replace the real image with an electronically coded one.
This for the first time succeeded in 1939 in the so-called Eidophor method, in which an image or film projection by a combination of xenon gas discharge lamps, concave mirrors, converging lenses , and cathode ray tubes is generated.
The image was generated using an oil layer on a concave mirror.
At the end of the 1960s , first attempts were made to transmit transmitted light through slide frames with a liquid crystal display (LCD) .
But it was not until the late 80s, to American, German and Japanese manufacturers at the same time the first LCD video projectors on the market brought to the described eidophor process repressed quickly.
The history of LED technology
The light-emitting diode (LED) as light -emitting semiconductor device is based on the discovery of the rectifier effect, by the physicist Ferdinand Braun , from the year 1876th
The real invention of the light-emitting diode is attributed to the scientist Nick Holonyak in 1962 . Significant further learned the technology by the chemical company Monsanto in the 1970 ‘s.
The rapid development, up to the current state of the art, took place mainly with regard to the luminosity of the diodes and the achievable color spectrum. The aim of the current manufacturers is mainly a increase of efficiency at the same time reducing production costs.
Modern LEDs offer a luminous efficacy of 303 lm / W, whereby the color of the measured LED is decisive for their brightness .
The story of the actual LED projector begins in the first years of the new millennium. Initially, the technology struggled primarily with the limitations of LED technology with regard to its luminosity.
With their further development , however, they also become more competitive than other systems, above all because of their clear advantages in other areas.
Structure and operating principle of an LED projector
In addition to the light source , the type of imaging is the decisive criterion of a projector. Modern LED projectors rely on a so-called digital light processing (DLP) element or more precisely a digital micromirrordevice .
The process patented by Texas Instruments is based on a special microchip on which so-called micromirror actuators are arranged in a matrix .
These tiny, reflective surfaces have an edge length of approximately 16 µm ( 1 micrometer = 0.001 millimeter ) and their number corresponds to the number of pixels that the respective projector is capable of displaying , i.e. its (native) resolution. These mirrors are tilted and pass selectively incident light by the projection optical system of the projector or draw it off.
In the case of LED projectors , the coloring is done by using differently colored LEDs. If the light beam is guided through a rotating color wheel on the classic DLP projector , the color of the LED projector is achieved by superimposing the three basic colors (red, green, blue) .
Advantages of an LED projector
The LED technology provides over established Beamer variants, such as LCD and DLP clear advantages:
- LEDs generate less heat, which means that extensive cooling systems can be largely avoided
- LEDs do not require waiting times for cooling before switching off or on
- Loud and dust-raising fans are not absolutely necessary
- LEDs have a significantly longer lifespan than classic projector lamps (this is more than 20,000 hours for LEDs, compared to a maximum of 4,000 for incandescent lamps)
- LEDs have a significantly lower power consumption than projector lamps
- LED projectors can even be operated with batteries
- LEDs enable a significantly smaller design
- LEDs are less sensitive to shocks, for example
- Simple models are already offered inexpensively
Limitations of an LED projector
The LED technology but also brings disadvantages compared to the other technologies with them, but with further development of the technology is becoming increasingly important to lose:
- The light intensity of an LED projector is significantly lower than that of a model with incandescent lamps
- They are only of limited suitability for daylight use
- They have comparatively high acquisition costs
- The size of the projection area is limited
Types and areas of application
Basically, projectors can be differentiated based on their purpose . At the same time, the different technologies enable different designs and thus favor different areas of application. There are two types of projectors :
- stationary projector
- mobile projector
In addition to this distinction after the of use, can be Beamer also after application divided:
- Home theater projector
- (professional) presentation projector
The demarcation takes place not at all models strictly according to the illustrated arrangement. A projector is often suitable for both stationary and, at least to a limited extent, for mobile use. In addition, many models are suitable for film screening as well as for the presentation of other media formats.
