Application of color temperature and color rendering in lighting design

Indoor lighting design is an important part of interior design, with the support of humanized lighting, green lighting concept, indoor lighting to create a good effect, should be based on the fundamental principle of people-oriented, meet the people's physiological and psychological needs.

Therefore, the research on the application of color temperature and color rendering is becoming more and more important, especially the effect of color temperature on the light environment.

LED indoor lighting and general LED indicator light, to be closer to the effect of natural light, so that the object under the irradiation of the light source colorless distortion.

Color temperature refers to the color of the light emitted by the light source is the same as that of the blackbody at the same temperature. Color temperature is a measure of light color index, color temperature low light color (red), said the warm high said color slants cold (blue). The color is actually a kind of psychological and physical effect on all color impression, is due to intermittent reaction spectrum in the eyes, so that the color of the color is used for visual impression [6].

Color rendering refers to the performance of the light source to the color of the subject, that is, the degree of color. The color rendering is indicated by the color rendering index Ra. Good color rendering of the color of the light source is better, the color is closer to the natural color of the object; the poor color rendering of the light source of the reproduction of the color, the larger the color deviation. The color rendering of the light source is determined by the spectral power distribution of the light source, and the color of the continuous light source is good.

Choose a suitable light source color temperature and color is very important for the indoor lighting design, or a good decoration, furnishings, art will be due to improper selection of light source and by [4].

Method and application by analyzing the different light source color temperature and color in interior lighting design, combined with the living room lighting design as an example, LED color temperature and color rendering in the indoor lighting design advantages, and LED color temperature and color rendering criterion.

1, indoor lighting design for color temperature and color rendering of the demand analysis

Space user requirements

(1) the demand for indoor lighting

Since ancient times, the sky is the most consistent with the physical needs of people, people demand for light is the transition from the original simple lighting needs and development up to now on light art demand, now put forward higher requirements on the lighting environment, the dynamic simulation of natural light and lighting in the indoor environment, including dynamic lighting and atmosphere lighting.

Indoor users not only pay attention to the brightness of the lighting, but also pay more attention to the influence of different spectral distribution on people's physiological and psychological state.

The traditional incandescent lamp, gas discharge lamp, energy-saving lamps and other light source, color difference, it is difficult to use as a dynamic lighting source. The LED light source color is pure, can have a variety of color selection and distribution of light, easy to control the realization of dynamic lighting, and energy saving and environmental protection, is a new generation of green lighting source.

(2) living room lighting

Usually the living room function is more complex, it is the family activity center, and the reception communication places, the living room lighting environment should be more clear, elegant, warm, in order to reflect the owner's enthusiasm, frank.

According to the different needs of users, people in the living room activities can be roughly divided into: physiological behavior, housework, cultural behavior, entertainment, social behavior, etc..

As a result, the living room lighting can be divided into 5 ways: daily lighting, reception lighting, lighting, lighting, pre bed lighting.

Determine the space to be displayed

(1) the effect of color temperature and color rendering on space atmosphere

From ancient times to now, people live in the natural light environment for a long time, it is decided to adapt to the natural light and comfort. And all kinds of artificial light source color temperature of different color, different physiological and psychological effects on people. The brightness and color of the light is the main factor to determine the spatial atmosphere, the indoor atmosphere is different from the light source changes.

In physiology, the physiological effects of color temperature on the human body include: the transmission of the visual organ and the optic nerve, cerebral cortex, and physiological feelings; the impact of pulse, heart rate, blood pressure.

Warm colors increase heart rate, pulse, blood pressure, mood, appetite, and nervous system and digestive system. Cool colors are calm, relieve tension, inhibit cardiovascular activity and so on.

In terms of psychological experience, low color temperature light to give people a warm feeling (known as warm light), high color temperature light to give people a feeling of cold.

The relationship between light color and human psychology is shown in table 1.

Table 1 the relationship between light color and human psychology

The effect of the color rendering of the light source is mainly manifested in the ability to see the color of the object. In indoor lighting, the color rendering index is generally above 80.

But for the specific scene lighting in the indoor lighting, sometimes more need to highlight the ability of a certain color, depending on the spectral distribution of the light source.

(2) selection of color temperature and color rendering

With different color temperature and physiological and psychological effects of color display on the basis of different functional characteristics of places with different color temperature and color rendering index of light source, to achieve the purpose of people's physiological and psychological needs, such as table 2[5], table 3[3].

Such as in the bedroom or living room with low color temperature light source, will make people have a casual, warm home feeling. In the color printing plant, in order to reflect the quality of the printing, the color rendering index of the light source should be above 90.

