Display Substrate and Display Apparatus

A display substrate, comprising:

• a backplate;
• an anode layer, a first auxiliary layer, a second auxiliary layer, a third auxiliary layer, and a cathode layer that are stacked on the backplate in sequence, with a microcavity formed between the anode layer and the cathode layer;
• a plurality of first light-emitting layers of at least two different colors provided between the first auxiliary layer and the second auxiliary layer, wherein the plurality of first light-emitting layers at least include a plurality of first blue light-emitting layers;
• and
• a plurality of second light-emitting layers of at least two different colors provided between the second auxiliary layer and the third auxiliary layer, wherein the plurality of second light-emitting layers at least include a plurality of second blue light-emitting layers;
• wherein the first auxiliary layer includes film layers stacked in sequence, a number of the film layers is a;
• and a portion, opposite to a first blue light-emitting layer, of the film layers with the number of a has an optical thickness of L1, and L1 satisfies:
• L
• 1
• =
• ∑
• h
• =
• 1
• a
• n
• h
• ⁢
• r
• h
• ;
• wherein a is a positive integer, nh is a refractive index of an h-th film layer among the film layers with the number of a, and rh is a thickness of the h-th film layer;
• the third auxiliary layer includes film layers stacked in sequence, a number of the film layers is b;
• and a portion, opposite to the first blue light-emitting layer, of the film layers with the number of b has an optical thickness of L2, and L2 satisfies:
• L
• 2
• =
• ∑
• i
• =
• 1
• b
• n
• i
• ⁢
• r
• i
• ;
• wherein b is a positive integer, ni is a refractive index of an i-th film layer among the film layers with the number of b, and ri is a thickness of the i-th film layer;
• and
• L1 and L2 satisfy a following formula:
• ❘
• "\[LeftBracketingBar]"
• L
• 1
• -
• L
• 2
• ❘
• "\[RightBracketingBar]"
• ≤
• 20
• ⁢
• n
• _
• +
• (
• k
• -
• 1
• )
• ⁢
• λ
• B
• 2
• k
• -
• 1
• ;
• wherein n is an average refractive index of film layers located between the first auxiliary layer and the third auxiliary layer and opposite to the first blue light-emitting layer to a center wavelength of blue light, λB is a wavelength at a target spectrum peak of the blue light, and k is a positive integer.