At best, stationary projectors are set up and connected at a suitable location and remain there permanently. The size and weight of a stationary projector are therefore usually of minor importance. Of greater significance are at stationary projectors individual comfort features:
- Easy to use, also by remote control
- Low operating volume, especially as a home cinema projector
- Interfaces for common multimedia devices (audio and video)
A stationary home cinema projector is often set up outside the direct range , which is why remote control is often indispensable. The structure and functionality of a remote control are important criteria.
The noise level of a classic projector with fan is usually between 26 and 36 decibels. With loud models, a volume can be reached that drowns out, for example, quiet passages of a film and is perceived as annoying.
A home cinema projector should have connection options for the classic audio and video sources . A stationary projector can be integrated into a home network using suitable connections and components .
At first glance, mobile projectors differ from stationary models in their sheer size .
Some mobile projectors do not differ significantly from those for purely stationary use.
Often the only difference is that they have a suitable case for transport .
In addition, there are models that the at least slightly smaller and lighter are marked Minibeamer and much smaller Micro Beamer as a pocket projector called.
With the size , however, the generally reduced performance of a projector.
A particularly compact design usually requires compromises in the type and scope of the interfaces installed and, above all, the quality of the optical components used.
LED projector in stationary and mobile use
The LED technology offers advantages for both types, both stationary and mobile projectors.
Stationary LED projector
Because of the comparatively short time , since the LED projector available, most are devices on the latest state of the art in terms of their connectivity. Since LEDs themselves hardly generate any heat during operation , high-performance cooling systems with correspondingly loud fans are often not used. As a result, there are significantly less disturbing noises in the immediate vicinity.
At the same time, the power consumption of an LED projector is so low that nothing stands in the way of completely replacing a classic television, at least for cost reasons . Projector lamps in LCD or DLP projectors generally have an output of 200 to 250 watts and therefore cause significantly higher electricity costs than a classic flat screen TV, which often does not work depending on the model and sizeconsumed more than 50 watts in operation . The power consumption of an LED projector is significantly less than 100 watts in most models , and even no more than 20 watts in some models .
However, LED technology also includes aspects that restrict its suitability as a stationary home cinema device . The light output of an LED projector is limited compared to classic projectors with incandescent lamps . Accordingly, for an appealing image with that of other technologies or even one classic television image compete possibly a can, darkening the room required.
In addition, the resolution and the maximum screen diagonal are restricted in some models and a comparatively small distance from the projection surface is required.
Mobile LED projector
The LED technology is ideally suited for use in mobile devices. LEDs enable a compact design, require little electricity and produce little heat. These advantages allow sizes ranging from pocket trousers or even the integration of a projector into a second device , such as a smartphone.
Due to the low power consumption of the LEDs, mobile LED projectors can be operated independently of the mains by suitable batteries and thus enable additional mobility.
Features and functions
In addition to the size and not least due to related applications of LED projector, are features and functions relevant to the evaluation of an offer and the usability of an LED projector.
LED projector tests analyze and compare these criteria and evaluate the models of individual manufacturers on the basis of this comparison .
The image quality of an LED projector
What very subjective as the quality of the image is viewed, based, in addition to the spatial conditions on a variety of factors, which in individual models significantly differ can.
In addition to the distinction between individual LED projectors , the specifications described also show the differences between the LED projector and classic projector types .
The light intensity of a projector is the central criterion for the image quality of a projector. It not only determines the quality, but also influences the maximum distance between the projector and the projection surface, the maximum display size and any darkening of the room that may be necessary .
The light intensity depends on the built-in illuminant. Classic light bulbs are clearly superior to LEDs here. A daylight projector, i.e. a device that can also be used in bright daylight without dimming , produces a light intensity of at least 2,000 lumens.
Classic projectors achieve between 1,000 and 5,000 lumens, professional presentation beamers reach up to 30,000 lumens. Most simple LED projectors provide a maximum of 1,000 lumens, a few models up to 1,600 lumens.
Depending small and mobile , a LED projector is constructed, the lower is its light intensity. So are mobile devices usually around 500 lumens, micro projector even less than 100 lumens.
