Compatibility
The general purpose of the glasses is specified based on which device they are to be used with:
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For PC/Console. Glasses connected during operation to an external device and receiving a video signal from this device. Most often, it is supposed to be connected to a computer or game console, but there are models that can be connected to mobile gadgets, drones, etc. In general, they provide a good compromise between accessibility and functionality, and besides, quite advanced graphics can be displayed on such glasses. On the other hand, for the full use of such models, powerful video cards are often required.
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For a smartphone. Models designed to turn a smartphone into a virtual reality device. To do this, the smartphone is installed in a special slot on the glasses so that its screen is turned towards the user's eyes; glasses themselves do not have screens. And the effect of virtual reality is achieved through the operation of smartphone sensors and (accelerometer, gyroscope) and the use of special applications created specifically for this format of work. The key advantage of glasses of this type is simplicity and low cost: most often these are purely mechanical devices, without built-in electronics (and even advanced models with additional hardware are much cheaper than other types of glasses). On the other hand, the quality of virtual reality directly depends on the capabili
...ties of the smartphone, despite the fact that not all devices correctly process such content. In addition, the glasses must be compatible with the smartphone being used, and this is not always guaranteed (for more details, see “Maximum phone size”).
— For quadcopter (FPV goggles). Video glasses used to control drones and radio-controlled unmanned aerial vehicles (UAVs) to provide a first-person view. FPV goggles allow pilots to receive a video feed from a UAV camera in real time. To do this, the design of such glasses provides two separate miniature screens for each eye and complex optics to provide binocular vision. Lenses often have adjustable focal length to suit the visual apparatus and the varying needs of the pilot. Many FPV goggles are equipped with a built-in receiver and antennas to receive signals from the video camera on board the UAV, as well as control the quadcopter. FPV systems are actively used in the segment of racing drones, aerial photography, and even in combat operations. Glasses with a first-person view provide the pilot with a more complete perception of the surrounding environment and improve the controllability of the aircraft.
— Standalone device. Points that function completely autonomously and do not require the use of external devices. To do this, the design provides for its own processor, "RAM", video adapter, drive for storing content and a battery for power. Thus, with such a gadget, virtual reality becomes available literally anywhere in the world; and at a cost, such glasses are comparable to models for PC / consoles. On the other hand, the capabilities of stand-alone devices are noticeably more modest: the relatively low power of video adapters does not allow for the same advanced graphics as on PCs or consoles, the amount of internal memory is usually small, and the continuous operation time is limited by battery charge.
— For quadcopter (FPV glasses). Video glasses used to control drones and radio-controlled unmanned aerial vehicles (UAVs) to provide a first-person view. FPV goggles allow pilots to receive a video feed from a UAV camera in real time. To do this, the design of such glasses provides two separate miniature screens for each eye and complex optics to provide binocular vision. Lenses often have adjustable focal length to suit the visual apparatus and the varying needs of the pilot. Many FPV goggles are equipped with a built-in receiver and antennas to receive signals from the video camera on board the UAV, as well as control the quadcopter. FPV systems are actively used in the segment of racing drones, aerial photography, and even in combat operations. Glasses with a first-person view provide the pilot with a more complete perception of the surrounding environment and improve the controllability of the aircraft.Field of view
The viewing angle provided by virtual reality glasses is the angular size of the space that falls into the user's field of view. Usually, the characteristics indicate the size of this space horizontally; however, if you need the most accurate information, this point needs to be specified separately.
The wider the viewing angle — the more the game space the user can see without turning his head, the more powerful the immersion effect and the less likely that the image will be subject to the "tunnel vision" effect. On the other hand, making the field of view too wide also does not make sense, given the characteristics of the human eye. In general, a
large viewing angle is considered to be an angle of 100° or more. On the other hand, there are models where this indicator is 30° or even less — these are, usually, specific devices (for example, drone piloting glasses and augmented reality glasses), where such characteristics are quite justified given the overall functionality.
Refresh rate
The refresh rate supported by the glasses' built-in screens, in simple terms, is the maximum frame rate that the screens are capable of delivering.
Recall that screens are provided in models for PC / consoles and in stand-alone devices (see "Intended use"). And the quality of the picture directly depends on this indicator: other things being equal, a
higher frame rate provides a smoother image, without jerks and with good detail in dynamic scenes. The flip side of these benefits is an increase in price.
