Toyota Group companies account for about 75 to 80 percent of Denso's sales in the field.
But its millimeter wave radar is used in safety systems on the Mazda3 and Mazda6 sedans, as well as the Hyundai Sonata sedan. The Kia Soul subcompact also uses a camera sensor from Denso.
New regulations, such as those being in introduced in Europe, should make it easier for Denso to find new customers.
That is because the regulations set a baseline for sensor performance that must be met by all carmakers. And the clear specifications make it easier to develop standardized sensors. Standardization, in turn, allows for higher volume and lower costs, meaning a wider array of customers can use the same part.
At least that is Kato's expectation.
"If we can achieve those NCAP targets, then we can apply our product to many customers, beyond Toyota," he said.
"Sensors need standardization, otherwise they won't be widely used by many different customers."
Yet when it comes to sensors, there is no one-size-fits-all solution. The industry generally deploys several kinds of sensors, each with their strengths and weaknesses.
Denso, like the industry at large, is still groping for the best mix and a breakthrough to reduce the number of sensors.
For now, Denso is turning to systems that mix different kinds of sensors to cover one another's weaknesses.
For example, millimeter wave radar is good at long-range detection and not easily disrupted by bad conditions such as rain or fog. It also is very precise in measuring distance.
That makes it good for adaptive cruise control. But it is weak at discerning shapes such as pedestrian silhouettes.
Laser radar is more cost-effective but has a shorter range and is weak in inclement weather. It is used in low-cost systems.
Optical or camera-based sensors are best at discerning the shapes of pedestrians from trees or decoding roadside signs.
But they too have range and weather limitations. Any active safety system that wants to tackle vehicle-on-pedestrian collisions typically deploys a camera-based sensor.
"They all have strengths and weaknesses," Kato said. "But sensing has to be very, very reliable. So the current trend is using a combination, or fusion, of different kinds of sensors."
And that redundancy is yet another cost hurdle to overcome.