The number of horizontal and vertical pixels that are represented by an optical device is colloquially referred to as resolution. Instead of the pure numbers, manufacturers use established terms such as HD, Full HD, HD ready and similar , especially for advertising purposes, which are intended to underline the image quality as an incentive to buy .
With regard to resolution , manufacturers try to outperform themselves and to constantly push new boundaries technically. How much resolution is actually necessary remains a subjective judgment.
While conventional projectors with projection lamps now even achieve the new 4K format , HD realistic LED ready projectors have so far been the realistic maximum resolution. Some manufacturers have recently launched models with a Full HD resolution.
Since the light intensity is decisive for the maximum resolution , it decreases with decreasing light output. Accordingly, the resolution for mobile or micro-projectors is usually significantly lower.
As a decisive criterion for the image quality , the contrast ratio is simply the difference between the light and dark areas of an image.
The higher the contrast ratio specified by manufacturers , the greater the difference between the representation of white and that black image areas.
The contrast ratio falls in LED projectors, between individual models greatly different from. If simple models are satisfied with a ratio of just 100: 1, the average of the models offered is already 100,000: 1 and according to the manufacturer, individual premium models even reach a fantastic 600,000: 1.
In addition to the image quality, in the form of the maximum resolution and the contrast ratio, the minimum and maximum image size are also decisive criteria for the selection of an LED projector. Especially models with only low intensity and low resolution are only capable of a proportionate small image to a suitable surface to project.
In contrast, screen diagonals of several meters can be easily achieved with high light intensity and high resolution . The ratio of the so-called projection distance is always part of the evaluation of the maximum image size .
The projection distance indicates on the one hand which maximum image size can be achieved at a certain distance , and on the other hand which distance must be maintained in order to achieve the maximum possible image size . In addition to the light source , the built-in lens is decisive for the projection ratio.
The 3D process has been tried and tested by the cinema . Many flat-panel televisions have today already have appropriate functions and projectors offer the possibility according to appropriate media play and function properly.
For viewing of 3D content one is basically suitable glasses required.
Since a 3D effect is created by separate individual images for each individual eye of the viewer , the refresh rate is decisive for the quality of the display.
Without a connection to a suitable playback device or at least a data carrier , no matter how high quality the LED projector is, it is useless. To establish this connection , appropriate interfaces, i.e. connection options , are essential.
Common connection standards include:
- HDMI / Mini HDMI
- Composite audio (chinch)
- Component input (YUV)
- Mobile high-definition link (MHL)
- Mini jack
These connections are used for the wired transmission of image and sound signals to the LED projector and from this to optionally connected devices.
The smaller the LED projector, the more limited the choice of interfaces .
In addition, numerous models have the possibility of integration into a network or the wireless transmission of data. In addition to a classic, wired LAN connection, the WLAN standard and the Bluetooth method are used for this.
With the latter, it is possible both data to the LED projectors to transmit, and to use these.
In addition to the image quality , the quality of the sound is largely responsible for the pleasure of an LED projector .
Especially if this is to be used as a home cinema projector , high-quality sound output is essential.
Many LED projectors, especially larger models, are equipped with their own speakers .
Even if manufacturers use state-of-the-art technology , especially in the high-end price segment, the possibilities are severely limited due to the maximum possible size of the speakers installed .
That is why LED projectors usually have suitable audio outputs for connection to an existing audio system.
Media players and internal recipients
Traditionally, LED projectors are connected to an external signal source . A DVD or Blu-Ray player can be connected in the same way as a satellite receiver, a DVB-T receiver or a video or hard disk recorder.
The signal is generated in the connected device and only finished picture and sound signals are sent to the LED projector and reproduced by it.
The easiest way to do this , especially with modern devices, is via an HDMI connection.
If files are to be played directly from a connected data carrier , the LED projector requires a suitable connection, usually USB, and an internal media player.
This media player must be able to reproduce the data format of the corresponding media files .
The leading manufacturers, which are regularly named and rated by LED Beamer Tests , are mainly already known and experienced through other products from consumer electronics . Most of them restrict themselves not to the development and production of LED projector.