The table 2 color temperature

The table 3 color index

(3) the living room space atmosphere

In modern interior lighting design, one of the most important content is to determine the lighting space to show the atmosphere, that is, the use of lighting needs. Living room, according to its different functions, its lighting space atmosphere is divided into 5 kinds:

Daily lighting

Daily activities, the average indoor illumination should not be too high to warm tone, seasonal factors will affect the choice of color temperature, color rendering index requirements.

Reception lighting

The bright light environment can create a good atmosphere for the exchange between the host and the guest. Usually the light of artistic expression is reflected in the illuminated objects, three-dimensional light brightness and contrast, which requires the color index is high, if taking into account seasonal factors, can also be appropriate to improve the brightness, color change.

Agglomeration lighting

Reunion lighting is different from the reception lighting, to maintain a bright, warm, warm light environment, is conducive to people to communicate with each other and create a good atmosphere.

TV lighting

Is the night watching TV, family activities, occupy most of the time, the light environment when watching TV needs illuminance level is relatively low, while watching TV with other activities, should take into account the illumination requirements of other activities. The use of LED lighting, lighting at this time can be adjusted according to the needs of the appropriate color temperature can be determined according to the plot.

Lighting before bedtime

Night 22:30 (according to each family's rest time), the family will be based on their own schedule, has entered the preparation stage before bedtime, appropriately dim the lights, to reduce the psychological excitement level, warm lighting makes people have a warm bed feeling, so as to maintain a high quality sleep state.

2, color temperature and color rendering

Selection of light source

(1) color temperature and color rendering of general indoor lighting

Different types of light source, with different color and color rendering performance, the indoor atmosphere and the color of objects have different effects and effects. When the indoor lighting design, the main choice is the appropriate light source, the main use of the color temperature and color rendering index see table 4[1].

Table 4 is the main use of the light source color temperature and color rendering index

(2) the characteristics of LED light source

The utility model is applied to the LED indoor lighting light source device, mainly white LED, and is made of white light LED light source with a single chip type and a multi chip type (double chip type and three chip type).

Among them, the multi chip type is that the chips with different light colors are assembled in the same package to produce white light after mixing. There are several main ways to make a single chip [2]:

1 through the LED red, blue, yellow, the combination of the three primary color light-emitting chip synthesis of white light

Advantages: high efficiency, color temperature control, good color rendering.

Disadvantages: three color light color temperature leads to different instability, complex control circuit and high cost.

2) blue LED chip to stimulate yellow phosphor

The yellow green light emitted by the blue light and white light synthesis of LED phosphors, obtained 3500-10000K color temperature can be colored white YAG phosphor by altering the chemistry composition of the phosphor layer and adjust the thickness; to change the color performance can also add appropriate amount of green and red fluorescent powder in which add a small amount of red fluorescent powder or. White light LED is the mainstream mode of production.

Advantages: high efficiency, simple preparation, good temperature stability, good color rendering.

Disadvantages: poor consistency, color temperature, angle change.

3) near ultraviolet LED chip excited phosphor issued three primary color synthetic white light.

Advantages: good color rendering, simple preparation.

Disadvantages: the current LED chip efficiency is low, there is the problem of UV leakage, phosphor temperature stability problems to be solved.

Compared with the traditional lighting source, LED light source has the following advantages:

(1) long working life;

(2) low power consumption;

(3) response time: generally within a few milliseconds (NS) response;

(4) small size, light weight, resistance to fight;

(5) it is easy to adjust light, color and controllability. It can control the brightness by changing the current, and can realize the change and adjustment of color by the configuration of LED with different wavelength.

(6) no pollution: no mercury, lead and other environmental pollutants.

You can use the advantage of rich white LED color gamut, by controlling its color, and white LED project implementation convenient adjustable, and has the advantages of small volume, good concealment, easy to realize the controllability of indoor lighting products, provides a solid foundation for the application of LED in the indoor lighting.

Living room lighting

In the indoor environment, the highest utilization of the living room, lighting is also a variety of ways. The basic lighting of the living room lighting depends on the ceiling light, in the center of the room to install a chandelier as the main lamp, should be able to see the facial expression is appropriate, so the color rendering index should be greater than 80.

As a conventional light source in the family living room, mainly LED lamp, LED lamp, LED fluorescent lamp etc.. According to the different needs of the living room, the living room can be created to create a different atmosphere of the scene model, the use of computer control to achieve flexible adjustment.

LED lamp color temperature, the summer can be transferred to 5000K, a cool feeling; Festival transferred to 3000-5000K, to create a festive atmosphere of joy