Author: Michelin

In recent years, what cars lack the least may be various “revolutions” in the cabin: using a central control big screen instead of a small and exquisite LCD screen; using touch control and voice interaction instead of physical buttons; adopting naked-eye 3D technology in the dashboard…

Since last year, various models equipped with HUD or even AR-HUD have appeared. This technology, which used to be the “icing on the cake” in luxury brand high-end lines, not only appears more and more in models that the public can accept, but also takes on more functions. The recently released Ideal L9 even directly uses HUD to replace the dashboard.

Is replacing the dashboard with HUD just a flash in the pan or a future trend?

What are we looking at when we look at the dashboard?

120 years ago, when the automobile magnetoelectric mechanical speedometer was born, its significance was undoubtedly huge. With a series of gauges such as tachometers, oil temperature gauges, and fuel gauges installed, driving is no longer a technology that is beyond reach.

With the existence of automotive instruments, drivers can know the fuel level of the car without lifting the machine cover to insert the fuel gauge into the fuel tank. You can also control the shift based on the engine speed and know the current driving speed based on the speedometer…

Vehicle speed, engine speed, water temperature, gear position, fuel level… essential information during the manual shift era. With more and more automatic transmission cars on the road, part of this information has lost its meaning, and even the mechanical instruments in the car have gradually been replaced by LCD instruments.

As car technology evolves, it seems that people rely less and less on instrument information. With the introduction of LCD instruments, the performance of dashboard, such as size, display effect, information capacity, data accuracy, and stability, has been linearly increasing.

As vehicles and LCD instrument clusters “run-in” with each other, and when everyone is no longer worried about whether the LCD instrument cluster is unstable or lacks mechanical feel, car manufacturers have also explored their own design tone on their own LCD instrument clusters. With the advent of the smart car era, navigation and ADAS functions have become “newcomers” on the dashboard: the center of the LCD instrument cluster is opened up to display navigation and visualized driving assistance information.

In the era of LCD instrument panel, the dashboard, as an attribute of “meter,” has gradually been weakened, becoming an information display area closely related to driving, whether it is vehicle speed, speed limit, fuel or electric quantity, or navigation and ADAS. As long as it can be viewed clearly and conveniently by the driver, it is enough.

By this account, in the “post-LCD instrument panel era,” whether it is like Tesla Model 3 placing instrument information on a touch screen, or like the Ideal L9 replacing physical instrument panel with HUD, it only changes the location of the information display, and the instrument panel is not irreplaceable.

The only remaining question is: can HUD replace the instrument panel sufficiently well?

Can you accept HUD replacing the instrument panel?

Not long ago, GeekCar conducted a “soul-questioning” with some deep users of intelligent cars about daily car use, and one of the questions was: “Can you accept using HUD instead of the instrument panel?”

Perhaps because the interviewees were all intelligent car owners, unexpectedly, a 60-40 answer was obtained:

About 60% of respondents can completely accept HUD replacing the instrument panel, believing that as long as the information display is clear and the effect is good, it is no problem. Some even said that they can accept Tesla Model 3, which directly cancels instrument devices, and replacing the instrument panel with HUD is simply a small case.

About 40% of the respondents expressed that this replacement was too bold and unacceptable, fearing that the HUD display effect was unstable or that fancy graphics would affect driving.

Although both sides gave completely different answers, they almost all mentioned the same problem: the display effect of HUD.

This also reflects a crucial issue with HUD: information presentation on complex roads is also easily affected by external environmental factors. When the lighting changes, or there is rain or fog, or there are fancy and complex obstacles on the road, whether the display effect of HUD will be discounted becomes a question, and it is also one of the several issues that need to be solved before HUD replaces instrument panels.

Clear display effect

To replace the instrument panel with HUD, the display effect is the first issue to be solved.

The advantages of HUD are almost “old and common”:

• Projecting information onto the windshield, drivers can see key information without looking down;

• At complex intersection, guidance arrows in front can accurately guide the route;- After activating ADAS, the lane lines, the position of the preceding vehicle, as well as the warning of the vehicles and pedestrians around, can be displayed…

These advantages enable the driver to focus more on the road ahead, and improve both safety and comfort significantly.

However, all these advantages depend on one premise: being visible. Otherwise, the HUD becomes not only a useless decoration but also a distraction.