You already have relevant experience with their predecessors, the classic projectors with incandescent lamps. Since the LED technology is comparatively young, the offer is still very clear for most manufacturers in addition to classic projectors .
The 1976 in Taiwan under the name Multitech , founded and in 1987 in Acer renamed company sells about trading partners a wide range of devices in the field of consumer electronics, for small commercial and private use.
The range includes PCs and notebooks, smartphones, tablet PCs, monitors, televisions and also projectors.
The range of portable LED projectors includes models of various sizes and performance, with mains operation and individual models with a power supply via battery.
The Taiwanese company BenQ reached his fame above all through the production and distribution of computer drives, such as DVD burners. The entire division was acquired in 2006 by the Taiwanese company Lite-On .
The BenQ company was founded in 1984 as a subsidiary of the electronics group Acer .
The offer of the company BenQ today consists of LCD TVs, laptops, scanners, mobile phones and other products of consumer electronics. This also includes LED projectors. The few models build on versatile usability and mobility.
The LG Electronic Inc. is a South Korean company, with offices in Germany Ratingen in North Rhine-Westphalia. LG Electronic is in turn a subsidiary of the LG Group , which is active in a wide variety of fields in the fields of electronics, chemicals , services and telecommunications .
LG is among other world leader in mobile phones of 3G standards and produces LCDs for mobile phone manufacturers Samsung. LG also produces household appliances, flat screen TVs and various computer components.
The extensive range of LED projectors includes portable and micro projectors as well as models expressly suitable as home cinema projectors .
The Chinese company Aiptek , founded in 1997 , produces components from the consumer electronics sector . These include graphics tablets, digital pens, digital picture frames and LED projectors.
Aiptek offers online and through authorized trade so-called picoprojectors : LED Micro Projectors, partly specifically for use with smart phones or digital cameras.
The American company ViewSonic is one of the leading manufacturers of computer monitors in the USA . Founded in California in 1987 , the range includes various types of monitors and displays as well as smartphones, tablet PCs and projectors.
The extensive range of projectors the company ViewSonic includes a manageable selection of portable LED projectors.
Cheap LED projector in the test
If you want to buy an LED projector, you will soon find that there are also very cheap models on the market. There are even LED projectors for less than 60 euros. The question is: is it cheap to buy? We have analyzed customer reviews on cheap LED projectors and examined external practical tests.
There are many inexpensive LED projectors on the market. They are called: LED projector Artlii HD 3200, LED projector DBPOWER Mini, LED projector Bluestercool 1080P HD, LED projector Tenker Q5 Mini, LED projector, LED projector iBosi Cheng LCD home theater, LED projector VPRAWLS Wifi Full HD.
Cheap projectors between 55 and 130 euros are expressly not suitable for office presentations , but are shown as a projector for video games or as a movie screen. This is due to the comparatively poor picture . The most striking thing about a typeface for a Power-Point presentation, as external practical tests show. The image becomes blurred, particularly towards the edges. A keystone correction does not help, as many Amazon customers report. The colors are not what you would find in a better LED projector from our test.
What we found unpleasant in the reviews is that the manufacturer of the LED projector DBPower apparently promises a free projector bag for a 5-star review.
Nevertheless, there seem to be real reviews and testers who are completely satisfied with the result and enjoy video games or are happy about ” nostalgic feelings ” during the series evening in the bedroom.
Of course, it always means “for the price”.
Conclusion: if you don’t expect too much ” for the price ” and would rather set up the projector as a party gag, a cheap purchase can definitely pay off.
However, if you expect more or want to use the LED projector for a power point presentation , you have to spend a little more money for a model like our LED projector test winner.
For example, in the higher price segment, Acer has just launched two new LED projectors , the Acer PD1520i LED projector and the Acer PD1320Wi LED projector . These are expressly intended for the businessman who wants to impress customers with the portable LED projector.
Sources of supply Internet vs. Specialized trade
Due to the in comparison to traditional displays, monitors and televisions still rather limited distribution and demand and the still manageable offer are LED Beamer today in retail stores mainly on the dealers sold. In addition, there is the offer of well-known electronics markets as well as isolated offers in classic retail.