It is also worth considering that in some cases the actual frame rate will not be limited by the capabilities of the glasses, but by the characteristics of the external device or the properties of the content being played. For example, a relatively weak PC graphics card may not be able to pull out a high frame rate signal, or a certain frame rate may be set in the game and not provide boosting. Therefore, you should not chase after large values and
points with a frequency of 90 fps will be enough.
Proximity sensor
The presence of a
sensor in the glasses that reacts to approaching the user's face.
A similar sensor is used to automatically switch between operating and standby modes: for example, when the user takes off the glasses, the sensor turns off the built-in screens (or the phone, if it is connected to the glasses via a connector), saving battery power and equipment life, and when put on, it turns on points for full functionality.
Lens distance adjusting
The ability
to move the lenses of the glasses back and forth, thus changing their location relative to the screen and the user's eyes. The specific meaning of this function can be different: it can adjust the angle of view (so that the screen fits completely in the field of view and at the same time is not too small), play the role of diopter correction (which is important for users who wear glasses) or focus, change the setting interpupillary distance (see below), etc. These nuances should be clarified separately. However, anyway, this function will not be superfluous — it makes it easier to adjust the glasses to the personal characteristics of the user.
USB A
The glasses must have at least one USB A connector. This is a full-sized USB connector, the same type as standard USB ports on computers and laptops. But its functions may be different, depending on the functionality of the glasses (see "Purpose"). So, in models for PCs and consoles, USB is one of the connection connectors used in conjunction with a video interface such as HDMI or DisplayPort: an image is transmitted via a video connector, and data from sensors on glasses is transmitted via a USB connection, which is necessary to change the picture and create " immersion effect. And in independent devices, USB A is used to connect various additional accessories — for example, flash drives with applications or other content. It is also possible to use this connector to charge the battery, although this method of use in general is not typical for it.
HDMI
Availability of HDMI input in glasses; the version of this interface can also be specified here.
HDMI is the most common interface for high-definition video and multi-channel audio today; it is widely used in both computers and video equipment. In VR glasses, this type of connector is responsible for receiving video and audio signals from an external device; accordingly, only models for PC / consoles have such a connector (see "Intended use"). As for HDMI versions, the options may be as follows:
— v.1.4. The earliest of the current standards, the 2009 model (with subsequent updates). Allows you to work with Full HD video at a frame rate of up to 120 fps, but with 4K content, the speed is limited to 24 fps.
— v.2.0. Standard introduced in 2013. Also known as HDMI UHD, thanks to full support for UltraHD 4K (provides frame rates up to 60 fps). And in further updates of this standard, support for HDR was added.
— v.2.1. Version released to the market in 2017. It allows you to achieve a frame rate of 120 fps even at 8K resolutions, not to mention more modest ones. HDMI Ultra High Speed cables are required for full use, but the features of earlier versions are available with regular cables.
Microphone
The presence of
a microphone in the design of VR glasses.
This function is mainly equipped with models for PC / consoles (see "Intended use"). The built-in microphone is mainly used for voice communication in online games. At the same time, it often turns out to be more convenient than a desktop microphone or a microphone built into a headset: glasses can interfere with the comfortable wearing of a headset, and a desktop device is not applicable because at least the user’s head (or even the whole body) is constantly moving in VR games, and constantly it is impossible to be at the optimal distance from the microphone.
For added convenience, your own microphone can be made retractable or removable.
Headphones
The presence
of your own headphones in the design or delivery of virtual reality glasses.
A full-fledged "immersion" in the virtual world requires not only a picture on the screen, but also an appropriate sound accompaniment, for which headphones are the best option. However, glasses take up quite a lot of space on the head, and not all “ears” can be comfortably combined with them (this is especially noticeable on large over-ear headphones). In addition, when connecting headphones with a wire, there may be problems related to the length and/or location of the audio cable. Thus, some models provide this function. These models can have any purpose (see above); most of these are for PC/console glasses, but headphones are also popular in standalone devices. Also note that some glasses use speakers located in the ear area; such speakers are also considered headphones in this case.
An alternative to the bundled "ears" is a headphone output; however, there are models with both functions at once — either folding / removable cups or the simplest speakers mentioned above play the role of headphones in them.