Just like when choosing a projector for your home, the brightness, contrast, and projected size are essential criteria to evaluate car-mounted HUDs.

In terms of size, to replace the LCD instrument panel that is often over ten inches in size, it is necessary for the HUD to have a size of over a dozen inches at some distance. For example, the ideal L9 HUD has a size of 13.35 inches, while the Mercedes-Benz S-Class equipped with AR-HUD last year had a 33-inch display at a distance of 10 meters.

Larger HUD displays ensure the size of the image information, and provide retina-level picture quality with a contrast ratio of over 1000:1.

Apart from picture quality, the brightness of previously mass-produced HUDs has been criticized the most: it is hard to see in strong sunlight during the day and too bright at night while driving. When the HUD replaces the instrument panel and becomes the only channel of instrument information, these issues must be addressed. Currently, the competition of HUD brightness has reached a level of over 10,000 nits, such as the maximum brightness of the ideal L9, which is 12000 nits, and the Huawei HUD previously mounted on the RisingAuto R7 also reaches 12000 nits.

It is worth noting that the peak brightness of the mini-LED screen used by MacBook Pro is only around 1600 nits, which cannot be compared with the HUD. Nevertheless, it can help us to feel more intuitively the displaying effect of high-brightness HUD under strong lighting.

HUD, as an optical design-based product, is as precise and complicated as a camera. While standardized parameters such as size, contrast, and brightness can evaluate the basic capabilities of HUD, the actual effects may differ. Several months ago, in an interview with the HUD supplier of the ideal L9, FUTURUS Future Technology, GeekCar got this description of the difficulty of implementing HUD: “It is a process of seeking a suboptimal solution.”In designing each HUD device, the field of view, contrast, and brightness may be the same, but the optical design scheme and customized free-curved mirrors need to be adjusted according to the windshield angle of each vehicle model. Careful calibration is necessary to eliminate distortion, ghosting, and even dizziness caused by HUD.

Through the combination of hardware parameters and software calibration, HUD can replace the instrument panel with clear display effect.

After solving the problem of display clarity, what information HUD displays and how it is presented is the most intuitive feeling for the driver.

There is an obvious common sense: when too much information appears at the same time, we will be at a loss as to which information to look at first. Similarly, the more information is displayed while driving, the longer it takes for the driver to react in case of emergencies.

Similar problems can also be seen from some comments on the concept map of AR-HUD by some netizens: When facing the detailed road information of the AR-HUD effect, many netizens’ first reaction is, “Can you still see the road clearly?”

Of course, this design is more for the future era of autonomous driving, when vehicles can drive automatically and users do not need to look at the road while driving. These pieces of information are like real-time information boards on sightseeing buses, and there is no interference naturally.

However, at this stage, when we consider replacing the instrument panel with HUD, we still need to achieve high readability by providing simple and clear information with clear priority. Studies have shown that drivers can perceive 5 to 9 items at a time when driving, and can make timely reactions, including information about vehicles and pedestrians ahead, so the information display space left for HUD is generally 3 to 5.

This kind of “simplified” design can be seen in the HUD/AR-HUD models launched in the past one or two years:

The HUD on the Volkswagen ID is divided into two areas, the upper augmented reality display area displays AR dynamic guidance, and the lower conventional information area displays three types of information, including adaptive cruise control, speed limit, and speed.

The HUD of WEY Mocha is divided into three areas, the right displays navigation information, the middle is AR dynamic guidance, and the left is speed limit, speed, and adaptive cruise control information.

On the ideal L9, the HUD is also divided into three areas: navigation information on the left, driving assistance visualization information in the middle, and speed and speed limit information on the right. When the navigation and driving assistance visualization are turned off, only the speed and energy consumption can be displayed.

Dividing the HUD into two or three areas, displaying one to two types of information in each area, and choosing to display only the speed and speed limit in the introduction mode when the navigation or driving assistance visualization is turned off are common choices for HUDs.

By contrast, the AR-HUD on the Mercedes-Benz S-Class displays navigation, speed limit, speed, cruise control, turning, distance to destination, predicted time, and AR guidance animations on a huge 33-inch screen 10 meters away. Despite providing such a huge display, many people still criticize the effect as too flashy due to the excessive elements.