The comprehensive range of all manufacturers , with all available models, can be found in online retail. Some manufacturers sell their products independently via their own online shops, others use sales via known platforms .
In the Internet it is possible to offer various manufacturers carefully, based on the technical specifications to check and compare. LED beamer tests provide a suitable approach to choose a suitable model from the range .
A selected source of supply usually also offers extensive, suitable accessories and any necessary spare parts. Warranty and guarantee do not differ in general from online retail from brick-and-mortar retail.
Making claims here is rarely difficult for reputable providers . In case of doubt, the processing is stationary as well as online via the manufacturer.
Some accessories are indispensable for handling an LED projector , others are optional, depending on personal preferences and operating conditions .
In many cases, accessories depend on the manufacturer and model and can therefore usually be best obtained from the manufacturer .
In addition to the projector itself, the quality of the projection surface is crucial for the image quality. Basically, an image can be projected onto any even, as white a surface as possible . However, a simple white wall will never be able to take full advantage of a projector .
Canvases are made from various cloths , which are particularly suitable as a projection surface.
A special feature of a suitable canvas is a narrow black border. If the canvas is used over the entire surface, this increases the subjective perception of the image contrast.
The so-called gain factor, also known scientifically as the luminance factor, describes the radiation behavior of a surface, in this case a screen.
For home theater screens , a gain factor between 0.8 and 1.2 is recommended . With canvases of this quality , a picture is pleasantly bright and easy to see even from an oblique angle .
After their construction , canvases can be divided into different types :
Frame screens , which at a wall mounted are thereby always the optimum voltage have, however, always in maximum size , with a fixed mounting permanently in a body remain visible.
Roller blinds are usually fixed to the ceiling or to a wall in a housing . If necessary, they can be lowered manually or, in the case of higher-quality models, by motor and can be removed comparatively space-saving and inconspicuously after use .
To save space, in blind-screens often used thin cloth under circumstances waves and the image impression may deteriorate.
Tripod screens offer the greatest flexibility. When not in use, they can simply be stowed away in a closet or in a suitable place .
Also Tripod screens often use thinner cloth and then tend to waves.
If the remote control of an LED projector is intended, the necessary handheld device is usually part of the scope of delivery.
However, the accessories trade also offers universal remote controls that can replace a lost or damaged manufacturer’s remote control and support common functions of commercially available projectors for this purpose .
Modern LED projectors also occasionally enable remote control using a suitable smartphone app.
Apart from particularly tiny micro or pocket pocket beamers , a classic LED projector requires a certain amount of space.
In addition, for an unclouded home cinema enjoyment or also in use as a presentation projector , a setup that is tailored to the projection surface is recommended.
Since installation in a room is often not possible without hindering an existing facility or unnecessarily restricting freedom of movement , especially in smaller rooms, retailers offer suitable brackets for walls and ceilings.
In addition, allows increased position an unobstructed projection.
Wall brackets can basically be mounted on any type of room wall . They usually consist of a rigid arm, which is optionally substituted by pulling can be extended, either on which a plate is fixed on which a video projector may be placed or has a suitable mounting bracket to which a projector is mounted hanging.
Models offer greater flexibility in that instead of a rigid arm, one with one or more joints is used. This allows the projector’s projection direction to be optimally changed and adjusted.
Ceiling brackets are screwed tightly to the ceiling and allow the projector to be suspended from the ceiling , a few centimeters below the ceiling.
For very high ceilings which offers commercial adjustable ceiling mounts, a variable mounting height allow the projector.
In both variants, one is swinging the projector is usually not possible, the angle of inclination , however, may never be.
Electrical ceiling mounts are particularly luxurious and usually correspondingly expensive . These are usually only available from specialist dealers and must be precisely matched to the respective projector . Depending on the model, the height and inclination of the beamer can be adjusted by motor.
Hidden variants are particularly attractive , in which the projector can be lowered from a false ceiling at the push of a button and hidden after use .
With all variants , an image correction ( keystone correction / keystone correction) is usually necessary in order to generate a distortion-free image from the selected position . Beamer models with lens shift function enable lossless adjustment.
