BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the technology field of MPE (maximum permissible exposure time of retina) calculating, and more particularly to a device and method for simply determining maximum permissible exposure time of retina.

2. Description of the Prior Art

It is well known that natural light consists of visible and invisible lights, wherein infrared (IR) light and ultraviolet (UV) light are two of the invisible lights. On the other hand, it is understood that the visible lights comprise red, orange, yellow, green, blue, indigo, and purple lights. Retina is an important part of human eyes, and has specific function of converting light signal to neural signal.FIG. 1illustrates one diagram for showing a sunlight spectrum, and there is another one diagram for showing an emission spectrum of a white light LED provided inFIG. 2. It is known that, the specific light irradiated from sun commonly has a continuous spectrum. Differing from the sunlight, however, an LED lighting element that is configured for emitting an artificial light (i.e., white light) has been widely applied in various illumination devices, backlight modules and self-luminous display panels. FromFIG. 2, it is also found that the white light emitted by the LED lighting element has a discontinuous spectrum that merely contains visible wavelengths in a range from 430 nm to 680 nm. Moreover,FIG. 1also indicates that the intensity of the green light is greater than that of the blue light in the sunlight spectrum. On the contrary, however,FIG. 2shows that the artificial LED light specifically contains a high-intensity blue light.

As explained in more detail below, blue light contains a visible wavelength in a range between 400 nm and 500 nm, and a proper lighting of blue light can lift a person's spirits and make the person has a feeling of pleasure. However, many different research reports all conclude that, too much illumination of blue light would bring light pollution, disturbance of human biological clock, loss of sleep, and eye damage on. To be more seriously, too much illumination of blue light may cause a man suffer from macular degeneration. Therefore, sinceFIG. 2has showed that the artificial LED light specifically contains the blue light with high-intensity as well as that people every day have a considerably long elapsed time of using their 3C products (like laptop computer, smart phone or tablet PC) in every day, ophthalmologist, eyewear manufacturing companies and lamp manufacturing companies have made great efforts to propaganda the important issue of blue light hazard.

Blue light is the part of the spectrum with the highest energy content and that still can reach the retina. It has been studied that, photochemical means that due to the high energy content of the incoming light some chemical reactions take place on the retina, eventually bringing photoretinitis on, which is a retinal lesion induced by light, in particular the high-energy blue light. Herein, it needs to explain that, how to calculate a specific light's maximum permissible exposure (MPE) limit for retina has been disclosed in American National Standards Institute (ANSI) Z136.1-1. Nowadays, MPE limit is usually expressed in terms of the allowable exposure time (in seconds) for a given irradiance (in watts/cm2) at a particular wavelength. Therefore, a specific light's MPE limit value would grow with the increase of the illuminance thereof. Of course, the MPE limit of a short-wavelength light is certainly higher than that of a long-wavelength light in case of the forgoing two lights being modulated to have the same illuminance.

Briefly speaking, when calculating a specific light's MPE limit value, it needs to use a spectrometer to collect a spectrum data of the specific light, and then obtaining corresponding spectral weighting value by looking up a blue-light hazard function. Consequently, after using the mathematical formulas provided by ANSI to calculate effective radiance (LB) and effective irradiance (EB), numeric value of the MPE limit of the specific light would be therefore calculated.

The unit of the forgoing maximum permissible exposure (MPE) limit is “second”, such that the MPE limit is also called as MPE time or MPE. In other words, MPE is adopted for describing a maximum endurance time of retina for a specific light such as a light provided by a desk lamp. However, for generic users, it is unlikely for them to purchase a spectrometer in order to collect spectrum data for further achieving the calculation of a specific light's MPE.

From above descriptions, it is clear that there is a lack of a device for helping generic users in the calculation of MPE of any one kind of light. In view of that, inventors of the present application have made great efforts to make inventive research and eventually provided a device and method for simply determining maximum permissible exposure time of retina.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to disclose a device and method for simply determining maximum permissible exposure time (MPE) of retina. The device principally comprises a light receiving unit and a core processor. Particularly, there are a color temperature determining unit, a luminous flux determining unit and a calculating unit provided in the core processor. After the light receiving unit receives an illumination light from a light source, the color temperature determining unit and the luminous flux determining unit complete a color temperature determination and a luminous flux determination of the illumination light, respectively. After that, the calculating unit is able to consequently calculate a maximum permissible exposure time (MPE) of retina of the light source based on a use distance, a value of color temperature transmitted from the color temperature determining unit and a value of luminous flux received from the luminous flux determining unit.