In addition to the amount of information, the specific presentation method also affects readability. For example, to distinguish between speed, cruise control speed, and speed limit, which are all straightforward numerical values, different image sizes and symbols are used to enable drivers to distinguish them with a glance in emergency situations, and facilitate the understanding of drivers who have just hit the road, without the need to read complex manuals.

In the face of complex road environments, clear and strongly contrasted colors and minimal effects can also make the HUD clear at a glance, such as the predominantly blue and white color schemes chosen almost universally by the current crop of cars equipped with a HUD, making the HUD image clearly visible in external environments, especially on black roads.

System Reliability

Regardless of whether it is a touch screen or a HUD, there is always a concern about the stability of electronic components. For example, what would happen if the system suddenly freezes or crashes, which are sudden occurrences that can happen in everyday use of phones or computers? If they occur in a vehicle, particularly one displaying important information, it can be a huge trouble.Therefore, the current cockpit LCD dashboard and central control screen usually adopt two independent systems, with the LCD dashboard generally choosing a more stable Linux system. When the dashboard is replaced by HUD, there is also the same demand.

If the previous models equipped with HUD also have a reliable backup of the instrument information, then this time, the ideal L9 that directly cancels the instrument panel’s work in terms of HUD reliability can serve as a reference.

According to the official information of the Ideal L9 Interaction Team, in order to ensure the reliability of HUD, a safety backup is done. Even if one hardware system fails, the backup system will run within tens of milliseconds, ensuring the same safety as the dashboard and not affecting driving.

Do we have to remove the instrument panel for some people and some models?

When writing this article, a colleague in the office raised a question: “Why do we have to remove the instrument panel?”

Indeed, although displaying instrument information with HUD brings various advantages, it does not seem contradictory for HUD and the instrument panel to coexist. Even for the Model 3, which has long removed the instrument panel, it has not used the area of ​​the instrument panel for other purposes, and the resulting space seems to have no use.

Currently, except for the Ideal L9, more vehicles still choose to coexist with HUD and the instrument panel. On the one hand, this is due to considerations for the stability of the current HUD performance; on the other hand, the instrument panel is not only used to display instrument parameters, but also to convey the brand tone of the automaker to a certain extent.

Taking the most obvious mechanical and dynamic attributes on the car as an example, technological progress simplifies many functions, but making a reduction in the manifestation of the dynamic properties of certain brands and models is not always the way to go.

This reminds me of 50 years ago, when digital dashboards first appeared on cars, Aston Martin matched the avant-garde full digital dashboard with the Lagonda Series 2, abandoning the pointer instrument, and using three screens to display speed, mileage, fuel, tachometer and other parameters fully digitized. However, after a brief attempt, the mechanical retro-style pointer instrument, the turret design, and so on returned to the instrument panel.

This “addition” is also reflected in HUD.

For example, in the HUD concept of Wayray’s cooperation with Porsche, HUD did not insist on the usual digital simplicity, but integrated Porsche’s sports essence, displaying racetrack lap times, speed, gear position, turning points, racetrack maps, and other information on the HUD.

BMW did not use the common blue and white color scheme in the HUD design of the BMW VISION NEXT 100 concept car, but instead used dynamic red and white, and specially set the “boost mode” for the driving experience…

These elements bring the HUD one step closer to replacing the instrument panel: do we have to cancel the instrument panel? Not necessarily. But the HUD can indeed replace the instrument panel in terms of function, decoration, driving safety, and brand characteristics.

Finally

Let’s return to the two questions from before.

Can the HUD replace the instrument panel well enough?

Technically, it can; in terms of display effect, it can too; emotionally, well, when the engine is replaced by an electric drive system and the mechanical instrument panel is replaced by a liquid crystal instrument panel, it’s also hard to say how attached the supporters of today’s liquid crystal instrument panel are.

Will the future replacement of instrument panels by HUD be a flash in the pan or a trend?

At least in the short term, the HUD is still a feature that only a few models have, and its optical structure determines the difficulty of large-scale standardized production and requires “customization based on measurements”, which directly affects the speed of popularizing high-quality HUDs.

After all, to make the replacement of the instrument panel by HUD a trend, at least every car model can be equipped with a HUD. By then, I believe that car manufacturers who are meticulous with their budgets will also voluntarily make choices between the instrument panel and HUD.

As Li Xiang said, “HUD should not just be a show of skills.”

This article is a translation by ChatGPT of a Chinese report from 42HOW. If you have any questions about it, please email bd@42how.com.