Cleaning and maintenance of an LED projector
As with most electrical appliances , are regular maintenance and cleaning even with LED projectors appropriate and important measures, the complete and uninterrupted functioning to maintain a device in the long term and a possible long life to ensure.
External cleaning of the LED projector should be carried out regularly at short intervals , depending on the conditions of the installation site or mobile use .
Before cleaning , the device should be switched off for safety and disconnected from the power supply .
In any case, it is advisable before the first cleaning in accompanying documents existing manufacturer’s recommendations to study, even for any warranty restrictions in the note event of damage to.
Dust and surface dirt on the housing can be removed with a suitable soft cloth .
The use of water or other liquids should be avoided as far as possible . A penetration of moisture into the device can in the worst case a short-circuit and cause irreversible damage to lead.
If such damage can be attributed to improper cleaning , a loss of the guarantee and warranty claims is to be expected.
A regular and thorough cleaning of the lens is particularly crucial for the reproduction quality of an LED projector. Dust collects on the lens , which can deteriorate the image quality after a while . Dirt on the lens should be removed with a clean, dry, lint-free cloth .
On water or other liquids, especially on alcohol, should also find possible waived are.
Here too, improper handling can lead to serious damage . Thus, a scratching of the lens, for example by aggressive cleaners or rough, dirty surfaces significantly to the image quality impact.
The trade has special means for cleaning of lenses, in addition, the gentle provides cleaning action of compressed air .
In addition to the simple outer and the cleaning of the outside of the optical lens , cleaning and maintenance work should only be carried out by expert personnel . Under no circumstances should the housing of an LED projector be opened without the appropriate qualifications .
This leads to a loss of warranty claims, can also lead to serious damage to the device and, if not properly carried out, subsequent use of the device can lead to far-reaching consequential damage.
Depending on the type of LED projector and not least related acquisition investment, worth under circumstances a regular professional maintenance, by a specialist or under circumstances the manufacturer or its authorized service provider.
LED projectors are characterized by the lifespan of the built-in lamps . A change of the LEDs is usually not necessary or provided.
Should such an event be necessary , contrary to expectations , for example due to damage, it should also only be carried out by specialist companies within and outside the guarantee or warranty period.
If an LED projector only occasionally used, recommended in the split times a storage in suitable packaging, a pollution or damage prevented as much as possible.
Alternatives to the LED projector
LED projectors have clear advantages over alternative technologies. However, they also have limitations, one does not use in any environment and at any purpose it appear optimal.
In case of doubt , it makes sense to familiarize yourself with the available alternatives, their advantages and disadvantages compared to an LED projector .
A liquid crystal display , from the English known as liquid crystal display (LCD) , there is, to put it simply, a liquid film composed of crystals. LCDs are divided into segments .
The liquid crystals contained therein change their orientation and thus the light transmission of the respective segment (pixel) due to electrical voltage .
To produce LCDs images, the link LCD projector, by means of a translucent light source by an optical system, onto a suitable substrate to be projected.
The coloring of modern LCD beamers is carried out by using three separate LCDs (3LCD technology) , one for each basic color , the images of which are superimposed on special mirrors .
The classic LCD projector uses a special light bulb as the light source , which enables high light intensities .
Advantages of an LCD projector
- inexpensive models
- good readability of texts and graphics
- compact design possible
- good color intensity
Disadvantages of an LCD projector
- Pixel structure of the image can be perceived as annoying (especially applies to older models)
- Inertia of the LCDs can be used for tightening lead
- LCDs require intensive cooling, so projectors are usually louder
- Incandescent lamps have a limited lifespan, which increases the cost of continuous operation significantly
- LCDs can burn in (LCD memory effect)
- LCDs are sensitive to dust and smoke
DLP projectors work according to the principle described , which is also used for LED projectors . The image is generated by a digital mirror device (DMD) , in which millions of tiny mirrors, by their movement, control incident light and direct it through the optics of the projector .
