When the iPhone 4 launched in June 2010, it was not without its glitches. The first reported glitch was with the iPhone 4 wireless 3G antenna. This was suspected of causing poor reception and high volume of dropped calls. The next reported issue was with the proximity sensor on the iPhone 4. Apple addressed this issue at the software level, with the release of iOS 4.1.
Since the release of iOS 4.1, there have been many questions about whether or not the update solved the iPhone 4 proximity sensor problem once and for all. From my own experience, I have not had any complaints since this software update was released.
Some of you may be wondering, “What the heck is a proximity sensor and what does it do?” Without getting too involved, all iPhones (including the original iPhone 2G, 3G and 3GS models) have a proximity sensor. This sensor emits infrared (IR) light that detects the presence of a solid object (such as a head or hand), while you have a call in progress or while listening to a voice message. When it detects a solid object, it turns off your iPhone’s LCD panel. This is a feature that will probably never be lost until it stops working.
The proximity sensor feature has two distinct advantages. First, you’re not muting your phone, accidentally pressing buttons, or hanging up with your cheek on callers. The other benefit is that it conserves power consumption and improves your phone’s battery life between charge cycles.
As an Apple Certified Macintosh Technician who makes a living supporting and repairing Apple products, this is a problem that cannot be ignored. The reputation of my business depended on the ability to find a reliable and professional solution to this problem. I have done extensive research and testing on this topic and feel that I have made significant progress in resolving this annoying error.
In the four years that I have been repairing iPhones, I have only recently begun to experience problems that have been widely documented and reported. Since the release of iOS 4.1, I have not seen any cases where the iPhone proximity sensor has failed on a phone that has not been modified. When I say “modified” I mean a phone that has undergone a color conversion, or one in which the front glass and LCD screen have been replaced due to the phone being dropped and the original glass breaking. I noticed that the occurrence was more apparent after color conversions had been done.
Since the proximity sensor in the iPhone 4 is located in the middle frame of the iPhone and is not part of the front glass and LCD assembly, I had never questioned the quality of the parts I was buying. With that in mind, I started testing all the phones before repairing them. I wanted to be sure the phones were working properly, before doing repairs or color conversions. So far I have yet to find a malfunctioning one before repair. It turns out that the problem was attributed to two factors.
1. The unique sensitivity of each iPhone proximity sensor.
2. The proximity sensor cover on some of the replacement glasses is not tinted dark. This allows too much light to pass through.
I have read many articles and blogs suggesting the use of black tape with punched holes or a black magic marker to cover the proximity sensor of the iPhone. I didn’t feel like any of these fixes offered a professional solution, or one that I wasn’t even proud to employ in my practice.
After talking to my parts dealer, I found that the best solution to this problem is an inexpensive “sensor cover.” This cover is a small piece of film with a coating that appears to be the same red polarized coating on some sunglasses. This small piece of film is installed over the top of the iPhone’s proximity sensor.
At the end of the day, it would seem that too much light is coming in and confusing the phone. The proximity sensor cover filters out excessive light from entering the phone and solves the problem.