As such, by using this novel device, generic users are facilitated to achieve the calculation of any one kind of light's MPE by themselves, without needing to collect spectrum data, and also without needing to look up a blue-light hazard function in order to obtain corresponding spectral weighting value.

In order to achieve the primary objective of the present invention, inventors of the present invention provides an embodiment for the device for simply determining maximum permissible exposure time of retina, comprising:a light receiving unit, being used for receiving a specific light that is irradiated from a light source, wherein there is a use distance between the light receiving unit and the light source; anda core processor, being coupled to the light receiving unit for receiving the specific light, and comprising:a color temperature determining unit for completing a color temperature determination of the specific light;a luminous flux determining unit for carrying out a luminous flux determination of the specific light; anda calculating unit, being configure for calculating a maximum permissible exposure time (MPE) of the specific light based on the use distance and a color temperature and a luminous flux of the specific light.

In one embodiment, the forgoing device further comprises:a distance sensing unit, comprising a data processor and a distance sensor that is selected from the group consisting of optical distance sensor, ultrasonic distance sensor, and radar distance sensor.

In one embodiment, the forgoing device further comprises:a display unit, being coupled to the core processor, thereby being controlled by the core processor so as to display the use distance, the color temperature, the luminous flux, and/or the MPE;an input unit, being coupled to the core processor, such that a user is facilitated to input the use distance to the core processor; anda communication unit, being coupled to the core processor, such that the core processor is able to communicate with an external electronic device through the communication unit.

In one embodiment of the forgoing device, the calculating unit comprises a mathematical algorithm for completing a calculation of the MPE, and the mathematical algorithm being presented as

M⁢P⁢E⁡(FLD)=J+K⁡(e-TL)+M⁡(e-TN);
wherein MPE is the maximum permissible exposure time, FLbeing the luminous flux, D being the use distance, T being the color temperature, and J, K, L, M, and N being statistical experience constants.

In a practicable embodiment, the forgoing device is an electronic device selected from the group consisting of desk optical measuring instrument, portable optical measuring instrument, smartphone integrated with optical measuring unit, smartphone connected with external optical measuring module, tablet PC integrated with optical measuring unit, tablet PC connected with external optical measuring module, laptop computer integrated with external optical measuring unit, laptop computer connected with external optical measuring module, all-in-one desktop computer integrated with optical measuring unit, all-in-one desktop computer connected with external optical measuring module, and desktop computer connected with external optical measuring module.

In a practicable embodiment, the forgoing distance sensing unit comprises a data processor and a distance sensor that is selected from the group consisting of optical distance sensor, ultrasonic distance sensor, and radar distance sensor.

For achieving the primary objective of the present invention, inventors of the present invention also provides an embodiment for the method for simply determining maximum permissible exposure time of retina, comprising:(1) letting a core processor be coupled to a light receiving unit;(2) letting the light receiving unit receive a specific light that is irradiated from a light source, wherein there is a use distance between the light receiving unit and the light source;(3) configuring a color temperature determining unit and a luminous flux determining unit in the core processor, so as to complete a color temperature determination and a luminous flux determination of the specific light; and(4) configuring a calculating unit in the core processor, so as to carry out a calculation of a maximum permissible exposure time (MPE) of the specific light based on the use distance and a color temperature and a luminous flux of the specific light.

In one embodiment, the forgoing method further comprises:(5) letting the core processor be coupled to a display unit, so as to control the display unit to show the use distance, the color temperature, the luminous flux, and/or the MPE.

In a practicable embodiment, the forgoing method is applied in an electronic device.

In a practicable embodiment, the use distance is inputted to the core processor by using an input unit.

In a practicable embodiment, the use distance is measured by a distance sensing unit comprising a data processor and a distance sensor that is selected from the group consisting of optical distance sensor, ultrasonic distance sensor, and radar distance sensor.