In contrast to the LED projector , a projector lamp is used for image generation with the classic DLP projector, as is also used with the LCD projector .
The colored image is generated by a rapidly rotating color wheel , through which the DMD guides the generated image .
Advantages of a DLP projector
- high image speeds without dragging
- no branding
- high contrast
- low pixel structure
- low sensitivity of the optics
Disadvantages of a DLP projector
- fixed resolution by the DMD, increase requires scaling, thereby loss of quality
- Rainbow effect
- Flickering at certain color values
- low color fidelity
- Noise caused by fan and color wheel
The laser projector is the latest stage of development in the video projector market . In principle, laser projectors are the same as the LED projectors described here .
A digital micromirror device (DMD) , as is known from the DLP projector , is also usually used for laser projectors . The laser diodes used are clearly superior to classic LEDs due to their luminous intensity and clear and deep colors .
There are also so-called hybrid laser projectors, which work with a combination of laser diodes and classic LEDs .
Advantages of a laser projector
- high light intensity compared to the LED projector
- excellent color performance
- long lifetime
Disadvantages of a laser projector
- very high acquisition costs due to low distribution
A display is basically different from a projector, but when it comes to creating a flexibly usable image that is as large as possible , OLED technology offers interesting possibilities, at least in theory.
Organic light emitting diodes (OLEDs) are organic semiconductors manufactured using the thin-film process . Put simply, they enable very large, very flat screens to be manufactured cost-effectively .
However, the technology is not yet fully developed and faces some challenges that currently stand in the way of marketable use . Above all, the life of an organic light emitting diode is currently very short. Only when these problems have been solved can the technology, due to its theoretical possibilities, pose serious competition for all types of projectors .
When dealing with the subject of LED projectors , you are confronted with a variety of technical terms that require explanation . In order to be able to decide on the individually suitable model , it is essential to deal with these terms, at least superficially, in terms of content.
Some manufacturers also simply state this as brightness , the specified value denotes the luminosity of a projector, generated by the illuminant used, i.e. the projector lamp or the LED.
The light intensity is specified in ANSI lumens , whereby ANSI stands for the standardized test procedure (American National Standards Institute) . Most manufacturers only use the term lumen in their specifications . In simple terms, the value indicates how much light a light source, in this case the projector, can emit on a certain limited area .
The value of the light intensity advisable for a projector depends on the ambient conditions, i.e. on the one hand on the size of the desired projection surface and on the other hand on the ambient brightness.
Values below 100 lumens per square meter ( m² ) are generally not recommended; between 100 and 250 lumens / m² are suitable for well darkened rooms; 250 to 500 lumens / m² deliver convincing results even with moderate darkening ; With more than 500 lumens / m², it can also be used outdoors in daylight .
The contrast ratio describes the ability of a projector to display black and white with a maximum difference in brightness . The higher the contrast ratio, the richer and sharper an image is perceived.
The contrast ratio is given according to the scheme light: dark . In other words, if a projector with a contrast ratio of 1,000: 1 is specified, the brightest displayable pixel of an image is a thousand times brighter than the darkest.
A projector with a high contrast ratio is particularly suitable for use in a darker environment, for example as a home cinema projector, since differences are perceived more clearly and a deep black is required for a high-quality image . In bright conditions, such as outdoors, the contrast of lesser importance, since the ambient brightness the Black perception supported.
The stated value for the resolution of a projector indicates the number of pixels (pixels) from which the device composes an image. The value is given in the style pixel / row (horizontal) x pixel / column (vertical) .
Certain resolutions are assigned to certain standards with which manufacturers of optical devices advertise their resolution :
VGA (Video Graphics Array) – 640 x 480 pixels
WVGA (Wide VGA) – 854 x 480 pixels
SVGA (Super VGA) – 800 x 600 pixels
XGA (Extended Graphics Array) – 1024 x 768 pixels
HD ready (720p) – 1280 x 720 pixels
WXGA (Wide XGA) – 1280 x 720/768 pixels
WUXGA (Wide Ultra XGA) – 1920 x 1200 pixels
Full HD (1080p) – 1920 x 1080 pixels
4K (Ultra HD) – 3840 x 2160 pixels
Maximum resolution and native resolution
Many manufacturers state high values in the form of a so-called maximum resolution . This primarily serves the advertising effect.
However, the maximum resolution only indicates which resolution a projector supports, i.e. the resolution in which media may be available in order to be displayed. However, only the native resolution, which is lower when in doubt, is shown in practice .
Example: a projector is advertised by the manufacturer with a full HD maximum resolution of 1920 x 1080 pixels. A video recorded in 1080p is played back via a connected Blu-Ray player.
Due to its design, the projector has a native HD ready resolution of 1280 x 720 pixels. The video can be played, but is only displayed in 720p.
The process of adapting the higher resolution to the projector is called downscaling . This process can lead to loss of quality.
Also known as the refresh rate , the value indicates the number of individual images that a projector can display per second .
The frame rate is specified in Hertz (Hz) and corresponds to the alternative value Frames per second (fps) , i.e. the number of pictures that are displayed per second .
Are usual values of 50 or 60 Hz. Manufacturers apply individual models due to a significantly higher refresh rate of 100 or 120 Hz.
May be a non-beamer , centrally in direct line with respect to the projection are situated, it comes through the necessary displacement to a distortion of the image. This distortion is eliminated by a so-called keystone correction , however, through which image information is lost.
A lens shift function enables distortion-free movement of the image without having to move the projector , i.e. without keystone correction and without loss of quality.
When keystone correction – also known as Keystone referred – is to compensate for image distortion caused by oblique incidence of the Lichstroms a projector to the screen is created. Due to the oblique impact, one side of the rectangular image appears longer than the opposite side.
This effect is alleviated or completely eliminated by artificially compressing the longer side . Since the point density of an image is changed by interpolation , image information is lost.
Classic DLP projectors create color images with the help of a rapidly rotating color wheel with the three primary colors. Three individual images are actually created, but are perceived as one by the human eye.
A small percentage of people (approx. 5 – 10% ), however, recognize individual images , particularly in the case of very fast image sequences and in a dark environment. This perception manifests itself in the rainbow that gives it its name, i.e. color gradients on the edges of the picture.
This can be remedied either by a faster rotation of the color wheel, a finer subdivision or optimally a color image generation in three separate stages.
If a projector moves closer to a screen , the picture becomes smaller and brighter, if it moves away from the screen , the picture becomes larger but darker.
The projection ratio describes the relationship between the size of a projected image and the distance of the projector from the projection surface .
Manufacturers give the quotient from the ratio of distance to canvas: image width in meters. If a projector is specified with a projection ratio of 1.8 , this means that a distance of the projector of 1.8 m to the projection surface produces an image with a width of one meter .
In this way it can be calculated exactly which distance is necessary for a certain image size or which image size results in a certain distance .
If a manufacturer specifies a range instead of a fixed value, for example 1.5 – 2 , this means that the projector has a zoom lens with which the ratio can be varied.
LED projectors are on the rise. The LED technology has in recent years developed rapidly and offers compelling advantages in use especially for home theater projectors.
In particular, the long service life and thus the possibility of continuous use without high follow-up costs make LED projectors a serious competitor for classic projectors with projection lamps as the light source.
Nevertheless, has the technology still weaknesses in the direct comparison with the alternatives are clear. This means that the light intensity, especially with inexpensive models, is significantly lower and thus the area of application is limited.
However, it can be assumed that the further development of the technology will quickly lead to a significant increase in performance . In the medium term, LED projectors will be able to further replace other technologies .
Until then, you have to weigh up in individual cases whether the restrictions are compatible with the required purpose . In terms of functions and equipment , LED projectors already do not differ from other projectors.
Pronounced micro or pocket projector must in today’s state of the art rather than interesting gimmick are considered and as a presentation of technical feasibility.
Sure, these devices or combinations with other devices , such as smartphones, have a high entertainment value and a spontaneous utility value, but in terms of performance, they are not yet able to compete with larger devices, both from LEDs and from projectors with other functional principles .